Ideal tire width ratios(front to rears) for road course/autocross?Tire recommendation

[Typhoon1015]

I am in the market for new tires on the chevelle.

I am currently running 18x8 and 18x9.5 rims with 245/45 and 275/40 tires. I want to be able to fit 275/35 and 295/35's but will need to widen teh front rims to 18x9 or 18x9.5 at least.

The car is a street car but will be seeing track days on road course's and autocrossing.

As far as handling is, is there a proper tire width ratio front to rear that is preferred for autocrossing vs road course? I need all the rear tire i can get in the stock wheel tubs thus trying for a 295, but I dont want to go so big that it will make the front push too hard while autocrossing. If I can get away with not widening the fronts and run a 245/35 with the 295/35 it would save about 500 bucks in widening the rims over running a 275 front tire. Is the 275 front worth that $$ handling wise over a 245 front running a 295 rear, or would a 245 front and 275 rear be a better combo?


The car is upwards of 750 WHP so thats why want wide meats in the rear.


Also any recommendations on tires too?


Thanks

[Paul Huryk]

Your Chevelle is a front heavy RWD car - just like all the other cars on this board.

That said, you want to stuff as wide of a tire in the front - whether it be a 245 or 275, or anything in between. My company, CTW Motorsports sells 17" x 9.5" wheels for the 3rd generation f-bodies to fit all 4 corners - the car handle much more neutral and will easily outhandle a 245/275 stagger. Of course, the real issue is how much tire you can fit under the front of your Chevelle - if you can get a 275 under the front on a 9" or wider wheel, do it.

If you can sell your old wheels and pick up the wider ones for the front, that would be a good option. 245/275 will give more neutral handling than a 245/295, but a 275/295 combo would be the best (if a 275 fits).

[dontlifttoshift]

For autocross you would have to try very hard to have too wide a front tire.

Road course, debatable. I still lean towards the wider is better mentality. New Z28 has 305s all around. Looking forward to others opinions.

[Typhoon1015]

Your Chevelle is a front heavy RWD car - just like all the other cars on this board.

That said, you want to stuff as wide of a tire in the front - whether it be a 245 or 275, or anything in between. My company, CTW Motorsports sells 17" x 9.5" wheels for the 3rd generation f-bodies to fit all 4 corners - the car handle much more neutral and will easily outhandle a 245/275 stagger. Of course, the real issue is how much tire you can fit under the front of your Chevelle - if you can get a 275 under the front on a 9" or wider wheel, do it.

If you can sell your old wheels and pick up the wider ones for the front, that would be a good option. 245/275 will give more neutral handling than a 245/295, but a 275/295 combo would be the best (if a 275 fits).

Thanks for the input. I currently have OEM BMW wheels, so my only option at this point if to find another set of rear rims(18X9.5) to install on the fronts, but due to availability they are hard to get. That's where I was thinking of getting the fronts widened. I am not sure if its worth 500 bucks to widen 2 wheels really, thus my though if it would be better to have the 245/275 combo( not widening) over the 245/295 combo( widening)

I tried fitting the rear set on the front ( 18x9.5 275's) and they fit the drivers side with no problems, however I did not get a chance to check the passenger side which has the turbo housing protruding into the wheel well. Once I can verify that they will work on that side, then the search is on for the 9.5 wide rims for the front, or get these 8 inch wide rims widened for 275's.

Any other opinions are wanted as well.

Tires: I am thinking NT05's, KDW's, the new rival's, or falken's?

[LS1NOVA]

I think wider is better on that thing. Like said, its a heavy pig up front. NT05 would be my choice.

[GrabberGT]

There is another thread here somewhere discussing this. Perhaps buried under something about wider rear tires being necessary. What I took from that discussion was trying to keep the front to rear ratio close to 90%. More or less depending on power levels. My target sizes are 275/295 which puts me at 93%. My car is close to 50/50 and is underpowered compared to most. FWIW, Mike Maier runs or DID run 265 on all corners with no issues.