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 I race my 240 Volvo in SM in the DC region and I have 18x10.5 wheels all around.  Half of last season I ran v710 285/30/18 front and a 305/30/18 rear.  The 305s i bought new and the 285s I bought were used and had already run them for a while.  With the 285s in front the car had a mild push but seemed to do ok,  This weekend I switch the fronts and rears and had massive oversteer.  I added up the estimated runs on the 285s and they were well over 140 runs.  There is still rubber left and you can still see the grooves but they are dead in comparison to the newish 305s. 

 I need to get a new pair of tires.  I like the 285s because they are shorter and I can only get the rear of my car so low due to packaging constraints.  The 285s are shorter and lighter and let me run the car lower, I can run about .5" lower but the 305s are wider with more grip.  I cant decide on which path I should go,  Is the extra width worth the increase in ride height and extra weight?

Has anyone done a back to back comparison?

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www.kaplhenke.com

15x10 and 275/35/15

I've been using two sets of V710s, one for practices and one for championship events.  The practice set of tires started the last practice around 110 runs and we had pretty poor grip, both bad understeer coming out of the sweepers and overall oversteer that forced us to dial back the rear compression damping.

Putting on the fresher set to scrub them in after sitting for six weeks, the car's behavior was dramatically improved.  No more understeer and the rear rotated beautifully both on and off throttle.  It was like driving a completely different car.

I suggest getting a new set of the 710s in 285 and seeing how you like them.  But don't try pairing fresh 285s with the used 305s or you won't have any idea if your car's behavior is balanced.

Mike

 

 

 

Ben, it was nice meeting you in DC.   As Mike said, mixing old and new tires is going to  mess with the feel of the car dramatically. Try a new (er) set of 285's or 295's and see how it feels. 295's have a slightly larger sidewall so the feel might be different (better maybe?) compared to the 285's....

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Marteen V.
Charleston WV
Toyota Celica Alltrac #561 SM
BMW 318i