Fork Rake Question
 

I have an old Schwinn Tempo frame in unbuilt NOS condition. No fork though. This is not a mechanical question per se, but I am trying to figure out what fork rake would work best with this frame. Its a 64cm frame. I can go old school and do a 2.5 inch rake(NOT trail) for a lower trail set up, or I can get a Nashbar carbon fiber fork with 43mm(less than two inches) rake and higher trail. I could also have a fork made, but pretty pricey. I would be building this up to be as light as I can, not as a touring frame. The frame has about a 60cm top tube, 72 head angle, 43.5 chain stays.

Any help appreciated

well the longer the rake the shorter the trail,, Broad Generalization..

Carbon choice suggests not putting a bag larger than handlebar mount.

add lower race thickness and fork crown to axle length & you could
dio a scale drawing.. , then know the trail numbers, on the ground.

Either rake would make for a perfectly rideable bicycle. I got real curious about trail a couple of years ago and made a fork with adjustable rake. After reading a great deal about how great certain trail figures were, and how awful others were, I was surprised at how unimportant it actually turned out to be.

IMO, if you are happy with the ride of racing bikes made within the last few decades, and are looking to go as light as possible, you should buy the carbon fork.

It's hard to answer, and partly depends on whether you want nimble sporty handling, or more natural stability. One thing I can say, is that back in the days of 72° head tubes, longer 2"+ fork rakes were the norm.

All the stuff I have has 2.5" rake and about 72 degree angles. So, long rake I know how it woud ride. Short rake, long chainstays is the odd man out. I think that could be odd.

Well, I went to the frame geomtry project site. Long stays, short rake=Riv Romulus. Basically a sport touring design. Probably nice and comfy, but not exciting.

I have a stock fork from a 64cm Tempo that I may be willing to part with.
PM me an email address if you are interested.

This was originally from a 1988 Schwinn Tempo with the Red/White/Green paint scheme.
The frame cracked the head tube just above the lower lug so the frame just hangs on my wall now (it was my first bike).
-Rick

That would be cool. Another big frame riding knuckle dragger like me? I hate to part with my big old stuff, it just seems to work well for 6'4" and above.

Yep. Same situation here. 6'4" with a 36" inseam.
Currently riding a 64cm Surly Pacer that I transferred most of the components off of the Schwinn onto when I found the cracked head tube.

If you haven't tried it yet, this is a neat calculator for bike geometry: http://yojimg.net/bike/web_tools/trailcalc.php

That sounds intriguing! Do you have any pictures of this setup?

With a 72 degree HT;

43mm rake = 65mm trail

64mm rake (2.5 in) = 43mm trail

Take yur pick, both'll do.

Nice calculator, pretty handy. Interesting that small head angle inputs make such a difference.

I will take some and post them when (if) the deadbeat who borrowed it ever gives it back. It's really not much to look at, though. I filed four slots into matching pieces of 4130 plate and then brazed them into a straight-bladed fork. the slots don't correspond to any exact rake (one ended up being 36mm, another 44 mm, etc.) but it did give me a very good idea of the feel of different rakes/trails. As I wrote, I was pretty surprised at how unimportant the differences were.