I'm ordering some 17x9 wheels for autocross and I'm looking for competition tires. Currently, the Kumho V700's are OOS in the 275/40-17 size, but they have 255/40-17 for the front.

Has anyone put the same rolling diameter on the front & back and had VDC problems? I am thinking of getting the 255's all around so I can swap f/r and make the tires last longer.

Also, do you think 255 is wide enough for the rears, for autocross? I heard wider tires help with staying planted while gassing it coming out of turns, but 255 is already wider than stock.

 

For my 6MT sedan, I'm running 18x8.5 with 245/40R18 tires all around. I have not had any issues with the VDC. Though if you have a coupe, the VDC system expects a staggered setup, so there might be an issue [I don't know for sure].

 

I have a 6MT coupe and when I bought it used it had 245/45-18 all around. I'm not sure because I havent driven one with the correct size but my VDC does kick in in the rain IMHO a little hard on the front. It may be the nature of the VDC but the brakes do seem to grab abruptly on the front.

 

I autox with 17x8 rims and 245/45/17 all the way around. In autox I turn the VDC off, but I have also put about 1500 street/highway miles on my setup and you would never know the VDC had any problems. I've even driven through some very, very, heavy rain and had no problems with the VDC. It may not be optimized when forced to kick in, but it does work when you drive aggressively.