While I'm working out getting the Kraton to Track bash with the best control, I've been pretty successful getting turn in, on/off power steering etc sorted, just recently with some new tires a bit of finer set up has prompted me to start experimenting with FRONT Castor adjusting.
The Kraton with the top upper A-arms generally centered on the pivot pin they have pretty severe negative castor rocking the wheels when turned severely on edge. While we know this helps dig in the front tire to aid tuning, there comes a point where there is NOT enough tire biting the ground and the front end pushes out more and more faster you corner.
So being able to fabricate round thrust shims ( used in lieu of the factory slip on clips ) we're able to make precise shifts in position of the upper a-arms forward or back on the pivot pin.
* Measured we have .155" of forward/back distance that indeed does change the castor quite a bit. So with a washer at each side of a-arm we simply use a combo of 2 washers who's total combined width equals @ .150" as to not create bind with pivot pin is secured tightly.
Picture is my latest setting being .050" on forward position & .100" at rear position. This places the castor angle more vertical ( Pivot ball to Pivot ball ) having wheels not tilt as severely.
Tire tread is still on edge when turning, but slightly more bite on the ground and it shows as less front end push / slide while cornering at speed.
At the same time also needed to shim the Lower A-arm ball link outward another .030" to maintain the @ 3 degree Front wheel CAMBER angle.
Done together the Kraton is really becoming a lot better planted and driveable throwing it around on a track surface.
Just sharing what I'm chasing .. and wondering if others have any input ?
Thanks,
BK
The Kraton with the top upper A-arms generally centered on the pivot pin they have pretty severe negative castor rocking the wheels when turned severely on edge. While we know this helps dig in the front tire to aid tuning, there comes a point where there is NOT enough tire biting the ground and the front end pushes out more and more faster you corner.
So being able to fabricate round thrust shims ( used in lieu of the factory slip on clips ) we're able to make precise shifts in position of the upper a-arms forward or back on the pivot pin.
* Measured we have .155" of forward/back distance that indeed does change the castor quite a bit. So with a washer at each side of a-arm we simply use a combo of 2 washers who's total combined width equals @ .150" as to not create bind with pivot pin is secured tightly.
Picture is my latest setting being .050" on forward position & .100" at rear position. This places the castor angle more vertical ( Pivot ball to Pivot ball ) having wheels not tilt as severely.
Tire tread is still on edge when turning, but slightly more bite on the ground and it shows as less front end push / slide while cornering at speed.
At the same time also needed to shim the Lower A-arm ball link outward another .030" to maintain the @ 3 degree Front wheel CAMBER angle.
Done together the Kraton is really becoming a lot better planted and driveable throwing it around on a track surface.
Just sharing what I'm chasing .. and wondering if others have any input ?
Thanks,
BK
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