apart from it being off the speedo and the sidewalls a bit tall, is there anything wrong with running 245/40/18 on the rears? possible braking failure etc... ?

according to tire calcs, its like an 25mm increase in rolling diameter when compared to ap1 size (R:225/50/16?).

 

anyone?

 

Nothing, I am running 245/40/18 all around right now on 18x9.5's and they feel great.

 

It's a tall tire but you'll be fine. Just watch your speed. At highway speeds you'll easily be going 5+ mph faster than your speedo says. If you normally drive fast sometimes that's just enough to get you pulled for speeding when you don't think you are.

 

What size (width) wheel? If you're running a 9" or wider, I'd go with a 255 in a 35 profile. That's what I'm running with a 225/40 front.

 

There is something wrong with that size. They are taller than the OE tires and will throw off the speedometer, odometer and gear ration. With the 225/40R18 on the front and the 245/40R18 rear you can also mess up the anti lock brakes.

 

if it means anything,

im running 17/18 combo

F: 215/45/17 on 9"
and
R: 235/40/18 over 9.5"
and want to run if possible R: 245/40/18"

i didnt want to increase the width for the front as i want clearance for my fenders and didnt want to go down on profile as i dont want to lower the car anymore to fill in the wheelgaps.

with 235/40/18's the sidewall looked a tad shorter than 215/45 which is why im asking about 245/40/18's instead.

any possible recommendations for some 17/18 combo tires?