There was so much damage to the bike I made the decision to customize it, create a G/S look.
I got the idea from the image above. The job will be done in several phases. I want different forks, but that will come later. My first job is to convert to wire wheels.
I bought used wheels. 1150 G/S for the front and 1200 G/S for the rear
Latest 2019/03/17: The photo on the left shows progress so far. The front is all but complete
I got the idea from the image above. The job will be done in several phases. I want different forks, but that will come later. My first job is to convert to wire wheels.
I bought used wheels. 1150 G/S for the front and 1200 G/S for the rear
Latest 2019/03/17: The photo on the left shows progress so far. The front is all but complete
Rear Wheel
I tried several options. In the end I settled for original K100 calipers, adapter plate, custom rotor. I did try using the original rotor but that's too difficult to make work in my opinion.
I think the logical first step is to get the wheel fitted so you have good front/back alignment. I read somewhere in BMW documentation about a tolerance of 5mm. A friend of mine fitted a GS rear wheel as is. It runs 10mm to the left of the front wheel - he experienced no handling problems. I took the wheel, tire and all, to a brake disk skimming shop. They were able to mount it on their lathe and remove about 8mm from the hub as indicated in the photo. It may also be necessary to skim the center locating part, prevent it from bottoming out - the surface with the mounting bolt holes needs to make contact.
When mounting the caliper there are a bunch of things that need to be considered:
I think the logical first step is to get the wheel fitted so you have good front/back alignment. I read somewhere in BMW documentation about a tolerance of 5mm. A friend of mine fitted a GS rear wheel as is. It runs 10mm to the left of the front wheel - he experienced no handling problems. I took the wheel, tire and all, to a brake disk skimming shop. They were able to mount it on their lathe and remove about 8mm from the hub as indicated in the photo. It may also be necessary to skim the center locating part, prevent it from bottoming out - the surface with the mounting bolt holes needs to make contact.
When mounting the caliper there are a bunch of things that need to be considered:
- Horizontally, left/right, the caliper position needs to be so that the disk runs exactly between the pads.
- Vertically it needs to be positioned so that there is optimal contact between pads and disk while also ensuring that the caliper body does not foul with the spokes. Because of the spoke angles the space available for the calipers varies with the vertical position of the calipers. This is why I had a bigger than necessary disk custom made; to move the caliper body up, away from the final drive housing and in so doing get optimum spoke to caliper housing clearance.
- Horizontally it also needs to move backward of the normal position a fraction to accommodate the constraint in the previous bullet point and allowing sufficient distance between holes in the adapter bracket. Refer to the photo of the rear mounting bracket. You will notice that pairs of mounting holes would overlap if the caliper body were to be moved straight up.
- Although mounting position must be within small limits shimming between caliper body, mounting bracket and/or the mounting lugs on the final drive cover can serve to make small adjustments. So too slightly oversize holes in the mounting bracket.
All three disks are custom made, laser cut, 4.5mm ss, cheaper than OEM. I took an original 1150 GS front rotor in as a pattern, but the rear had to be 306mm diameter. I have a dxf, CAD compatible file for that.
The brackets and spacers in the middle part of the drawing turned out to be not usable.
The brackets and spacers in the middle part of the drawing turned out to be not usable.