Front end woes.

[kdanie]

Farmer, Your caster sounds ok but +0.5 camber is not good. Camber should be 0 or 1-2deg negative for better cornering, although it may increase wear on the inside edge of the tires.

Toe should be 1/16" or slightly more in at the front. Some racers use a little toe out but it will make the car twitchy like you discribe.

Sprint star, If you take some measurements of your front suspension mounting points, your spindles inclination angle, wheel offset and draw the layout on paper you can see what your actual scrub radius is. The easy way to correct scrub radius is with different wheel offsets but if you don't know what it actually is you can't really know what to do. A little scrub radius is not really a problem, few cars actually have "0" scrug radius. excessive scrub radius can cause suspension "Jacking". That is where the scrub radius is so large that when the wheel is turned the weight distrubution on the tires is upset, not a good thing at all. For what it's worth, racing Karts use scrub radius to good effect as a tuning aid and changes can dramaicaly effect the handling, good or bad. Remember they don't have any suspension and the rules don't necessairily transfer to a car with suspension.

Get a copy of these two books. Carroll Smiths "Tune to Win" and Herb Adams book on suspension design.

ken