Tire spacing

[Matt Rowe]

Interesting back to back testing Greg. I do currently run a smaller size on the rear primarily because my fronts are corded faster than they heat cycle out while the narrower rears last 2-3 times as long. Of course I also used to like the balance with the narrower rears but with changes I made to the front last year I seem to find myself a little short of rear grip so it may be time to move back to wider rears. If my wear rate wasn't so high on the front I would see the advantage of only dealing with a single tire size.

[backformore]

It's funny that this thread has swung in this direction. I have considered the benefits of smaller rears and thought about a post to that affect to get opinions. Good info.

Anyone have age any old BFG R1 s in a 205/15 they want to part with?

[Flyinglizard]

Smaller tires= less weight= goes faster. I doubt that Greg will argue physics with me. There may be changes needed to realize the value. Maybe less spring rate to add grip. more or less bar. etc.
Each time I have reduced rear rolling drag, the cars go faster. Amazing .
Some drag reduction points of interest; Higher pressure ,like 41# , lowering spring rate to gain some grip back.
Zero scrub alignment ; using lower rear camber and some toe out for a zero scrub rear axle. IE if you have 2 * camber you need about 3-5mm of toe out so that the tires dont push against each other. Do a search for camber thrust, for a much better description. yada yada

Smaller rear tires may also lower the windshield angle , guess what? goes faster.. yes, the rear roll center may also lower and the car may need a balance trim.
Most of the time , I can take a VW race car, swap small rear tires onto the rear, up the pressures to about 40 hot and the car will go faster.
etc.
HTH, MM