want to lower trail

[amator]

Its a Concours (54 ctc ) .
STA 73.5,HTA 72.5 with f1 -43mm fork rake , span of 365mm.
wheelbase of 98.19cm,
Trail of 6.21cm,
chainstay of 41cm

Thinking of going to a 45mm rake fork-most likely the 372mm OP and possibly hoping to reduce the trail closer to 6.0cm and making steering a little more telephatic.

I was told that the increase in fork span negates the incrase in fork rake.. but does it completely negate it to the extent of having no reduction of trail?

Besides speeding the steering which Im focussed on, What would be the side effects if i increase the rake to 45mm and hence front centre and wheelbase .

[Peter P.]

Fork span has nothing to do with trail; only wheel radius. Whoever told you that was probably thinking the difference in fork leg length would change head angle, but I doubt it would be enough to consider.

I'd say buy the fork and give it a try. I also wouldn't worry about changes in front center and wheelbase. that 2mm is inconsequential.

[David Kirk]

Fork span has nothing to do with trail; only wheel radius. Whoever told you that was probably thinking the difference in fork leg length would change head angle, but I doubt it would be enough to consider.

I'd say buy the fork and give it a try. I also wouldn't worry about changes in front center and wheelbase. that 2mm is inconsequential.


You are right that fork span doesn't normally figure into trail but in this case, where the span will be increased and the head angle affected, it does. Not a lot but it does.

One could figure out how much it lifts the front end and the change in head tube angle but I haven't had any coffee yet so my numbers would be wrong but I feel safe in saying it won't be a big change. FWIW the span of a 1" Ouzo should be 370 mm.

As for the affect on front center - it will add 2mm to front center of course which will have an affect academically but in the real world will be hard to pin down. I personally wouldn't worry about it.

I'd say try it and see how it feels.

Dave

[Samster]

i've been told by reputable sources that there are many other variables involved that affect handling in general. best of luck with your quest.

[Dave]

The change in trail due to a change in fork length is roughly the fork length difference divided by 2.7, so in your case, the 7mm extra length would cancel out all of the trail reduction from the 45mm fork.

[PacNW2Ford]

A 45mm rake Wound Up has a 365mm length. They also make a 48mm.

[michael white]

I'm pretty sure that you'll like the handling better with the 45, but I suspect it'll be a small difference, like going from 25mm to 23mm tires.

Now: as to making the handling more "telephatic"--that is a very tricky personal matter, which no fork swap can itself accomplish. :)

[amator]

thanks for the replies to my Original post guys.
Yes, was looking at a Wound up initially... but sorta thought the reynolds would be the de rigeur....to preserve and update the look of a serotta
All i have for a 1 inch carbon right now would be a fork from my Fondriest which i think is a mizuno. Havent measured the span for that and the rake would probably be a guess at best

[amator]

The change in trail due to a change in fork length is roughly the fork length difference divided by 2.7, so in your case, the 7mm extra length would cancel out all of the trail reduction from the 45mm fork.

Yup , all but neutralized, I'd think if i went for 45mm . However if i plop in a 43mm Ouzo, it would increase trail further)