R1200GS judder on braking

[cjacwr]

Hello,
This is the first time I have posted to your forum. I have a 54 R1200GS with 29,000 miles. Occasionally on moderate braking I get a shuddering throught the bars. I have changed the original discs for wavy discs and also put on new pads. The juddering does not occur when the back brake is applied. I have tried the bike with the ABS turned off.

I am now at a loss. Could there be a problem with the servo?

Any help would be much appreciated.

Thanks

 

[GreatScott]

Welcome along. Great ssite for all sorts of info. Try a search and see what you come up with. Try this for starters

http://www.ukgser.com/forums/showthread.php?t=180163&highlight=judder

 

[JJH]

welcome someone will help you with your problem JJH

 

[Bryn]

Welcome to UKGSer

Looks like you're not the only one with similar problems... so you're in the right place

 

[Pukmeister]

Doesn't sound like a servo fault.

Try giving your disks a scrub with some scotchbrite pad and some aerosol brake cleaning solvent, could be a build up of brake pad residue in one spot.

Put the bike on the centrestand and have an assistant press the rear down so the front wheel is in the air. Spin the front wheel and listen/feel for tight spots or disk warp, a common problem.

 

[cjacwr]

Brake judder

Doesn't sound like a servo fault.

Try giving your disks a scrub with some scotchbrite pad and some aerosol brake cleaning solvent, could be a build up of brake pad residue in one spot.

Put the bike on the centrestand and have an assistant press the rear down so the front wheel is in the air. Spin the front wheel and listen/feel for tight spots or disk warp, a common problem.

Hi and thanks for your reply. The original BMW discs were said to be a tad warped on run out according to my local dealer. I purchased wavy discs and new pads and have fitted them. The problem remains.

 

[Pukmeister]

You could have some slight corrosion or raised threads on the faces of the disk mounting lugs on the wheel.

When I had slight disk judder I removed my front disks and the flat lugs had slightly raised areas on the thread around the hole. I used a very shall flat needle file to dress the faces flat, then refitted the disk.

It turned out it was my rear disk that was warped, not felt through the rear pedal but noticeable through the front brakes due to the linked braking effect. Easily detected by spinning the rear wheel whilst on the centrestand and listening for the pads rubbing/feeling the tight spot.

If you change the rear disk, be very careful to clean old loctite out of the disk mounting holes and check the mounting flange for cracks as per the thread below.

http://www.ukgser.com/forums/showthread.php?t=181453

 

[cjacwr]

R12--GS front judder

You could have some slight corrosion or raised threads on the faces of the disk mounting lugs on the wheel.

When I had slight disk judder I removed my front disks and the flat lugs had slightly raised areas on the thread around the hole. I used a very shall flat needle file to dress the faces flat, then refitted the disk.

It turned out it was my rear disk that was warped, not felt through the rear pedal but noticeable through the front brakes due to the linked braking effect. Easily detected by spinning the rear wheel whilst on the centrestand and listening for the pads rubbing/feeling the tight spot.

If you change the rear disk, be very careful to clean old loctite out of the disk mounting holes and check the mounting flange for cracks as per the thread below.

http://www.ukgser.com/forums/showthread.php?t=181453

Hi and thanks for all your advice. When I fitted the new front discs, I also fitted new screws. I re-used the old rollers and spring washers as Bahnstormers said that would be fine. Do you think I should replace them? If I do will I also need to replace the screws again or will a touch of loctite be good enough? Having returned from a biking break in Devon, yesterday I cleaned the bike and checked the front and rear wheels. Both wheels spin freely with no sign of high spots or catching. There is a slight lip on the rear disc but I don't think enough to worry about.

I am not sure I quite understand what you mean about raised threads on the wheel mounting lugs! Will a visual inspection show this or will I have to dis-assemble the discs from the wheel?
Many thanks once again

 

[Pukmeister]

The disk mounting lugs on the wheel are the alloy areas of the wheel casting itself where the disks are bolted onto. Corrosion could develop on the alloy wheel surface between the disk and the wheel where it is bolted. The only way to check for this would be to remove the disks again.

If your wheels spin freely with no tight spots then your disks are obviously running true and there would be no point in removing the disks to check. The only proper way to check is with a dial test indicator to measure both the wheel and disk runout relative to a fixed place on the forks eg caliper mounting bracket.

Sorry I can't be any more help than that, I'm out of ideas.

 

[cjacwr]

1200gs Judder AGAIN

Hi Guys,

I am very grateful fro all the helpful advise I have been given regarding possible soultions to my unpredictable judder.
Since my last thread, I have biked to Devon and back. A couple of my experienced pals advised me that my tyres were getting ridged and in need of replacement and that they could possibly contributer to the judder. I have since replaced both tyres with Bridgestone 020's. I am still scrubbing off the first 100 miles so cannot yet judge if the problem is solved. I also invested in the Haynes manual. Imagine my surprise to find on page 5.3 mention of anti-chatter shims on the front pads. Yes you have guessed, my bike does not have these shims. can anyone tell me if they were discontinued on the 54 model of R1200GS? If they are still required, I guess their absence could be my problem. I still have the discs and pads I took off (OEM equipment) and there were no shims attached to the pads.

Thanks