87_gta

Good day,

Looking for some thoughts.

I am wanting to change the rear gear ratio on my IROC. Currently have a fourth gen rear installed.

Rear tires are 18x10.5 (285/35/18) and the wheel/tire is a little over 26 inches tall.

What would be an appropriate rear gear to use with this wheel/tire combo. Been debating on either 3.73 or a 4.10.

Car is NOT daily driven, I do care a bit about gas mileage as I do a lot of back road driving with the car but I also want to launch hard from a stop and be able to break the tires loose if I want to.

Engine is not stock and has a Mini-Ram installed.

Thoughts?

Roblaza

iTrader: (1)

I'm running 275/40/18 in the rear of mine with a t5, 4th gen rear and 3.90 gears. Seems to be a happy medium. It launches very well and pulls like a freight train, but at cruising speed it doesn't rev to the moon.

The transmission that's in your car will make a difference in your choice as well...

87_gta

It's an auto 700R4.

Tibo

iTrader: (15)

What are you cruising at and what are the RPMs? Peoples definitions of acceptable cruising RPMs differ. Heck, my definition changes based upon engine size and cylinder number.

QwkTrip

iTrader: (22)

3.42 axle ratio gives more than enough final drive ratio for a typical street performance engine with 700R4 trans. Think in terms of final drive ratio, not the axle ratio.