frame question

[rabbit99]

Hello, Looking at a new frame to build up - thinking this one. http://pedalforce.com/online/product_info.php?products_id=8420 Just a little confused as to which size I should go for. I currently ride a 2003 Felt f50 - size 58cm. Which I feel is too big (73.5 angle 58cm top tube). I reckon the shop that sold me this one was keen to clear the bike out, and adjusted me to the bike, rather than put me on the right size frame. It has a very short stem on it to compensate. I am 178cm tall, 86cm inseam. Just not sure whether to order the 55cm (which has a 57cm effective top tube - see the geometry), or the 52cm (55cm effective top tube). The 55 and 52cm measurements appear to be the actual measurement of the seat tube - which is shorter than standard geometry due to the sloping top tube. My question - if I order the 52 (55cm effective top tube, 73.5 seat angle), is there any real problem if the seat post and stem is a bit longer? (as opposed to 57cm, 73 seat angle with a shorter stem). If this makes any difference - I'm a light weight (61kg), so I go well up hills. A lot of my riding is time trials - in which I will put a forward seat post and tribars on the bike.

 

[rparedes]

Originally Posted by rabbit99 .

Hello, Looking at a new frame to build up - thinking this one. http://pedalforce.com/online/product_info.php?products_id=8420 Just a little confused as to which size I should go for. I currently ride a 2003 Felt f50 - size 58cm. Which I feel is too big (73.5 angle 58cm top tube). I reckon the shop that sold me this one was keen to clear the bike out, and adjusted me to the bike, rather than put me on the right size frame. It has a very short stem on it to compensate. I am 178cm tall, 86cm inseam. Just not sure whether to order the 55cm (which has a 57cm effective top tube - see the geometry), or the 52cm (55cm effective top tube). The 55 and 52cm measurements appear to be the actual measurement of the seat tube - which is shorter than standard geometry due to the sloping top tube. My question - if I order the 52 (55cm effective top tube, 73.5 seat angle), is there any real problem if the seat post and stem is a bit longer? (as opposed to 57cm, 73 seat angle with a shorter stem). If this makes any difference - I'm a light weight (61kg), so I go well up hills. A lot of my riding is time trials - in which I will put a forward seat post and tribars on the bike.

No expert here, but if you want a very aggressive position, go for the 52 (55cm TT)

 

[MMMhills]

Google "bike fit calculator"

Do more than one and take the average. Most of them will ask many questions regarding your body dimensions and riding style. Be honest and you will get close. If you are building the bike yourself you can adjust minor stuff with components.

 

[steinbachphoto]

Originally Posted by MMMhills .

Google "bike fit calculator"

Do more than one and take the average. Most of them will ask many questions regarding your body dimensions and riding style. Be honest and you will get close. If you are building the bike yourself you can adjust minor stuff with components.

I agree, the most accurate one I've used is Wrench Science, they ask for a lot of measurements and give you all the dimensions you need for a proper fit.

 

[oldbobcat]

Originally Posted by rparedes .

No expert here, but if you want a very aggressive position, go for the 52 (55cm TT)

I'm 3 cm taller than you, and if I were buying one of these it would be the 55 with a 12 or 13 cm stem (depending on the handlebar bend). My position is quite aggressive.

Your leg length is average for your height, neither stocky nor lanky. Get the 52 for an aggressive fit or the 55 with a shorter stem for a more sedate position.

 

[baker3]

Visit Wrench Science or get a proper bike fit done.

 

[oldbobcat]

I tried putting my numbers into the PedalForce fit calculator. It was a disaster. Wrench Science is better, as is Competitive Cyclist's, but both seem to overestimate the reach of short-torsoed, long-armed blokes such as myself. In contrast, the PedalForce calculator came up with an implausibly tall and short frame configuration and underestimated my reach by 3-4 cm.