ryoung

The load carrying capacity of a tire is directly proportional to simply the amount of air in it. The sidewall may be stiff or soft, but it provides essentially none of the load carrying capacity of the tire.

1. Increasing wheel diameter with the same outside tire diameter (reducing sidewall height) reduces internal volume, which reduces load carrying capacity, and requires higher tire pressure to compensate.

2. A wider tire with the same outside diameter increases internal volume, load carrying capacity, and requires lower air pressure to keep the tread flat on the ground.

3. That little donut "spare only" both narrows the tire and reduces diameter, drastically reducing internal volume and load carrying capacity, and requires much higher tire pressures (like 60 psi) to compensate.

gtreng1

induce more oversteer in the *** end. I used to do the same in my GTI