I remember a post from whitelighting or someone who tried 255's all around. Claimed there was no rub. Also saw another post with "slight" rub. I just picked up a set of tires off ebay "cheap cheap" that are 255's. My guess is they'll fit. We'll see in about 6 months. Sorry I can't be of more help.
At $100 bucks a tire, I just couldn't refuse. I know I'll probably give up some bite and turn in, but the 360 treadwear is a trade off I wanted to try.
nobody has done this.
the problem lies in sizes front to back here.
255/35, 255/40, and 255/45 are all over 1% difference in diameter compared to the stock 245/45 size. This may throw off stablitrack/ABS, and you don't want to go there.
I can't believe that stabilitrak won't compensate for a .4" variance in diameter. It would seem to me that over and under inflation of the tires could cause a similar variance. I'm not saying you're wrong here Urb, just saying it's hard to believe.
Makes one wonder how the Stabilitrak handles the bald rears after only 4,000 miles or so on most V's. Never measured, but I'd imagine they were about 1% smaller in diamter or more when mine came off the car :lildevil:
Yes, Dreamin knows his tires, and now he also knows how my modded V drives compared to his. I also had the chance to drive a stocker again - I'm NEVER going back :bouncy:
Diameter = 2 times Radius
Circumference = 2 (Pi) Radius
Worn tires have lost 8/32nds or .25" when worn. This amount taken times two on the diameter would reduce diameter by .5 inches. I have to believe that stabilitrak can compensate for an increase of .4 inches in diameter if in fact it can compensate for a 1/2 inch decrease due to worn tires.
nobody has done this.
the problem lies in sizes front to back here.
255/35, 255/40, and 255/45 are all over 1% difference in diameter compared to the stock 245/45 size. This may throw off stablitrack/ABS, and you don't want to go there.
I did not think of the diameter difference. I would think, the 255/45 not only being taller but also wider would cause more understeer. 255/40 might balance out just fine but at this point I might just stay with 245s.
g50: You need to keep the front and rear diameter the same... as close to the same as possible. There will be no real benefit to run 255/45... get 9" or wider rims in the rear and run 275/40/18s!
CVP: Your math is correct. My info is directly from GM and Katech... GM tried to reprogram the Katech V's PCM (BCM actually) to get 255/35/19 and 275/35/19 tires to work, they could not (0.6" diameter differance). They had to go with 245/40 and 275/35. So maybe 0.5" is the limit before the PCM freaks-out? Maybe they were testing "worst-case", using your math, bald fronts and full rears, which would be 1.1" difference in diameter.
...just playing messenger here...
Yes, Dreamin knows his tires, and now he also knows how my modded V drives compared to his. I also had the chance to drive a stocker again - I'm NEVER going back
BTW, from our discussion yesterday about wider rear tires... The car is perfectly balanced for 400fwhp; it wont be at 500fwhp.
So i'm back thinking about widened stock rims with 275s... Not so much for traction off the line... but to handle power-on oversteer... like how i almost got the tail to come around on your car at 30% throttle in 1st going around that corner onto the freeway :bonkers:
I know you're right...but I'm just wondering how much more meat can hit the road before my rear diff implodes.
We need to figure out a plan...and widening isn't out of the question. I'm sure I can burn off these F1's (didn't put the GSD3's back on today, ran out of time) by the end of May or so :lildevil:
Then we'll have 4 rims to ship out and have widened before powdercoating :hmm:
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