Framebuilders - Matching a fork to frame, need advice
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11-30-09, 09:53 PM
So I've got an opportunity to pick up a nice frame to build up for myself. The frame was originally designed and sold with a fork that has a 400mm axle-to-crown and 45mm offset. I won't be getting the original fork, so I'd like to use one that has a 395mm axle-to-crown and 45mm offset. I'm thinking that the axle-to-crown difference is so slight that it would be imperceptible to the ride quality or handling when riding.
What say the learned masses? "Thanks" in advance!
Head angle 72.5˚
Seat angle 72.5˚
Top tube 58.5cm
Seat tube 60cm
Head tube 17.4cm
If it were me, I'd ride it as is, I would first look and see if you could fix all or some of the problem by looking for a headset with a taller stack height than was originally used, you should be able to make it up pretty easily I would think. let us know how it turns out.
12-03-09, 09:01 AM
Well, I guess my question is more about the head tube angle. I'm not a framebuilder, so I'm wondering if a 5mm drop at the front end would change the head tube angle in a significant way. The bicycle isn't built yet, so it's not a matter of "ride it anyway." I simply don't want to spend the time and energy building something that won't be a decent ride.
With absolutely no knowledge on the subject, my gut tells me that I probably won't even be able to tell the difference. Having said that, I also know that sometimes even very slight changes to geometry can have a tremendous effect overall. I didn't consider the idea of adjusting the stack height to compensate (good idea).
Really, a 5mm drop at the front end might change the head tube angle, what, about .01%? Right? Who's gonna notice that?
Even if it did change the head tube angle a degree, that wouldn't have much effect. Bigger issue to me is whether it is Right. It would bother me to be out almost 1/4" from where I want to be. So are you cobbling together something for practical use vs. making something that is supposed to be a cut above. I wouldn't spend a lot of energy on making a special ride if it was going to be out that much. But if I needed something to ride through traffic and chain to parking meters...
12-04-09, 06:27 PM
I wouldn't worry about it in the slightest. As a (very) amateur framebuilder I have made errors of greater than 5mm and haven't noticed them in the ride quality at all.
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