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[Kar15]

Hey guys,

I'm currently running a staggered set of 18" OEM BMW Authentic M3 Competition Wheels (ZCP/CSL). My front tire size is: 255/35/18 and the back tire size is 275/35/18.

I really like this size of tires on my car, it gives it a real aggressive look.
However, I recently purchased a set of replicas wheels of the same kind since I wanted them in 19" (AG M359).

My question is as follows; can I put the same tire sizes on the 19's or no? If not, what is the max I can go for the tires size on them? I know that the recommended tires for these wheels on my car are front: 235/35/19 and rear: 265/30/19. I've added some pictures below of the 18's on the car with the tires.

[Kar15]

Bump ... Anyone?

[bumere90]

Wouldn't it be too wide?

[VTECaddict]

A few things:

1. The AG M359 is a replica of the E90/E92 ZCP wheels. Your current wheels are E46 CSL/ZCP package style wheels. Similar, but not the same.

2. BMW never made the E46 CSL/ZCP wheel in 18", so whoever told you your wheels were authentic OEM were misinformed.

3. Your rear tires are too big. The fronts are bigger than stock, but same size as stock E9x 18" rear tire size, so the diameter is still fine. But your rear tires are over 2% greater in rolling diameter vs your fronts. This throws off your speedo, and more importantly your DSC and xDrive. It's important for AWD to have at least the same rolling diameter front to back, if not the same exact size.

Just go with the recommended tire sizes. If you want wider, you can go 245/35/19 front and 275/30/19 rear. It will not look the same as your current setup (beefy/squared tire look) because the M359 wheels are much wider. Your tires will look slightly stretched and much thinner.

[Kar15]

Originally Posted by VTECaddict

A few things:

1. The AG M359 is a replica of the E90/E92 ZCP wheels. Your current wheels are E46 CSL/ZCP package style wheels. Similar, but not the same.

2. BMW never made the E46 CSL/ZCP wheel in 18", so whoever told you your wheels were authentic OEM were misinformed.

3. Your rear tires are too big. The fronts are bigger than stock, but same size as stock E9x 18" rear tire size, so the diameter is still fine. But your rear tires are over 2% greater in rolling diameter vs your fronts. This throws off your speedo, and more importantly your DSC and xDrive. It's important for AWD to have at least the same rolling diameter front to back, if not the same exact size.

Just go with the recommended tire sizes. If you want wider, you can go 245/35/19 front and 275/30/19 rear. It will not look the same as your current setup (beefy/squared tire look) because the M359 wheels are much wider. Your tires will look slightly stretched and much thinner.

These wheels came directly from BMW from the dealership I bought my car. They we're thrown in to entice me to sign. My invoice has "18" M3 Competition Wheels" written on it....so it's kind of unnerving now that you tell me this. Is there a way for me to be 100% certain what kind/types of wheels these are by looking at them? Do they have like a serial number or some sort of stamp to identify them on the back somewhere?

Regarding the wheel size, the BMW technician said it would be fine to run with 275s in the back...from what your telling me, its a bad idea to have these massive tires on the car. Also, i don't want my tires to look stretched or thin, and I don't want them to wear out faster due to this. So i should just stick to the recommended tire sizes then?

[VTECaddict]

OEM CSL/ZCP wheels will have "BMW" and the part number embossed around the center cap where the lug holes are. If you take off the wheel, there will be "BBS" embossed on the back of one of the spokes as well.

275 is fine as long as the front tires are matched in rolling diameter, but in your case, they differ by about 2%. Going with a different rolling diameter than stock will only affect the accuracy of your speedo. The issue is the difference between front and back, which isn't ideal for DSC and especially xDrive. You want the difference to be as low as possible.

The tires won't wear out faster because of stretched tires. There is no way of getting around a thinner sidewall. You're going to a bigger rim, that means the tire needs to be thinner to keep the diameter the same.

You can probably go with
235/35, 265/30
235/35, 275/30
245/35, 275/30
245/35, 285/30

They're listed in increasing sidewall thickness. 235/35, 265/30 will be closest to stock rolling diameter. Not sure about fitting the 285 rear without rubbing problems though, so don't take my word on that one. If you're not lowering, you should probably be ok.

You can play around with different sizes using the wheel and tire calculator at the top of the wheel and tire forum.