Tire size help - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

chevy 3 · 01-10-2014, 12:22 PM

I won a set of tires for my 1le from mrt racing.
The tires are bf Goodrich comp2. Well as luck would have it they don't make a 285/35zr20. But they make a 285/30-20 and a 275/35-20. So keeping in mind I like to auto cross my car. Would any of these be ok to get or ? Thanks guys in advance to any replies.

Dropspeed · 01-10-2014, 12:34 PM

Quote:

Originally Posted by chevy 3

I won a set of tires for my 1le from mrt racing.
The tires are bf Goodrich comp2. Well as luck would have it they don't make a 285/35zr20. But they make a 285/30-20 and a 275/35-20. So keeping in mind I like to auto cross my car. Would any of these be ok to get or ? Thanks guys in advance to any replies.

285/35/20 = 27.85" OD (Stock)
285/30/20 = 26.73" OD
275/35/20 = 27.57" OD

Both tires will work from a height standpoint.....but you really dont want a 275 on the rear 11" wheel as it is already stretched as it is.

The 285/30/20 will lower the car just over 1/2". this will effectively lower you CG which will help for autocross.

The lower OD tire is similiar to adding a numerically higher gear.....not much, but this will be benifical for autocross as well.

Only major down fall is the car is now 1/2" closer to and parking curbs...

Matt

trackguy · 01-10-2014, 11:06 PM

The general rule of thumb is that the tire's tread width be +/-1" of the wheel width. Tire Rack shows that the 275 Comp-2 has a tread width of 10.1" when mounted on a 9.5" wheel, so that tire is within an inch of your 11"-wide rear wheel. The rim width range for the tire is 9"-11".

While it's certainly true as Matt says that a 275 tire will be stretched when mounted on the widest recommended wheel, that can be a good thing, especially on a race track where it will result in more tread on the pavement than would be the case with a narrower wheel. You may or may not see that as an advantage when autocrossing.

If it were me, I'd choose the 275 over the 285, as you're keeping the same aspect ratio and giving up at most .4" of tread width. If you've been running OEM tires, the biggest difference in feel will come from the new tire's compound and tread pattern.

Comp-2 specs: http://www.tirerack.com/tires/tires....e+Sport+COMP-2
OEM tire specs: http://www.tirerack.com/tires/tires....upercar+G%3A+2

chevy 3 · 01-11-2014, 12:43 PM

This is great guys thanks! Can't believe two post and I got a ton of info and great advice.
Sometimes it takes six or so post to get good info.
C 5 rocks!!

01-10-2014, 12:22 PM	#1
chevy 3 NEcamaro5 Drives: Black 2ss rs 1LE Join Date: Apr 2009 Location: mass Posts: 4,328 View My Garage	Tire size help I won a set of tires for my 1le from mrt racing. The tires are bf Goodrich comp2. Well as luck would have it they don't make a 285/35zr20. But they make a 285/30-20 and a 275/35-20. So keeping in mind I like to auto cross my car. Would any of these be ok to get or ? Thanks guys in advance to any replies.

01-10-2014, 11:06 PM	#3
trackguy Drives: ..... Join Date: Nov 2013 Location: OH Posts: 47	The general rule of thumb is that the tire's tread width be +/-1" of the wheel width. Tire Rack shows that the 275 Comp-2 has a tread width of 10.1" when mounted on a 9.5" wheel, so that tire is within an inch of your 11"-wide rear wheel. The rim width range for the tire is 9"-11". While it's certainly true as Matt says that a 275 tire will be stretched when mounted on the widest recommended wheel, that can be a good thing, especially on a race track where it will result in more tread on the pavement than would be the case with a narrower wheel. You may or may not see that as an advantage when autocrossing. If it were me, I'd choose the 275 over the 285, as you're keeping the same aspect ratio and giving up at most .4" of tread width. If you've been running OEM tires, the biggest difference in feel will come from the new tire's compound and tread pattern. Comp-2 specs: http://www.tirerack.com/tires/tires....e+Sport+COMP-2 OEM tire specs: http://www.tirerack.com/tires/tires....upercar+G%3A+2 Last edited by trackguy; 01-11-2014 at 04:13 PM.

01-11-2014, 12:43 PM	#4
chevy 3 NEcamaro5 Drives: Black 2ss rs 1LE Join Date: Apr 2009 Location: mass Posts: 4,328 View My Garage	This is great guys thanks! Can't believe two post and I got a ton of info and great advice. Sometimes it takes six or so post to get good info. C 5 rocks!!