04 525i Front Rotor Size Question (320mm vs 310mm) - Mine came with 320mm???
03-11-2013, 04:47 AM
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04 525i Front Rotor Size Question (320mm vs 310mm) - Mine came with 320mm???
Hi
I'm pretty new to the forum but I've been lurking for a while. I've owned my 04 525i for a couple years now. I'm just now getting around to replacing the brakes all the way around. I ordered Beck / Arnley rotors from rockauto, wagner pads, and URO wear sensors. The rear brake change out went fine but I got stuck at the front.
The problem is that I removed 320mm rotors from the front. The ones that rockauto sent me are 310mm. Assuming it was their mistake I hit the net and started searching. However, it appears that 310mm front rotors is standard for my 2004 525i. I am confused because it appears that the 320mm rotors I removed are sized correctly because they were worn till ~1mm from the edge. So now I'm wondering what's going on. Is the 320mm size something that just happens to fit? Is it possible the PO "upgraded" the knuckle and brake calipers to a higher model/year E60 that supports 320mm rotors? Should I go ahead and use the 310mm rotors?
Any help is GREATLY appreciated
Lane
I'm pretty new to the forum but I've been lurking for a while. I've owned my 04 525i for a couple years now. I'm just now getting around to replacing the brakes all the way around. I ordered Beck / Arnley rotors from rockauto, wagner pads, and URO wear sensors. The rear brake change out went fine but I got stuck at the front.
The problem is that I removed 320mm rotors from the front. The ones that rockauto sent me are 310mm. Assuming it was their mistake I hit the net and started searching. However, it appears that 310mm front rotors is standard for my 2004 525i. I am confused because it appears that the 320mm rotors I removed are sized correctly because they were worn till ~1mm from the edge. So now I'm wondering what's going on. Is the 320mm size something that just happens to fit? Is it possible the PO "upgraded" the knuckle and brake calipers to a higher model/year E60 that supports 320mm rotors? Should I go ahead and use the 310mm rotors?
Any help is GREATLY appreciated
Lane
03-11-2013, 05:04 AM
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edit: The fronts I took off could very well be 324mm. I only had the rotors off for a minute last night before I threw them back on (car is a daily) and took a quick measurement with a inches tape measurement.
Lane
Lane
03-11-2013, 05:21 AM
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My Ride: '06 530i, '07 C280 4matic, '98 ML320
on my '06 530i, front rotors are 324mm x 30mm, and the rear rotors are 320mm x 20mm.
Previous owner may have upgraded the front brakes on your car. If so, return those and get the rotors for 530i.
Previous owner may have upgraded the front brakes on your car. If so, return those and get the rotors for 530i.
03-11-2013, 05:30 AM
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Edit #2:
I believe this thread can be deleted / ignored now. I found out that 04 525is with automatic transmissions have 324mm front rotors. Guess what, I ordered the standard trans rotors from rockauto which are supposed to be 310mm so it was my own damn fault
Oh well, I'll get them returned and get the right ones on the way.
Sorry for the waste of space. I'm generally better about searching before posting.
Lane
03-11-2013, 01:02 PM
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My Ride: 2005 545i Sport
There should be a BMW Part Number stamped into the hub of the rotor.
310 x 24mm = 34116754021
324 x 30mm = 34116753221
Both are OEM sizes.
When in doubt about what is OEM, use this link:
BMW Parts - Authentic OEM BMW Parts direct from BMW of South Atlanta | BMW of South Atlanta
310 x 24mm = 34116754021
324 x 30mm = 34116753221
Both are OEM sizes.
When in doubt about what is OEM, use this link:
BMW Parts - Authentic OEM BMW Parts direct from BMW of South Atlanta | BMW of South Atlanta
Last edited by paran; 03-11-2013 at 01:05 PM.
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