Categories: RacingTechnology

Theory of Bike Fitting: Tall Riders Walk Their Own Path

Thor Hushovd

Fitting yourself to your bike properly and being comfortable while riding is probably the most important aspect of cycling. It doesn’t matter if you’re riding the Worlds Lightest Bike or your Clunker Rain Bike/commuter; if you feel good on your bike, it will be a pleasure to ride. My 10 kilo, 8-Speed Shimano 105, fender and mud-flap equipped Bianchi XL EV2 is almost as much a pleasure to ride as my 7 kilo Campy Record/Zipp 404 built  Cervelo R3 (as long as I don’t ride them side by side). It comes down to the fact that once you’re riding, all you know is how your bike feels, and the light weight and stiffness of my R3 is something I notice when I ride it, but I don’t miss it when I’m on my other bikes. All of my bikes are a pleasure to ride, and I personally believe that is due to the attention I have paid to getting my fit as perfect as I can.

I am a rather tall person by cyclist standards, and a dwarf by Basketball standards. I stand about 6’3″, have a relatively short torso, and have relatively long arms as compared to my torso, but normal for my total height. It seems to me that the American cycling industry has a very good idea how to fit a 5’10” rider to a 56cm frame. From there, it feels like most bike shops scale the model up or scale the model down from that point of reference. In my opinion, the US cycling industry is selling almost every bike customer the wrong bike. Tall riders have dramatically different biomechanics as do shorter people. The proportions and angles between limbs and torso don’t simply scale like you’re enlarging a photo of the same customer and fitting them to a proportionally bigger or smaller bike. Add to that the fact that the physics of the cycling world works against tall (and inevitably heavier) riders, and the problem of fitting yourself to a bike is compounded by the fact the fact that you’re a minority and the industry generally does not put priority on understanding what you need as a cyclist. The result is tall riders on frames that are too large and with handlebars that are too high.

My theory of bike fitting is very simple and is based on two principles:

  1. Bike stability is the key to a well-handling bike. Stability comes from three primary factors: angle of the head tube and rake of the fork, wheel base (the frame’s geometry), and – most importantly – center of mass of the entire rider/bicycle unit.
  2. Flex (and error) within the system increases (usually proportionally) with the length of the tubes involved. Basically, when you apply the same force to a short tube versus a long tube, the long tube will bend farther. Now, measures can be take to mitigate this issue, such as cramming a whole crapload of material near the highest stress points as you make the tubes longer, but any kluge you throw at the problem doesn’t change the fact: a longer tube is less efficient at transferring power than a shorter tube or the same dimensions.

I think most bike manufactures understand the second point and their mitigation strategies vary from using different tube sets for different frame sizes to applying more material (and making a relatively heavier bike) to the tubing. That’s fine, the Sasquatch in us taller riders can handle a little extra weight. The keys to bike fitting lie in the first point.

The difference between a tall and average rider's bar height

How does a cyclist lower their center of mass? Well, you can be shorter, that works pretty well. Or cut yourself off at the knees, but that has other side effects that I don’t want to get into right now. You could also lower the bottom bracket like Look and Eddy Merckx used to do (I think they raised their BB to the standard height recently).

Buth the real solution is that in most cases – at least in the cycling world, taller means lankier and that means that proportionally, the distances and angles between legs, arms, handlebars, saddles, and pedals start being very different – and should be much more extreme – than the scaled-up picture model of the 5’10” rider on a 56.

I have found over the last 23 years of riding that when I lower my bars, two things happen. First, I have better control over my machine. Second, I go faster. After having my bars as low as they would go on my R3 and consistently feeling they were a bit too high, I bought a 17 degree stem for my R3 which lowered my bars by 2cm- more than I thought I wanted. The results were astounding. Not only does my bike handle better, but I ride about 1-2kmph faster on flats and on climbs. The speed factor can be attributed to freakish bio-mechanics (that may be unique to my physiology) and/or increased aerodynamics, but the bike handling is, I believe, directly related to my lowered center of mass. In fact, John – who is also an Eros Poli-sized rider such as myself – noticed how good a low, aggressive position feels after borrowing one of my bikes during a visit to Seattle.

The bottom line is that you have to be comfortable on a bike, and that means different things to different people based on their size, flexibility, and style of riding. That said, I urge tall riders to experiment with riding the smallest frame you can while still getting enough saddle height and top tube length needed to ride efficiently – and then ride your bars as low as you can. If you need an example from the pros, take a look at Axel Merckx’s position (at the top of this post, as well as compared to Floyd Landis above), or keep in mind that Greg Rast on team Astana had Trek build him a frame with the dimensions of a 61cm frame with the head tube height of a 56cm frame – and slams his handlebar stem right down on his top tube.

It’s all about your center of mass, baby.

frank

The founder of Velominati and curator of The Rules, Frank was born in the Dutch colonies of Minnesota. His boundless physical talents are carefully canceled out by his equally boundless enthusiasm for drinking. Coffee, beer, wine, if it’s in a container, he will enjoy it, a lot of it. He currently lives in Seattle. He loves riding in the rain and scheduling visits with the Man with the Hammer just to be reminded of the privilege it is to feel completely depleted. He holds down a technology job the description of which no-one really understands and his interests outside of Cycling and drinking are Cycling and drinking. As devoted aesthete, the only thing more important to him than riding a bike well is looking good doing it. Frank is co-author along with the other Keepers of the Cog of the popular book, The Rules, The Way of the Cycling Disciple and also writes a monthly column for the magazine, Cyclist. He is also currently working on the first follow-up to The Rules, tentatively entitled The Hardmen. Email him directly at rouleur@velominati.com.

View Comments

  • @Rob @frank
    One of his yellow jerseys is enshrined at my local coffee shop. Very cool.

    @Marko
    Thanks for the link. More for Frank than me, and he does seem to be talking about fit rather than performance, which was Frank's theme above. I can't really comment one way or the other; I just see pics of Frank's seatpost and I feel so, well, inadequate...

  • @Marko
    You hit the nail on the head, I think - and you have a point with being too far back over the wheel being odd, but I haven't seen that happen on my bikes, but maybe they all have steeper seattube angles. But I think you nailed it; it comes down to weight distribution and being well-balanced on the bike, which is impossible with the high center of mass that comes with having the bars and the "normal" height that you would for smaller riders on a smaller frame. What's even worse is bike shops that set big riders up with extra high stack-heights to put the bars up even with their saddles; I've seen 6cm stacks; I shudder to think of the speed shimmy associated with that!

    I'm going to go online and order me some 345mm cranks and see if I can pop a reverse wheelie every time I pedal.

    @Steampunk

    I just see pics of Frank's seatpost and I feel so, well, inadequate...

    Did I mention it's a 31.6?

  • @frank On your side, Frank, I suggest the handling problems of tall lanky guys may have nothing to do with the physics of the bike. It didn't take us shorter, more muscular guys very long to figure out when we were growing up that the taller, lankier kids lacked all coordination, balance, and power. I used to love ripping tall, lanky wide receivers in half on the football field. They seemed so helpless out there. The fact that you don't have that problem may mean you are one of the few of them are fortunate to have normal coordination and balance. To explain it, I would suggest it may be due to your big head. More neurons and sheeit devoted to motor-control, or else simply an inflated ego that will not allow itself to believe it's not superior in some respect.

  • One of the key points in arm comfort is having a 90° angle between the body and the humerus. Get on the floor like you are going to do a push-up, but get on your elbows instead, now look at that aforementioned angle and rock back an forth changing that angle, it's not easy to hold if it isn't square to the body.

    Within this guideline you have actually a lot of flexibility on position, you can drop the bars way low so your back is parallel to the ground or have both your back/humerus at 45°/45° or 60°/30°. This will simply be dictated by comfort or intent, intent being aerodynamics, comfort often being dictated by your saddle, flexibility, age. Look at Thor's arms above, 90° to his back/body, the rest of the peleton is much like this. As Americans, we tend to look at these guys and think their position is either very low or stretched and almost always have stems that are too long. Most Europros have a very healthy overlap between elbows and knees when in the drops tucking low.

    Your pelvis will only rotate as far forward as it does, limited either by hamstring flexibility or by the structure of your pelvis and how your femurs insert into it. Watch your pelvis as you bend down to touch your toes, it goes a certain amount the stops and your spine starts to bend to make it the rest of the way down. So this is probably the limiter on most people how low your bars can go.

    One thing to keep in mind, is that NONE of these positioning things have had any science applied to it (other than wind tunnel testing, and saddle comfort vs. pelvis structure). You can put a saddle all the way back and your cleat all the way back and maybe show an increase in power while YOU are sitting on your bike RIGHT NOW. Train like this for months, and who is to say where you will be. There is no good way to test this, control group, double-blind, continuous training data over time, etc.

    I could go on, but I have to get to work.

  • @michael
    Great insights, thanks for that. Reading the post again I realize that the pictures got mixed up when we migrated to the new site layout last Spring. Obviously that's not by boy Axel Merckx. I'll try to dig up those pics again at some point. I also will look for some pics of me from the side - everything from before this year is out of date re: positioning.

    Bottom line, my position is something I've arrived at over years and years of trial and error; it works, for me anyway.

    What you say about none of this not being scientific is bang-on; it's all theory and experience, and very hard to prove aside from saying, "gee, this works" or "this doesn't".

    A few things to also consider, from a physics perspective that ARE scientifically proven: low centers of mass are more stable than high ones, and long tubes are more flexible than short ones. Therefore, tall riders should keep their frames as small as possible and their center of mass (shoulders) as low as possible. I see tall riders on huge frames with their bars up in the "sit up and beg" position and I weep for them. I bike doesn't need to feel like a unicycle.

  • Ignore the cans of Australian piss water in my jersey which I had an inexplicable hankering for; but these pics here are about as close as I can find to side-shots of me on the R3. Try not to be too envious of how Awesome I am.

  • @frank
    Beautiful: you really are an aesthete of the highest order. I can't even see where the straws enter or exit your jersey. Top grade work!

  • Frank, how do feel after a century with a good bit of climbing? As a larger chap (taller, don't want to imply I'm too fat to climb) I have been struggling to get a great fit. After reading this post during the early spring, I tried some of your fitting techniques. To be honest I felt great all season on shorter to moderate rides. But last strenuous century of the season killed me. My position looked alot like yours above. Ended up with the killer pain between the shoulder blades/lower neck. Just curious how it works for you in those situations. I'm thinking a shorter stem might help.

  • It's hard to see from those photos, but in the bottom one you look fine, for some reason in the other two you look pretty low, like being in the drops or out on the hoods would be a short term thing, but that's just the top two photos.

    My friend and I went for a fitting a couple of months ago and he's 6'4" or 6'5" (sorry about the rule breakage, not going to convert to metric). He ended up at 45/45 on the hoods where he rides most. It looked too high for me, but IIRC he still had a 6-7cm drop (or more) from saddle to bars.

    I ended up in a much more acceptable racing angle, but since then I have lowered my bars as I felt scrunched up, like I was arching my back to ride, which on a long climb is not comfortable. We put me at a 4cm drop from saddle to bars, I'm 5'10". Later I scooted my saddle forward, then switched back to a longer stem, so all of this fit stuff is opinion anyway. I actually like the way a long stem (>120mm) handles and 'feels'.

    So if my tall friend is at a 6-7cm drop and sitting high and I'm at a 4-5cm drop and sitting moderately low, it makes sense that you could have something much more than 7cm in drop and be completely comfortable.

    Watching my tall buddy ride, is strange too, his ankles come down behind the crank bolts and when he is spinning fast, it looks slow, like a freight train looks like it's going slow because of the size.

    Those sunny-in-shorts photos look so out of season already, you do have a nice Washington tan though.

    Either way if your position works for you that's great.

  • @pakrat

    But last strenuous century of the season killed me. My position looked alot like yours above. Ended up with the killer pain between the shoulder blades/lower neck. Just curious how it works for you in those situations. I'm thinking a shorter stem might help.

    I think the longest ride I did in this position is 285km or so, so not a crazy marathon, but long enough to know it's comfortable. But I'm pretty flexible in my hips from a life of doing this and skiing.

    As for the stem length; it's ver counter-intuitive, but I suggest you go up in length, not down. There's a reason pros ride more stretched than regulars. My VMH had the same pain between her shoulders and we put her on a 120mm up from a 100mm and - boom - pain gone, just like that.

    You can't be sure it's the stem, though, because at the same time, she issued a moratorium on me talking during rides, so it could also have been that.

    @michael
    My Washington tan, indeed. That pic would have been in June, as I was still riding my XL jersey, which is too big for me, hence, it fits big beer cans. By summer's end, I was a definite off-pale. It looked sweet.

    So I'm back to "Seattle Clear."

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