bud4ya

Just spoke to the tire place and I told them I wanted 255's on the back and 235's on the front. He said that will work but it will throw the mileage off and the speed off by just a bit. Does this sound correct? Is this what others are using for size that bumped up a bit?

He said on the back
255-40-17

Front
235-45-17

Thanks

jacek9478

That is correct.
if you go w/ 255/40/17 your speed will increase aprox 1mph per 30mph on your speedo. ( Speedo shows 60mph you r traveling at 62mph )

regards
Jack

MRAMG1

DO IT, I did with bridgstone 050 PP's. WHAT a tire. I passed several R-tired cars at Beaverun with them.

Oh yeah, the speedo error is SOOOOOOOO small, I don't worry about it, even passing cops doing 62 in a 55 zone. Factor in a little treadwear, and your back to stock my friend.

See yeah

AWDman

Craig- the theoretical diameters are 24.71 for 245/40 and 25.03 for 255/40. the reality is tires don't hold true to specs anyway plus as mr amg pointed out the wearing down of tread makes it all moot.

more grip is what you really need so compound plays a part. i think mramgs suggestion is good.

i put 1000 miles on my winters, finally had them mounted about 6 weeks back. are you driving on yours?

AWDman

the speedo error is very small i just roughed it out by dividing 25.03 by 24.71 = 1.0129. multiply that by 60 mph gives 60.8. less than 1 mph pessimistic.

you do pick up 2 mph at redline in 5th gear tho!!!!! haha

bud4ya

I have probally put 20 or 30 miles on them. Can not bring myself to drive it in the bad weather. I do need to try it to see how they go.

bud4ya

how does the math work for mileage? Would I actually be putting less miles on the car with the 255's and 235's up front or would it be more miles like the MPH.

So from what you are saying is that if my speedo reads 60 I am really doing 60.8 MPH? As the tread wears down that margin of error is reduced

AWDman

yeah. as you see it inconsequential, slighty less registered miles as each rotation of rear tires carries you a smidgen farther on 255s. (all things being equal)

weather has been fairly warm here coastal connecticut. the thing that pisses me off in winter driving is the sand and gravel on the highways......due to the mild winter i95 is mostly free of the usual crud so i've been letting myself enjoy the c32 for commuting.

bud4ya

Same here with the sand. The salt you never get totally off either. But if I was smart I would drive the car year round since I only keep them about 2 years. If I was going to keep it for 10 years then it would make sense to leave it garaged

bud4ya

They are not that expensive

AWDman

one last thing......225/45 and 255/40 are virtually identical in overall diameter.

i ran 235/45 in fronts (yoke a048) when i first started track days......the profile is kinda high. try to get a tire mounted before buying. discount tire or tire rack have accomodated me with this in past and allowed me to return tires undamaged by road contact or dismounting process.

now would be a good time to go for the 18"s tho. the best compromise looks vs handling IMO.

MRAMG1

Plus they STICK like glue my friend. Just one word of caution, they do only have a treadwear of 140. So don't expect 20,000 mile from them. But BOY ARE THEY FUN

See yeah

bud4ya

I have been keeping an eye open for CLK or C55 wheels also

bud4ya

I am going to see if I can find a place around here that has them. As long as they stick well I am happy.

MRAMG1

One word TireRack.com

See yeah

bud4ya

I was going to go with the Toyo T-1 R's again but these sound more sticky. Any have experience with these two tires that can comment.

My buddy who manages a tire store can get me the T1R's in the 255's back and 235 fronts for $480 just for the tires. I will see how much he can get these others for

FrankW

http://www.1010tires.com/TireSizeCalculator.asp