Effects of shorter and slimmer headtube on handling and ride feel

[cyan]

Going from a 44mm head tube of 145mm length and a fork of 43mm rake and 370mm axle-crown to a 33.9mm head tube of 130mm length and a fork of 45mm rake and 367mm axle-crown.

What should I expect in terms of the change of handling and ride feel? Also, assuming the saddle height/position kept the same, does it mean I also need spacers to compensate the difference in head tube + fork axle-crown length in order to maintain the same riding position?

[ergott]

145 + 370 = 515
130 + 367 = 497

We are missing other data points, but you can start with about 15mm more spacers.

We don't know if headset stack is considered or headtube angle.

Handling will be impossible to tell. Too many other variables in the frame geometry that we don't know. Even if we did, nothing will be a better confirmation than riding them.

[weisan]

. Even if we did, nothing will be a better confirmation than riding them.

That's my philosophy as well.

Try it and you will know.

All the pre-calculations and expert opinions will only get you this far.

[buddybikes]

Merkx did pretty well with 1" headtubes...

[JAGI410]

It'll still ride like a bike. You won't be faster or slower. You're over thinking things. :banana:

[Road Fan]

Assume the two headsets stack the same.

You are shortening the fork blades, so the crown race will be closer to the ground. You are shortening the head tube, so the top race will be closer to the ground. Your new frame/fork design has shorter stack than the first one, and I assume reach will be the same. If the BB height is the same, you will have deeper saddle to bar drop. assuming you don't have too many spacers already, you can adjust this. But, maybe not.

I think the reduction in stack is a bigger consequence than a little added or reduced fork offset or a smaller diameter head tube.

But yeah, it's still a bike!

[EricEstlund]

If you are asking about feel based on head tube flex, you won't feel a thing between those two based on that particular section of tube.

Any feel differences will be a cumulative effect of the total systems including the forks, components, etc. But actual deflection in the head tube won't be a factor.