View Full Version : KPI and Castor

08-04-10, 10:55
I'm sure everyone is aware of the relationship between SAI/KPI and castor. However what are people designing into current under 1300cc cars. Our current upright design has 9 degrees of SAI using ACB10 tyres and we can drop this to 7 degrees without a massive redesign - more becomes somewhat problematic.

jo white
08-04-10, 19:17
Me reckons thats a trade secret Neil

09-04-10, 12:41
Probably thought of as so I guess. Strange really as you get a good idea if you take a photo. It seems that very low KPI's (whilst still controlling scrub) are in vogue and a relatively low castor angle too - too much would generate tyre wear issues in the longer term. This is perhaps one reason why care is taken with matching SAI/Castor, though naturally competition cars can sometimes ignore such things. If the above is correct then perhaps self aligning torque is generated largely through mechanical/pneumatic trail?

10-04-10, 07:26
Oh well. Went back to Milliken and forget the SAT issue.