NoleenELT

Apologies, but I did not find this info in the many kinematic toe threads that came up in a search.

When adjusting the cam bolt to adjust kinematic toe, you are effectively lengthening or shortening the KT arm. I'm using the Tangent kinematic toe gauge. Making the arm longer makes the gauge read numerically higher. This rotates the top of the hub towards the front of the car if I remember correctly.

If you make the arm longer (bolt head towards the outside of the car), will that create more toe in (understeer) during bump, or less toe in (oversteer)?

Bill Verburg

the effect of increasing the effective length of the KE link is that both caster ( KE effect) and camber decrease - and increase the height of the suspension by straightening the caster angle towards vertical: what happens is that the hub rotates both forward and moves downwards simultaneously. More caster at either end puts more toe change aka bump steer into that end. The more toe change the slower that end will be , the less the faster it will be, at some point a fast rear will be described as twitchey.

NoleenELT

Thanks Bill, this info is extremely helpful!

So as I understand what you have said, lengthening the KT arm will give less toe change, or more oversteer/twitchy. This matches the feeling in the car.

I have changed from M033 springs and Koni FSD dampers to H&R PCS coil overs (rebranded PSS9) and set up my car in between RS and M030 ride height. The alignment is set to RS specs with F/R toe at center spec, F/R camber and caster (front) to the max end of spec tolerance. So of course the car feels different than before, but I am trying to figure out if I have set up KT correctly (I'm thinking not).

The instructions for the Tangent gauge recommend to set up so that the gauge reads between 4.5 and 5. With the camber and toe set where I want them, I was only able to get the Tangent gauge to read as high as 3.5 on one side, and 4 on the other side, and that was with the KT arms at max lengths.

The car feels quite "lively" now. It has really nice sub-limit turn in, but I can feel the rear end wanting to step out as I approach higher lat G. Probably great for autocross, but a bit much for a 99% street car, and I'm not sure that this is from the damper/spring changes alone.

Setting the KT arm to the max length did not seem logical to me, and the feeling in the car seems to match. The question is, if I reduce the KT arm length, the Tangent gauge will be farther away from the recommended setting (lower number), so where should I set it?

I'm thinking to set both sides KT close to the center adjustment. Then adjust camber and toe and see where the Tangent gauge ends up. Then balance KT side to side if needed.

Bill Verburg

You set the car up to be comfortable for you, Shorten the KT arm. But you also need to reset camber and toe, changing one affects all the others, be sure to run a little toe in back, you can go to zero toe in front, camber depends on tires and usage, -1° +/-10' in front and a little more in back for street use up to -3.0° +/- f&r

NoleenELT

Thanks!

So it seems like a trial and error thing, and the numbers on the gauge are not so useful as an absolute target.

Your alignment recommendations are in line with what I'm doing too. Thanks!

OverBoosted28

NoleenELT

Agreed, I was going back and forth trying to get all three adjustments in sync!