Matt69 Posted May 31, 2011 Report Share Posted May 31, 2011 Can anybody point me in the right direction for some good reading material, ie an idiots guide, on the effect of increasing fork offset on steering geometry. I've got a couple of books I've read but they don't have much info. For some background, I've got hold of a pretty cheap set of early Honda RS250GP triple clamps and am thinking of putting them on my NC29 racer as they are heaps prettier and beefier. The fork diameter is the same and I can get a steering stem made up and fitted for the right price. They do however have about 7mm more offset then the NC29 ones. Matt Link to comment Share on other sites More sharing options...
deviant Posted May 31, 2011 Report Share Posted May 31, 2011 Most obvious effect will be to reduce the trail - the distance that the contact patch is behind the steering axis. Will make the steering lighter but potentially less stable. I've got a book by a guy called Gaetano Cocco (Motorcycle Design & Technology Handbook), who worked for Aprilia. It's somewhat comically translated from Italian, but pretty good. Otherwise Tony Foale's book is supposed to be pretty good, but I've not read it Link to comment Share on other sites More sharing options...
2 smokes 4 ever Posted June 1, 2011 Report Share Posted June 1, 2011 The Late JR's Chassis Tuning book explains it well More fork offset = less trail and hence faster, more responsive steering Link to comment Share on other sites More sharing options...
Paul McPherson Posted June 10, 2011 Report Share Posted June 10, 2011 This formula should allow you to work out the effect of changes to offset on the trail of your set up: Trail= (RxSinø - 0) / cosø Where: ø = Rake Angle, R = Tyre radius, 0 = Triple clamp offset Paul Link to comment Share on other sites More sharing options...
Matt69 Posted June 11, 2011 Author Report Share Posted June 11, 2011 This formula should allow you to work out the effect of changes to offset on the trail of your set up: Trail= (RxSinø - 0) / cosø Where: ø = Rake Angle, R = Tyre radius, 0 = Triple clamp offset Paul Paul, Thanks very much for this. I found this site http://www.rbracing-rsr.com/rakeandtrail.html which even though it is for tractors seems as though it should do the job. Off overseas for work for a couple of weeks so will get stuck into it when I get back. The length of the forks and the step down on the top triple tree should give me a bit of room to play with the geometry as well. Link to comment Share on other sites More sharing options...
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