Tire combination tech

[MuscleRodz]

I thought this would be the proper location to ask my question since it I am not asking "what size fits my car" or "which look the best". If not, please move the thread. I will be running Michelin 345/30/19 out back and 275 or 285 series up front. I have some concern about push or understeer due to the 345's. My thought is running a "R" compound up front to balance out the tires better on track day. Naturally if I got serious about it, I would run a track only setup but not in the budget until the car is done and driving for awhile. In theory I think it would work but I was wanting some good feedback on the issue.

Mike

[Norm Peterson]

I think I'd rather work up an adjustable rear sta-bar (or add one for the track if one is not present for street duty).

Methinks "R" tires heat up (and potentially overheat) at different rates than non-R tires. I'd expect the handling balance to shift over the course of a session, in addition to whatever happens to the levels of available grip. There are certainly handling differences to be found when you mix tires across manufacturers (or even across different tire models from the same manufacturer), which may ultimately not be in the direction you seek, or excessively so in the direction you do.

Norm

[MuscleRodz]

I really don't want to cross manufacturers, this was more of a thought in theory. Rear stab bar has been considered but not decided upon yet. I will be running a splined bar up front for tuning ease and packaging.

Mike

[Norm Peterson]

Please note the late edit to add "or even across different tire models from the same manufacturer" to the above post.

Norm

[Norm Peterson]

Given the relative effects on roll, I'd use the front bar primarily to define the amount of roll (and, by extension, camber change and your static alignment settings). The rear bar has relatively little effect on the roll angle, so tuning the lateral load transfer distribution with it has fewer/smaller consequences.

Norm

[MuscleRodz]

Thanks for the input. Using a rear stab bar looks to be a better choice for multiple reasons. Tunability and financially.

Mike

[David Pozzi]

The concern is not only with compounds, but in tire construction. A tire of different construction may not have the same slip angle to load curve as another, even within the same brand.