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Discussion Starter #1
The old thought is you can machine your rotors just fine, but with BMW's everyone tells you that you NEED to always buy new ones. My rear rotors show a minimum of 20.4 and I measured them at 20.51. They have a decent groove and would need to be re surfaced... what would you recommend?
 

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Discussion Starter #3
The guy at the auto repair store said I would be fine cutting them at least once.... even though they recommend new ones.
 

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I tend to agree with your auto guy. I think you could get by machining them once.
 

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The guy at the auto repair store said I would be fine cutting them at least once.... even though they recommend new ones.
Now do you honestly think that was thoughtful response from the auto store guy considering the details of your particular car and situation?

Or did the high school drop out just tell you what the training manual said to tell everyone:
"Hi, I've got a 1996 super lardwagon, what should I do with my rotors?"
"Well, you can usually cut them at least once, but we really recommend replacing them"

And just for fun, let's say you did decide to resurface them. Do you really think trying to take 0.055mm off each side is a reasonable idea?
 

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The old thought is you can machine your rotors just fine, but with BMW's everyone tells you that you NEED to always buy new ones. My rear rotors show a minimum of 20.4 and I measured them at 20.51. They have a decent groove and would need to be re surfaced... what would you recommend?
You're really thinking about installing rotors that are .11mm from the minimum thickness????
 

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Discussion Starter #8
Well the guy we go to isn't a complete idiot, and he first off started saying that for BMW's and Mercedes you should almost always replace them, but you can usually be fine cutting them once. He knows I have a 330ci and has worked on my and my father's car before... offers us discounts because we have gone back to him.

Nonetheless, I dont know enough about the topic to make a well informed decision. I dont know if 20.51 is enough width left to resurface... or if it really matters to go below the minimum specs...

At $100 per rotor, vs $10-$15 to resurface them... thats where im trying to make a decision on.

Thanks for your opinion though.
 

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Discussion Starter #10
Yea I just did my search and basically you get the same arguments for any other discussion, some people say you can't and some people say you can... I'm leaning towards I SHOULDN'T because 20.51 compared to 20.4 is is .055mm for each side.

One other thing im confused is on Tire rack it says $100 each for a rotor, but on turner motorsport is $93 for a pair for the same OEM rotors? Did I misread tirerack or are the prices that off?
 

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The guy at the auto repair store said I would be fine cutting them at least once.... even though they recommend new ones.
Everytime I do a brake job I do machine them at least once before replacing with new ones.
 

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you can get blank brembos for 40 each. the thinner the rotors the hotter the pads get, they will wear out faster get hot faster and will need to change them sooner, i would like to resurface them myself but it isnt really a good idea. Im thinking maybe we can get away with doing the rear ones but not the front ones??? anyone have any though on this.
 

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Yea I just did my search and basically you get the same arguments for any other discussion, some people say you can't and some people say you can... I'm leaning towards I SHOULDN'T because 20.51 compared to 20.4 is is .055mm for each side.
Well, if you decide to machine them, be sure to use at least 240 grit sandpaper, otherwise the grit particle size will be larger than the depth of material you are trying to remove.
 

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Discussion Starter #18
Hahaha. nice I'm going to replace them... jpr you seem to be a knowledgable smart ass... Is there a difference between brembo, zimmerman, or balo when it comes to OEM rotors? Bimmerworld has a PAIR of OEM rotors for $88.99 where they are 99 each at tirerack...
 

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I did once, big mistake with factory rotors. Even though they were within "spec", they warped in no time.

Luckily the OEM rotors are cheap at $45 each. Total brake job from a BMW indy shop for front and rear, including 4-rotors, pads, brake sensors, and labor should cost no more than $600 out the door, or $300 for 1 side.
 
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