Saturday, November 19, 2011

Rider Fatigue and Bicycle Design

Randonneur Flying, Hanscom AFB
While I'd heard cyclists speak of rider fatigue in relation to bicycle frame design and ride quality, I did not understand what exactly this meant until I got a chance to experience and compare a number of different bikes myself. Riding a variety of bicycles over the same routes, I've noticed that some make me more tired than others independent of the ride's intensity. I can be cycling strenuously on Bike A and really feeling it in my leg muscles, yet remain energetic for the duration of the ride and even feel "refreshed" rather than tired at the end. Or I can be cycling at a moderate speed on Bike B and not exerting myself much, yet feeling more worn out than during the more strenuous ride on the other bike.

A reasonable assumption would be that a heavier and slower bicycle would be more fatiguing than a lighter, faster one, but for me that is not always the case. It seems to have more to do with how the bike feels on the road. When a bike does not do a good job dampening road shock, I begin to feel exhausted very easily. I also seem to be sensitive to a bicycle frame's tubing, because some bikes just feel more effortful to propel forward than others, despite similar geometry, size and fit. Oddly, positioning does not seem to have as much to do with it for me as these other aspects: Some bikes I can ride for a long time in an upright position and some bikes I can ride for a long time in an aggressive drop-bar position, whereas on other bikes these very same postures begin to feel exhausting sooner.

What has been your experience with fatigue on different bicycles? Have you noticed any patterns or connections? I suspect that there is no one formula to this. No doubt it is a complex interaction between a number of factors, including individual anatomy.

37 comments:

  1. In my experience, both physiological and psychological factors are at play here.

    Physiological: In testing more than 50 bikes for Bicycle Quarterly, we have found that the "ease of pedaling" correlates strongly with the flex characteristics of the frame.

    Psychological: If a bike feels slow, then the effort of pedaling can appear futile and mentally draining. I believe this is why some riders have a hard time with supple wide tires: They (the tires) don't vibrate at the high frequencies that we associate with high speed, and thus appear slow and sluggish, even if they are not.

    The fit of the frame does not appear to be that important to me. I do much better on test bike with marginal fit, but the right flex characteristics, than on a perfectly-fitting bike that is too stiff or too flexible.

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  2. In order to make this comparison, don't you need to do something to control how YOU are performing on any particular day by tracking your resting pulse?

    I've found that I can have fast/easy days on slow bicycles and slow/hard days on fast bicycles.

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  3. I feel like, even on my own urban commuter bike, I have days where I am pumped and full of energy when I get to work, and I have days where I am exhausted and just forcing myself to get there. Luckily, I have more of the former than the latter, but I'm sure individual energy levels / wellness / weather / moods, and all sorts of other variables come into play.

    Although I'm sure if someone consistently feels worn out after their commute, it could be they are riding the wrong bike for them!

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  4. It seems to be related to frame flex for me as well. If the frame "gives" a bit as I mash the pedals, I can ride harder for a longer time. Like a trampoline: I can jump up and down on a trampoline for hours before getting tired out, but if I did the same on a concrete floor, I'd be exhausted in a few minutes!
    I have yet to find a frame that is too flexible, but I keep looking.

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  5. a good deal of ride quality resides in the wheels. my tubular rims provide a much softer ride than clincher rims--their cross section is a simple rectangle (with no flange) so that they can flex easier. plus their inherent lightness need less energy to angular accelerate, they would 'feel' faster.

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  6. I'm pretty sure that the difference comes from your own muscles and what they're used to doing -- if you've been riding on one bike, with a specific set of angles, then a different bike will feel more difficult because it will work different muscles. I've noticed this with skis, too.

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  7. This morning I test rode an early 70s Alan, Campy equipped and a late 70s Schwinn Continental. The Schwinn rode better. Low expectations? Who knows. The bikes you like you keep and ride, the disappointments inevitably occur and you let those go.


    Bikes that fit, that are tuned and aligned go better. Jan Heine is very right about tire vibration - the one thing I always always notice when friends ask me to ride their new pride and joy race bike is the overinflated tires. One big factor like tire pressure out of balance is enough so that little else can be noticed.

    Many factors have to be right before a bike sings. Many of them are elusive. I've sold a good few bikes I couldn't stand to friends who ride them for thousands of happy miles. When I sold those bikes to people who were already friends I used to warn and worry. But it doesn't matter. If you can't isolate a specific fault it's a bike and someone will probably like it if you don't.

    If you're riding a lot of bikes from time to time you should jump on a "junk" bike like this morning's Schwinn. There are quite a few bikes as revelatory as that favorite Steyr.

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  8. I find my hands get fatigued first, because of the pressure against the handles. I'm surprised more bicycle makers don't make flattened out handles like some Trek models have. I haven't tried one of those yet, since my local bike shop stopped carrying the Allant.

    The basic round shape offers little to reduce the pressure. I've tried different grips, but I'd still think a flattened out handle would ease the stress.

    As for frames and tubes, I haven't ridden enough different kinds to judge really.

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  9. I've noticed that my Peugeot UO-18 is the most tiresome bike ever. It's a comfortable enough ride on the bum and hands but it feels like I am pedaling through molasses for the thighs. I've seriously considered tearing it apart and rebuilding it with everything better, but then I wouldn't have a bike to leave at the train station for long periods of time and not worry about theft.

    The tires are heavy and slow me down, but I know I can abuse them. I run it over grass and tree roots, jump off curbs and generally treat it poorly. It may just be a matter of changing some gear ratios and lifting the seam more. Dunno. I've got an old Suntour BMX triple I may experiment with when I get bored this winter. I don't think it's the frame per se. It feels like an old Chevette jalopy and is kinda fun. I expect it to start puttering and sputtering and making chitty-chitty-bang-bang noises.

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  10. I'm surprised people haven't mentioned steering. It seems to me some designs may require lots of attn and thus energy steering- perhaps good in some situations, but in others, potentially very tiring.

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  11. I wonder how much of the difference is attributable to tires? I find flat resistant tires to give quite a harsh ride. They can have stiff sidewalls that have no give so your back and butt do the giving. My touring bike has Panaracer Pasella tires and my Bike Friday which was custom built to the same geometry has Schwalbe Marathons. The latter are noticeably stiffer.

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  12. "A reasonable assumption would be that a heavier and slower bicycle would be more fatiguing than a lighter, faster one,"

    If you ask me the opposite is true. The lighter, faster bicycle encourages the cyclist to maximize his or her aerobic and anaerobic output; while the heavier bike encourage the cyclist to drop a gear or two and take it easier.

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  13. ...also, a lighter and faster bicycle is likely to have a riding position that maximizes pedaling efficiency, which will exhaust the cyclist faster than a heavier bicycle with a more relaxed fit and less pedaling efficiency.

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  14. "I'm surprised people haven't mentioned steering. It seems to me some designs may require lots of attn and thus energy steering- perhaps good in some situations, but in others, potentially very tiring. "

    Yes! I have a front heavy bike with a delivery basket, which requires me to keep my arms very stiff. For any ride under a half hour it feels perfectly natural to me, but after a half hour becomes quite exhausting. That's an extreme case, of course, but I'm sure degree of trail, or the lack of it, has a similar effect on longer distance riders.

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  15. "I wonder how much of the difference is attributable to tires?"

    For me, not that much; I've felt differences on bikes with identical tires.

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  16. "Psychological: If a bike feels slow, then the effort of pedaling can appear futile and mentally draining. I believe this is why some riders have a hard time with supple wide tires: They (the tires) don't vibrate at the high frequencies that we associate with high speed, and thus appear slow and sluggish, even if they are not."

    This is why trying the Royal H Randonneur was an especially interesting experiment/experience. The wheel/tire factor remained constant. In fact, visually the bikes were so deceptively similar that when I'd get on one of them, my brain would often get confused about which one I was on. However, the confusion would dissipate once I'd start riding. The 650B Randonneur I tested was distinctly less fatiguing for me than my own Rivendell. Didn't matter how tired vs fresh I was to begin with, I noticed the difference every time.

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  17. A few months ago I swapped wheels/tires between bikes experimentally. My poorly-controlled experiment hled me to conclude that if the bike doesn't feel right in the first place, better wheels and tires won't make enough difference to offset my feeling of fatigue. The right tires on a bike I already love will just make it even more fun to ride.

    This morning I took my lightest, fastest road bike out for a spin, and remembered why I'm planning to sell it. After about five miles it wasn't very fun anymore. The fit just isn't right somehow, and I missed my slightly heavier (by about 1-2 pounds) but better fitting touring bike. I don't think I'm actually any faster on one bike or the other - at least according to my computer - but I always feel as though I'm flying on the touring bike because it's such a joy to pedal, even uphill. I always enjoy the sprightly feel of the road bike at first, but for some reason that feeling fades as the miles stretch out. Clearly psychology and geometry interact.

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  18. Aside from being exhausted from work, or feeling sick, or just tired/low energy I can definitely feel the difference on certain bikes. When I still rode the aluminum bike like object it was very tiring because it was so harsh and the gearing was meant for a simpleton or very occasional rider. My old raleigh is always fun to ride. my surly is very fatiguing because while it is a relatively light bike, it is still overbuilt for me, and it has some bizarre instability issues that cause me to slow down, ride more carefully and try maintain balance.
    Tires are a big part of the equation too. Back when we all still rode mountain bikes for commuting I would often wonder why I was going so slowly, why I felt like I was riding in molasses. It was because of the small wheels and big fat knobby tires meant for thrashing around on dirt-not for riding on pavement and flattish dirt trails.
    I've yet in all my years on bikes to try a proper high end bike vintage or otherwise.

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  19. You are right on top of the subject with road dampening. I've noticed it more as I've....ah...matured (yeah,that's the word). Several years ago I changed from speedy 23mm to 28mm tires on my road bike. I was much more comfortable on long rides as a result. The constant vibration causes much more stress than one realizes.
    The bike I have now for touring,a Hunqapillar,is a full 12 lbs heavier and riding fully loaded,with 30 lbs of camping equipment,on 38 mm tires, I can cover 80-100 miles much more comfortably than on my road bike.
    The weight becomes a benefit in dampening the moment-to-moment stress the road surface creates. Geometry and position are important,but eliminating constant vibration eliminates fatigue.

    Marc

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  20. @Rona, I know some people swear by their UO-18s (not just at them!), but they really are one of the heaviest bikes in existence. The ride (and stopping power) would certainly be improved by replacing the steel rims with alloy, but the heavy frame might still be quite dead to ride even with good components.

    I have had an interesting experience with an old Gary Fisher HKII which I have had fun converting to 650B. Unfortunately, in spite of replacing all the MTB-ish component's with lighter, better quality randonneur-esque ones, the rigidity and weight of the frame make it an unlikeable bike to ride over distance. It is stiff AND heavy. Good for riding short distances up hills and down over rough stuff.

    I'm a big advocate of frames that flex. Being not particularly strong or heavy, I've never found a frame that flexes too much, only frames that flex too little and give nothing back, like the Gary Fisher. Even frames that are light but still stiff, like your average aluminium or carbon road bike, I find tiring. This is why I personally favour very thin-walled steel frames.

    However the other day I was riding an old Shogun Metro and was finding it a bit tiring. Symptom: couldn't seem to find a gear that let me optimise my output, everything was either too hard or too easy. I started to feel that this was the result of a heavy frame, as everything else was running well and the bike had just been serviced. Then I changed the crankset to one I had used and loved on a completely different bike. Lo and behold I seemed to find the 'right' gear. In fact there were lots of them that felt right. The whole bike felt different.

    So now I don't feel like I know anything about how and why a bike feels right. Maybe it's gearing as well...? b

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  21. My experience over years of riding found three big variables: position, tires, personal energy on a given day.

    First "adult" bike: Schwinn Varsity, next a steel Frejus with tubulars. Vast improvement!

    Other race bikes (PX10, all-531 Trek) felt fundamentally like the Frejus.

    Put Specialized Armadillo's on the Trek, and it was an instant stone.

    Now have several bikes, some single-speed, some multi-speed. There is surprisingly little advantage to multi-speeds...maybe two or three minutes in an hour ride...and I feel less whipped on the single-speed. My guess...and it's only that...is that the variety required by the single speed...out of saddle uphill, coast down, spin/hammer the flatter sections is more refreshing than relatively even effort.

    Finally, as a long time runner, we can't discount the physiology. With no differences in equipment or weather, energy and objective speed can vary quite a lot day to day.



    Now

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  22. From the Frejus guy, again.

    I strongly agree with the advocates of fatter, softer tires. There's little or no increase in rolling resistance, and a big gain in comfort.

    A ride on a rutted, frozen rail trail at 60 PSI
    is all chatter, at 40 PSI, not bad at all. That's with 700x35's on the Peugeot PX10. The same principal applies on anything but the smoothest pavement.

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  23. "if the bike doesn't feel right in the first place, better wheels and tires won't make enough difference to offset my feeling of fatigue. The right tires on a bike I already love will just make it even more fun to ride."

    That has been my experience as well. Whenever I've tried to "fix" a bike with different wheels and tires, it did improve things but did not change the "underlying personality" of the bike.

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  24. @Nanseikan I suspect you are right about the UO-18. I had bought it in hopes to find out why so many people love them (and have a fun project)...and all I can come up with is that it's pretty indestructible. Maybe that is a big concern for some people?

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  25. I strongly agree with Jan Heine on frame flexibility. I ride seven bikes regularly. My Ritchey Road Logic, the bike with the most perfect fit, is more fatiguing. I definitely feel more road vibration. My touring bike, a Miyata 1000, when unloaded is fairly stiff but when loaded it becomes a bit more flexible and more comfortable.

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  26. “I strongly agree with the advocates of fatter, softer tires. There's little or no increase in rolling resistance, and a big gain in comfort.”

    The wider tire would have to be inflated to the same pressure as the narrow tire and have an appropriately flexed sidewall in order to achieve rolling resistance same or lower than the narrow tire. Otherwise deformation and frictional losses would make the bigger tire slower. Wide tires are generally inflated to a lower pressures. Therefore, their deformation provides for a plush ride but brings a penalty of increased rolling resistance. Perhaps the fatigue from riding on plush tires with greater rolling resistance is offset because they mitigate the fatigue otherwise brought on by discomfort (e.g. from harsher bumps and vibration) associated with the narrower, harder and faster tire.

    I think flexible vs stiff frames involves similar kinds of tradeoffs in energy transfer and loss, comfort, and fatigue. As GRJ likes to say, YMMV.

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  27. In my limited, very urban experience, positional discomfort is the killer.
    I have two major wek points: my wrists and my neck.
    No amount of "component quality", hand made frame or what ever can solve that other that positioning on the bike.
    Super high quality expensive bikes with agressive position will tire me as my neck hates that and my wrists can't handle my own weight.
    On the other hand, even the worst 50$ upright second hand junker will have me go for hours.

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  28. A very interesting set of comments indeed! Usually when Velouria asks an open question, one sees a sort of consenus develop. No consensus here! Things are splattered all over the conceptual landscape.

    "I suspect there is no one formula..." I suspect the question has no objective answer.

    How do we separate out factors like our associations with the bike in question? Where did we get it, where and when did we first ride it? Did we buy it new, rescue it from a dumpster or receieve it as a gift? From who? Is it an "old friend" or a slightly suspicious new-comer? In what language do we think about it in? (In the language we say our prayers in or use to talk to our horse in? -Emperor Charles V.) Is it the bicycle you used when you totally exhausted yourself that one dark day, or the one used for some great personal success?

    Now factor in all the geometry, tire width and pressure, the steering, the weights, etc., add in level of energy that day, blood sugar level, bad dreams the night before and the grouchiness level of ones partner that day....

    Try to reduce it all to one formula please!

    Leo :)

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  29. Leo - I suspect that individual + bike interaction is a bigger factor than we all want to admit (i.e. there is no single bike that will feel the same for every person).

    Montrealize - For me it is not as simple as upright vs leaned forward, since there are different variations within each category. Some upright handlebars make my hands go numb; with others I can cycle for hours. It also has to do with angle, size of the gripping areas, to what extent I can feel road vibration through the bars, etc. I am difficult!

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  30. Absolutely! Sometimes it can be possible to point out low tyrepreassure, tight bearrings or similar but sometimes it is really difficult to know. I think sometimes it is just about what muscles are fit and not, if you ride a bike where you need to use muscles that yoy normally does not use then you can feel tired fast. Just rode my "studded tyre mixte" for the first time this fall today. I can hardly walk, my knees and legs are almost failing to carry me. On this bike I feel I need to push the saddle back as far as possible on this seatpost (short rails on a B17) to be able to ride it, but still it hurts a lot the first few rides. I know it is going away, but I ride a lot of different bikes- from 16" folders to 28" ones and this is the only bike that gives me such problems.
    badmother

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  31. This topic is of particular importance to me right now. I am soon going to have to put my seat in the saddle for 6,000 miles. i am planning to ride my bike from Kodiak, Alaska to Key West, Florida. I initially was looking for hard rigid frames and tires. I was thinking about efficiency and speed.

    Now I am thinking that comfort my play a role in endurance.

    What type of bike frame and tires could create the best of both worlds?

    Check out my blog. johnsamericabiketour.blogspot.com

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  32. Along with tires/wheels, I definitely believe frame material affects your fatigue level. I remember when I switched from a steel frame to aluminum.

    I was so excited when I got it - I remember being thrilled with how light it was. I'm only 5' 3, so the difference in weight seemed amazing to me.

    Unfortunately, at least for me, that was the only good part of having an aluminum frame. I would get home from my commute feeling totally hammered. It was just too rough. The fit was good and I used the same wheels, so it wasn't that. I never realized how much steel absorbed the bumps on the road.

    I sold that bike after a year of trying to get used to it, went back to steel, and never looked back. YMMV, but that was my experience with rider fatigue related to a specific bike.

    Maryk
    Philly, PA

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  33. The picture shows you riding by an Airfield. You might want to stay away from those places... Planes are WAY more addicting to some of us than bikes and I wonder about you in that way...

    Just sayin'...

    Spindizzy

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  34. Spindizzy - Nope. I'm more in danger of falling for ships. Thankfully I can't afford to.

    That is Hanscom Airfield in Bedford, MA in the picture.

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  35. Ooh, sailboats. I avoid them like self aware alcoholics avoid opium dens.

    Spindizzy

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  36. See Bicycle Quarterly Vol 9 No 3 Spring 2011 "Frame stiffness: the balance of a frame" by Jan Heine and Hahn Rossman. Key nugget under the sidebar "Frame Flex" on page 53-- "In testing many bikes over significant distances, we found that on the best bikes, our pedal strokes get in sunc with the frame ('planing'). The frame appears to flex during the maximum power phase of our pedal stroke, rather than pushing back against our legs, allowing us to push harder on the pedals. The flex energy stored in the frame is released during the dead spots of the power stroke, when it helps to drive the bicycle forward."

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  37. One further note: the word is damping, not "dampening". To use "dampening" suggests you are all wet, which you are decidedly not. Look it up: damping.

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