Im not trying to start a flame war and Im not trolling. This is a serious question/discussion. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o> Before I winterized my 02 GSA last year, I noticed that the front brakes pulsed a bit. Not real bad but noticeable to the point where another rider rode it and told me he thought the rotors were warped. Being a skeptic and a cheap SOB, I opted to try and clean the rotors this winter. So I pull the front wheel and rotors and then using my trusty Porter Cable random orbit sander and some 100-grit sandpaper, I cleaned them up. And now, like magic, there is no more pulsing. Im not a machinist but I dont think 100 grit sandpaper is going to true up a warped piece of steel. <o></o> If my bike had been under warranty and I had taken it to the dealership with stories of warped rotors my guess is they would have figured it was brake pad residue and they would have had a couple options. 1) Tell me they really werent warped and I that was mistaken and should learn how to use the brakes or 2) take the bike in for a look-see. #1 is not real consumer friendly so I think most dealers would go for option #2. <o></o> With the bike in the service department, they would need to put in the time to remove the front wheel to really see what the problem is. If the problem is pad residue, they would have a few options. 1) They can tell the customer its not a warranty issue, and it will cost $135 to make it right, 2) clean the rotors, put them back on the wheel and re-install the wheel for free or 3) tell the customer the rotors are warped and get paid with a warranty claim from BMW. #1 pisses of the customer. #2 pisses of the owner of the dealership. #3 makes the bike owner happy, the dealership happy but pisses off BMW. Since the bike owner might buy another bike, Im guessing most dealers will choose #3. <o></o> Im not saying brake rotors DONT warp, but I am guessing the vast majority of warped rotors, arent warped. So heres the question. For those that had warped front rotor warranty claims, did you get a report on what the rotor run-out was?
Probably not but removing the rotor and caliper may have freed up a sticky caliper slide and or the rotor rivits.....
<BR> Blanchard grinder in-a-box. Whatever you did, it worked. It could have bee the R&R. - Jim<BR><BR>
GSes have four pot calipers. They don't have caliper slides. I had the discs (rotors) and front pads on my 1200 replaced under warranty at 3K miles. They were displaying all the symptoms of being warped. The shuddering got worse when I used the brakes hard and they were worse when they were hot. The dealership checked the run out and quoted it to me along with the service spec. The figures they quoted were outside BMW's tolerance. 9K miles later, the replacement discs are still fine. The 1200 uses almost identical discs and calipers to the Ducati Multistrada which also suffers from warping of the discs. I think that using fixed four pot calipers without fully floating discs isn't a particularly smart system. That's not to say that in some cases what appears to be warped discs isn't due to a build up of pad material on the braking surface.
RRRRR How about I edit my comment to say caliper things They may be floating discs and solid mounted calipers but those pads have to move on something and if they get hung up its just bad.
My dealer replaced my rotors at 4000 miles. Now at 8000 they are going to be replaced again, "under warranty". Sucks
It appears that some "warped rotors" are not actually warped. In actuality they have an uneven build up of brake pad material. The common fix is to sand the rotors and the pads. This seems to help with a smaller percentage of bikes, probably yours. Jim
My '07 adventure is exhibiting pulsing with light braking at 3k miles. Never had an issue with my '05 1200gs. Will have to see what the dealer says. I do not see any evidence of "brake residue buildup" whatever that is.
The pulsing brake problem is fairly common with Buell XB bikes. It appears that the problem is caused by uneven deposits of brake pad material onto the rotors. Buell's solution is to replace the rotors when this happens, which is covered by warranty. Many people have reported that the problem can be cured by switching to a more abrasive brake pad. The Lyndal gold pads are what most people use. My Ulysses'es brakes began to pulse last summer. I ignored it for a while, then switched to the Lyndal pads. This did cause the pulsing to diminish, but it never went away. I eventually got the rotor replaced, which eleminated the pulsing. I've still got the Lyndals on the bike. Hopefully they will keep the pulsing from returning.
90% of the time warped rotors are not warped just pad material transfer symptoms. Some times rotors truly do warp but I have found most of the time its due to a disk lock incident. The bigger question is what causes pad material transfer and how do you avoid it? Its really pretty simple to avoid. When sitting still at traffic lights with hot brakes try to not use the brakes to hold you in place. If you have to use the brake then use just a little bit of rear. Whenever possible, hold yourself in place by flat footing the bike and release your brakes. If you can change your habits as described your pad material transfer issue will go away.
My understanding of the problem is that the build up happens mostly when the rotors are hot and the pad stays in contact with the same position for an extended period of time. i.e. at a stoplight Instead of keeping the front brake held down use the rear brake since it does less actual braking it should be a little cooler and less likely to cook the pad material to the rotor. rideLD we were typing at the same time....
This problem is also present with many superbikes thus I clean my rotors during every service cuase it's really not hard to do and makes a difference when stopping from 180MPH And the idea of not holding the lever is GREAT. Its just a habit for me BUT I have no idea why ??? Probably from riding the big ass aluminum dual leading shoe drum braked bikes. If you got them hot then held the lever it was garrenteed to go out of round..... OH Crap I just aged myself didn't I
My '05 gs had surging brakes. i thought they may be warped. I took a palm sander to them and problem solved
Sounds like a good idea to do on a regular basis, 6K service? What is the best procedure to remove the deposits? Jim
I recently cleaned a bit of scoring and pad transfer on my 12GS rear rotor. I simply used a sanding block and let the bike idle on the centerstand in 6th gear. That's the easy way for the rear, the front I would probably just reach in wiwh some sandpaper. Look ma, power sander :huh Keep your hands outta the spoke folks.
YA its really easy just a good sanding block and some fine grit ( i use 220 ) You just have to take your time and not get all violent