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August's 101 Mysteries of Cycling

Polymer Head

Polymer Head

Warming-Up
May 13, 2008
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Assuming reach is constant in both cases for a road racer.

Is it better to have a small frame with a long seat post or a bigger frame and a short seat post?
 
Polymer Head said:
Assuming reach is constant in both cases for a road racer.

Is it better to have a small frame with a long seat post or a bigger frame and a short seat post?
Click to expand...

I've often wondered about that too...thinking my frame may be a size too big.
The smaller framed bike also weighs less which is an added bonus.
Smaller frame is lower to the ground and if you put the seat up higher you should be more aerodynamic than on a larger frame... your head can get down very low...

Common sense tells me a smaller frame may be better but the guys at the LBS tell me the size I'm riding is correct... (I look big but I'm only 172cm tall... the Japanese guys in our club just assume I'm taller...).Might have to put all my sizes in one of those online calculators and see if they can shed some light on what is best for me.

How small is too small and how big is too big as well...
I've been on 2 bikes smaller than mine and they felt uncomfortable...but would I get used to it after a long time and then find my usual bikes too big?

:eek:uch:
 
You say "for a road racer", so I'd say yes, the smaller frame offers advantages (lighter weight, bigger drop for more aggressive position, weight on top of the bike rather than behind, and, some would say, improved stiffness from the smaller frame dimensions) that outweigh the disadvantages (discomfort from large saddle to bar drop).

How small to go depends on your build (eg. leg length to height ratio), flexibility, etc etc.

It's interesting to see how much bikes have trended smaller, especially over the last, what, two decades?

See for example Fausto Coppi looking dwarfed by his bike (about 5th pic down):

http://www.ultimateitaly.com/festival-events/giro-d-italiaia.html

Compared to someone like, say, Jens Voigt today:

http://www.cervelo.com/wallpaper/1/w028_800.jpg
 
Phil said:
You say "for a road racer", so I'd say yes, the smaller frame offers advantages (lighter weight, bigger drop for more aggressive position, weight on top of the bike rather than behind, and, some would say, improved stiffness from the smaller frame dimensions.) that outweigh the disadvantages (discomfort from large saddle to bar drop).

How small to go depends on your build (eg. leg length to height ratio), flexibility, etc etc.

It's interesting to see how much bikes have trended smaller, especially over the last, what, two decades?

See for example Fausto Coppi looking dwarfed by his bike (about 5th pic down):

http://www.ultimateitaly.com/festival-events/giro-d-italiaia.html

Compared to someone like, say, Jens Voigt today:

http://www.cervelo.com/wallpaper/1/w028_800.jpg
Click to expand...

I tend to agree with phil...one size 'too small' might be easily compensated by the seat post and provide the enhancements he has mentioned...I have often wondered if my bike was a size too big actually! (I am assured its not and I tend to agree....but...
 
Sizing

is a complex subject.

When I had my bike sizing done I discovered many things. I have a short torso, but long legs and arms relative to the average of the Dutch cycling population that was being used as the database. Against the Japanese data then there was even more of a deviation.

This led to the current set up. Most of you have seen this. Relatively small frame (Ash - I also doubted this !) high seat post, saddle a long way back on the rails, 172.5mm cranks and a short stem of 90mm. This was also tuned for cyclosportive type setup rather than out and out racing.

Logically you might think - hang on - if I put the saddle forward and I have a longer stem then that achieves the same effect. Well, for me at least, that is chalk and cheese and changes my efficiency altogether. I guess it has to do with the relationship between hip and crank positions.

This setup has fitted me like a glove since day one. I am very careful with saddle height and cleat position too. As long as I keep to the dimensions worked out for me then all is well. I have never had an uncomfortable day in the saddle and I believe my riding position is good. I would like to take a video at some stage to see how it looks.

The only pain I suffer is on bib shorts, my cheapie Shimano`s do a much better job than the Nalini kit. Probably the only upgrade I would think about now would be some Assos bib-shorts, when I have the spare cash !

So I do recommend being properly assessed and sized. There are some decent on-line tools but remember the objective of all of these is to sell you something at the end of the day. Taking your current set up and then being assessed for tweaks and improvements seems a good idea to me. As long as you are prepared to be told, in the worst case, that your current frame is too big or too small (hopefully rare !) then you will benefit from a proper setup.

Of course the best is to start from scratch and get measured first before choosing or building anything !

chazzer
 
Polymer Head said:
Assuming reach is constant in both cases for a road racer.

Is it better to have a small frame with a long seat post or a bigger frame and a short seat post?
Click to expand...
in short: its an aesthetic thing. Which ever floats your boat. here in japan smaller frames are useful going into bags on trains. you can also sell a compact frame to more people, which is what giant found out.
googled this thread, looks on track http://www.bikeradar.com/forum/viewtopic.php?p=14621328
 
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