Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling - "Super compact" double gearing?

Gearing is a very individual thing and there are a lot of variables involved that you have to take into account.

I agree with you, within reason. The same is true with saddle height as well, but only to a point. If one fellow likes his seat 5 mm higher than average then it's nobody's place to tell him he's wrong, but if it's three inches higher most people will agree that he's "not doing it right". To me, suggesting a 60 ring for an LD rider falls into the same category as telling him to raise his seat three inches.

Realize, that I never suggested that anyone go out and put a 60t sprocket on their bike and if you remember my earlier post I said I have a box of chainrings and cassettes that I change depending on the event I'm doing. I usually run a 53th sprocket on my single. For RAAM and other ultra's I run the 60T but I also have a second bike with climbing gearing, usually with the compact. I realize that the 60T is at the extreme just like a 24t sprocket is extreme on the other end (I have one of those too). They are all different tools that I use for the appropriate job, as a former racer I'm sure you understand that. You also have to realize that if you are spinning at 120+rpm on a regular basis you are on the high end of the cadence spectrum and your gearing is going to be significantly lower than the average person. There are people have cadences in the 60-70rpm range. Cadences are all over the place and therefor the appropriate gearing will be all over the place.

http://store.velo-orange.com/index.php/components/cranksets/vo-polyvalent-crankset.html

Looks like it's just a 110/74 triple without a big ring. VO put a bash gaurd on the big ring.

The VO blog posting linked to in the post you quoted was made 18 months ago. The VO-branded crankset that you linked to is not the Sugino crank shown in the VO blog posting, but is something that VO ended up selling instead because the Sugino model turned out to be too expensive. See this thread (http://www.bikeforums.net/showthread.php?t=676732) for full info on the Sugino super compact crank, which they are calling the "Compact Plus".

Realize, that I never suggested that anyone go out and put a 60t sprocket on their bike and if you remember my earlier post I said I have a box of chainrings and cassettes that I change depending on the event I'm doing. I usually run a 53th sprocket on my single. For RAAM and other ultra's I run the 60T but I also have a second bike with climbing gearing, usually with the compact. I realize that the 60T is at the extreme just like a 24t sprocket is extreme on the other end (I have one of those too). They are all different tools that I use for the appropriate job, as a former racer I'm sure you understand that. You also have to realize that if you are spinning at 120+rpm on a regular basis you are on the high end of the cadence spectrum and your gearing is going to be significantly lower than the average person. There are people have cadences in the 60-70rpm range. Cadences are all over the place and therefor the appropriate gearing will be all over the place.

Okay, I went back and read your post and I see that I'm in the wrong. You never made any recommendations. You were just bragging. :p

And yes, there is a range of cadences. There is also a range of correct cadences. Gearing is pretty easy to select for the latter, and gearing isn't the answer for the former.

HTH! :lol:

We could get into the what's the proper cadence but I think we've derailed this thread enough. Maybe another day. ;)

btw, I do appreciate our pleasant banter as well as your opinion.

I'm going to continue the side track just a little further.

Homeyba, does completing the RAAM on a relay team consists of a series of short sprints? It sounds like your sprints were as short as 30 minutes. That would help explain the speed, but 7 days of intervals sound very demanding.

Michael

I've decided to try the VeloOrange 50.4 bcd crankset with 46 and 30 chainrings, along with the 11-28 cassette on the Masi Speciale CX I've just bought (won't post pics until I've done at least a metric on it!)My previous post was responding to other comments. I would agree that the gearing mentioned above sounds like a good setup.

My previous post was assuming the need for gears even lower than a 30x28. My point being: There are reasons inherent to spring-loaded power trains for using higher tooth counts.

A low gearing system that uses a sprocket containing at least 30 teeth is favorable to ultra-small low gear designs -such 24x26 etc..... but I digress.

The spacing on an 11-34 cassette is wider than I like.


I am not sure whether you mean by this that the spacing between gears is not a constant percentage across the cogs, (say, 16%) or that the 34T just puts too many big gaps in between.

Anyway, one solution might be to drop into Abbottsford Cycles under the Richmond Railway Station and have a look at the board they have set up with all the cogs you could possibly want. Provided you have the spacers and your base cassette is not the high-level spider versions (ie, the first five or six cogs are fixed on a spider) you can mix and match to your heart's content to get the right gaps on the rear to suit your riding.

You could also reference Sheldon Brown's page on cassettes and setting up a touring version as a cross-reference.

It's a bit of a problem with Shimano cassettes when you get to the ones with the 32 or 34 cog... several of mine have a gap in the middle exactly right where my cadence would suit.

I guess I don't get the whole compact thing for touring and/or LD. Unless the load is so light and the rider is so strong that a wide gear range is completely unnecessary, why limit oneself? I'm sorry but I just don't get it. Having ridden in company with riders with triples and riders with compacts, it seems to me that compacts are a PITA. Being a triple rider, if I have a choice, I'll ride away from a compact and find someone to ride with who isn't constantly breaking rhythm to shift.

I recently built up a new bike with 26-39-52 and 12-25. That puppy always has the right gear and a good chainline. Nice to climb with a really small ring in front and close ratios in the back. I hate it when I get exhausted on the nth long climb and my cadence drops way down, having run out of gears, which only makes things worse. Nice to have plenty of low gears and the choice to dial it in.

Odd. It's the triple ring guys who strike me as always hunting for the right gear, often making multiple shifts front and rear trying to find perfection. One of the benefits of the compact double, for me, is that I can essentially leave it in the "big" ring for everything but significant climbs. I shift much less at the front than I did with standard rings of 53x39.

I'm all for different gears for different courses and terrain. I used three different cranksets & three different cassettes this year, including a 50/39/30 with a 12-27, a 50/34 with a 11-32 and a 50/39 with a 11-23 at three different events this year. Some routes are almost totally flat and others have 22% climbs. Having a selection of gears is needed, IMO.

I'm going to continue the side track just a little further.

Homeyba, does completing the RAAM on a relay team consists of a series of short sprints? It sounds like your sprints were as short as 30 minutes. That would help explain the speed, but 7 days of intervals sound very demanding.

Michael

We aimed at 30 minute pulls on average. On steep climbs the pulls got as short as 15 minutes and on descents they got as long as an hour. It just depended on the speed. We were actually closer to 6 days flat than 7 days and are going to be aiming a breaking into the 5 day range this year. Basically it was a 30minute TT followed by 90 minute break 24hrs a day for 6 days 10hrs.

Odd. It's the triple ring guys who strike me as always hunting for the right gear, often making multiple shifts front and rear trying to find perfection. One of the benefits of the compact double, for me, is that I can essentially leave it in the "big" ring for everything but significant climbs. I shift much less at the front than I did with standard rings of 53x39.
Remember that you are a former pro racer with legs of steel. Said with respect.

I don't have particular a problem with triples -- that small rng is really handy for decent climbs very late in a 600 or 1000 or 1200 randonnee, and heaven knows I have done a few of those sorts of rides in Tasmania.

I really can't see that people with them can be hunting for the right gear if the cassette on the back is not deficient in the % change between cogs. For me, I know when to knock down to the small ring and use the three big cogs on the back.

The issue for me if the cogset isn't right is finding too great or too small a percentage difference while in the same front chainring for a given incline.

Of course, we could solve all this by going to single speed... I didn't have any gear shift issues whatsoever with the fixie! :)

Odd. It's the triple ring guys who strike me as always hunting for the right gear, often making multiple shifts front and rear trying to find perfection. One of the benefits of the compact double, for me, is that I can essentially leave it in the "big" ring for everything but significant climbs. I shift much less at the front than I did with standard rings of 53x39.

Exactly! But I'm not a strong enough rider to do that with a 50 at the front for rides longer than an hour or so, or even on my hilly commute (30km Malvern to Ferntree Gully for those interested) if I'm carrying work gear. I simply don't need the top ring in a road triple at my current strength and weight.

30/46 or 32/46 double with 13-26 or 13-29 works well for me. Most of my riding is done in the 'big ring', climbs in the small ring. Only way I would go back to a triple was if I setup a 22-32-42 or similar for mountain / dirt road touring. And then I would most like have a wide range cassette on the rear - something up to 34 or maybe that new 36. I run my current setup for lite touring.

For me, optimizing the low end is more important than having gears to fight wind with, as I think one gets more bang for your energy climbing.

But, YMMV, as always.

30/46 or 32/46 double with 13-26 or 13-29 works well for me. Most of my riding is done in the 'big ring', climbs in the small ring. Only way I would go back to a triple was if I setup a 22-32-42 or similar for mountain / dirt road touring. And then I would most like have a wide range cassette on the rear - something up to 34 or maybe that new 36. I run my current setup for lite touring.

For me, optimizing the low end is more important than having gears to fight wind with, as I think one gets more bang for your energy climbing.

But, YMMV, as always.

A man after my own heart. The 53/39 is way overrated. Personally I spend most of my time in the 39.

A man after my own heart. The 53/39 is way overrated. Personally I spend most of my time in the 39.

Agreed. 39/53 is designed for the pros, and the flat-landers can get away with using it without many problems most of the time.

34/50 is still too big - the 50 tooth ring is too large to stay in for long without doing a lot of cross chaining. The 34 doesn't give you a real low gear when you need it (unless you use a heavier cassette with non road-friendly, wide spacing).

If people would admit that they are not pro' racers and that they should keep a decent cadence in all gears, then something like 30/46 setups would become very popular. Unfortunately, I don't think these two realizations are going to happen for enough people to make this setup common. Too many people think that what the pro's use is what they should use, without appreciating that the pro's are riding at average speeds 30+% faster than them.

A low gearing system that uses a sprocket containing at least 30 teeth is favorable to ultra-small low gear designs -such 24x26 etc..... but I digress.

I've seen a few mentions of this idea here and there, but no solid information on the matter. Is there a meaningful difference between running a 24x26 gear and a 30x32 gear (front x rear)?

I've seen some data showing that there are efficiency losses as the cog's tooth count gets down in the range of 11 to 16 teeth, but the differences seem negligible above that. It could certainly be true that wear will be slightly faster on a 24 tooth chainring than a 30 tooth, but I'm not sure there are meaningful efficiency differences.

However, when Shimano introduced their new DynaSys 10-speed mountain bike gearing, one of their selling points was that by having a 36-tooth cog out back, you could stay in the middle 32-tooth chainring in the front for longer, and they suggested that this is more efficient than having to use the 22-tooth inner ring (which has now been stepped up to 24 teeth). They are not joining the push towards using MTB-doubles like SRAM are (e.g., 26/39) for similar reasons (Shimano may be starting to offer such MTB-doubles, but they are not treating it as the default like SRAM are) - Shimano seem to suggest that riding the 26-tooth inner ring of the double will not be as efficient as using the 32-tooth middle ring of the triple.

As I said, I keep hearing things like this that would suggest that there is a difference between using a 24x26 gear instead of a 30x32, but I have seen no solid data or numbers documenting the actual differences. If anyone has some real information on the matter, then I'd love to see it.

Odd. It's the triple ring guys who strike me as always hunting for the right gear, often making multiple shifts front and rear trying to find perfection. One of the benefits of the compact double, for me, is that I can essentially leave it in the "big" ring for everything but significant climbs. I shift much less at the front than I did with standard rings of 53x39.I don't think we're talking about 53/39 for brevet work. Running a double or a triple, I'm not comfortable riding in the big ring below the 3rd cog in back, while on a triple I'll run the whole cassette from the middle ring.

If we stipulate a 90 cadence on the flat, and 80 climbing, and a 700c/23c rig, my middle ring on a 12-25 gives speeds from 23.5 down to 10 mph. A 50 big ring with 12-27 gearing gives speeds 30 to 15 or down to 12 big/big.

If a 50/34 compact rider goes to an 11-34 to get about the same low end I get with a triple, then they go from 33 down to 12 in the big ring, or down to 9.5 big/big, about the same usable speed range I get in my middle ring. except that the compact gears are crosschained worse and 5" to 7" apart at the bottom, where my middle ring gears are 4" apart. With this setup, in the key 18-21 mph range, the compact rider's gears are 11" apart, while my middle ring's are 5" apart.

My triple shifts 13 teeth between rings. A compact shifts 16. I just don't see the advantage.

I've seen a few mentions of this idea here and there, but no solid information on the matter. Is there a meaningful difference between running a 24x26 gear and a 30x32 gear (front x rear)?

I've seen some data showing that there are efficiency losses as the cog's tooth count gets down in the range of 11 to 16 teeth, but the differences seem negligible above that. It could certainly be true that wear will be slightly faster on a 24 tooth chainring than a 30 tooth, but I'm not sure there are meaningful efficiency differences.

However, when Shimano introduced their new DynaSys 10-speed mountain bike gearing, one of their selling points was that by having a 36-tooth cog out back, you could stay in the middle 32-tooth chainring in the front for longer, and they suggested that this is more efficient than having to use the 22-tooth inner ring (which has now been stepped up to 24 teeth). They are not joining the push towards using MTB-doubles like SRAM are (e.g., 26/39) for similar reasons (Shimano may be starting to offer such MTB-doubles, but they are not treating it as the default like SRAM are) - Shimano seem to suggest that riding the 26-tooth inner ring of the double will not be as efficient as using the 32-tooth middle ring of the triple.

As I said, I keep hearing things like this that would suggest that there is a difference between using a 24x26 gear instead of a 30x32, but I have seen no solid data or numbers documenting the actual differences. If anyone has some real information on the matter, then I'd love to see it.Yes, there is a meaningful difference. The bigger the rings, the lower the chain tension, which means longer chain life and fewer broken chains. We were just out with a tandem team that keeps getting stiff links because they shift standing in their granny ring. A stronger team would break chains doing that. We only shift standing in the middle ring, run mostly in our big ring, and get great chain life on the tandem, counter-intuitive.

Torque = force * distance, T = FD, or F = T/D. Increase D, keep T the same, and F goes down.

Yes, there is a meaningful difference. The bigger the rings, the lower the chain tension, which means longer chain life and fewer broken chains. We were just out with a tandem team that keeps getting stiff links because they shift standing in their granny ring. A stronger team would break chains doing that. We only shift standing in the middle ring, run mostly in our big ring, and get great chain life on the tandem, counter-intuitive.

Torque = force * distance, T = FD, or F = T/D. Increase D, keep T the same, and F goes down.

Lower chain tensions also mean less frame flex.

Lower chain tensions also mean less frame flex.Can you back that up with an analysis? Seems to me that BB torque & pedal force peaks are the same either way, smaller ring and cog are loaded more heavily, but the lever arm is also reduced, so torque on the frame remains the same.

Can you back that up with an analysis? Seems to me that BB torque & pedal force peaks are the same either way, smaller ring and cog are loaded more heavily, but the lever arm is also reduced, so torque on the frame remains the same.

I'll give it a shot. I agree that BB torque is independant of chainring size for a given force at the end of the crank arm, but as you've rightly said, the magnitude of the reactive force applied by the chain varies with chainring size. It also changes in location depending on how far the ring in use is from the centerline of the frame. These two changes (location and magnitude) in the reactive force of the chain must necessarily change the loads applied to the frame (particularly in form of lateral flex of the rear triangle, I believe) since the frame has no choice but to resist those loads. The more flexible the frame, the more one notices the effects of diminishing chainring size. On my 531 lugged road bike, the effect is quite pronounced. In the granny, there is noticable flex that I belive I can feel moving in synch with the pedaling (what Jan Heine's might call 'planing"). that disappears in the middle and large rings. On both of my recumbents, the whole effect is even worse than it is on the 531, where the whole frame feels like it's"winding up" with every pedal stroke when I'm climbing in the small ring. Again, just like on the road bike, this effect disappears in the larger chainrings. I've also heard the term "biopacing" for this.

I'll give it a shot. I agree that BB torque is independant of chainring size for a given force at the end of the crank arm, but as you've rightly said, the magnitude of the reactive force applied by the chain varies with chainring size. It also changes in location depending on how far the ring in use is from the centerline of the frame. These two changes (location and magnitude) in the reactive force of the chain must necessarily change the loads applied to the frame (particularly in form of lateral flex of the rear triangle, I believe) since the frame has no choice but to resist those loads. The more flexible the frame, the more one notices the effects of diminishing chainring size. On my 531 lugged road bike, the effect is quite pronounced. In the granny, there is noticable flex that I belive I can feel moving in synch with the pedaling (what Jan Heine's might call 'planing"). that disappears in the middle and large rings. On both of my recumbents, the whole effect is even worse than it is on the 531, where the whole frame feels like it's"winding up" with every pedal stroke when I'm climbing in the small ring. Again, just like on the road bike, this effect disappears in the larger chainrings. I've also heard the term "biopacing" for this.OK - nothing like experience! And since it happens on your recumbent, it's not just the surging effect of standing in a small gear at low speed. Stoker and I once tried standing on a very steep grade in our 26 X 34. We sat down very quickly, because the rear wheel lost traction on the stroke and then the bike stopped when our pedals hit BDC. Much better to sit and grind it out!

Remember that you are a former pro racer with legs of steel. Said with respect.

I don't have particular a problem with triples -- that small rng is really handy for decent climbs very late in a 600 or 1000 or 1200 randonnee, and heaven knows I have done a few of those sorts of rides in Tasmania.

I really can't see that people with them can be hunting for the right gear if the cassette on the back is not deficient in the % change between cogs. For me, I know when to knock down to the small ring and use the three big cogs on the back.

The issue for me if the cogset isn't right is finding too great or too small a percentage difference while in the same front chainring for a given incline.

Of course, we could solve all this by going to single speed... I didn't have any gear shift issues whatsoever with the fixie! :)

I'm afraid it's been several decades since I had legs of steel... These days I wonder if there's any muscle at all under all the fat! But after having used 53x39, 50x36, and 26x36x48, I finally settled on the 46x30 a few years back and have been utterly satisfied with is since. For general use I have a 12-27 9 speed cassette, and for off-road in our steep canyon areas I use a 12-34 on my "cyclo-muletisme". I have found that, on-road, by the time I need a smaller gear than 30-27 I am just as well off on foot! The only thing I sacrifice is a large gear for sprinting and pedaling downhill at high speeds. I've addressed that problem by not sprinting or pedaling downhill at high speeds.

And I do enjoy my fixed gear bike! Although in truth my British-style four speed (internally geared hub) has perhaps become my favorite bike of all, and I honestly find that I don't miss wide range gearing as long as I stay out of the high mountains.

Agreed. 39/53 is designed for the pros, and the flat-landers can get away with using it without many problems most of the time.

34/50 is still too big - the 50 tooth ring is too large to stay in for long without doing a lot of cross chaining. The 34 doesn't give you a real low gear when you need it (unless you use a heavier cassette with non road-friendly, wide spacing).

If people would admit that they are not pro' racers and that they should keep a decent cadence in all gears, then something like 30/46 setups would become very popular. Unfortunately, I don't think these two realizations are going to happen for enough people to make this setup common. Too many people think that what the pro's use is what they should use, without appreciating that the pro's are riding at average speeds 30+% faster than them.

Personally, I like triples. My favorite is a 48/38/28. I could see using a 46/30 on a compact though like you mentioned.

Well this thread has gone to bizarro world. Anyone computing the wear of a chain relative to chain tension is either bonkers or just terribly dim.

The purpose of maintaining higher amounts of chain wrap in spring-loaded transmissions is for both overall "gear wear" - not chain wear - and for mechanical efficiencies relative to shifting accuracy.

How otherwise seeming bright people could make some of the comments above is remarkable. However, I've learned over the years that cyclists are often idiots. I guess I'm not surprised.

I'm afraid it's been several decades since I had legs of steel... These days I wonder if there's any muscle at all under all the fat! But after having used 53x39, 50x36, and 26x36x48, I finally settled on the 46x30 a few years back and have been utterly satisfied with is since. For general use I have a 12-27 9 speed cassette, and for off-road in our steep canyon areas I use a 12-34 on my "cyclo-muletisme". I have found that, on-road, by the time I need a smaller gear than 30-27 I am just as well off on foot! The only thing I sacrifice is a large gear for sprinting and pedaling downhill at high speeds. I've addressed that problem by not sprinting or pedaling downhill at high speeds.

And I do enjoy my fixed gear bike! Although in truth my British-style four speed (internally geared hub) has perhaps become my favorite bike of all, and I honestly find that I don't miss wide range gearing as long as I stay out of the high mountains.46-30 would be more useful than the usual 50-34! Some years ago I was having trouble with my front brifter so that I couldn't use the big ring on my triple which left me with essentially a 42-30 compact. I was able to keep up with the group with that rig. I was running a 12-25. Would have been even easier with an 11. Now that I'm old, I run a 12-27. And now that my back is feeling better, I have to repaint my Trek by March . . .

Well this thread has gone to bizarro world. Anyone computing the wear of a chain relative to chain tension is either bonkers or just terribly dim.

The purpose of maintaining higher amounts of chain wrap in spring-loaded transmissions is for both overall "gear wear" - not chain wear - and for mechanical efficiencies relative to shifting accuracy.

How otherwise seeming bright people could make some of the comments above is remarkable. However, I've learned over the years that cyclists are often idiots. I guess I'm not surprised.Funny how people who haven't thought about an issue think that those who have are wrong. Chain wear causes cog and ring wear. The teeth on a worn cog or ring aren't any further apart, y'know. That's the reason a new chain skips on a worn cog. If higher loading doesn't increase wear, then a whole chunk of engineering science has just flown out the window and we'd be spending a lot less money on bike parts.

Years ago I had a grumpy, bitter old uncle. He mostly stayed upstairs during the annual family gathering, but every once in a while would come down to complain about everything and kick the furniture around. We'd just ignore him. Eventually he died, and nobody really minded.

Don't know what made me think of him after all these years...

Years ago I had a grumpy, bitter old uncle. He mostly stayed upstairs during the annual family gathering, but every once in a while would come down to complain about everything and kick the furniture around. We'd just ignore him. Eventually he died, and nobody really minded.

Don't know what made me think of him after all these years...

http://www.dlisted.com/files/grandpasimpson.jpg

Yeah - back in my my day - people called BS just what it is - -- BS!

(and they like calling BS BS)

If you have a transmission that involves 56 teeth when going fast, you don't want it to be using 50 teeth when going slow. The reasons for my comments are valid in the engineering world, accurate for this thread and not rooted in the BS the others offered.

In other words you want gearing extremes you wrap nearly the same amount of chain. And anyone who thinks derailleur springs exert wear the way hundreds of pounds of force being applied to rollers and pins during pedaling does is just - (insert RC-tested expletive here)

i'm puzzled, richard, exactly what posts are rooted in said BS?

chains are used up. you replace them.
cassettes are used up. you replace them.
chainrings are used up. you replace them.

all these parts are expendable, and often with service lives measured in years.

not that you TRY to intentionally crosschain or destroy cogs.. but y'know.. in riding since the early 80's.. i've never broken a chain, i've replaced probably several freewheels, and one cassette. NOT an enormous amount of squandering, and i can't say i've ever really suffered poor shifting until the end of a gearing component's service life. after that-- easy peasy-- swap 'er out: fixed. done and done.

i'm sure what you're talking about (although i haven't really figured it out) MAY make good engineering sense.. but isn't it a bit of a tempest in a teacup to worry about it given the fact that every piece of gear in a transmission IS in fact, expendable, and also engineered to be replaceable, not to mention, a bit of a stretch to refer to cyclists as idiots?

honestly-- 'fast' and 'slow' are such relative terms, it's really not even worth undertaking the argument-- but i do wonder what 'optimal' gearing IS, and in what conditions in your definition, as it doesn't really appear to have all that much to do with what most folks are positing as 'comfortable'. slide rule be damned-- i'm listening to my quads, knees, lungs, and heart- not engineering data.

I've learnt that you have to be careful with RC's comments -- they contain a strong element of truth, but could be couched in less aggressive terms.

And anyone who thinks derailleur springs exert wear the way hundreds of pounds of force being applied to rollers and pins during pedaling does is just - (insert RC-tested expletive here)

I agree, but what do derailleur springs have to do with anything being discussed here?

I have a feeling different folks are talking about different sources of chain tension (because I think we all know deraillieur springs aren't really a valid target.)