Front Rotors are warped at only 8100 miles (13000 Km)?2008 R1200R

[deilenberger]

About the calipers- I thought that calipers where made to find center (within reason). I've always thought that both sides were independant of each other and hydrolically driven. They both come up to resistance from both sides and they self center???....or am I all wet on this?

You're correct, but only "within reason".. if a shop could take a very fine cut - a few thousands of an inch - (I have no idea how they'd do this since they would have to put the rim in a huge lathe) - then it probably wouldn't be an issue, but if the rotors wear enough and you had worn pads, and they took a bigger cut there is the possibility of pushing the outboard piston past it's normal travel design - which could result in failure.

If you can find a shop that thinks they could do this sort of job - please let us know who they are and what the results are.. I spent a lot of time trying to find a shop that would resurface a K75 rotor - and the only shop that tried it ruined the rotors to the point of making them unsafe.

 

[rad]

Just my take on the subject having had two BMW's with warped rotors, I would invest no money on fixes unless it also address the cause of the warpage. I learned this lesson on my GS that warped its rotors and I replaced them. Yup, second warped like the first in under 10,000 miles.

 

[BobbyB26]

Just to be clear, I'm not talking about re-surfacing the rotor, I'm talking about resurfacing the rim itself.

My thinking here is that I don't want to warp out a third set, so yes agreed, have to figure out what is causing the problem or it'll just repeat itself. I have a hard time believing that the first set warped badly and then the second set started out wonky also. I guess there is a chance that the second set showed up wonky from the factory, but I think I'm better off exploring the possibility that the rim mounting points are off. Seems to me that if I could find a machine shop to do the job, that they'd only be taking a very incremental amount off to align things perfectly. I understand keeping the caliper within specs for travel, but I just can't imagine removing such a small amount would take it out of specs? Am I off on my thinking here?

If there is a concern here about ending up out of specs on the caliper, then couldn't you also shave the caliper mounting points by that same increment and keep it within tolerance?

 

[BobbyB26]

Just my take on the subject having had two BMW's with warped rotors, I would invest no money on fixes unless it also address the cause of the warpage. I learned this lesson on my GS that warped its rotors and I replaced them. Yup, second warped like the first in under 10,000 miles.

Rad- How did you finally resolve the issue?

 

[rad]

Rad- How did you finally resolve the issue?

Well, before I warped a third set on my GS its second final drive failed. I also went with a new front wheel, it was a 21" one for off road. Our local BMW shop, where I bought the bike gave me a great price on a trade in after they fixed the second final drive failure on their dime again

On the 2007' I purchased new factory rotors and the rotor button/fastener retro fit upgrade from BMW.
BMW was replacing front wheels early on before they came up with the fastener upgrade.

I have always felt it was completly a wheel surface issue and not a rotor issue. I don't know of anybody who has resurfaced the wheel rotor mating surfaces. The theory sounds good, the issue might be finding a shop capable and staying within tolerances.

 

[EvryDayRide]

I have a 2011 R1200GS. Warped 2 sets of rotors on one side. The problem ended up being where the rotor mounts to the wheel. Even though the wheel met the outside edge of still being within spec, BMW replaced the front wheel while on warranty. Problem solved. I am still mad at BMW for not replacing both rotors when they put the new wheel on. One rotor has 12000 miles of more wear than the new one. But, from what I have been told, I am lucky that I got the wheel replaced. No problems now......

John

 

[deilenberger]

Just to be clear, I'm not talking about re-surfacing the rotor, I'm talking about resurfacing the rim itself.

Bobby, I realized that.

The question is how?

What tool are you going to use (or is a machinist going to use) to do this? I worked closely for a few decades with one of the best "model-shops (a very special machine shop)" in the world - and bet even they would be challenged to come up with a way of doing that doesn't involve the custom machinery that is used for wheel manufacturing. You have to get 5 small mounting points, located about 6-7" from the center of a bearing (which will have some play in it) to be absolutely true as the wheel is rotated, then get the other side the same and absolutely true and parallel to the first side.

Perhaps with a lot of special fixtures this might be doable - but I don't know of any machine shop other then a wheel manufacturer who would have the fixtures - and making it would cost many many times over what a brand new rim would cost.

 

[BobbyB26]

Got it. Sounds like you've explored this much farther than I have. I figured it would be a "do-able" thing to have a local machine shop tackle, but probably not huh. Checked into a new rim and at over $1K that's a big fat ouch! Can't see paying that much coin at this point.

So, where does that leave me? Milling the rim- probably not going to happen. Getting a new one- probably not going to happen. So, I either live with a shimmy, or I come up with another plan. Can someone tell me more about the "button/fastener retro fit upgrade " that's been mentioned? Does this only work with stock rotors, or can it work with the ones I just put on? How do these "buttons" install and work?

 

[rad]

Got it. Sounds like you've explored this much farther than I have. I figured it would be a "do-able" thing to have a local machine shop tackle, but probably not huh. Checked into a new rim and at over $1K that's a big fat ouch! Can't see paying that much coin at this point.

So, where does that leave me? Milling the rim- probably not going to happen. Getting a new one- probably not going to happen. So, I either live with a shimmy, or I come up with another plan. Can someone tell me more about the "button/fastener retro fit upgrade " that's been mentioned? Does this only work with stock rotors, or can it work with the ones I just put on? How do these "buttons" install and work?

They clearly allow more movement. Yours may already be the upgraded ones. Stop by your local BMW dealer with your bike and they should be able to tell you very quickly if yours are upgraded.


I think, but I'm not positive that the rotors are also different.

You could start by just doing some quick research on line with a parts Fiche like one at Max BMW and compare part numbers between the early rotors and buttons and the ones a year or two later.

 

[ANDYVH]

I'm taking my 07 RT into the shop to have them measure the front rotor runout and possibly determine the shudder/pulsing cause. If I need to upgrade the front rotors to a floating style mount I'll buy the parts and do the work myself.

My question though, has anyone just changed the front rotors to an aftermarket brand (Galfer, etc) that has cured the sudder/pulsing issue?

Oh, to those that claim that holding on the front brake after coming to a stop causes hot brake pad material to migrate onto the rotors,.....really? I don't buy that at all. If that were the case then hundreds of thousands of cars and motorcycles would produce the same result.

 

[alancoles]

Andy, the idea that keeping the brakes applied after coming to a stop can "warp" the rotors is a common misconception regarding brakes. However, if one does this with rotors and pads that are extremely hot from very spirited mountain riding, a track day, etc., than it can result in uneven brake-pad material transfer to the rotor which will cause a pulsating in brakes that most misdiagnose as warped rotors. This can also occur from improper bedding in of new pads.

Regarding the idea of going to a different rotor, I haven't read every post in this thread, but am of the impression that the cause of the warping has been identified by BMW as an uneven mounting surface and the cure that they have initiated is to switch to a newer semi-floating mounting system. If both of those items are correct than going to a different rotor would not solve the issue. It might postpone it, but the underlying cause would still exist.

 

[dpspeer]

I replaced the front rotors with EBC's on my '07 RT at 110k miles due to warpage. I trued them by using shims between the rotor and mounting bosses on the wheel - attempting to "true" the bosses by removing material is totally impractical. Also, just bolting up new rotors using the old style "buttons" is not likely to work - they just don't "float" like the newer style.

Shim thicknesses ran from 0 to .004". Final runnout was < .002" as measured using a dial indicator with the wheel mounted on the bike. It took 2 iterations of "shim-assemble-check" to get it so don't use locktite (or new screws for that matter). Once you have it shimmed right, remove the bolts one at a time and carefully add locktite and retorque - the blind holes cause it to "push out" and may gum up the mounting hardware.

50k miles later they still work great. The downside to the EBC's are that they rust rather easily and the discs were .005" thicker than the originals (which reduced what little "float" they had even further).

 

[steveinVT]

'07 R1200R warped rotors

The front brake started shuddering at around 15K. I suspect it did it when I spent half-an-hour practicing panic stops. It didn't seem to affect the actual stopping, but after riding another bike, I realized I had to address it. I changed the mounting shims, checked the rim for runout (none), bought some aftermarket rotors, tried stoning the originals, all to no avail. I finally sent the original rotors off to a place that resurfaces them for about $100/side. Problem solved. That was 10K ago. Now I'm dealing with a failed ABS module. Hell, my '84 R65LS was less trouble.

 

[alancoles]

...sent the original rotors off to a place that resurfaces them for about $100/side. Problem solved. That was 10K ago...

If there was no run-out on the discs but resurfacing cured the shudder, than that definitely sounds like uneven pad material transfer onto the discs.

Every once and awhile we would run across that issue on my old race car and the quick and inexpensive fix was that we'd install a set of very aggressive pads that we used for short sprints. Too aggressive for an actual race but perfect for very short sprints where you needed strong cold-pad bite. The aggressive pads would clean up the discs in just a few laps and on we'd go.

 

[BMARC153920]

If there was no run-out on the discs but resurfacing cured the shudder, than that definitely sounds like uneven pad material transfer onto the discs.

Every once and awhile we would run across that issue on my old race car and the quick and inexpensive fix was that we'd install a set of very aggressive pads that we used for short sprints. Too aggressive for an actual race but perfect for very short sprints where you needed strong cold-pad bite. The aggressive pads would clean up the discs in just a few laps and on we'd go.

This is interesting. I'm getting a brake shudder the last few feet if a stop on my GT. I didn't check the run out but he discs feel smooth. I noticed the pads were just about at the end of the wear bars so put new pads on.

Haven't gotten to ride with the new pads but would worn pads cause a shudder as the bike slows to a stop? It only happened during the last few feet, hard braking or light braking at any speed had no ill feeling.

 

[alancoles]

Marc, I'm no expert in this area but have a fair bit of experience with brakes and when I was racing I had one of the largest independent brake retailers in the US as one of my sponsors. That provided me with some great technical support and education on brakes.

When you say it happens during both easy and hard braking, during the hard braking does it happen even if you maintain the braking force until a complete stop? We virtually never do that but rather reduce brake pressure as we get very close to a complete stop to avoid the harshness of those final few feet if equal pressure is maintained to the very end.

My thinking is that if it only occurs during the final portion of braking under moderate to light brake pressure than it might be a small amount of uneven pad transfer, or uneven pad wear. Most of the time uneven pads can be seen by simply removing the pads and looking at them, feeling them, or placing them on a flat surface and shining a light from behind. If it is the problem of uneven pads than one should ensure that the caliper pistons are moving freely, and there is no misalignment between the rotor and the caliper and perhaps replace the pads if they are too uneven. If you suspect a warped rotor, check not only the runout at the outer edge of the caliper, but also in the middle of the rotor face.

A shudder like you describe can also be sometimes caused by pads that are starting to get a bit wooden from under usage or too much light application, however that's rare and IIRC you ride your bike at a good pace. I've run across this only a few times in the past. One was when I bought my Ducati ST3s and no amount of trying to recondition the pads worked so I had to replace virtually new pads because the previous owner had not ridden the bike much and always used the brakes very very lightly.

If it is wooden pads that aren't past the point of no return, or a very mild uneven pad material transfer situation, than often a repeat of the proper pad / rotor break-in process can fix things.

Here's a link to the proper process: http://www.stoptech.com/technical-support/technical-white-papers/bed-in-theory-definitions-and-procedures/stoptech-sport-brake-pad-bed-in-suggestions

Some background material: http://www.stoptech.com/technical-support/technical-white-papers/bed-in-theory-definitions-and-procedures

Method for removing uneven pad deposits: http://www.stoptech.com/technical-support/technical-white-papers/uneven-pad-deposit-removal

Nighttime reading: http://www.stoptech.com/technical-support/technical-white-papers

 

[BMARC153920]

Thanks for the reply. Let me clarify a bit it is perfectly smooth during hard or light brake applications at all speeds, just the last five or so feet of the stop dis I get the shudder.

With the new pads I'll see how it is, bike is still under warranty so if it's the rotors then it's BMWs problem.

 

[temesvar]

Thanks for the reply. Let me clarify a bit it is perfectly smooth during hard or light brake applications at all speeds, just the last five or so feet of the stop dis I get the shudder.

With the new pads I'll see how it is, bike is still under warranty so if it's the rotors then it's BMWs problem.

Just thought i mention it here, since i had experienced same with my single arm Triumph. A few mechanics looked at it, took it for a ride,
and the verdict was either faulty brakes, ABS, suspension, broken wire in the tire. lose upper fork cross brace nut. It turned out to be
a lose rear wheel nut. Your bike rear wheel has 5 nuts, so is not the case. But are the bearings good?
Just a thought.

 

[BMARC153920]

Just thought i mention it here, since i had experienced same with my single arm Triumph. A few mechanics looked at it, took it for a ride,
and the verdict was either faulty brakes, ABS, suspension, broken wire in the tire. lose upper fork cross brace nut. It turned out to be
a lose rear wheel nut. Your bike rear wheel has 5 nuts, so is not the case. But are the bearings good?
Just a thought.

Didn't think of the bearings. I will check them out. Thanks.

 

[ANDYVH]

I had my 07 RT in at the local BMW shop (where I used to work part time) and the technician checked both front discs and the rear disc for run out. He said all three were within BMW specs for run out. But the bike still pulses/surges significantly toward the end of the stop especially if I maintain light brake application. If I ease the front brake off and more rear brake to the end of the stop I can avoid most of it. But when I ride two up I tend to use a bit more front brake, and at the end of the stop the surge is enough to cause my passenger to push forward. Either way, the surge is unacceptable and has to be corrected. Since the rotors are solid mounted to the wheel the run out cause is either the rotors or the mount surface for the rotors.

I have gone out on back roads and practiced repeated high effort stops to the point of getting some brake fade. Once I let the brakes cool off the surge is still there. As a point of reference, I still ride my 94 R1100RS (full floating discs on 12 buttons per disc) which now has 188,000 miles on it, original discs, and no surge/pulse at all, even though I use the same braking style. So the full floating rotors on my 94 RS makes the braking smooth even if the discs have some run out. Since the Wisconsin riding season will be done in about a month, I'll take the front discs off and get them ground flat by my brother in the machine shop he works in.