Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling - Long Distance Fitting... Is it different?

Hey guys,

Is it better to ride one size larger, when riding long distance. I'm curently riding a 120m stem and aren't so sure that would ideal for longer rides. Seems like a slightly stretched-out stance would work better.
Any comments?

Interesting how similar questions seem to come up simultaneously in different forums. There's a discussion about this in the touring forum right now.

For long distances, my personal preference is to ride the biggest frame that will fit me. Not really much to do with the length of the stem per se, ​it's that in my experience the taller head tube puts me in a slightly less aggressive, more relaxed posture.

since I build my own frames, I always find it hard to wrap my head around "sizes." For most bike companies, going up a size will not change the top tube dimensions as much as it changes the head tube dimension, so it generally will be ok. I think most people who ride long distances raise their stem a little and keep their reach approximately the same. I'm not positive that it's a good idea, but my current bike has a head tube that's about 1 cm taller than I normally would use. I tried adding a 2cm spacer, and it really slowed me down, so I wouldn't make radical changes. For 200/300k, I think a regular position should work fine.

since I build my own frames, I always find it hard to wrap my head around "sizes." For most bike companies, going up a size will not change the top tube dimensions as much as it changes the head tube dimension, so it generally will be ok. I think most people who ride long distances raise their stem a little and keep their reach approximately the same. I'm not positive that it's a good idea, but my current bike has a head tube that's about 1 cm taller than I normally would use. I tried adding a 2cm spacer, and it really slowed me down, so I wouldn't make radical changes. For 200/300k, I think a regular position should work fine.

OK, it is really interesting to have a framebuilder's perspective.

I'm reasonably flexible, I manage a big saddle/bar drop on my Giant TCR, which is the bike I race. I am utterly comfortable on that bike up to about 40 miles, and have used it for centuries without issues. But my 64cm old Raleigh has me in a marginally more upright position - my belief is that the taller head tube brings the bars nearer, shortening the effective reach - and soaks up the bumps like a dream. No distance would be a problem on that bike. And to add to the complications, I have a 58cm FG that, with judicious use of spacers, I can set up virtually identically to the 64cm tourer, yet that bike isn't quite as relaxing. It's a perplexing business, sizing...

I think it's one of those things you have to learn for yourself. I have never been a big proponent of saddle/bar drop -- I have a very long reach though which puts your upper body in a very similar position. I rode a bike with a shorter stem than normal for a while, and then my flexibility got better and I felt cramped. So I went back to a longer reach. Saddle/bar drop shouldn't cause you any problems if your seat is in the right place, but if you are on a really long ride you are putting stresses on your neck that you don't usually see. I don't have this problem at 600k, at 1200k it starts to be a little bit of a concern. My neck finished PBP in fine shape, but my lower back was a little wonky.

I think it's one of those things you have to learn for yourself. I have never been a big proponent of saddle/bar drop -- I have a very long reach though which puts your upper body in a very similar position. I rode a bike with a shorter stem than normal for a while, and then my flexibility got better and I felt cramped. So I went back to a longer reach. Saddle/bar drop shouldn't cause you any problems if your seat is in the right place, but if you are on a really long ride you are putting stresses on your neck that you don't usually see. I don't have this problem at 600k, at 1200k it starts to be a little bit of a concern. My neck finished PBP in fine shape, but my lower back was a little wonky.I've heard people say, "go up 1cm, go out 2cm," meaning in that ratio. Do you think that's about right?

I also am much more comfortable stretched out. I can vary my bar height quite a bit, as long as the stretch is about the same. Depends on the frame where the bar height comes out, though I only put 5mm under each stem. I ride a 50, a 52, and what's probably a 54. The 50 works, but is a little cramped.

I've heard people say, "go up 1cm, go out 2cm," meaning in that ratio. Do you think that's about right?

I also am much more comfortable stretched out. I can vary my bar height quite a bit, as long as the stretch is about the same. Depends on the frame where the bar height comes out, though I only put 5mm under each stem. I ride a 50, a 52, and what's probably a 54. The 50 works, but is a little cramped.

Have you noticed a definate milage improvement when riding the 54 vs the 50? That's the question. The "go up 1cm, out 2cm" theory seems logical, though, - more relaxed position, better air flow.

...my belief is that the taller head tube brings the bars nearer, shortening the effective reach - and soaks up the bumps like a dream. No distance would be a problem on that bike. And to add to the complications, I have a 58cm FG that, with judicious use of spacers, I can set up virtually identically to the 64cm tourer, yet that bike isn't quite as relaxing. It's a perplexing business, sizing...

I discovered that, too, that taller headtubes actually seem to shorten the reach, regardless of the indicated effective frame size. Now, if we could just figoure out the ratio, that would make fitting all so easy...

Have you noticed a definate milage improvement when riding the 54 vs the 50? That's the question. The "go up 1cm, out 2cm" theory seems logical, though, - more relaxed position, better air flow.Heh, heh. The 54 is the tandem. No way to really know. For sure I can't power the tandem for 18 hours like I can the 52, but probably nothing to do with size. But guessing, I'd be faster on the 52 because like you say, the headtube is so much shorter that my bar drop is greater, hence faster. Neither bike is uncomfortable. The 50 is fast, too. Probably no faster than the 52, comparing descending speeds. I know people who say everything has to be just so, within a mm, and the frame flex just so, rake and trail just so. I'm not that way - I can ride most anything. It's just a bicycle.

FWIW, here are my theories....

A more aggressive (flat back) position will make you a little more efficient/faster, and puts more weight on your arms. This can be better for your lower back, but worse for your neck.

Sitting more upright will create a little more drag and a little more pressure on the lower back. However, it can also give you a little more leverage/power when climbing.

I also find that general principles aren't necessarily going to be the perfect guide when you go past the 6-hour/~80 mile mark. A position that feels great for a 50 mile ride could be so-so after 90 miles, and unpleasant at 130. You might even find that no position really feels good after 120 miles, or that after a certain point you just ignore minor discomfort. Finding out what works for you will likely involve experimenting with positions, keeping precise track of your subjective impressions at various points on training rides and events, and hoping your body's reactions stay consistent over time.

In terms of frames, the "larger/smaller" is really more about stiffness than position, and is less applicable to "compact" / sloping tube frames (which have fewer sizes, and thus offer a little less latitude). E.g. racers want super-stiff bikes; smaller frames are marginally stiffer; therefore they are more inclined to go with a smaller frame with a huge stem. Even in those cases we're dealing with tiny changes in handling that may only matter when you're putting out tremendous wattage.

But if the bike doesn't fit, it's not going to be good no matter what. I'd go with the right fit, and hopefully a bike that can accomodate some experimentation, over "too big" or "too small."

I like to be a bit more upright and a little less stretched out, currently. But I'm pretty new to this game, and my fit is evolving. I have 1 cm less in the reach compared to my sporty bike, and my brevet bike has bars almost level with the saddle, again compared to significant drop on my other bike.

A more aggressive (flat back) position will make you a little more efficient/faster, and puts more weight on your arms. This can be better for your lower back, but worse for your neck.
I think the value of a better aerodynamic position is undervalued if one wants to average faster speeds.


Sitting more upright will create a little more drag and a little more pressure on the lower back. However, it can also give you a little more leverage/power when climbing.
Even with a low bar to seat setup, you can move around to get this extra leverage.


I also find that general principles aren't necessarily going to be the perfect guide when you go past the 6-hour/~80 mile mark. A position that feels great for a 50 mile ride could be so-so after 90 miles, and unpleasant at 130. You might even find that no position really feels good after 120 miles, or that after a certain point you just ignore minor discomfort. Finding out what works for you will likely involve experimenting with positions, keeping precise track of your subjective impressions at various points on training rides and events, and hoping your body's reactions stay consistent over time.
For really long rides, something is almost certainly going to hurt. Maybe, the goal should be real pain or damage rather than chasing "perfect" comfort.

=============

I think there's a fairly wide range of positions that work for people. That is, more upright might be necessary (or work better) for some people but not for others.

In terms of comfort, I don't think people consider tires and tire pressure enough.

In my limited experience, my Cervelo RS, slightly small with a moderate bar to seat drop is very comfortable (for me) on 300k rides. I do use lower tire pressure than many people. Being more aero is a significant contributor to more speed with less effort.