Max tire size on 9x18 rear wheel

[BYprodriver]

Loss of torque multiplication is the unavoidable downside of running taller than spec rear tires. This is very noticeable on 986's. That leaves a 285/30/18 as the only option along with 10" X 18" wheels. Now the car resists rotating into turns!

[KRAM36]

Originally Posted by BYprodriver

Loss of torque multiplication is the unavoidable downside of running taller than spec rear tires. This is very noticeable on 986's. That leaves a 285/30/18 as the only option along with 10" X 18" wheels. Now the car resists rotating into turns!

I'm not following you on this one.

Here is what my car originally came with.



This is what I'm moving to.



Not only is the tire diameter smaller the front to rear tire rotation speed is much much better. The car should handle much better.


.

[woodsman]

Originally Posted by KRAM36

I'm not following you on this one.

Here is what my car originally came with.



This is what I'm moving to.



Not only is the tire diameter smaller the front to rear tire rotation speed is much much better. The car should handle much better.
.

Your car came with 265/35/...not 40 series

I also look at tire weight. I'd run 255/35/18 since it decreases overall dia, and weight and will provide me with enough lateral grip.
Tire choice within the mfg's range also determines how the tire performs because it affects the shape of the contact patch ie. how fast it breaks away in various directions. These ultra -low profile tires offer the sharpest response at the expense of a gentle breakaway and the widest 'approved' choice will provide the most lateral grip at the expense of a gentle breakaway to wheelspin and a locked tire.