Originally Posted by JulieDriving
Hey trackman - I bought my tires from Ben at tirerack (great guy btw and often recommended here) and he advised to go with the slightly larger 255/275.
He said his experience is that the OEM 245/265 tires are just too small for the ZCP wheels. The stock (summer) tires are already very stretched, and he explained that the issue is exacerbated with winters, which generally need to be slightly larger for a given size of wheel.
I also saw a thread on bimmerpost where that actually happened to someone. The guy brought his tires to the dealership and they tried and tried but could not fit his winter 246/265 tires on his (stock) ZCP wheels.
The tire shop even had trouble installing my 255/ 275 tires, so I'm glad I didn't go any smaller!
Here's a screen shot of what I purchased.
Originally Posted by Agent-GHQ
I refuse to buy into such rhetoric! Just cuz he's been selling tires for some times doesn't mean he works at BMW where the real engineers test out the best fit tires. After all, if it becomes a safe issue by the manufacturer that would lead to a legal suit. If anything, I suspect a sales pitch!! I will stick with OEM size 245/265 on my ZCP
FYI - I understand skepticism about some vendors but Tire Rack is a solid and honest vendor (based on my experience purchasing multiple sets of wheels, tires, suspension bits), been supporting of E90post for years, and Ben is very active on the forum and knows the M3 well. They have nothing to gain by recommending something that doesn't work. Keep in mind that the OEM PS2's are a lot more expensive than the 255/275 PSS that they typically recommend (thereby they actually have something to lose..). Furthermore, the application that she was referring to was snow tires which run a little narrower, and aren't even available in OEM sizes. BMW does not recommend snow tires in any size on ZCP wheels (they don't recommend against it either, as far as I know) so Tire Rack's recommendation is actually very good considering.
Also... Numerous forum members have switched to the 255/275 combo on ZCP wheels. The regular 18" and 19" wheels are 8.5 / 9.5 widths and also runs the 245/265 tire sizes. ZCP is 9 / 10 width. The extra width the ZCP wheels works very well with the wider 255/275 tire size. BMW had cost and efficiency considerations when choosing their tire specs (didn't make sense to switch to a different tire size for the ZCP option package). I have tried many different wheel and tire combos on the car and almost all performed better than OEM (except for the 20" wheels/tires I had briefly).
My point is that there is a lot of knowledge around here and it would serve you well to be open to it. All auto manufacturers have to make compromises in order to please their accountants and appeal to a wide spectrum of buyers. Tweaking the car to better suit your needs can be very successful (and can fail if done incorrectly...). The BMW engineers did not set out to build the best car - at any cost -.... that's what Pagoni does.