Answers to Steering Geometry

11 Aug

Published, August 8, 2007
Hi Steve, this is a dark area for most and I spent a huge amount of time researching it when putting my new bike together as I was not certain if it had anything to do with the old bike going out of shape and dumping me unceremoniously. There is not a single figure that will work with every bike. Every chassis is different, and guessing is a sure path to disaster if you get it wrong. Here is a site I found useful and though it deals with choppers the maths provided works for any application, just click on this link and have fun playing with the figures http://www.rbracing-rsr.com/rakeandtrail.html .The most critical figure for ANY motorcycle is the trail figure. Rake will slow down or speed up the steering, depending on which way you go ( the higher degree of rake = slower steering) and the biggest problem with too much rake is your forks may not work correctly due to the direction of load under compression. I did initially have this problem with the new bike and built a ! new set of forks which were designed to directly overcome the load problem from the rake angle and they now work extremely well. Forks are an area on dragbikes also easily misunderstood and my research into this area surprised me too. More on that later, but effectively what works on the road and for circuit bikes will not work on a dragbike. The good thing is when you get it right the faster you go, the better your bike will handle. Going slow on these big tire bikes is a pain and getting towed back from a run can be quite an experience! Have a play with the figures, call me and we can discuss your results in more detail.
ian wilkins
Email: atmos@xtra.co.nz
Tel: 021 773 250                    BACK TO QUESTIONS PAGE                                 BACK TO TA's PAGE
Published, August 8, 2007
Hi
If you go here...http://www.stripbike.com/ and look down the left hand side of the page for Puppet's Chassis Design. Then you can learn from an expert.
Welcome to the tribe. Hope to see your bike on the track soon.
Richard                                   BACK TO QUESTIONS PAGE                                 BACK TO TA's PAGE
Published, August 11, 2007
Steve. Steering is a tricky one. Put some pictures on the site so we can see. The scary part I see is that everyone forgets the load transfer when braking. Your bike would weigh a bit. this loading is transferred onto the front forks. make shore they are up too it. Damping rates change the way the bike brakes and handles.
Roger