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dualdj1
07-19-2011, 09:29 AM
Running an 08 Rayburn with swing left, z right, and got wrecked last weekend. Broke out the mount for the RR swingarm. Now we were running the short swingarm, and the easy fix is to use the long bar mount. What can we expect going from the 12" to the 19" lower bar length? Do we need to change anything with the standard upper trailing arm? Any other changes needed on the left side, etc?

MasterSbilt_Racer
07-19-2011, 09:39 AM
You will lose loose rollsteer and gain dynamic rr wheel rate.

dualdj1
07-19-2011, 01:19 PM
OK Thanks, I actually thought it would be opposite, because the longer bar will have a "flatter" arc than the shorter bar; since it's starting on a downward angle, as the RR compresses it moves the bottom of the birdcage towards the back more than the shorter bar, which, with the upper movement being the same, would pull the RR further back and index the cage less.

There isnt' a lot of angle on the bar, and at ride height, the long bar passes almost directly over the short bar mount.

MasterSbilt_Racer
07-19-2011, 02:07 PM
Hold on a sec...

Both swing arms have the chassis bolt higher off the ground than the birdcage bolt, correct? That means both are uphill to the frame.

The shorter one will lose the uphill angle more quickly during roll, so the bottom of the cage goes back more with it. If your coilover is attached to the front, that also means less spring travel vs chassis travel or a softer rate.

dualdj1
07-19-2011, 04:20 PM
yeah sorry upward from birdcage to frame, or downward from frame to birdcage.

I think I follow you now. Hard to picture it without the car in front of me. Thanks for the help!

dualdj1
07-26-2011, 03:13 PM
just an update, ran this last weekend and to me really didnt' seem to be much noticeable difference between long and short, maybe slightly less roll steer but was negligible.