fork travel

arbalest · 1 fork travel Sun Nov 28, 2021 12:19 pm

arbalest

Silver member

Number of posts : 147

Spec's say front wheel travel is 185mm. Is that the unladen travel from droop to full compression? I am considering modified fork legs in a version of a leading link fork for my sidecar rig. I'm shooting for about four inches of travel. I would like to shorten the fork tube considerably, using a cut down stock fork spring. Cutting down the fork spring has two advantages. First the spring rate increases with decreasing length. The question is, how much can I shorten the spring to get my four-ish inches of compression with the correct amount of rebound?

92KK 84WW Olaf · 2 Re: fork travel Mon Nov 29, 2021 5:01 am

92KK 84WW Olaf

Life time member

Number of posts : 7967

From my limited thoughts I cant see that you can cut the spring. I dont s the travel as a problem but damping and springs need to be matched. you dont mention the forks type, some of the Ks have one stanchion compression and one rebound but I dont see leading link units doing that.

arbalest · 3 fork travel Mon Nov 29, 2021 7:02 am

arbalest

Silver member

Number of posts : 147

92KK 84WW Olaf wrote:From my limited thoughts I cant see that you can cut the spring. I dont s the travel as a problem but damping and springs need to be matched. you dont mention the forks type, some of the Ks have one stanchion compression and one rebound but I dont see leading link units doing that.

Early 85 K100

arbalest · 4 fork travel Mon Nov 29, 2021 7:08 am

arbalest

Silver member

Number of posts : 147

92KK 84WW Olaf wrote:From my limited thoughts I cant see that you can cut the spring. I dont s the travel as a problem but damping and springs need to be matched. you dont mention the forks type, some of the Ks have one stanchion compression and one rebound but I dont see leading link units doing that.

Just looked at the K100 damper rods. The damper rods are wholly contained in the lower leg. The damper is a hydraulic damper controlled by orifice diameter. It has no relation to fork travel (to my untrained brain).

stanthomas · 5 Cut it in half Mon Nov 29, 2021 7:00 pm

stanthomas

Silver member

Number of posts : 107

I would cut the spring in half then make up to the required ride height with a spacer. Maybe try just a third off to start with.

There is more to it however. The cut end of the spring will not be properly formed but you could fashion a cap with a spring shaped ramp to give proper support. And then there's the fork free length - the damper rod stops the fork over extending so you'll need to rework that too so there's a little bit of preload on the spring at full extension.

arbalest · 6 fork travel Mon Nov 29, 2021 7:09 pm

arbalest

Silver member

Number of posts : 147

stanthomas wrote:I would cut the spring in half then make up to the required ride height with a spacer. Maybe try just a third off to start with.

There is more to it however. The cut end of the spring will not be properly formed but you could fashion a cap with a spring shaped ramp to give proper support. And then there's the fork free length - the damper rod stops the fork over extending so you'll need to rework that too so there's a little bit of preload on the spring at full extension.

There are nylon looking caps that have the ramp for the end of the coil. The springs have tangential ends, the springs will not stand by themselves. Cutting the springs a little at a time sounds like a good idea.

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1 fork travel Sun Nov 28, 2021 12:19 pm

arbalest

2 Re: fork travel Mon Nov 29, 2021 5:01 am

92KK 84WW Olaf

3 fork travel Mon Nov 29, 2021 7:02 am

arbalest

4 fork travel Mon Nov 29, 2021 7:08 am

arbalest

5 Cut it in half Mon Nov 29, 2021 7:00 pm

stanthomas

6 fork travel Mon Nov 29, 2021 7:09 pm

arbalest

7 Re: fork travel

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