Sizing a Road vs. Mountain Bike

All I know is to sit on it and then move everything into position. 😄

Quoted post said:

Originally Posted by new_rider
I find it a lot easier to get properly fitted on a mtn bike as opposed to a road bike.

My current mtn bike has a 58 cm top tube, with a 9 cm stem. I could possibly go 1 cm longer in the stem but otherwise, feel the bike feels nice in terms of reach.

On my previous road bike, I had a fit kit done, but the shop employees didn't want to follow the fit kit recommendations. The fit kit recommendation was for a total reach of 66 cm, very similar to my mtn bike setup.

I wound up getting a road bike with 53 cm top tube and 11.5 cm stem (originally spec'ed with a ridiculously short 8 cm stem).

This setup was ok, but I never felt like I was adequately stretched out. The stem was also too low and the handlebars too narrow (41 cm) but that's another topic.

I've read that you should go at least 4 cm shorter with a road top tube + stem setup. This is to account for the additional reach on the hoods and drops.

This would yield a 63 cm reach (tt + stem) compared to my 67 cm reach on my mtn bike. But 64.5 cm was too short on my previous road bike.

How do you all size your road bike tt + stem in relation to your mtn bike?

So ...

Yet another rider who was dissatisfied with his/her "professional" bike fitting!

I am not surprised.

BTW. Based on your MTB's size, I presume that you are 5'10-to-5'11" ...

Is that right?

OR, are you taller?!?

OR, is all the MTB riding in your neck-of-the-woods on gently rolling paths?

OR, are you shorter?!?

By MY reckoning (that is, my wussy personal preference), allowing for variances in terrain & rider skill, a MTB frame will often have a top tube which is about 2cm-to-3cm longer than a Road bike frame ... that's because there is ZERO reach on a MTB handlebar BUT the terrain tends to mean that a more upright riding position is typically more suitable on a MTB ...

So, if your MTB has a 58cm virtual top tube, then you probably wanted a Road frame with a 55-to-56cm top tube.

BTW. I'm 5'9" tall & the combined TT + stem length (NOT counting the reach on the handlebars + brake hoods length) on my bikes tends to be ~66cm.