Replacing Crown bearing R1150GS

Bearing

Hear a lot about shimming under the bearing. Do I not just go with whatever shims are already there. If not what is shimming used to achieve. What specifications/tolerances am I trying to meet.
 
Hear a lot about shimming under the bearing. Do I not just go with whatever shims are already there. If not what is shimming used to achieve. What specifications/tolerances am I trying to meet.

If it has done about 50,000 with current shimming and that is cool for you, leave the shims as is and budget for the same in another 50,000:beer:
 
Hear a lot about shimming under the bearing. Do I not just go with whatever shims are already there. If not what is shimming used to achieve. What specifications/tolerances am I trying to meet.

Bearing tolerances are very tight so if the factory built it right then the shims should be fine as long as you don't damage them. I believe that they are there to provide the correct preload on the taper roller.

My original lasted 25,000 miles, I replaced the big bearing and seal myself using the original shims which then lasted to 61,000 miles.

If you want the entire FD sorted I can recommend Scriminger Engineering. I think they charged me £250 including the carriage to send it back to me. Mine had failed again at 70,000 ish, shortly before I shipped the bike to the USA for an 8,000 mile trip. I didn't want to do it myself as the taper roller was knackered as well and I didn't have the equipment, knowledge or time to do it myself as it would almost certainly need different shims.
 
Bearing

The offending part. Interestingly we measured the parallelism of the inner race of the crown bearing at 13 microns prior to removing it for reference purposes, thats fairly impressive.
 

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Marcopol The most important thing is to get the bearing settled in the outer cover so that there is no space between the inside of the outer cover, the shims, and the outer bearing face

I think this were a few novices end up with failures somewhere down the line

Getting the outer pretty hot will allow it to "Fall Over the bearing"

But be careful also not to load too much pressure on the bearing cage of the little one!
 


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