Dr.TuB

Previous owner fitted
front: 225 40 18 Dunlop SP Sport 9000
back: 225 45 18 Bridgestone Potenza RE040

would this cause any problems for me?

carbonRX8

iTrader: (1)

Do you have DSC?

Dr.TuB

yes i do :D

yiksing

The slight difference in circumference between front and rear tires would/might trigger the DSC under certain driving conditions where it normally wouldn't have.

SayNoToPistons

iTrader: (8)

^ +1. Front tire will be spinning faster. Might make DSC go "WTF is going on!? Lost of traction!"

REDRX3RX8

The good thing is: you probably won't get DSC when you turn and accelerate hard. That's when I get it a lot.

If you ever want to rotate those 3% smaller fronts to rear.... well just don't do it or you'll know why.

Dr.TuB

im not sure what you mean by if i ever want to rotate those 3% smaller fronts to rear......

REDRX3RX8

DR.TuB,

225/40r18 are 25.1 inches in diameter approx 830 rpm per mile
225/45r18 are 25.9 inches in diameter approx 804 rpm per mile

So the 40's roll 3% faster or more than the 45's for the same speed.

Dr.TuB

so if i were to replace the back with the 40s i should be okay?

yiksing

Yes, as long as the circumference is not beyond 3% difference, your DSC will not pop up.

Old Rotor

The 245X40X18 are a great upgrade.