[ctbear]

My 2015 F30 335i M Sport comes with the 19" 403M staggered setup:

225/40r19
255/35r19

I'm entertaining the idea of going square and wondering what the stock square setup from the factory is for the M Sport model.

According to what I found on Tirerack, stock square M Sport would be:

225/45r18

1) Can anyone confirm this?
2) Are there any differences in the suspension tuning from the factory between a square and staggered setup for an M Sport model?

I prefer to stick with oem sizing and oem rims (they sure are heavy though...) to maintain the original "BMW tuning" of the vehicle.

Reasons for going square:

I'm probably comparing apples to oranges here, but after driving a 330i loaner with a square setup, I feel like that car is more nimble and eager to turn in/respond to steering inputs (i'm sure the smaller engine up front contributes to this too).

My other reasons for considering a square setup:
a) being able to rotate tires
b) these 19" wheels (oem runflats) ride very harshly over potholes/manholes/non-perfect roads

[Spielzeugauto]

There's no difference in suspension tuning between wheel setups. And yes that would be the stock square size.

If you're worried about potholes and ride quality, consider going up to a 235/45-18 all around.

[ctbear]

Originally Posted by Spielzeugauto

There's no difference in suspension tuning between wheel setups. And yes that would be the stock square size.

If you're worried about potholes and ride quality, consider going up to a 235/45-18 all around.

Thanks for confirming.

That is not a stock bmw size is it? Would it be compatible to use tires of that sizing on bmw oem 18" rims with no modifications (ie. stretch)?

[Spielzeugauto]

Originally Posted by ctbear

Thanks for confirming.

That is not a stock bmw size is it? Would it be compatible to use tires of that sizing on bmw oem 18" rims with no modifications (ie. stretch)?

It is not a stock size, slightly wider and taller but you'd be hard pressed to notice on casual inspection.
245-45/18 will also fit onto stock 18" BMW wheels, but that may be noticable.

[Pipe335i]

I have 403m staggered with 255/35r19 in all corners, no issues at all .