Way Big Forks VS the rest of them.

[Spokes]

Hmm .. Anyone got a spare '57 carbon swing arm?

Chris

[Spokes]

22"and 24" is what me gots




What's the black circle around the top fixing point of the top link, on the fork leg? On the yellow painted section. Mine are all yellow and screw directly into to link. Are yours bushed?

Chris

[whisperdancer]

To maintain geometry of the fork, the difference in lenght of the fork should be the difference in lenght of the shock, as they are different according to the fork size.

[w2zero]

Yup, appears to be about two inches longer between the pivots and there is an extension on the bottom of the shock.

Wonder how much difference that makes in the action down at the axle?  Does it increase the much dreaded J-path?  Not that I give a rip.

[Spokes]

It won't make any difference to the travel or J path as the top and bottom links are still the same length. They're just physically longer to suit the taller frame.

Chris

[w2zero]

I have built linkages and changing any of the dimensions will make a difference.  How much difference depends on how big a change and where. 

[Colin]

I think a "Long" fork might have a slightly different axle path to a "Standard" as the top and bottom link lengths are not the same, so placing them further apart (than the std 148mm at headtube and 155mm on fork) will probably create a difference. I've modelled the std pivot points previously on here, but didn't extend this to the axle path ..........

Although if the headtube and fork mount points of the links were kept in some sort of proportion maybe the axle path would remain the same.
I expect Bob allowed for this back in the day..............

Col.

[Spokes]

Hmm in my head I was thinking as long as the links are the same length and the fork legs are the same length below the bottom link then the j path would be the same. But thinking on it, I don't think the legs sit perfectly parallel to the head tube. The top of the fork leg does sit slightly further out so yes I guess it would make a difference as lengthening the fork legs would increase the angle at the top? Hmm interesting this!
Draw us another picture Col! Lol

Chris

[w2zero]

Used to design and fab remote damper links for ship's fan rooms so had to deal with straight, rising and falling rate linkages.  Was pretty good at it too since the machinists didn't have a go-to guy at the time.  Now it just gives me a headache and I go back to simple stuff like shift linkages for engine/transmission swaps.

Just spitballin but the longer length between the top pivots (if the links are the same as smaller X-link forks) would probably decrease the length and speed of the J-path.