You should listen to me. No, seriously, listen to me.
Join Date: Oct 2008
Location: Santa Barbara
Motorcycle: Blue 2006 GSX-R1000
Re: Chain length and stock swingarm
A decent formula for the center-to-center distance between the sprockets is
D=(NL-(T1+T1)/2)*0.3125 where NL is the number of links in the chain and T1 &T2 are the number of teeth in the sprockets. It ignores things like chain stretch and droop. Thus the OEM chain is 25.16" and a 112 link chain is 25.78". You can finesse things a bit by going to a different sprocket set with the same overall ratio. For example, an 18/44 sprocket set has nearly the same ratio and with 114 links gives a length of 25.94". This allows you to move the axle back in finer steps to get closer to the back of the slot. I'm guessing the distance from the front sprocket centerline to the swingarm pivot is about 4" so even that gives a pivot to rear axle distance that is less than SPL's 23" value.
Last edited by BillV; 10-27-2011 at 08:39 PM.