[jeffthx]

Let me preface this by saying that my knowledge of understanding wheel fitment is limited to understanding how to interpret tire sizes. I don't know anything about offsets, spacers, etc. I'm hoping to get some guidance from this forum to help me make a decision about a possible change from a square 18" setup to a staggered 19" setup. My suspension and brakes are stock, and I don't plan to change either of them. I'm not interested in lowering the car, stiffening the suspension, etc. So... here's what I'm considering:

I recently bought a 2015 435i Xdrive convertible (F33). I have the factory square setup with 400m wheels and a new set of 225/45/18 P7 RFs (they were put on by the dealer before I bought the car; this wouldn't necessarily have been my tire choice, but I don't actually mind them).

I'm considering buying a set of 19" 366 rims from a member that came off of a 650i. He has indicated that the specs are:

Front: 19x8.5 +33
Rear: 19x9 +44

I'm considering Michelin Pilot Sport 4S tires, but I'm wondering:

a) Would these wheels fit my car without any modifications/concerns/etc?

b) If the answer to a) is yes, what tire sizes would be recommended for this wheel setup? TireRack's site returned: 225/40ZR19 (F) • 255/35ZR19 (R). However, when I put my car into Discount Tire's site, the widest tire size that was returned was 245.

I'd love any guidance to help me understand the pros/cons of what I'm considering, and also what I should know about my fitment options. My primary motivation is appearance, but any gains in traction, etc would also be welcomed.

Thanks,
Jeff

[.BMW.]

The wheels will fit fine!

But with xDrive you need to be a bit more careful with tires sizes.

I would recommend 275/35-19 for the rear wheels, then you have two options for the fronts. Either 235/40-19 or 245/40-19.

235/40-19, dia. 671mm
245/40-19, dia. 679mm

275/35-19, dia. 675mm

The front sizes differs about ±0.5% from the rear, both setups will work with xDrive.

[alohasurftoad]

oem diameter is 26". for x-drive(transfer case), the max difference between front and rear diameters should not exceed 1.2%, equal front and rear diameters is optimum.

tire size combo i'd suggest on the wheel specs you've given is 235/40/19 front, 265/35/19 rear. 26.4" dia. front, 26.3" dia. rear, difference 0.4%. slightly larger diameter=taller sidewall=reduced fenderwell gap from oem spec.

you may also use 225/40/19, 255/35/19 oem specs. 225/40 will be somewhat stretched on 8.5

or 245/35/19, 255/35/19, 25.8"/26", 0.8%, front fenderwell gap will be increased slightly from oem spec due to shorter sidewall

[jeffthx]

This is all helpful. Thanks.

Just to confirm-- the tire size combos that are being recommended would be able to simply be swapped out with my current wheels without any other spacers or modifications?

Thanks,
Jeff

[alohasurftoad]

my suggestions are for the 366 wheels you are considering

[jeffthx]

Originally Posted by alohasurftoad

my suggestions are for the 366 wheels you are considering

Thanks--I should have been more clear with the wording of my question; that is what I thought you meant with your suggestions, and I appreciate it.

Thanks,
Jeff

[jeffthx]

One more question: A different set of wheels I'm looking at has the following specs:

19x8.5 ET 33
19x9.5 ET 39

This is a bit wider in the rear than the first set I posted above. 2 questions (again):

--With stock suspension/brakes, are there any concerns with these wheel widths? I have no plans to do anything with suspension/lowering/etc.

--What would be a good tire size combo for xDrive with these wheel widths? I want a fairly low-profile look, but don't want the ride to be too harsh (my car currently has 225/45/18 P7 run-flats, and don't want anything that would ride rougher than that).


Thanks in advance,
Jeff

[alohasurftoad]

same recommendation as previous. 235/40/19, 265/35/19 is the best size for x-drive and the wheels you're considering. what brand/model of tires are you planning? because unfortunately the selection of brand/model is limited with those sizes.

[jeffthx]

Originally Posted by alohasurftoad

same recommendation as previous. 235/40/19, 265/35/19 is the best size for x-drive and the wheels you're considering. what brand/model of tires are you planning? because unfortunately the selection of brand/model is limited with those sizes.

People seem to be raving about the Michelin Pilot Sport 4S, which do appear to come in that size combination. I'm open to other suggestions, though. I don't know that I dislike my P7s like some people seem to, but maybe I'll understand why they're not held in high regard once I get something else on there.

Thanks,
Jeff

[alohasurftoad]

the fitment will look like thx@wdeerfield except your rear wheel/tires will be 6mm further out and the front 2mm further out. if you can afford it, get the mps4s and be done with it.

https://f30.bimmerpost.com/forums/sh...hlight=vmr+803

[jeffthx]

Originally Posted by alohasurftoad

the fitment will look like thx@wdeerfield except your rear wheel/tires will be 6mm further out and the front 2mm further out. if you can afford it, get the mps4s and be done with it.

https://f30.bimmerpost.com/forums/sh...hlight=vmr+803

I really appreciate the responses. And you're in my favorite state (my wife and I escape to Hawaii to get away from the MN winters every year for a week or so). It seems like a great place to live.

Thanks,
Jeff