i present have a frame which is too small for me and whose head tube measures 8 cm- tiny, i know. i was looking at another frame whose head tube measures 10 cm.

if i am presently using 5cm of spacers to get the bars where i want them, will i only need 3 cm of spacers with a 10 cm head tube?

I believe that is correct, but it is really the relative position of the bars to the saddle that is important. There could be other differences in the geometry that would affect the saddle position and therefore the absolute height of the bars to have the same relative position.

Here's what you can do to get an idea of the spacer height on the new bike:

1) Go to https://www.bikesuperhub.com/bikefit/ -> Rider's Preferred Setup. Enter the measurements from your current favorite bike.

2) Go to -> Bicycle Geometry. Enter the geometry of your new bike here.

3) Go to -> Stem, Headset Spacer and Seatpost. Click on the Calculate button. It'll suggest the proper stem length, spacer height and seatpost length for your new bike.

the other frame i'm looking at is the same builder- so all things should be equal.



thanks both-