In an effort to better support this Forum, specifically @GrumpyGoat and @Motorhead1977 in this thread,
https://rswasserboxer.com/R1200RSforum/thread-1159.html about participation, I wanted to expand a little on the steps I went through in getting these rims ready for use on Tom's RS.
These rims for Tom's RS were originally on my 2016RT which was totaled in a rear end accident back in 8/21 with yet another set of rims on that bike. (I had 5 complete sets of built up rims at that time for use during the Tour of Honor ride which I finished first back in 2019... 41k miles in 7 months on my RT)
This basic cast rim, 3.5"x17", is used on several of the "street oriented" bikes in the WetHead/ShiftHead generation. Staying with this specific generation rim helps assure that the configuration of the brake rotors and the speed sensor ring are correct, you will have incompatibilities that you can't overcome if you try to use previous HexHead/CamHead generation rims.
The casting is the same, but the size of the bearings, spacer, and seals are different from bike to bike model, so that's what you need to swap out if you expand your shopping on the second hand market for donor rims.
The rear rim is basically the same, so I'll point out the specifics of what I changed to build up the front rim here for the R1250RS.
All of the parts needed are referenced from RealOEM.com for this bike.
https://www.realoem.com/bmw/enUS/showpar...Id=36_2144
A convenient starting point is to just buy a set of AllBalls bearings and seals...they have 2 bearings and 2 seals that are used specifically for the RS axle...which is the controlling part we need to match up to when building up a front rim. The set I used is AllBalls 25-1750
https://www.allballsracing.com/25-1750.html I buy them from Amazon
https://a.co/d/cfPaEt8
Using their configurator, you can only find fitment for the R1250R, but cross reference with RealOEM.com confirms these bikes have the same bearings for the front wheel.
Aside from the removal of the R1200RT bearings and seals, the inner spacer needs to be changed as well for the R/RS. The correct size for this RS build is listed as 25.5x105mm.
Having previously converted a cast rim from an F800R for my RT (the set that went away with my totaled bike) , I had the correct "spacer bush" as it's called in RealOEM.com.
I always refer to the factory OEM DVD Service RepROM for correct procedures as well as limitations and specs needed to do just about anything on these bikes...old "wives tales" or techniques passed down from different applications need to be "nipped in the bud" when working on these German machines. Examples include NOT using any kind of lubricant on Spark Plug threads, or rear wheel lug bolts, or the where to use or avoid some type of thread locker, or what torque values and tightening sequence to follow...the list of specific guidance from the manufacturer is important to say the least!
The specific details for removal of the wheel bearings indicates that heating the rim casting to 100 degrees C is required.
Another critical sequence for building up the wheel is that the bearing on the LH side (speed ring side) needs to be installed first, and seated completely against the machined rim step.
This establishes the correct wheel alignment between the forks for several things, like the spacing/air gap for the speed sensor pickup, and ensuring that the rotors are going to be centered in the calipers and not offset to one side or the other because the wrong side bearing was used as the alignment reference.
Next, flip the rim over to drop in the spacer/bush. Now that the spacer is resting against the reference bearing, the RH bearing can be "pulled in" with a threaded rod. (not pounded in with a hammer and socket). It is important to only seat this side bearing inner race up against the spacer and not seat it in against the machined step in the rim.
Finally, ensure that you seat the seals as squarely as possible to avoid too much wear on the axle or the spacer due to the effect of an oscillating contact with seal lip.
Noting that anytime you remove/install the Quick Release Axle on these bikes, it needs to be torqued to the proper value to "pre-load" the bearings and then the 4 pinch bolts need to be torqued "6 TIMES in alternate sequence" according to the RepROM...
For Tom's bike, I also installed a new set of TPMS sending units that needed to be linked to the bike's RDC for proper indication on the instrument panel using the GS-911 when I mounted the tires/rims on the bike.
https://a.co/d/2RuOVss
Mounting/balancing new Dunlop RoadSmart IV tires was like refreshing tires throughout ownership of any bike.
Hope this gives a little insight as to what was involved with building up a set of rims (mostly just the front rim) and to the importance of referencing the BMW RepROM for all the details of completing any maintenance on your bike.
Brad
Boxflyer
