[johnsims100]

im a newbie, so please be nice...

im the owner of a 318i E90 on a 06 plate, i was looking for some advice on upgrading my wheel size to 18" and what tyre size i could get away with.. i am right by saying a 225/40/18 will be ok??

[Slalom]

Welcome to the board.

The owner's manual may give you inflation pressures for different sizes of tyre - that is one source. The other is a tyre size calculator, such as this: http://www.tiresizecalculator.info/

TireRack also lets you look up your car and shows the original fitment and options to increase wheel diameter. I am not certain that your current setup will be there, since the E90 318i was not sold in America.

[sdavidson0316]

Use this to compare the width/height/offset/etc of any 2 tire/wheel combos you want. It will tell you exactly what the differences between your existing setup and your new steup will be:

http://www.rimsntires.com/rt_specs.jsp

My car is down to the last little 1/4" on spacing and this is what I use to seamlessly switch between wheels/tires.

[reprod]

If you are looking to stick to the OEM sizes then you should be looking at

Front: 225/40/18
Rear: 255/35/18

[hipnotic]

+1 or go to the tire and wheel section in the forum

[johnsims100]

Thanks guys for the advice and warm welcome.

[johnsims100]

Originally Posted by reprod

If you are looking to stick to the OEM sizes then you should be looking at

Front: 225/40/18
Rear: 255/35/18

Would that 5mm between front and rear make that much difference?