Road bike sizing help

by kenong   May 9, 2014  

Looking to get a Wilier GTR and my height is 174cm, inseam at 81cm.

My old bike's effective top tube is 545mm and I use a 100mm stem with a 172.5mm crank arm.

For this new bike, it comes with a 170mm crank arm, 100mm stem. The size I am looking at is the S size, which gives an effective top tube of 523mm.

Does this new bike fits me well, if i plan to install a 120mm and slam the stem?

Or should I go for a M size, which gives 537mm effective top tube and a 100mm stem?

Between these 2 sizes, the M's head tube length is 145mm compared to the S's head tube which is 115mm.

3 user comments

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If your current bike fits you well and you get the Wilier in a small expect your saddle to bar drop to be pretty damn big. You need to ride it.

posted by ajmarshal1 [402 posts]
9th May 2014 - 20:19

1 Like

Have a look at where you can put the dimensions go both bikes in and compare the results

posted by carytb [57 posts]
9th May 2014 - 20:27


In danger of sounding a bore... If you're dropping money on a quality bike get a fit from a decent bike fitter (not the shop lad who's 'been doing this for ages').

I thought my position was fantastic; slammed front end, nice and flat, low, sleek... But I'm faster and put out more power in my new position after having a fit session.

It is easily the best upgrade you'll buy.

posted by dannycarr2k [25 posts]
10th May 2014 - 10:34