caster help (replace front axle caster set up advise)

[Mel Ruffner]

Hi everyone, have a question. I  have to replace front axle on my a bone. I know I need caster  before the welder welds the front axle, but I don,t know how much caster I need. Does anyone happen to know what degree I should run? Thanks again for your  answers. take care Mel

[David Luciani]

ask rob stanton at robron. i seem to remember laying rupps back at 12 degrees but last rupp i jigged up was 5 years ago.

[Brian Sheridan]

Mel,
Castor is a relative dimension. The higher the castor, the more the frame flex's. A good number for a old style frame is 9 degrees. 0 castor axles tend to make a kart handle like a wagon. Castor gives the steering (trail), where the spindle shaft pivot is in front of the wheel center at the ground. Where the king pin travels in an arc back down, forward up. Go Kart 800 had approximately 9 degrees of castor. However castor should also have king pin inclination, for it to really work right. All this is why a "Go Kart" would steer so much better than the same year "Bug" kart. Duffy had the front axle worked out way better than Tom at Bug.
Brian
Shamrock Race Karts

[ted johnson]

I've seen Darts and Go Karts anywhere from 12 degrees to 15 degrees of castor. My Pop's GK 800 was at 12 degrees. He had a bit f a collision with one front wheel and bent that axle side back. We were careful to measure both the undamaged axle end, and for insurance, we measured my undisturbed 1200 front axle. Both were at very near 12 degrees, so we jigged the bent side of Pop's at that angle. We couldn't tell any handling difference after fixing it to before it was bent. 7 degrees kingpin inclination seems to do well. The three CAD designed karts I have built are all at 12/7 degrees, and handle well, steer easily and give the poor old arms and shoulders little fatigue. Ted

[Dick Teal]

The Fox satellite seat karts have 12 degrees of castor and the king pin angle is 7 degrees. We messed with different angles but this proved the best. The karts need to have 1/16th toe in to make it handle great.

Dick Teal