Recumbent - Cranks

I see a lot of talk about shorter cranks and the benefits that some people get.

Here in Oz, they only stock the 'normal' sizes ie, 170 and upwards.

Any suggestions on brand names and where to get the things?

Then the eternal argument about what length. Any suggestions?

I'm really only changing the cranks because I need new cranks on the commuter and there's a sort of manic sense in taking the 172.5mm cranks off the bent, putting them on the commuter and getting the bent some shorter cranks. Money is a problem so premium solutions aren't an option.

Richard

I believe I've seen a Shimano Sora available in 165mm and 167.5 - these are relatively inexpensive.

Personally, I found some Shimano Ultegra (WAY nicer and lighter) on eBay, that are 167.5 and which I have received for my recumbent. I believe I paid $75 for them. You'll need to change your bottom bracket however. I ordered a Shimano 5500... it's an entry level bottom bracket, but has sealed cartridge ball bearings, plus extra needle bearings on the drive side. (needle bearings can withstand hundreds of times more pressure than ball bearings, and thus the crank lasts much longer).

Also look under the brands Truvativ and FSA... they may make some.

I'm assuming you don't want singlespeed cranks, which are easy to find in 165 but not compatible with narrow chains.

Here is an eBay search tip:
When you find any crankset on ebay, within the listing, at the top, you'll see what category it is under, such as:
Listed in category: Sporting Goods > Outdoor Sports > Cycling > Bicycle Parts > Road Bike Parts > Cranksets & Bottom Brackets
Here's the link for you:
http://sporting-goods.shop.ebay.com/items/Cranksets-Bottom-Brackets__W0QQ_sacatZ56195
Click on it, and enter your search words.
Enter only the terms 165 and double (or triple, but you'd be crazy to go with a triple instead of a compact double, because a triple sends your right foot out so much farther than the left, messing with the Q-factor), and check the box to search titles and description.
It's important that you go to the sub-category first, or you'll get thousands of unrelated products. This way, you find what you want.
You probably have a square taper, so make sure the crank you get has that as well. Beware, because there are cranksets for square taper (most common in used parts, and some new parts), ISIS (truvativ, fsa), Octalink (v1) and Octalink v2, and with external bearings (probably not compatible with an older frame).
Unless you want to swap the bottom bracket. In which case, get a 108-110 for a double, 113, for triple, crankset, and make sure it matches your frame's threading and bottom bracket shell width, and make sure the interface matches your crankset (splined ISIS, splined Octalink, splined Octalink v2, square japanese, square).

How in the world did this thread get sucked into the recumbent forum? The OP is not a bent rider and the subject of short cranks is not bent-specific.

I use 155mm cranks on my latest lowracer. Not that I'm a convert, it's just that I need the short cranks because otherwise I can't adjust the bike short enough to reach the pedals. Short cranks give up a little bit in torque but the advantage is that you don't need to bend your knees as much at the top of the pedal stroke, meaning less strain and higher output in the first 1/4 of the circle. To compensate for the torque, you have to spin better, which may mean lower gears.

My 155s are made by Thorn. Current searches don't show any made by them that are that short. Whereas 165 are easy to find, 160 are a bit harder and 155 are very hard. Well, maybe that's an exaggeration - you can always get cheap short cranks that are made for kids' bikes. You may be able to get your current set shortened, depending on what you've got.
http://bikesmithdesign.com/Short_Cranks/shorten.html

How in the world did this thread get sucked into the recumbent forum? The OP is not a bent rider and the subject of short cranks is not bent-specific.

This got 'sucked into the recumbent forum' because, as you know from reading and replying to my posts in the 50+ forum, I AM A BENT RIDER and I am buying these cranks for my bent ... as stated in the last paragraph of the post.

Thanks for your input and I'll look it up, but once again, the bent community turns on someone who finds that bents aren't super wonderful for him. Note to all people considering buying a bent, don't ever criticise the things, the bent community doesn't like it. Jeez, I ask a question with the aim of improving things with my bent in the hope that I might learn to like the thing (and, I admit, trying to save a bit of money) and I get jumped on. I'm sorry that I don't find my bent wonderful like you find yours. I really wanted to, but it hasn't bloody worked out that way.

Richard

This person is an expert on short cranks. He has some for sale and will also shorten your present cranks if they meet certain criteria. Give him a call or email. http://bikesmithdesign.com/

Sorry europa. I didn't mean it as a complaint about you but about the mods moving another thread for reasons unknown except that the word 'bent' was buried in the text. I wasn't real clear on what you were proposing, and tigrrrtamer must not have been either or he wouldn't have recommended a compact for a 'bent.

My Thorn set cost 75 pounds, which at the time was at least 50% more than a 105 set would have cost. And chainrings were extra. I'm wracking my brain trying to remember what cranks Brian Harnett used on his homebuilts a few years back at one of the BROL rallies. I think they were Bullet brand. At the time, he said the advantage was they were cheap.

or he wouldn't have recommended a compact for a 'bent

Could you please explain to me what is the matter with using a compact crankset on a recumbent?

I want to keep my Q-factor in check, and keep the pedal offset on left and right as equal as possible, to prevent back problems brought about by the right pedal commonly being too far outwards.

Sorry europa. I didn't mean it as a complaint about you

That's cool mate. Take it as an over reaction from an old phart over stressed by his load who's had a few too many disappointments from something he'd lusted after since a teenager. A bit of thought from me would have told me you weren't taking a shot at me. Sorry about that.

Looks like most of you are talking about modified cranks - funny, the impression you get from Bentrider is that you can buy them over the counter. I've got a mate who'd probably do that for me (he builds model engines from scrap as a recreation).

I hate trying to sort out this bent in isolation, there are things that can realistically only be tackled in person, but that's not my lot I'm afraid.

I'll have another chat with my lbs and see what he can source though he's already intimated that the aussie suppliers only bring in 'normal' df stuff, which in this country means 'roadie'. I wouldn't even be looking at this if I had road gearing on the commuter - the commuter has an mtb crankset and the gearing is such that I'm constantly swapping between the big and middle ring which is annoying at best. Having seen so many positive reports about short cranks on bents, the thought was to put the bent's cranks (currently 172.5 long with road type gearing, I forget the tooth count but it's a good selection for my riding) on the commuter and put short cranks on the bent (again with road type gearing) in the hope that I'd gain even a marginal improvement.

That won't fix the main problems which are a seat that doesn't allow me to stretch my legs out (I slide forward unless I have a boom length that doesn't allow my leg to fully extend), a bottom bracket height that requires really fit abs (and hence reduces my breathing) and the flying hamster handle bar position that leaves me cramped for breath. There's probably a good bent in there somewhere trying to get out but I lack the money or the expertise to stuff around with the sodding thing much more than I already have. If you can't get a bike to work for you within 1000km you're probably well served giving up.

I'm ranting again aren't I. Probably reacting to too much study (uni) and with the end of the semester coming up, it's only going to get worse. I'll return to the bent over the long break at the end of the year, but don't hold a lot of hope for the thing.

Richard

Trisled.com.au sell them in any length you are likely to want and then some.
I found 155's nice and I am 5'8'', I was immediatley faster on the flats but the hills took some cario adjustment.

Trisled.com.au sell them in any length you are likely to want and then some.
I found 155's nice and I am 5'8'', I was immediatley faster on the flats but the hills took some cario adjustment.

Would it be rude to electronically kiss your feet? :love:
The cranks they offer sound spot on and at the price, I can afford to exeriment.

I'd forgotten about the local racing scene. For those of you unlucky enough to live out of Australia, we have a very active human powered racing scene. Cripes, I even forgot that I have a cousin who runs the racing program for his school. The emphasis is on trikes with full fairings belting around a race track as opposed to road riding - when I last spoke to him, that same cousin expressed the same sort of wonderment about riding a two wheeled bent on the roads as most people do :(

Richard

All other things being equal, you give up your two lowest gears when you go from a triple to a compact. Most recumbent riders aren't willing to do that. Maybe you are?

My tricycle has a Schlumpf (mountain drive) BB. I currently have 152mm cranks that work nicely (able to "spin" much better than when using 170mm). As an experiment, I have a 127mm set coming in the mail.

My tricycle has a Schlumpf (mountain drive) BB. I currently have 152mm cranks that work nicely (able to "spin" much better than when using 170mm). As an experiment, I have a 127mm set coming in the mail.

127mm :eek:

Are the pedals welded to the spindle or something?

Richard

All other things being equal, you give up your two lowest gears when you go from a triple to a compact. Most recumbent riders aren't willing to do that. Maybe you are?

Why yes I am! LOL and I don't see the point in going so slow I would no longer be able to balance and would just fall over. (isn't that the point of recumbents anyways? going fast? (comfort too, but speed is the fun part) after all, I think almost all recumbent owners also own other bikes, that are probably already well geared for the hills)

I have NEVER used the internal chainring - I could remove it from my 1997 mountainbike or off of my 2006 recumbent and sell them as parts removed from new bikes if I wanted to. I didn't use it while climbing Rougemont and Mt-Tremblant on my mountainbike (a heavy 1997 Specialized aluminum RockHopper), I haven't needed one to climb that 18% grade in St-Hyppolite with my racing bike in a 42x(26?) gear, the front wheel lifted off the ground on some pedal strokes if I didn't lean forward, so that's pretty much as steep as you'll go I suppose... it's never been a problem for me.

So I don't have a use for a granny gear... and for those who need one nothing stops you from gearing the rear cassette differently... instead of having 11-26 or 11-28 with a triple front, you could have 11-32 or 11-36 with a double front compact crankset instead and have a similar lowest gear... I'd much rather have a better Q-factor with symmetrically placed pedals (in relation to centerline), instead of an extra chainring I'll never use with lowest gears I never use. Swapping a couple of cassette chainrings pales in comparison to messing up your Qfactor with a triple in order to get lower gearing.

As a matter of fact, if you changed from a triple, with a small chainring of 34 and a rear sprocket of 28, to a compact double, with a small chainring of 36 and a rear sprocket of 32, you'd get a smaller gear with the new compact crankset (and even smaller with 36x36). Of course, it all depends on what you're comparing, my point is that with some very standard cassette combinations you can still get the same low gear as you had with a triple. My belief is that the benefits strongly outweigh any counter-arguments, when it comes to a double compact versus a triple.

BlazingPedals, if you are the guy in your avatar, you certainly don't look like the kind of man who needs a granny-gear either!

As a matter of fact, if you changed from a triple, with a small chainring of 34 and a rear sprocket of 28, to a compact double, with a small chainring of 36 and a rear sprocket of 32,

Hmm. My large chainring is a 52 and my smallest rear cog is 11 ... on both bent and upright.
My granny is 26 on the df though still 30 on the bent with a rear cog of 32. That granny gets used around here. I like to spin at a cadence of 90 up a hill and I have a couple of regularly tackled hills that require that gearing. So not only does your compact not have the range I need, it has that huge hole between the rings requiring a multi gear change on the rear when you change on the front - that would annoy me intensely.

One of the nice things about bents is the fact that the long chainline reduces the effects of cross chaining so, provided your front dr allows it, you can work the full rear cassette from whatever chainring you're on.

Compact gearing - I've never been able to understand why people choose such a compromise but then again, people tend not to understand why I have a 26 tooth front granny mated to my 32 tooth rear.

Richard

Hmm. My large chainring is a 52 and my smallest rear cog is 11 ... on both bent and upright.
My granny is 26 on the df though still 30 on the bent with a rear cog of 32. That granny gets used around here. I like to spin at a cadence of 90 up a hill and I have a couple of regularly tackled hills that require that gearing. So not only does your compact not have the range I need, it has that huge hole between the rings requiring a multi gear change on the rear when you change on the front - that would annoy me intensely.

One of the nice things about bents is the fact that the long chainline reduces the effects of cross chaining so, provided your front dr allows it, you can work the full rear cassette from whatever chainring you're on.

Compact gearing - I've never been able to understand why people choose such a compromise but then again, people tend not to understand why I have a 26 tooth front granny mated to my 32 tooth rear.

Richard

Richard, you have LOTS of overlap in terms of duplicate gears. LOTS. Sit down and make the calculation yourself. You can have your cassette spaced wider apart and when you switch from the large to the small on the front you won't have to switch way over on the rear - in fact, if at the bottom of a hill, chances are, this time you might even fall into the correct gear the first time, with just one shift (at the front). On a triple, the chainrings are too close in gearing and you end up having to switch on the rear soon after you've switched on the front. You're just displacing the problem. And when you're coming to a downhill, one front shift and you're in high gear to sprint down - no messing around. I think compacts are more no-nonsense, in addition to less weight and improved ergonomics over a triple.

If you are strong enough to push a 52x11, you don't need a granny gear period: But maybe you are geared incorrectly to begin with. Do you really need that x11? Or even a x12? Back in the days I was racing, us strong racers didn't even have access to 12t! The smallest made up to a certain time was 13t, and when the 12 became available mainstream it wasn't allowed in race regulations anyways. I'm sure you could find a way to make your range on a double optimal and just as good as with a triple, by simply thinking out your gears on the rear cassette.

You're no young spring chicken... how's your back? Mine is terrible. Don't ergonomics count for anything in your book? Q-Factor hasn't been talked about back in the day, and pedal offset is a discrepancy still overlooked or voluntarily ignored today, yet such a cause of back problems for cyclists... I mean, just imagine if you were forced to walk with your right leg stretched out to the side... ALL of the time. If bad shoes can ruin a back, imagine the damage this can do.

I encourage you to re-think your position on this. Annoyance is a personal decision, as to what course of action one adopts in the face of something... in other words, it's more a question of personal attitude towards a phenomena than the phenomena itself.
Cheers! Timm

Richard, you have LOTS of overlap in terms of duplicate gears. LOTS. Sit down and make the calculation yourself.

Yep, lots of overlap, no need to do any calculations, it's obvious on the ride. However, with the gearing I have, I can sit on the large ring for fast work, the middle ring for slow or uphill work and, of course, the granny for the monser hills and there are lots of them in my area - if I ride more than 10kms, I will need that granny to get home (why are the big climbs always on the home leg?).

I like my configuration because I can go from one chain ring to the other without excessive messing about with the rear gears - widen that seperation and every change on the front will necessitate changes on the rear. Further, reducing the middle ring will just make it less useful on the roads I use - I can say that without fear as my commuter has a middle ring similar to a compact setup.

Note: I monitor my cadence pretty well and like to stay in the mid to high eighties - slowing that cadence down or spinning frantically is foolishness I save for my fixed gear bike.

Nope, for me and my riding, compact cranksets are just a recipe for inefficient gearing, but you do need to remember that I have a rather wide range on the back and genuinely need that granny gear.


If you are strong enough to push a 52x11, you don't need a granny gear period: But maybe you are geared incorrectly to begin with. Do you really need that x11? Or even a x12?

With all the hills around here, the 11 gets used quite a bit. I can't pull it on the flat but tilt the earth the right way and it gets a workout. In fact, I use my entire range of gears. I like to climb with a cadence in the 90's and don't like having to stand to climb - it does horrible things to my heart rate.

Of course, standing's not an option on the bent and I'm selective of my hills with her - mind you, with the twist grip gear change, I wouldn't want the mucking about that a compact crank set woould entail (if I ever get a bent to work for me, twist grip shifters WILL be replaced with something that works). If I rode it more, I wouldn't have to worry about hills as I'd be able to spin up them, but I'm not riding it much and hence am not bent strong.


I'm sure you could find a way to make your range on a double optimal and just as good as with a triple, by simply thinking out your gears on the rear cassette.

Sorry mate, the gearing on my df sportster is optimal already ... for my purposes. Based on my previous ride, I did a lot of thinking when I built the sportster and chose my gearing accordingly (she was built up from a bare frame).


You're no young spring chicken... how's your back? Mine is terrible. Don't ergonomics count for anything in your book?

My df sportster causes me no back problems at all because the bars are at saddle level, the saddle is far enough back to give me a balanced sitting position, the reach has been tinkered to suit me and the cleats have been set back as discussed by Steve Hogg (aussie fitting expert). Add to that a Brooks saddle (so I don't need padded pants and, in fact, never use them) and I've got a very comfortable bike ... along with its optimised gearing (sorry, couldn't resist a tease).

Teasing aside, Steve Hogg talks a lot about back issues and, unless you're carrying an injury (like my dicky shoulder), back problems are usually associated with a poorly fitted bike - using KOPS and similar, old school fitting methods cause me no end of trouble and pain. Steve's methods remove pain.

The bent, on the other hand, has a seat that doesn't support my back properly because it's hard and the wrong shape for me, the pad is slightly too wide for my shoulder blades and causes trouble, the head rest fouls my helmet (compulsory here) which leads to neck pain and I slide forward everytime I hit a bump ... hence I find a shorter than optimal leg reach is needed to keep me on the thing. It's not major but it's bloody annoying. It's probably sortable too but I've yet to find a solution that doesn't involve making new bits for the bike.


I encourage you to re-think your position on this. Annoyance is a personal decision, as to what course of action one adopts in the face of something... in other words, it's more a question of personal attitude towards a phenomena than the phenomena itself.
Cheers! Timm

You won't convince me on compact cranks. I have considered them but for me and my riding, my triple setup is optimal.

The bent? If I had someone here who knew what to look for and what he was talking about, AND I had spare money to spend on the thing, I could probably get it right or at least a lot better. But I don't have either the support or the money. It doesn't help that my sportster is sooo darned comfortable and well set up nor that my commuter is much better suited to the commuting I do than the bent. The thing's has been relegated to 'toy' status ... which is not what I envisaged when I bought it.

Richard

Nope, for me and my riding, compact cranksets are just a recipe for inefficient gearing, but you do need to remember that I have a rather wide range on the back and genuinely need that granny gear.

Teasing aside, Steve Hogg talks a lot about back issues and, unless you're carrying an injury (like my dicky shoulder), back problems are usually associated with a poorly fitted bike - using KOPS and similar, old school fitting methods cause me no end of trouble and pain. Steve's methods remove pain.

The bent, on the other hand, has a seat that doesn't support my back properly because it's hard and the wrong shape for me, the pad is slightly too wide for my shoulder blades and causes trouble, the head rest fouls my helmet (compulsory here) which leads to neck pain and I slide forward everytime I hit a bump ... hence I find a shorter than optimal leg reach is needed to keep me on the thing. It's not major but it's bloody annoying. It's probably sortable too but I've yet to find a solution that doesn't involve making new bits for the bike.

The bent? If I had someone here who knew what to look for and what he was talking about, AND I had spare money to spend on the thing, I could probably get it right or at least a lot better. But I don't have either the support or the money. It doesn't help that my sportster is sooo darned comfortable and well set up nor that my commuter is much better suited to the commuting I do than the bent. The thing's has been relegated to 'toy' status ... which is not what I envisaged when I bought it.
Richard

There is no "inneficiency" there. On a normal double you often have one quarter to one third of the gears that is duplicated. Most people, when they hit a hill, they have to shift both front and back, with a double, they actually ahve less shifting. No need to argue, we get the message that you are happy with your triple and will stick with it.

If you're not stubbornly closed-minded however, you get my point, and understood that the reason I was making it was because someone here said that a double on a bent is plain wrong. And I disagreed. Then you jumped in and I felt obligated to defend my opinion, because of where it all originated.

Yep, lots of overlap, no need to do any calculations, it's obvious on the ride. However, with the gearing I have, I can sit on the large ring for fast work, the middle ring for slow or uphill work and, of course, the granny for the monser hills and there are lots of them in my area - if I ride more than 10kms, I will need that granny to get home (why are the big climbs always on the home leg?).
I like my configuration because I can go from one chain ring to the other without excessive messing about with the rear gears - widen that seperation and every change on the front will necessitate changes on the rear. Further, reducing the middle ring will just make it less useful on the roads I use - I can say that without fear as my commuter has a middle ring similar to a compact setup.
Nope, for me and my riding, compact cranksets are just a recipe for inefficient gearing, but you do need to remember that I have a rather wide range on the back and genuinely need that granny gear.


Richard,
By the sounds of it, you put a lot of thought into your gearing.
I'm curious, what IS your gearing anyways?
Timm

Gears.

My bent wears what it came with but it's not a lot different to my Jamis except that it has 26x1 wheels ie, 26" diameter with 28mm tyres as opposed to the 700c on the Jamis.

My Jamis (df) which has darned near perfect gearing for me has a 50, 39, 26 crankset mated to a one of the SRAM 11-32 rear cassettes which is arranged 11-12-14-16-18-21-24-28-32
The shifters are Ultegra, the front dr is a 105 and the rear dr is DeoreLX (for the long cage).

That gearing allows me to work either on the large ring or the middle ring depending on whether it's a bit hilly or flat. I can only pull top gear going down hill but there isn't a ride I can do from home that doesn't have me pulling top gear at some point and there are other hills that have me not bothering to try to keep up.
The Ultegra shifters and 105 front dr allow me to use the full range on the rear cassette though obviously, I only go on the smaller cogs for shortish periods or if anattentive - I still subscribe to the theories against cross chaining. I can spin quite happily up most hills on the middle ring and for those that demand the granny, I NEED the thing.

I've got one hill that I do regularly that is 3km on the granny with a cadence of around 90. There's another brute that is shorter but steeper. Maybe nothing for you young blokes but hard on this old wombat. I've yet to get up that first hill in one hit on the bent but I'm happy to put that down to lack of bent fitness - as I've said elsewhere, if I'm not riding the bent every day I loose that fitness very quickly and seeing I'm not climbing hills every day on the thing, I don't expect to be able to. Different with the Jamis, she climbs like a cat up a tree no matter how long I've been off the bike.

If lazy, I can live on the middle ring but the Jamis is so much fun to ride the big ring gets used a lot.

Coming up to a climb, I'll flick onto the middle ring, and the jump between top and middle is such that that rarely requires a change at the back. I'll work my way down the rear cassette until in bottom then, if needed, will drop onto the granny which gives me an extra three gears (the equaliser between the two is the fourth cog). Sometimes I'll go up a cog or two on the back, but usually if I need the granny, I stay on it to conserve my heart rate. Coming over the top of a hill, I'll work my way up on the rear cogs, then change onto the middle at some point - it's a jump but I've deliberately chosen a big jump from granny to middle to give me that stupid bottom gear.

There are roughly 2 gears between the big and the middle (it's not a clean split, the cross over gears are slightly different). When going from middle to big, you need to be spinning in the 90's to make the change cleanly but if you aren't, why would you bother going onto the big ring? Similarly, I'll drop onto the middle from the big when slowing where again, the gear difference isn't really a problem.

However, were I to have a larger jump between the big and middle rings, I would have to muck about with the rear cogs and I can't see the point in that. That's especially pertinent in that I've all the top speed I'm brave enough to use and when the middle ring is too high for a hill, I've got my granny set up - I do not need to expand the range of gears available to me on those two rings in normal riding.

For me, expanding that jump between big and middle rings would be inefficient because I would no longer enjoy a clean change. Further, lowering the middle ring, would force me into more changes on the front as the middle ring span out or I cross chained more while trying to use the smallest cogs.

Interestingly, my commuter has a smaller middle ring - a 34 courtesy of an mtb cranket - and that's bloody useless, get it rolling and get it onto the big ring. Maybe it's not interesting, maybe I'm just pissed off with it.

The Ultegra shifters handle the triple crankset with ease - I really don't know why people complain about them. Further, the relatively small jump between middle and big ring is also handled quickly and with ease. The leap from granny to middle is slow but it's also well outside the range recommended by Shimano, and it's not done often enough to be a problem.

So, for me, changing to a compact setup would mean:
1/ getting rid of changing between granny and middle ring ... which isn't a problem on any of my bikes (except the fixie where I get upset if the chain comes off the ring)
2/ widening the gap between middle and large ring which isn't desirable
3/ lowering my middle ring which would take it out of the sweet zone it's in now, result in more cross chaining and probably more shifting between big and middle
4/ result in me having a higher bottom gear which is undesirable because I use the bottom gear I have now - no, I'm not going to stand and grind up hills because that spikes my heart rate and it already runs close to my maximum (yes, I hit and maintained my max for 10 mins one day and have no desire to do it again, my REAL max, not some calculated number).

The only positive I see in going to a compact (for me, YMMV), is that it'd be 'trendy' - I ride a steel framed bike, with a frame that is oversized to modern eyes so I can get the bars up at saddle height, using a Brooks saddle wearing kakhi shorts and t-shirts. Come summer, there's a bandana or cycling cap under my peaked helmet to protect my scalp from sunburn (bald where the hair isn't thin and I've already got skin cancers up there) There ain't nuffin trendy about me, though I do use clipless pedals on the Jamis (SPDs) and the bent while the commuter wears toe clips.

All of which is a bit weird on a bent forum, so I'll go back to my original question. I like the gearing I have on the bent which is similar to the Jamis. It does wear a higher granny (still the stock 30) but the wheels are 26", not 700c which seems to compensate. I can't ride the bent up the big hills but come close enough to know that if I was riding the bent all the time, I'd be able to ... or I could just put a 26 on the granny and go even slower, possible now that my balance is a lot better.

The commuter has this dreadful mtb setup with the useless middle ring and a large ring that's okay because when you stick this fat old wombat on top, in a non-aerodynamic riding position, with over 10kg of text books in the pannier (I weighed them one day and nearly died with shock), in traffic, top speed isn't a problem. That middle ring is.

The bent has 172mm cranks.
Sooooooo, seeing so many people have found short cranks a positive experience, I thought I'd swipe the cranks from the bent to give the commuter half reasonable gearing and put short cranks on the bent, killing two birds with the one stone so to speak, but only if I can do it at a reasonable price - if it's going to be expensive I'll just keep swearing at the gearing on the commuter (which stops me swearing at cars I guess).

But yeah, compact cranksets? I can't see the point ... but maybe you aren't in your fifties, shaped like a wombat and having to muck about with some pretty decent hills.

Richard

I've just repeated myself a lot haven't I. Sorry about that. I'm supposed to be doing an assignment for uni so am probably in procrastination mode.

Richard

Wow, yes, that is long! I thought I was the world-champion in procrastination, but I guess, I, finally met my match.

Now, just to find a big enough timeslot in my schedule to read that novel of yours...

Allright... I made some verifications... I went out and sat in the sun with a calculator, pen and paper. (I ended up plunking it all into my spreadsheet anyways, but it was too nice outside, I couldn't resist).

Now just a note so you know I'm not trying to start a war here! So everyone, please, stay calm, as this may shock you! If you have a heart condition or are easily offended by alternate points of view, please change the channel now! ;-)

The purpose of this is to examine the feasability of replacing a triple with a double-compact. And because Richard gave us an example of a triple that works really good for him, he gave us the opportunity to do some analysis with a good triple as our baseline.

Some of our criteria shall be to minimize chain flex (crossover), unecessary sifts, and too wide gear gaps when changing from one chainring to the other. (if I read everyone correctly, I think that pretty much encompasses the discussion here).

Please take note that one thing I don't want to get a retort on, is that these are not actual gears. I know! So let's just call it a "multiplication factor", which inserts (in bold) into the gearing as follows:
(Chainring/Sprocket)*wheel circumference=development
It doesn't matter whether you're looking at just PART or the total formula, because it's all multiplication and division... so proportionally it stays the same. So lets reduce things to their simplest form, shall we? That way it applies as much to 20", 24", 26", 700C wheels.

As a side note, since we're on the topic of cranks, I may as well mention the entire formula we would concern ourselves with, if we calculated what this all means to us ERGONOMICALLY. Thus, the formula gets a little bit longer:
PedalStrokeCircumference*ChainRingT/SprocketT*WheelCircumference
(where PedalStrokeCircumference = (CrankarmLength*2*pi) ...I don't substitute "wheelcircumference" with a formula because you SHOULD measure it right with marks on the ground and rider weight reducing the radius at the crush point with the ground - or contact patch if you prefer).
That last formula is to compare SPEED (NOT RPM) your feet are going in relation to the wheel's linear displacement on the ground. Speed as in muscle-twitch speed - important. This is useful when changing from a 170 to a 165mm crankarms for example... you'll feel like you're pushing bigger gears, so watch out. For this reason, you can use smaller gears, and because of reduced circumference, it's easier to spin, and with the increased RPM bring the speed back up to where it was.

The below table has 3 sections, as you can see.
First, is Richard's gearing - this will be our baseline, our starting point.
Second, Compact with an actual SRAM cassette configuration that can be bought in all good bike stores (and on eBay if you like to shop there).
Third, is a proposed configuration, for which not all derailleurs will work. However, I've seen some new rear derailleurs come out in the past year that can handle a gap of 6 teeth quite comfortably.

Triple Crankset, our baseline:
11 - 12 - 14 - 16 - 18 - 21 - 24 - 28 - 32
50T
4.55 4.17 3.57 3.13 2.78 2.38 2.08 1.79 1.56
39T
3.55 3.25 2.79 2.44 2.17 1.86 1.63 1.39 1.22
26T
2.36 2.17 1.86 1.63 1.44 1.24 1.08 0.93 0.81

Compact Double, with standard/stock SRAM cassette:
11 - 13 - 15 - 17 - 20 - 23 - 26 - 30 - 34
50T
4.55 3.85 3.33 2.94 2.50 2.17 1.92 1.67 1.47
34T
3.09 2.62 2.27 2.00 1.70 1.48 1.31 1.13 1.00

Compact Double, with more aggressive spacing in the smaller gears:
11 - 13 - 15 - 17 - 20 - 24 - 28 - 33 - 39
50T
4.55 3.85 3.33 2.94 2.50 2.08 1.79 1.52 1.28
34T
3.09 2.62 2.27 2.00 1.70 1.42 1.21 1.03 0.87

And btw, if your brand of compact is a 50/36 rather than a 50/34, the numbers aren't that far off the above.

Now, looking at Richard's table, it is easy to see why he likes his gearing. When he shifts on the Front, from the Large Chainring, to the Middle Chainring, he is only skipping One Gear. So, instead of landing in the next sequential gear (as if he'd stayed on the same chainring), he is skipping one, thus shifting by two. Not a bad thing when you're meeting up with a hill. Great!

Things get less optimal though, when Richard goes from the Middle Chainring to the Small Chainring. He skips Two Gears (downshifts by three gears). And most of us at that point would certainly shift the back at least one higher to bring that back in line before shifting down again as the ascent continues.
At a glance his largest gap seems between 50x12 and 50x14 at around 0.6 - there is a big sudden jump in percentages, higher than the difference between x11 and x12. Not perfect, but not dramatic either, except we may have one high gear too many, a slot that could be put to better use in the lower gears.

Now, I don't know how many of you are like me, but I just HATE shifting gears in a hill, and the less the better.

In the middle, you see a Stock Compact Double setup (some compacts will be 50-36, others 50-34, so depends on which brand you have - I chose 50-34 for the example because I thought it might be better for the granny-gear).

The gap between 2 gears in this setup goes gradually from 0.7, in the highest gears, to .5, .4 in the middle gears, and .3, .2 in the smallest gears... this is probably a nice progression in percentages. This is good... when Richard is going downhill, he wants wide shifting swings, because he's got gravity helping him out, and he's resting anyways (compared to going uphill), and just having fun... and in the small gears, the gap gets smaller to allow to better fine-tune for those climbs where it's more important.

Now when you shift from, say, 50x23 to 34x23/34x24, you can see that you're also just 2 gears lower. We're coming to a hill and we just shifted down 2 gears a single front shift.

So as you can see, we have about the same gaps. Percentage difference is only slightly higher between gears. We're doing less shifting and landing closer to an ideal gap when shifting on the front.

Compact Double, with more aggressive spacing in the smaller gears:
11 - 13 - 15 - 17 - 20 - 24 - 28 - 33 - 39
50T
4.55 3.85 3.33 2.94 2.50 2.08 1.79 1.52 1.28
34T
3.09 2.62 2.27 2.00 1.70 1.42 1.21 1.03 0.87

And btw, if your brand of compact is a 50/36 rather than a 50/34, the numbers aren't that far off the above.



Oh dear, I knew you'd run into trouble as soon as you tried to make the numbers work for you :D
(oh I do so love it when other people justify my own misconceptions ;) )

My much maligned commuter, the brute that spawned this thread, wears an mtb crankset. The rear cassette is actually the same as my Jamis (btw, I really like SRAM cassettes, but that's beside the point).

That bike gets ridden mainly on the flats. Adelaide is a large, flat city surrounded by hills. I live in the hills but when commuting, park at the bottom of the hills and ride in from there. Yes, I know it's lazy but it's still a 10km commute and to go all the way home requires negotiating a very dangerous bit of multil lane road with a 70km/hr speed limit, then a sharp climb that hits 10% for a sizeable slab of it and which usually takes me a good 20mins followed by 6kms of rolling 80km/hr road - at the end of the day, I'd rather drive that.

So I choose the lazy option and commute on the flats. My commuter is what you'd call 'weighty' - she's a beefy touring frame with one of the heavier Brooks saddles, carrier, mudguards, thumping great big steel hitch for my wee daughter's tag-along, hefty U-lock and typically, over 10kg of text books in the panniers. Not heavy weight touring but lower gears are preferred to higher gears.

That's to set the scene.

She's got an mtb crankset ... because when I built her up, I was able to get a second hand crankset for not a lot of money (and the sodding thing has cost me heaps in other bits trying to work around it :mad:).

The middle ring on the commuter is ... wait for it ... a 34 tooth!
Just like Tim suggests.
And I hate the useless thing.

You get the bike rolling, pop up a gear or two and bing, you need to be on the big ring. My big ring is nothing like the 50 you suggest, possibly a 42 but I don't know at this time.

To make any use of a 34 on the back, I'd need to be able to run it right across onto the small cogs ... which I can't do with an mtb front dr dammit though I could with a road dr ... which then wouldn't shift with my mtb shifters (did I mention this crankset has spawned other issues?).

The main point being that 34 is ludicrous for flat or even undulating bike path running - she's often on a narrow bike path that follows the River Torrens and is up and down the bank like a dancer's knickers. The jump between the 34 and the big ring I carry now is enough to annoy me, increasing that jump even further just justifies my choice of a triple set up.

Tim, you are a far more forgiving man than I am ... but I'm old enough and grumpy enough to refuse to put up with too much bulldust from machinery.

Now, if I think about the undulating territory around home, such as my favourite 20km loop where I need and use the full range of gears on my middle and big rings but not the granny, having to muck about going from big to middle would drive me nuts, especially with the extra shifts needed at the back every time you change chain ring. Maybe there's a difference in riding style. I change gears a lot and work to stay in a relatively consistent cadence zone and when you lack torque like I do, you change often.

Richard
(at uni ... procrastinating)

Now just a note so you know I'm not trying to start a war here! So everyone, please, stay calm, as this may shock you! If you have a heart condition or are easily offended by alternate points of view, please change the channel now! ;-)

The purpose of this is to examine the feasability of replacing a triple with a double-compact. And because Richard gave us an example of a triple that works really good for him, he gave us the opportunity to do some analysis with a good triple as our baseline.


Richard, did you read that part? This isn't about you and your choices anymore. :notamused:
I didn't want to argue with you - I was moving on to something bigger than one individual's needs... and I was using your wonderful and great works-for-you gearing as an example.

I didn't want your long stories justifying your choices. Being closed minded is constantly feeling yourself threatened (which I was not trying to do) and having to defend yourself, even when it is being said that we are using this as an example to continue another discussion, namely, the feasability of a Compact Double instead of a Triple... not for you! But for others in general! But maybe it's my fault for making it too long and you didn't read it... just looked at the tables and then replied.

So could you please just take it for what it is? Accept it as such? I already told you, since you keep on fighting for my approval, that I do give you my blessing with your choices :love: (not that I ever felt you needed my permission, but you keep on coming back at me here, so I'm officially going on record that I approve and am sending you some love!). I wrote that because someone here attacked me, and pretty much told me that a sane knowledgeable person couldn't possibly want to put a Compact Double onto a recumbent. :eek: I mean, a double on a recumbent... God forbid!!!

As I said, I'm only taking your triple as a baseline for comparison, because it seems like very good gearing to use for comparison's sake. You just gave us a wonderful example to go with is all!
Cheers! :beer:
PS: your condescending tone in your opening sentences wasn't cool.

Hey, were'd that come from?

Not fighting mate, just carrying on the discussion. Sorry you took it the wrong way but there was nothing intended in it. Gearing is something I find fascinating and people's choices are part of that.

Richard

Tigrrrtamer,
Do you have a compact on your recumbent? Exactly what gears are you using? What kind of hills do you ride? Also, when you're not climbing hills, how fast do you ride? I think the answers will give us some insight into why you're advocating losing gearing range for what I see as no good reason.

Thanks for the question.

Section 1: WHY
I'm not losing "gearing range". The tables are showing a range far wider than I need. I'll repeat myself, I'm not advocating that Richard reduce his gearing range (he needs his just the way it is). I merely used his setup as a starting point to make a simple comparison with a double-compact, because of the challenge that his unusually low gear represented. I had to compare with something... His smallest gear is far smaller than what is standard on most triple cranksets (how many triples do you see with an inner chainring of 26, huh?). So I figured that if I could come close to his extremely low gearing with a double, and still have a good range, from a high top gear to a low low, with good increments, I'll have proven the merits of a double. And my tables also offer a smallest geat just shy of Richard's smallest, but smaller than what is standard issue on most road bikes with triples... all this while offering reasonable and very useful incrementations between gears. Good highest gear, good lowest gear, good increments, good landing spot (gearing-wise) when shifting on the front. I'm sorry to diverge in opinion, but in my book, it's great!

Section 2: WHAT I USE
I currently have a Shimano Tiagra triple crankset on my recumbent. The small inner chainring has zero wear on it, so I may as well have a double. My smallest gear with the middle chainring could be one gear smaller, but I don't ever bother to shift onto the smallest chainring to get a smaller one, because I KNOW I'd have to shift a few spaces over on the rear just to get the right gear I'm looking for. So my front derailleur stop screw is set to not be able to accidentally shift onto the smallest chainring and potentially derail and end up between it and the frame. My setup will be changing (more on that later).

Section 3: WHERE
I live in Montreal. In the center of the city, is a mountain. Not as big as in the rockies, but a small mountain nevertheless. Around the mountain is a plateau, and around that, a lower level. The geography affects most streets in the city's center. I can't get anywhere without encountering steep hills on the way. 2 decades ago, I used to go up and down the mountain itself for half a day, every day, to train, when I wasn't doing a 100 mile loop bringing me north of the city, towards the Laurentians (part of the Apalachians mountain chain).
Here I find that everytime I hit a hill, I'm fussing with gears, front and back, more than I should have to. There is no simple crossover from the large chainring to the middle one, where I can just do one shift in the front and keep going without shifting the back too. Nope... I have to shift the front, then start messing around with the back... and in doing that, I slow down, and often have the frustration of having to downshift again because I've lost my inertia. ...and with the slowing down, while shifting at ever lower speed, I hear the rear sprockets bang and crack, and I wonder when one of them is just going to break.

I find that I have way too many gears than I need... that aren't in the right places.

Section 4: WHAT I WANT
A cadence within 10% of our ideal is easy to handle. a 15% gear spacing gives us small enough increments so that when we go out of our sweet-spot range of RPM, we have a gear waiting for us thre. So, what I want, is for them to be spaced with a 15% difference, and have a wide enough range to handle anything the topography dishes out at me... that means, for me, having a 53x11 or 53x12 as highest (I'll go with 11 and 12 just in case my derailleur doesn't make it onto 11), and a lowest gear of say, 39x26, is fine for me. I can go up ANY incline with this. (I've been doing that on a 42x23 I think prior to that).
So I ordered myself a Shimano Ultegra crankset, 167.5mm arms, 53T/39T, and a SRAM 11-28 cassette. I think I will be very happy with that. And a new chain... because, even after swapping out my Deore derailleur for an SRAM X.7, it still rarely shifts onto x11.

Two chainrings give me a reasonably wide range with each, and when I shift from 53 to 39 I'll have downshifted just the right amount to take a hill without having to shift on the rear right away, and it's the same the other way round, 39 to 53 while staying on the same rear sprocket will put me in a gear taller enough to benefit right away from a changing slope without having to shift on the rear right away.

When I do the gearing calculations, and transpose this into my riding situations, a compact double is much better for me.

And this gearing should work where well over 80% of the north american population lives. Just not where those grueling hills are, like where Richard lives... those people will have to put up with messing with three chainrings instead of just two. But then again, maybe 11 speeds (see Campy), or 12 speeds, will change things for them too.

Section 5, SPEED
I have no idea how fast I go. I put a speedometer on my recumbent last week, but have had some problems and haven't tested it in the hills yet. On the flats I've approached 50km/h, top speed 58 on some small inclines. But I don't know yet how fast on a real downhill. Plus, I have some problems... the lousy Z chain, standard issue on an Actionbent, doesn't shift onto x11. Or on x12 half the time... not even after I swapped out the rear derailleur from a Deore to an SRAM X.7. I'm not changing the chain, because I'll be selling the recumbent.
The new recumbent, I'll be building out of carbon fiber in a couple of weeks, just as soon as my ex moves her daycare out of my place, so when I can reclaim the space, in other words.
The new one will have the folowing setup: Shimano Ultegra double with 167.5mm crankarms, 53/39 chainrings, SRAM 9 speed cassette, 11-28.

Ahh, the personal touch. THAT's where gearing gets interesting because to my mind, the engine driving the gear box is more interesting than the gear ratios. I find gear charts interesting but personal quirks can distort the information.

I'm guessing you're younger than me but no youngster either.
It seems you've been on a bike and working those hills for many years.
You've probably a reasonable body shape too.

Just guess work, correct me if I'm wrong (without embaressing yourself).

This suggests that you've built up some genuine strength in those legs and your body is well tuned to the hills you're climbing. This would suggest an ability to ride through a large jump between chainrings. I don't have that and so notice the jump.

Am I also right in imagining that you're either climbing or on flatish roads? ie, there's two distinct styles of riding without much transition between them? In that case, if you get your ring size right and one ring will serve you for some distance.

For example: On my Jamis, I get onto a ring and stay there for some time because the three rings are pretty much right (you're right about the ultra small ring - that took some thought and looking at charts). Rolling country on the other hand, has me wearing out both shifters. On the other hand, the very low middle ring on my commuter has me swapping rings on a frequent basis even on the flat unless I can stick to a steady speed.

Just trying to understand why it works for you in the hope that I'll learn more about making my own choices.

The other thing that comes into the equation these days is the widening number of gears and the skinny chains to suit. I'm still wary of the need to go to 10 gears or beyond, particularly as it increases the amount of cross chaining we do. However, I read recently where someone commented on the flexibility of the new, very thin chains. He claimed that cross chaining just isn't an issue now, something I still regard as marketing hype, however there is probably some truth in it and maybe it is okay to use the full cassette from any chain ring (if your front dr allows it).

Richard

Here I find that everytime I hit a hill, I'm fussing with gears, front and back, more than I should have to. There is no simple crossover from the large chainring to the middle one, where I can just do one shift in the front and keep going without shifting the back too. Nope... I have to shift the front, then start messing around with the back... and in doing that, I slow down, and often have the frustration of having to downshift again because I've lost my inertia. ...and with the slowing down, while shifting at ever lower speed, I hear the rear sprockets bang and crack, and I wonder when one of them is just going to break.

I do find this interesting and am trying to work out where it's coming from - again, I suspect it's from sudden changes from flat to mountain.

As you noted, I've got a change of about two gears between big and middle ring (which is the appropriate comparison here). Nearly all my hills have a gradual entry and so moving down onto the middle ring, then working down through the gears is pretty normal. I do often use the double shift function on my shifters (ie, two rear cogs at a go) and it's true that I'll often find myself going down through the gears pretty quickly, but it's change and ride, change and ride, not bang bang bang bang bang through the gears such as you get when stopping from high speed.

With a larger change between big and middle (as you get in a compact), you'd change off the big ring and find yourself in too low a gear for a period until the bike slows a bit - I'm well experienced with this going from the middle to the granny though in those cases, the hill is usually steep enough to make shifting up to compensate an annoyance - it's easier to just relax for 10m and let the bike slow under gravity.

In fact Tim, the more I think about your experience, the more I'd address that with a narrower gap between the rings rather than a wider gap. What am I missing?


I find that I have way too many gears than I need... that aren't in the right places.

That's a statement I can understand - do we need 10 speed cassettes? What about the 12 that are supposed to be coming out?


... that aren't in the right places.

Which has always been the bigger challenge - it's not the number of rings you carry, it's how many teeth they each have.

Richard

I'm guessing you're younger than me but no youngster either. It seems you've been on a bike and working those hills for many years. You've probably a reasonable body shape too. Just guess work, correct me if I'm wrong (without embarassing yourself). This suggests that you've built up some genuine strength in those legs and your body is well tuned to the hills you're climbing. This would suggest an ability to ride through a large jump between chainrings. I don't have that and so notice the jump.
Just trying to understand why it works for you in the hope that I'll learn more about making my own choices.
The other thing that comes into the equation these days is the widening number of gears and the skinny chains to suit. I'm still wary of the need to go to 10 gears or beyond, particularly as it increases the amount of cross chaining we do. However, I read recently where someone commented on the flexibility of the new, very thin chains. He claimed that cross chaining just isn't an issue now, something I still regard as marketing hype, however there is probably some truth in it and maybe it is okay to use the full cassette from any chain ring (if your front dr allows it). Richard

Yes and no... I'm in my mid 40's, no, I no longer have a 6pack... I weigh 210 (6ft2)... my ideal weight is more around 175-185, but I was once below 150 when I was in my 20's doing lots of hills. I'm far from being in good shape, after gradually declining fitness, and my knees and back are killing me, every day. But low cadnces in a 170mm is all I can do - I have long legs that are used to moving less frantically (hence my wanting to switch to shorter cranks to spin more). (yet that didn't stop me from approaching 300 rpm cadence going downhill on my track bike for spring training in my late highschool years). I'm building up my track bike again, to be used as a singlespeed again, I'm stripping down my Cannondale back killer, and putting it and my recumbent up for sale on eBay. (I'll make a carbon fiber recumbent to replace it as I mentioned)

Please do take a moment to examine the gear charts I've come up with. And read my reasoning behind it in my previous post (the ~15-17% jump from one gear to the other). You should be able to see that it's pretty good. You can get a 50/34, 50/36, 53/39, depending on if you like to push hard (like me) or spin more (like you), in conjunction with one of those gear ranges in the charts I provided. You know, even with your terrain over there, you might actually like it. I'm not saying change all your bikes... they're probably not all geared the same... but maybe a change to the one that has gearing the least suited for you.... it might be worth a try. It won't replace your bike that has gearing so well adapted for your needs, but it might make a bike under-used more polyvalent.

About the new extra speeds... I totally agree with you. With China gone global and mainstream in manufacturing, and Shimano regularly obsoleting products, prices have nowhere to go but down. I had a sigh of relief when I started getting back into cycling and discovered I missed the wave of 8 speed stuff, so short lived - that's when I finally "upgraded" to 7 speed! LOL Currently, I buy 9 speed, it's cheap - because everything in manufacturing is switching over to 10 and 11 speed now. If 9 was good a year ago, it's good enough for me today! When 12 speeds hit the market, I'll be buying 10, maybe even 11 if it also comes down in price enough at that time.
Regarding mechanical strength, shortening the rivet has no effect on chain strength, since it's strength is dependent on material (the steel alloy used and consistency thereof), and thickness of the plates used. If you're just shortening the pin, no difference... or is there? Well there is actually. When the chain is not in a straight line, but crossing over, then pins and plates on opposing sides on each end are supporting way more than if the chain was taught in a straight line where everything would be suported 50-50 on each side. This discrepancy caused with deflection is reduced with narrower pins being used (simple basic trigonometry). So yes, I believe the theory that a chain can be a bit stronger if it is narrower (for a same plate thickness).
Now one thing that is definitely a nice feature of the new narrower chains, is cramming an ever increasing number of gears into the same space... not that we actually need to increase the total number of gears, now, but rather, the usable amount before your chain deflection starts to affect chain strength or mechanical efficiency (through more rubbing on the cogs), you can shift among more gears before that happens. With 11 speed, I think that compact double cranksets will serve every need.
You see, the probability of having this debate decreases with every extra gear they add on the back.
I mean, on my cirrent 9 speed setup, if I decide to not use the last smallest 2-3 gears with the large chainring, or the largest 2-3 gears with the small chainring, I have 6-7 gears left on each that I use. With a 10, that increases to 7-8, with an 11 it's 7-9. I mean... it seems that not that long ago, I was running a 6 speed freewheel where I was reduced to just 5 useable cogs with each chainring.

With a larger change between big and middle (as you get in a compact), you'd change off the big ring and find yourself in too low a gear for a period until the bike slows a bit.

Actually not quite... your average difference from one gear to another is 13% in your existing setup.
On a compact double, in the configurations proposed, it is 14% in the first example, and 16% in the latter. Not a dramatic change! Our cadence sweet spot is well in excess of a 10% variation, so all of these are quite comfortable. You do not have an extra gear lower after shifting with a double... look at the tables... it is quite similar actually. Maybe a quarter of a gear lower at worse, but not one full one.

This person is an expert on short cranks. He has some for sale and will also shorten your present cranks if they meet certain criteria. Give him a call or email. http://bikesmithdesign.com/


How in the world did this thread get sucked into the recumbent forum? The OP is not a bent rider and the subject of short cranks is not bent-specific.

I use 155mm cranks on my latest lowracer. Not that I'm a convert, it's just that I need the short cranks because otherwise I can't adjust the bike short enough to reach the pedals. Short cranks give up a little bit in torque but the advantage is that you don't need to bend your knees as much at the top of the pedal stroke, meaning less strain and higher output in the first 1/4 of the circle. To compensate for the torque, you have to spin better, which may mean lower gears.

My 155s are made by Thorn. Current searches don't show any made by them that are that short. Whereas 165 are easy to find, 160 are a bit harder and 155 are very hard. Well, maybe that's an exaggeration - you can always get cheap short cranks that are made for kids' bikes. You may be able to get your current set shortened, depending on what you've got.
http://bikesmithdesign.com/Short_Cranks/shorten.html

150mm Sugino used crankset for sale on eBay, if anyone is interested. 48T/36T, square taper.

Look up item number 130263594187 (http://cgi.ebay.com/SUGINO-IDOL-Alloy-Crankset-150mm-48-36t_W0QQitemZ130263594187QQcmdZViewItem?hash=item130263594187)

Closes in a little over 5 days. Looks like it's in good shape!

PS: no, I'm not spamming - I'm not the seller. My seller ID on eBay is "Super-Timm". I'm posting this because some mentioned needing shorter cranks.

For those who don't want to deal with E-Bay, Harris Cyclery sells Bulletproof cranks.

http://harriscyclery.net/itemdetails.cfm?id=1215

They come in 140-170mm sizes. They're 110 BCD for a single or double chainring system, so will take pretty much whatever size chainrings you want, from 34T up to 60+. To make it a triple, you'd need to get a triplizer, which is a middle chainring with additional holes for mounting a 58T granny ring.

http://www.interlocracing.com/triplizer.html

For those who don't want to deal with E-Bay, Harris Cyclery sells Bulletproof cranks.

http://harriscyclery.net/itemdetails.cfm?id=1215

They come in 140-170mm sizes. They're 110 BCD for a single or double chainring system, so will take pretty much whatever size chainrings you want, from 34T up to 60+. To make it a triple, you'd need to get a triplizer, which is a middle chainring with additional holes for mounting a 58T granny ring.

http://www.interlocracing.com/triplizer.html

LOL ironically they are an ebay seller as well.

BTW, while we're on the topic of talking about sources, I had ordered some nice 20" rims and the matching spokes from Cascade Cyclery (http://cascadecyclery.com/page.cfm?pageID=53), which were hard to find elsewhere.

For those who don't want to deal with E-Bay, Harris Cyclery sells Bulletproof cranks.

http://harriscyclery.net/itemdetails.cfm?id=1215

They come in 140-170mm sizes. They're 110 BCD for a single or double chainring system, so will take pretty much whatever size chainrings you want, from 34T up to 60+. To make it a triple, you'd need to get a triplizer, which is a middle chainring with additional holes for mounting a 58T granny ring.

http://www.interlocracing.com/triplizer.html

Ahh, that's something I didn't know about.

I haven't had a chance to follow things through this week - big uni assignments due, I'm not touching the bike to do anything except ride it :eek:

Richard

As I read my last post, I realized I wrote "58T granny ring." That is incorrect. I think that's the BCD for the inner ring on a 110mm crank, so the BCDs would be 110/58.