Originally Posted by
79pmooney
Huh? I have two issues with this. The optimum trail varies (a little) by head angle. And, much bigger issue - different people have different tastes as to what "feels right". I have tracked the fork rake and head tube angles on the bikes I have owned. Yes, I am doing rake vs headset, not rake vs trail. Until quite recently I wasn't using big tires and all the bikes were ridden 700c so there was good correlation between the two and rake is easier to measure (and spec to a builder).
I have found all the bikes I really liked the handling of fell on a diagonal line on that rake/HS angle chart. Also that the corresponding trails also fell on a diagonal line when plotted trail vs HS angle. In other words, there is not one "magic" trail for me for all HS angles. Also the trail and "feel" I like is quite different from most published
"right" trails. When I order a new custom fork or whole frame, I will spec the rake. I always get questioned/corrected but I do not give the go-ahead to build until the builder sees it my way. (Second time around is much easier after the builder sees how much I like the fork he felt he built "wrong".)
Ben
I'm not understanding your post. Trail is the product of rake and HTA. Regardless of HTA, if you use a rake that produces a certain trail, the bike will handle similarly in terms of what trail does.
23mm tires:
72.5° HTA + 48mm rake = 56mm trail
73.5° HTA + 42mm rake = 56mm trail
Both bikes will have very similar low and high speed handling because they have the same trail. Rake is the tool used to produce a particular trail given the need to vary HTA to produce different reach and wheelbases.