stock brake good?

raywong · 03-20-2013, 03:26 AM

I noticed a steering vibration when braking from high speed(180KMH or up). the disc were machined 1.5 years ago because of the same thing. does it mean I need new rotor?

TC Kline Racing · 03-20-2013, 09:35 AM

More than likely you are below minimum spec and they need replaced. When they get machined and are thinner, it is much easier for them to 'warp.'

How do the pads look?

aus · 03-20-2013, 04:15 PM

Could be pad deposit too.
Typically, BMW rotors are not machined. They are changed with the pads in most cases.
You may need different pads if it's pad deposit, but I've run stock pads at the track before without any problems.

lcrain · 03-21-2013, 10:28 AM

After my last track day (stock 1M) I noticed similar vibration feedback in my steering wheel. I was concerned my rotors were warped, but my shop believes it was uneven pad deposit.

My car only has ~9800 miles on it so I really don't want to replace the rotors if they still have some life. I am about to bite the bullet on some track pads, stainless lines, and fluid. Wondering if I should just go ahead and buy new rotors too.

The car has seen ~6 track days and is low on miles. Are my rotors shot? Any insight would be great.

HP Autosport · 03-21-2013, 09:54 PM

Quote:

Originally Posted by lcrain

After my last track day (stock 1M) I noticed similar vibration feedback in my steering wheel. I was concerned my rotors were warped, but my shop believes it was uneven pad deposit.

My car only has ~9800 miles on it so I really don't want to replace the rotors if they still have some life. I am about to bite the bullet on some track pads, stainless lines, and fluid. Wondering if I should just go ahead and buy new rotors too.

The car has seen ~6 track days and is low on miles. Are my rotors shot? Any insight would be great.

put a dial indicator on the rotors and check for runout. If runout is the issue, your shop can tell you how much material needs to be removed to make it true. If the machine process will take the rotor close to minimum thickness, replace them.

HP Autosport · 03-21-2013, 11:19 PM

Quote:

Originally Posted by Lute

Not suppose to cut these rotors, suppose to replace.

Sure, when you replace pads and rotors as a set, it's still okay to true it when there is excessive runout on a otherwise new rotor with low miles.

03-20-2013, 03:26 AM	#1
raywong Private First Class 42 Rep 132 Posts Drives: E92M3 Join Date: Jun 2011 Location: Hong Kong iTrader: (0)	stock brake good? I noticed a steering vibration when braking from high speed(180KMH or up). the disc were machined 1.5 years ago because of the same thing. does it mean I need new rotor?
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03-20-2013, 09:35 AM	#2
TC Kline Racing 45 Rep 345 Posts Drives: Many BMW's & Porsche's Join Date: Mar 2012 Location: Columbus, OH & Santa Barbara, CA iTrader: (0)	More than likely you are below minimum spec and they need replaced. When they get machined and are thinner, it is much easier for them to 'warp.' How do the pads look?
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03-20-2013, 04:15 PM	#3
aus Major General 892 Rep 9,032 Posts Drives: Odysse Join Date: Jul 2005 Location: Seal Beach, CA iTrader: (10)	Could be pad deposit too. Typically, BMW rotors are not machined. They are changed with the pads in most cases. You may need different pads if it's pad deposit, but I've run stock pads at the track before without any problems. __________________ Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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03-21-2013, 10:28 AM	#4
lcrain Captain 56 Rep 865 Posts Drives: e36 m3, TT-RS Join Date: Sep 2006 Location: Dallas, TX iTrader: (1)	After my last track day (stock 1M) I noticed similar vibration feedback in my steering wheel. I was concerned my rotors were warped, but my shop believes it was uneven pad deposit. My car only has ~9800 miles on it so I really don't want to replace the rotors if they still have some life. I am about to bite the bullet on some track pads, stainless lines, and fluid. Wondering if I should just go ahead and buy new rotors too. The car has seen ~6 track days and is low on miles. Are my rotors shot? Any insight would be great.
	Appreciate 0 Quote