caster block ºs represent


New member
I am somewhat new to kart racing but not racing in General . What I am tring to figure out is on my phantom phenom the right caster block says 15º and the left say less (can't remember off the top of my head) what does the represent. At 0º there is already 15º degrees built in ? or ?
You are on the right track. It's all about king pin inclination. In the most basic explanation the angle of the caster block will allow you more or less camber while keeping your kingpin close to vertical. This keeps your camber more consistent as the spindle rotates when turning.
No your camber is still 12 degrees. The effect is on the inward lean of the kingpin. I'm over my head now so I'm breaking out the manual. I'll get back to you with some high quality input thanks to Mike McCarty
Ok so I probably should not have dove into a chassis I don't know but it's late and I'm ambitious. What you are doing with these caster blocks is changing the bottom mounting position of the king pin. Assuming you come from big cars think lengthening or shortening the lower control arm. Looking at the Phantom info it looks like the degrees are telling you what the king pin inclination would be if you were to adjust the top all the way in with that caster block and not what the caster would be. So we know that on the RF the higher the number the more negative camber you could put in it and the opposite on the LF. This would also effect scrub radius which is way more than I can handle after midnight. There are many people here that can explain this far better than I so hopefully they will have some input.

If you are interested in reading about this I highly recommend "Understanding Chassis Theory and Dynamics" by Mike McCarty.

I also should note that it is further complicated by the fact that the spindles themselves will have camber built into them to allow more camber with less king pin inclination.
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New member
I wasn't aware that a 15 degree KPI block was ever made for the Phenom. However, if 15 degrees is mean as the KPI (and it likely is), then you'll end up with roughly 15 degrees of KPI which has nothing to do with what you set your castor to.