[pae9017901]

Hey everyone, I finally picked up my 06 325xi on Tuesday. I just got some 18x9 +34 inch rims. My question to you guys is what is a good tire size to go with? These are going to be my summer wheels. I was thinking about 235/45/18 front and 255/40/18 rear. Will this setup be ok?

[Bory E90]

That won't work for an xi. Your tire diameter has to be within 1% to -1% of each other. I used a tire calculator on those setup and it came up -1.1%.

[madskillzE90]

Go with exact same tire size because of AWD and future rotation of tires.
Always run same size and same tires

[Bluewater328iT]

TireRack recommends a 255/35 R18 tire with that wheel. However, I doubt if it will fit on the front as BMW and TireRack do not recommend anything wider than 8.5 on the front. As as you have an xi, staggered set up is not desirable.

[zipstic]

Fronts: 235/40/18
Rears: 265/35/18

The fronts will be stretched a little due to a 9 inch wheel.

[boro92]

+1 on running 235/40. They will fit if you have camber up front and u are not lci (for the rear). If you are lci I would run 225/45 and call it a day. It will be a safer fitment. Fwiw I run 235/40/18 all around on 18*9 +39 and the fronts would poke if I didn't run with camber plates. My rears barely clear on an lci wagon (but I only run -1.1 rear camber)

[3002 tii]

Originally Posted by Bluewater328iT

TireRack recommends a 255/35 R18 tire with that wheel. However, I doubt if it will fit on the front as BMW and TireRack do not recommend anything wider than 8.5 on the front. As as you have an xi, staggered set up is not desirable.

There are xi models that come staggered from factory. It's not a big deal since he's not tracking the car. And TR recommends conservative setups so they don't have to deal with returns.

Originally Posted by boro92

+1 on running 235/40. They will fit if you have camber up front and u are not lci (for the rear). If you are lci I would run 225/45 and call it a day. It will be a safer fitment. Fwiw I run 235/40/18 all around on 18*9 +39 and the fronts would poke if I didn't run with camber plates. My rears barely clear on an lci wagon (but I only run -1.1 rear camber)

Why do you recommend 225/45 over 225/40?

I would just go 255/35 square (non-extreme summer, i.e. avoid RS3, Star Spec, etc.) and throw on some Dinan fixed camber plates. You'll get -1.2 degrees or so which is fine for daily.

[boro92]

Originally Posted by 3002 tii

There are xi models that come staggered from factory. It's not a big deal since he's not tracking the car. And TR recommends conservative setups so they don't have to deal with returns.




Why do you recommend 225/45 over 225/40?

I would just go 255/35 square (non-extreme summer, i.e. avoid RS3, Star Spec, etc.) and throw on some Dinan fixed camber plates. You'll get -1.2 degrees or so which is fine for daily.

Whoops typo. I meant 225/40
FWIW dinan fixed camber plates will raise front ride height by half an inch or so (10mm). If it's on coilovers and one adjusts for that ride height change, one would lose 10mm bump travel.