[Ron Sutton]

Originally Posted by carbuff

I'm loving reading this kind of detail! Thank you Rob and Ron for having most of this discussion 'publicly'.

I do have a question about the C6 spindle. I wasn't aware that the C6 ran that much caster. Can you explain a bit about the effect of running that much caster, or perhaps asked different, if you run less caster with the C6 spindle, what would the effect be?

My setup uses that spindle, but I've been told to target 6.5 - 7.0* of caster, and my recent alignment check shows 6.8* and 6.2* (I haven't had it aligned fully yet, but that is with camber dead on at the moment). While I realize my setup is different, it supposedly uses pretty close to C6 geometry points.

Keep the techie stuff coming! I'm learning from all of this too!

Okie Dokie Carbuff ... here goes ... but it is so involved it takes 3 posts.

Most everyone knows camber, caster & KPI/SAI work together, but most don’t really understand HOW they work together & how they affect each other. I’ll do my best to explain it, but we’ll need to peel the onion one layer at a time, so bear with me.

For those that don’t know what this is, KPI stands for King Pin Inclination & SAI stands for Steering Angle Inclination. They mean the same thing.

KPI was a term coined back in the day of solid front axles when spindles actually used king pins. Steering Angle Inclination is a more correct modern term & is calculated simply by running a theoretical line through the upper & lower ball joints & comparing that angle to the actual spindle pin the hub spins on (rolling axis in the photo). (I use both terms because many race car guys are used to the older term of KPI.) See photo.


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