Diffrent type of brake rotor?

[rasmiph]

I'm replacing my rear brake rotors on my 1999 323I 4dr. The rotors that I received from my parts store are different from the ones on it now. I' ve had the store recheck the parts number to make sure these rotors are the correct ones.Which they showed to be correct. The difference is this: The rotors on the car now have a cooling space between the braking surfaces like you commonly see. The rotors I received from the parts store do not have this cooling space between the the braking surfaces; which makes the rotor surfaces about 3/8" thinner because of the lack the cooling space. Will my caliber pistons be able to expand or "ajust" to the the thinner surface or will these rotors just not work? I've owned several cars thats lacked this cooling space and some people may have these type rotors on thier BMW now. These are for the rear and I'm not a hard braker so I'm just wondering if they'll work. If anybody knows about this or has this type of rotor on thier car now with no problems let me know, Thanks

 

[Big Daddy]

According to RealOem.com the front and rear brake disc's (rotors) on your car were vented. The replacements you have are not and I would not use them! I could not find and optional non-vented for your car, now the 323i wagon has a non-vented option, but not yours. Here are the BMW part numbers I came up with, Front #34111165455, rear #34211165211. What brand rotors is he selling you? They are available from Pelican Parts for $47.00 for ATE's and up to $73.00 for Genuine BMW brand.

You can also get them from Arizona AutoHaus for about the same pricing.

Arizona AutoHaus also makes this note on ordering front rotors, "Please verify front rotor diameter on 323 models, BMW factory not consistent. 2 per car."

Again I would not use the non-vented they are going to run hotter and warp easier.