Recommendations for track wheels - 275 square set up

[destructure00]

The extra rubber of 18's weighs more than the extra wheel of the 20's

No, this is incorrect...

 

[FlyNavy01]

LOL...
285/30-18 27lbs 24.8" diameter
285/35-20 32lbs 27.9" diameter

For the second part of your comment you are correct that reducing unsprung weight does make a difference however even a few pounds of rotational mass per corner is NOT perceptible by feel to even experienced pro drivers.

I dropped 9.5lbs per corner on my car and the 0-60 dropped by a full tenth of a second. 3.14sec --> 3.04sec, highly repeatable.

Also professional drivers can absolutely feel a difference in nearly 40lbs of unsprung mass being removed, this happens all the time when manufacturer's are developing sports cars at places like the Nurburgring with pro drivers input during the pre-production phase. If weight didn't make a difference we'd all still be driving around on steelies...

No, this is incorrect...

My current wheels are 19x9.5" and 19.4lbs. The 18x9.5" version weights 17.6lbs. A difference of 1.8lbs.
The 265/35/19 tire is 24lbs. The 265/40/18 tire is 27lbs. A difference of 3lbs.

If you're running forged wheels, very often the extra rubber on a smaller wheels weighs more than extra forged aluminum of a larger wheel.

 

[Rexpelagi]

You have mentioned running both 19x10s and 19x10.5s. So those are both the same MMR wheel with the same offset?

Ah, sorry - wondered why you were asking again - typoed above, I only have 19x10, I've not tried 10.5. My comments above are in reference to the 19x10.

 

[destructure00]

I dropped 9.5lbs per corner on my car and the 0-60 dropped by a full tenth of a second. 3.14sec --> 3.04sec, highly repeatable.

Also professional drivers can absolutely feel a difference in nearly 40lbs of unsprung mass being removed, this happens all the time when manufacturer's are developing sports cars at places like the Nurburgring with pro drivers input during the pre-production phase. If weight didn't make a difference we'd all still be driving around on steelies...



My current wheels are 19x9.5" and 19.4lbs. The 18x9.5" version weights 17.6lbs. A difference of 1.8lbs.
The 265/35/19 tire is 24lbs. The 265/40/18 tire is 27lbs. A difference of 3lbs.

If you're running forged wheels, very often the extra rubber on a smaller wheels weighs more than extra forged aluminum of a larger wheel.

I guess neither statement is correct as an absolute. I dropped 3.5 lbs per corner going from stock 20s with PS4S (51.3 lbs) to flow formed 18s with RS4 tires (47.6 lbs). Depends on the tire and wheel combination.