245/45/16's or 265/45/16's on 16x8's?

I recently picked upa set of '01 T/A 16x8's. I'm buying a set of Kumho Victoracers for autocross next season. I've heard a lot of conflicting info about which size to get and I'd like to hear from people that have run both. Thanks

245 is recommended but you could also go 255. I wouldn't go with 265. That's pushing it in my book. ;)

I ran 265 Kumhos with no problems and that would be my preference. Whether they are any "faster" than the 245's is up for debate.

This same topic is being debated over at LS1.com

It seems that there are many opinions on this and no consensus. I am getting 245/45 Victoracers only because I can get somewhat used ones cheap.

I don't think you'll get past the opinion stage on this this topic.

I ran the Kuhmo 265's with no problems at all on stock 16x8 Camaro wheels. I am now running the old BFG G-force 255's on stock Firebird wheels with no problems either.

Well I guess there is no straight answer to this. But just out of curiosity what kind of air pressure did you guys use with 265 Kumho's to get them to wear evenly?

Well, I'm not sure about being able to get a straight answer... You will get people's experience, but probably their experience with one-or-the-other.

I think that the number of people with significant seat time with each of the different sizes of tires (while holding everything else constant) is very small.

Originally posted by WOT
Well I guess there is no straight answer to this. But just out of curiosity what kind of air pressure did you guys use with 265 Kumho's to get them to wear evenly?

I ran the 265's at 32 & 32 cold and 38-40 hot for the fronts and 36-38 hot for the rears.

They wore more on the outside egdes first, then just flipped them on the wheel so that the outside became the inside after a while.

I would recommend 245's over 265's. Frankly, they are about the same speed and all, but the 245's just help the car transition a bit better.

I ran both for a loooong time on FS cars (both 3rd and 4th gens) Started on Kumho's in '97 and stopped with them early this year.
Pressures: 245's, about 37 f/30 rear. 265's, 40 front, 28-30 rear. YMMV slightly but remember, tracked cars don't need as much air in the front as an autox car because they don't transition or load the tire as hard......

Originally posted by 01 FS Z28
I would recommend 245's over 265's. Frankly, they are about the same speed and all, but the 245's just help the car transition a bit better.

I ran both for a loooong time on FS cars (both 3rd and 4th gens) Started on Kumho's in '97 and stopped with them early this year.
Pressures: 245's, about 37 f/30 rear. 265's, 40 front, 28-30 rear. YMMV slightly but remember, tracked cars don't need as much air in the front as an autox car because they don't transition or load the tire as hard......

I'm going to be using them for autocross so transitioning is very important to me. Just to further my understanding how does the skinnier tire transition better? Is it because of the narrow wheels 8"-or is there such a thing as too big of a tire?

The 245/45 will have a significantly shorter sidewall, and thus will transition better.

Also the previous owner put 3.73's in my car. So would the shorter 245/45's make me hit the rev-limiter too much in 2nd?

Originally posted by 94bird
The 245/45 will have a significantly shorter sidewall, and thus will transition better. :o Didn't even think of that.

Originally posted by WOT
Also the previous owner put 3.73's in my car. So would the shorter 245/45's make me hit the rev-limiter too much in 2nd?

Check out the speed/gear calculator at http://www.f-body.org/gears/

With a 24.3" tire diameter (245/45/16 Kumhos) it calculates that you should turn 5700 rpm at 62 MPH. With a 3.42 gear and the same tire, that 5700 rpm is 68 MPH. For most local autocrosses I wouldn't worry about it that much since the speeds are supposed to be held to 60 MPH I believe. At divisionals you just might be hitting 3rd gear. I have a 3.73 gear in mine and with 275/40/17 tires I'm never out of 2nd gear on an autox course.

:D thanks for everyone's replies 245's it is!