Why is my R1200GS front disc pulsing?
Q. I recently took my pride and joy R1200GS to my local BMW garage for its 6000-mile service. I asked them to investigate a front brake pulsing at low speed. Now I had a Tiger that did exactly the same thing and was told it was warped discs.
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I was informed after the service that the mechanic could not find anything wrong with it and that it could be polish on the discs. So I went home and dutifully cleaned the discs to remove any contamination.
However this did not stop the pulsing. Should I get them independently checked to see if they are warped because I am having doubts about the BMW garage service?
Rich Eagles, email
Polish on discs is unlikely to be the cause and it¹s pretty easy to measure the run-out on discs with a dial indicator gauge tool that the average workshop should have, so getting a second opinion shouldn¹t be prohibitive.
It could also be because the front wheel spindle is bent, or the front-end has become twisted slightly.
If you slacken off the bolts that hold the forks and allow everything to settle into position that might cure it.
As to the cause of warping, if you are in the habit of holding the front brake on after a rapid stop, the disc could develop a hot spot where the pad heat dissipates through the disc, warping it.