How much does size matter?

hilaryworton

I'm getting back into road bikes after suffering for several years away on mountain bikes. I've been trying to do my research on brands/models etc but have got completely baffled by information overload. Can anyone give me some simple advice on 2 basic questions? Firstly how to decide what size to buy? One shop is trying to get me on to a 46cm and another is adamant I need a 50cm. I'm 5'7" (170cm). I've tested a couple of the smaller size bikes which felt OK (but what do I know as it's been so long since I've riden a road bike). My 2nd question is whether to go with a double or a triple? Again, it seems to depend who you talk to (and what stock they are trying to shift - or am I being too cynical?) I need all the help I can get on the uphill parts of a ride and thought that a triple would be the way to go but I've also been told that a compact double would be just as effective. Any ideas to assist the bemused would be gratefully received!

weedvspeed

Are they the same model of bike? There can be a large difference if one is a compact/semi compact frame (sloping top tube) or a traditional one. Also some manufactures measure the frame to the top of the seat tube some to the top tube.

Calculators are not perfect but this site gives a lot of info on fit and what all the geometry means. You can always ignore the results for what feels best.
http://www.competitivecyclist.com/z...ALCULATOR_INTRO
Cant advise you on the triple its flat where I live.
Good luck

Weed.

hilaryworton

Thanks for your advice. I've been out again today looking at bikes and have found exactly as you say that different manufacturers size the frames from different points. I actually found a bikesizing.com facility where they measured all the critical parts of my anatomy ( ) and so now I have a print out of my own geometry which I can use to match against the bikes I'm looking at so hopefully that should help demystify some of the decisions. Fingers crossed...

ibis1

triple or double?


what kind of terrain will you be riding on? and how old are you?

i live in a hilly/mountainous area, and i'm over 50 so a triple is important. i even went further and changed my rings to 48,38,26 (typically they are 52,39,30) so i could get up the 22% grades with bad knees.
if you are young and in flat terrain, a double will do. the compact double gives you a 34 as the small ring, so it is a compromise between the two..