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Brake Rotors...


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Anyone had issues with warped front rotors? My 05 developed a nasty vibration under braking and it was determined the front rotors were warped. Replaced and all was fine, I'm out on an extended tour and the issue has resurfaced. I rarely use the brakes under any hard braking and it would seem odd that a cross drilled rotor would warp? I guess I'll be in for another set on my return...

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With what you have described, I would have a look for a dragging brake.


Something to understand about cross-drilled rotors is that, although, they do enhance cooling to some extent, their intended purpose is that of reducing brake fade by giving somewhere for the gasses given off by the brake pads when used under heavy load (i.e.; hot).


If everything is in its correct alignment and all moveable parts are moving as designed, take a look to how the rotors were put on the wheel. A mis-torqued rotor or one that was not put on with progressively increased torque in a proper format/pattern can cause a warping.


Also, try some brake clean on the rotor surface to ensure that there is no oil contaminating the rotor surface.


When you got your new rotors, did you get new pads? At a minimum, I would take the old pads out of the caliper and "rough" them up with a bit of sandpaper. Then, go through the normal marriage process of new pads to rotors.


Just some options to consider. Either way, be cognizant of how you are operating your motorcycle and relay the specifics to your dealer to help point them in the right direction.


Hope this helps some! thumbsup.gif


keep us posted!

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My '05 RT with 12,000 miles had the warped rotor vibration, too. I went by the dealer and I was told that it would be 3 weeks before their only BMW tech would be able to look at it. I wasn't about to wait 3 weeks so I just took my rotors off and had them reground at work. My vibration is cured, but I wonder how long it will take to come back again. If it happens again, it should do it within another 12,000 miles. I have enough meat left to do one more regrind, and I will be looking for an aftermarket set after that. Someone on this forum has mentioned that Wunderlich has some wave rotors available for the GS. I assume that the RT won't be far behind.


Unfortunately, others on this forum have been told by their dealers that BMW classifies brake rotors as a wear item and not covered under warranty. I could see them saying that at 30,000 miles, but not as early as 12,000.


At what mileage did you have your rotors replaced and at what mileage did you notice the symtoms again?

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Aren't the rotors on these bikes full-floating? That should make them pretty resistant to warp under any kind of normal operating conditions. confused.gif

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Rotors bolt directly to the wheel.. the calipers float. My 05 RT rotors warped at about 8k for no apparent reason.New rotors fixed the problem and so far they haven't warped again. There have been several reports of RT's on this web site and GS's on another with the same problem, which leads me to believe there was a bad batch of rotors on early 05 models. The allowable runnout for flatness (per BMW service CD) is 0.005"... mine had 1 rotor that measured about 0.010" and the other side had about 0.015".

Several dealers have tried to blame it on tires, wheels, and most every other thing except warped rotors. If you are experiencing heavy vibration while braking, it is absolutely a warped rotor.

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Yeah it's been a problem on some 12GSs and now starting to show up on 12RTs.


Some dealers are warrantying them, some (like mine tongue.gif) are not, claiming the rotors are a wear item.


When I can swallow the $400 I'm going to switch to Wunderlich rotors.

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which leads me to believe there was a bad batch of rotors on early 05 models.
Or a bad batch of wheels. If the rotor isn't floating then it will be sensitive to the flatness of the mounting surface on the wheel. If there are any irregularities at that interface it can cause recurrent warping of the rotors. I've heard of this many times and even experienced it personally myself. The cure is to machine the rotor mounting surface on the wheel perfectly flat. If this is the problem and it isn't rectified you will continue to eat rotors indefinitely.
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My ST started the vibrations recently during harder braking. Now it's doing it during moderate braking. Feels like a lumpy tire. I'm putting it in the shop when the banjo bolts and wire clips come in, and have it all done at once.

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Rotors bolt directly to the wheel.. the calipers float.

The 2005 RT's may be different, but on a 2004 RT, the front wheel rotors float and the calipers are fixed, while on the rear the rotor is fixed and the caliper floats.


I just replaced the front rotors on my RT because of vibration/shudder under hard braking. Runout on the rotors was under .002" Not sure what the problem was, but new rotors appears to have corrected it.

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The 2005 RT's may be different, but on a 2004 RT,
They are. The new hexhead series have fixed rotors.


The uneven wheel mounting surfaces is an interesting theory I hadn't thought of though. Hummm...

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