Looking at the study in more detail than I should have bothered to, the only place I can find any claim for a 5% improvement in efficiency for a larger cog was where it showed a 5% difference between the least efficient gear selection in the 27 speed derailleur system vs. the most efficient. In other words, the worst case. The least efficient used the small cog (12T) and the most efficient used a 20T.

The second and third most efficient gear choices were with a 16T cog. This on a cluster that had cogs up to 34T. So the concept of "bigger is better" isn't really demonstrated by that study. Also worth mentioning is that even though 20T cog was part of the most efficient combination, when used with the middle chain ring it was the 3rd least efficient.

In fact as it turns out, an even bigger impact on efficiency than using the small cog was using the middle chainring for some reason they couldn't explain.

It's also worth noting that every gear option tested on the derailleur system except one was more efficient that any of the gears on a Rohloff.

Both the derailleur systems and the IGHs had a sort of roller coaster pattern when came to efficiency as you moved up the gear range with the general trend being downward. So by choosing a larger cog, you may actually be spending more time in a less efficient gear. But there are a lot of variables.

Even if it were true that bigger is better you could certainly set up a derailler system that has you spending more time on the larger cogs. With many IGHs you're limited as to how big you can go when it comes to cog size.

I'd say that your claim that IGHs are more efficient when set up properly is pretty shaky. By knowing which gears are the most efficient in your hub you could certainly select a cog that places you in the more efficient gears more often (and it's not always a bigger cog), but you can do the same with a derailleur system.

:popcorn:

:)

I don't want to come off as anti-IGH. I've spent a few hours this weekend building one into a wheel and I'm pretty excited to get everything else in place so that I can try it out.

It's just that I've never seen anyone claim that an IGH is more efficient before and Chucky has a less than endearing way of presenting his arguments. ;)

Oh, for sure.
This is the first I've also heard of the claim that IGH is more efficient. The banter is fun to watch. Chucky has "set himself up" by virtue of the immobile stance and hyperbole that is infused in his posts. He clearly has his point of view and is willing to battle to the death to persuade everyone that he is right. I have no desire to become tangled in that mess of thorns. *sniffs the air* I smell a troll.

I use IGH's on my bikes and like them, after having ridden for 35 years on derailleur drive trains, and see the benefits of both. I really don't care to discuss the finer points of the two with scientific reductionism, so have sort of sat back and watched the fray unfold.

I've been reading about your IGH project and look forward to seeing your experiences with it.


EDIT:
I do feel the context for scientific studies has its place, namely top end racing, where minute differences in efficiency can mean the difference between winning and 4th place. However, such discussions in a commuting forum seem absurd to me. This is in no way meant to offend those who've felt compelled to engage Chucky, but I think the conversation has digressed into finer points that really have little influence on the commuting experience. There are so many factors outside of drive train efficiency (personal fitness, mood on any given day, wind, bike setup, terrain, etc) that essentially relegate the minute differences between IGH and derailleur systems to "background noise" in this context.

Life is about compromises... went with an IGH and a derailleur this evening.

http://ravingbikefiend.com/bikepics/...dualdrive5.JPG
SA AG dual drive conversion

And I don't want to come off as anti-deraillieur. Mrs IGH made me remove the Nexus 8 and put deraillieurs back on her bike (the 5-6 hole)...I spent my REI rebate/20% discount on a set of Askims with bladed spokes (Soma ES is "in the mail"). If I'm gonna suck some wheels on a century I better fit in :)

So, hey--back to the topic. I live in the same city as the OP, and I am a big fan of the IGH in theory. I've even gone so far as to calculate weight differences. There's some threads out there where people converted and ended up with the same weight (difference of .03 lbs or something). Still, looking at the driveline parts I just purchased for a drop bar conversion, their low weight and cost just make it pretty hard for me to justify a IGH. A belt sure would be nice, but with the hills here in SD I almost always have to shower and change at my destination which means I'm wearing clothes that don't mind chain grease anyway. An obvious win for a belt drive IGH would be the new Bike Friday Tikit;a folding bike would be quite nice to have without a greasy chain.

My derailleurs are 20 years old. I think they've been adjusted *maybe* 5 times. The chain itself is more annoying than the gears and derailleurs, though o sure dig the clean look. I just have to admit to myself that my money is best spent elsewhere (9 speed cassette for conversion was $13. Number of 7-speed cassettes bought in 20 years: one, and that was just cautiousness from knowing I had a pretty stretched chain but no real issues).

Yeah, I wonder how often people actually wear out a 7/8 speed cassette if they replace their chains frequently enough. I've replaced one 7 speed cassette on my old winter bike because it was worn out and I probably could have avoided/delayed that if I had been better about replacing chains. The only other cassettes I've bought were upgrades or for new wheels.

Roadie types that put thousands and thousands of miles on small, lightweight 10/11 speed cassettes may go through them pretty quick, but I don't know about typical commuters.

That is an excellent point. I used to go through cogs pretty quickly on the Tommasini, but I was putting 250-350 hard miles a week on it, and the cogs were lighter than what I would put on a commuting bike. One thing I liked about the Campy Record 8-speed was that I could replace individual cogs on the cluster, which came in handy since the middle 3-4 cogs took the brunt of the wear.

Anyway, commuters are more likely to put something a bit more robust on their rigs, so cog life would be greater than on a racing cluster.

The extra weight of an IGH drivetrain (however small it may be) has at least one advantage. I'm using it as an excuse to justify getting a bike that I have absolutely no real reason to get. The bike I'm targeting for an IGH is a Bianchi Project 3. I saw a Project 7 on CL this week. It has lighter Tange Prestige tubing rather than the Tange Infinity on my bike. The components are better too but a lot of those would get pulled off anyway. It's also Celeste. Of course the lighter tubing will nullify the IGH weight gain so I must get it. ;)

The deal probably won't go through as the seller would prefer to trade for another bike, but we'll see.

Wait. So you have cables hooked up for both derailer and IGH? Then you swap wheels in and out?

No if you read thru, you would see, there's 2 cogs on the IGH

It uses two drive cogs and the derailleur does the switching... it doubles the available gearing and when you switch between cogs with a 2 tooth difference the jump is 12.5% and it reduces the switch in the IGH to a 20% jump.

SRAM does this with a 3 speed and a 9 speed cassette drive which is especially good for high performance folders with very small wheels as a straight 52:11 only gives you 88 gear inches and by utilizing the internal gear hub switching into 3rd increases the final gearing to 120 gear inches which is what you get when you run a 700c wheel with a 52:11.

You don't have to work very hard to find a low gear on a 20 inch wheel and the challenge is with higher gearings... the Shimano 11 speed IGH should be very good at addressing this as it has a very wide range.

On my bike the 2 by 3 offers closer jumps and an expanded range... I guess that with the derailleur installed I could swap out the IGH and slip in a wheel with a cassette if I wanted to but my IGH also serves as my generator.

I don't know Paragon's specs, but I know some stainless bike components specify silver because nickel rods like AllState 11 have flow temperatures too high for the heat treatment of the stainless components. (The same reason silver was traditionally used in place of brass on heat-treated CrMo tubing.) You don't want to save $2 on filler and wreck a $100 component. I would definitely consult the manufacturer's specifications and instructions before choosing a filler.

OK, thanks. I've seen multiple chainrings up front with an IGH (thinking about one for my wife), but never something like this. Maybe I'm just not paying enough attention.

I've prepared a little chart that others might be interested in seeing. I certainly found it interesting to evaluate.
The chart compares several IGH and conventional drive train options (Gear inches) using a baseline wheel size of 700x28 and suitable gearing typical for each option.

I used three IGH models: Alfine 8 speed, Alfine 11 Speed and Rohloff 14 speed

The conventional Derailleur setups were as follows (all 10sp):

Compact Double Crankset, wide range cluster: 39/53, 11-32
Compact Double Crankset, typical cluster: 39/53, 12-27
Touring Triple Crankset: 26/36/48, 11-34

I think these cover the pretty typical setups that most commuters would consider, and it is interesting to see how the IGH's compare to the derailleur setups.

For the high gear, I wanted each option to achieve at least 100", which caused the Alfine 8 to have a higher low gear (34") than some might like. Obviously, this can be directly scaled lower to simulate using a lower gear combination.

When loading the data for the conventional derailleur configurations, I eliminated the obvious "no-no" gear combinations (big chainring + big cog, Small Chainring + Small cog, etc), on the triple I eliminated 3 cogs on each extreme (big/small) and the largest and smallest cog in the middle ring. Incidentally, those gear ratios were redundant with other (more chain friendly) combinations.

To normalize the chart, I set each option to its full 0%-100% range, so the different configurations could be compared directly. Gear changes are clearly indicated with the upward jumps between the horizontal gear levels.

I have also indicated the "comfort range" for typical flatland cruising (60-80 gear inches) sou you can see the options that each setup offers within that range. One thing that jumps out is the notorious 5-6 jump on the Alfine 8, which occurs in this zone, where having closer steps is preferable. The Alfine 8 could be optimized for this zone (i.e. different chainring/cog combos) but the low range would be compromised in doing so.
This chart also shows how the Alfine 11 and particularly the Rohloff come extremely close to offering the same range and similar gear steps to the conventional systems
Another thing that is apparent is that even with the elimination of the obvious (bad chain alignment) combinations, the derailleur drivetrains still have a number of relatively redundant gear combos (steps less than 3 or 4 gear inches). Obviously, using a 9 or 8 speed cog would spread the steps for these drive trains.
Where that is a boon is on the compact Double with the 12-27 - the "cruise zone" has many gear choices, giving much needed flexibility for subtle adjustments in headwinds or slight hills.

Anyway, here it is for your geeky enjoyment!

http://bikeforums.net/attachment.php...hmentid=198305

It is a little hard to see in that picture... with two drive cogs the chain line is excellent in either position and the jumps are closer than what you would get with a triple chainring single cog set up (I have tried this too).

Guess I could run a double and a front derailleur if I wanted a 12 speed that incorporated an IGH but then my head would explode trying to run three shifters.

Here is a close up... the conversion might have taken 25 minutes.

http://www.ravingbikefiend.com/bikep...dualdrive1.JPG

That is really novel!

LOL on the exploding head. I think mine would short out as well with 3 shifters.

I think what's very important when choosing a hub gear is to set it up with a gear that you feel comfortable riding all day long. My Sturmey Archer 5 speed with limited gears was not set to my liking since I prefer to ride all day in a 54 inch gear. Therefore, I purchased a 21T cog to get that gear and in doing so, lowered my overall gears on the hub. Using Sheldon's calculator, I was able to get the perfect gear for my riding style.

Other people may feel they perfer to ride in a higher gear and that's fine. However, if you find yourself like I did riding a hub geared bicycle that did not have my favorite gear, you may not enjoy and may hate the hub gear experience. My 5 speed hub was too high geared with 3rd, 4th and 5th waaaay out there to be practically unusable! I ended up riding most of the time in 2nd gear but that was a bit too low at 49 inches. There was no way I would have been happy with this setup.

I think this is in fact the reason many people look at the AW-3 speed (or any internal hub) as being too limiting. However, if you set up your middle gear to a ratio that you'll feel comfortable all day, then the hub can fulfill almost all your needs.

The SA 5 speed is rather notorious as it share the same middle three ratios as an AW 3 speed where 3rd is usually too high and then adds a big jump to 5th... these need a large driver or a much smaller chain ring to make them practical and this seems to be lost on many manufacturers and designers.

I do a lot of refits to IGH equipped bikes to bring their gearing into a manageable range as the stock set ups are too high for most people and think you should be able to use the full range the hub or drive offers for the majority of the time.

Since I fragged the back and developed neuropathy in my left leg I have taken to spinning lower gears to reduce stress to my good leg which does more of the work and have found that even though I can't mash those huge gears I can spin those lower gears faster and longer and still maintain some really good speed.

I am probably more fit than many able bodied riders as I spend a few hours riding every day for therapy and ride as much as 700 km a week during the summer. I continue to manage well without a car and feel that for most people any gearing over 90 is pretty much a waste as most will not use it and that drives should be designed with a better middle and low range.

When you spin more you do your body a favour as it really strengthens the cardio and reduces stress on joints... I know a few mashers who do not spin and these guys like those really tall gears but they are an exception.

My better half has exercise induced asthma and cannot spin too fast or suffers attacks and does push a higher gear... if she spun like I do she's end up in the hospital and riding is something that has really helped her with her health in many areas.

When we ride together she maintains a pretty steady cadence of about 70 - 75 rpm while I will be pushing a lower gear at 90-95 rpm.

Well put, sixty fiver. I'm a spinner, and my knees get an empathetic twinge whenever I see someone mashing (usually accompanied by pronounced swaying of their upper body) :D

I like to make sure I have a low enough gear to get myself up any hills I might encounter, high 20's to low 30's, and use that as my initial point when considering my gearing setup. I also look at the "sweet spot" from 60-80", which is where I spend most of my time (as most probably do), which when spinning at 90 RPM is about 16-22 mph. If that zone has a big void, I try my best to make sure I have something at about 70 inches for a good all day 18-19mph gear.

I can pretty comfortably spin an 80 to 85 inch gear on the flat when I want to pick up the pace, and I find I wrap out anything under 100 inches on even the slightest downhill. My current Alfine setup runs from about 29-96 inches and I can stay in 7th and 8th on the flats with a slight tailwind, at 90 RPM. while I don't mind the fact that I totally wrap out of usable gears on most downhills at about 25-28 MPH, I'd like to have something available in the 105-115 range.

I am intrigued by the gear range of the Alfine 11, and by its even steps between the extremes. I love the Rohloff, but can't justify the expense at this stage.

I think the Alfine 11 will be my next IGH when the time comes to play with hubs ;)

Most folks can't ride at 18-19 mph all day long... this is my target speed on centuries with my touring bike and can wind it up a little more on the road bike. There is something about the road bike being 20 pounds lighter than a loaded touring bike that makes some difference.

Those taller gears are good for high speed downhills (if you have the skills) and my vintage road bike currently runs a 40-108 gear inches and with my new wheels will offer 38-124 gear inches.

I am a small guy and have to pedal my way down too. :)

One of the few areas in cycling where mass is helpful :D

I'm 6'2 and 195 lbs - in my racing days I was the typical "domestique" type - steady momentum, setting the pace at the front but pretty useless in a sprint or steep climbs. However, I'd be the guy to bridge the gap once the sprinters settled down. ;) I found having the extra mass with not too much more frontal area than the sprinters allowed me to stay at a steady, strong pace, making quick work of reeling them back in. I finished fourth. Alot.

Those days are long gone, but I do still tend to ride at a steady pace on the flats, and can comfortably sustain it. Some days I feel stronger and push the pace for fun, others I kick back and relax - it varies.

This is why I focus so much on the 60-80 inch range, and one of my main issues with the Alfine 8. I love that hub, but I find myself in 6th and 7th most of the time, and if I have a headwind or slight grade, the drop to 5th is larger than I'd like. If I optimize the range to have 4th and 5th as my primary gears, I lose my lowest gears, which I value on my loaded commuter. Hmmmmmmmm...... Alfine 11 looks better by the day! ;)

All of that said, I really do like the Alfine 8, and for commuting duty it is a great hub. I've been spoiled in the past by close ratio clusters that allowed for plenty of fine tuning in the sweet spot (at the expense of lower gears), but as I've grown more accustomed to the larger steps of the IGH I find myself preferring the cleanliness and simplicity of the IGH drive train. Now that I have belt drive on my commuter, I'm really enjoying the setup.

That's a great century pace. The "five hour" century is an honorable target. Agreed that the difference between a loaded tourer and lightweight road bike is tremendous for such outings. :thumb:

Was just thinking that I did this on my P20 when it was only set up as a 12 speed and I thought a 7 hour century was pretty leisurely. I know I was enjoying the beautiful day and the scenery and wasn't pushing things too hard to keep a 15mph pace.

http://www.ravingbikefiend.com/bikep...est100bike.JPG

Time on the clock was 7 hours and 4 minutes and snapped this on the home stretch and after spinning at over 90 rpm all day I still felt really fresh... 31.7 kmh = 20 mph.

http://www.ravingbikefiend.com/bikep...est100mark.JPG

Used to be able to do 5 hour centuries and did not think that those were that hard... might try to do one in six after I get the new wheels on the road bike.

I swear, you have the coolest collection of bikes, Sixty Fiver!

It has been a few years since I've launched off onto a century - you've got me thinking about it again, for the sheer enjoyment of the ride.

I have been contemplating doing some ultra distance riding... there is a 600km ride we are looking at which would be a 300km ride out with a nap and then a return the next day although we will hold up the option of riding straight through for what will probably be a 30 hour ride.

3 years ago I did not think I would ever be able to ride a bike again so being able to go out and do a solo century, even at a pootle, was very significant. Never thought I'd be looking at doing 300km and 600km rides and mebbe one day I will find myself doing the PBP.

Had gone on some longer supported rides before this and was riding 100km a day working up to this... have since upgraded the bike more to make it a more capable tourer and it now has better gearing for distance and speed now.

In the spirit of the thread I will have to take out my 1954 Raleigh so it can earn it's big C and it is running a basic AW 3 speed but is pretty light and there are no killer climbs on my century route. It has been a very comfortable bike over middle distances of 70-80 km but has yet to go on a really long ride.

http://www.ravingbikefiend.com/bikep...ighsports5.JPG

I like the challenge of riding distances on bikes that most would consider odd or unsuitable for such tasks... my little 20 is a very capable long distance bike and I rode it over 4000 km last summer and used it for many weekend rips where I'd ride 200 plus km.

http://www.ravingbikefiend.com/bikep...11forrest5.JPG

Whether you ride an IGH, a derailleur equipped bike, or a hybrid of both systems it is all good as long as you are riding and that it makes you happy and healthy.

I like that Raleigh.

Just curious - what happened 3 years ago? I'm glad you have been able to get back on the bike, and the fact that you are looking at a Brevet / ultra distance ride is amazing, given the fact that you have overcome whatever difficulty that arose. :thumb:

Suffered a serious back injury and have permanent / partial nerve damage which affects my lower back, hip, and left leg... it works intermittently and can be a little ****zy as the signals are messed up so my right leg does most of the heavy lifting.

Cycling has been very good therapy and my physio and doctor say that aside from the not being able to feel my left foot and the whole chronic pain thing I am in pretty great shape... my physician and physiotherapist are both cyclists and my doctor jokes that he would not be able to keep up to me on a bike. My physiotherapist is a tri-guy so I get to rag on him about not really being a cyclist and he always picks my brain for tips on how to ride faster and get more out of his bike.

I signed up for a charity bike ride and I had been wondering if I should make myself tough it out on my single-speed or ... tough it out on my touring bike that is about 170% of the weight of the SS. Now I am thinking about a double cog setup, hmm...