The interesting thread on car tyres prompts this particular query. We have a BMW K1 with a sidecar attached, which we purchased already built. There have been a number of owners, most I know, and the rig is reasonably sorted. It should be at twenty years old. Overall its an enjoyable, satisfying ride. Car tyres are fitted all round. There are no issues with the bike front, or the sidecar arrangement. Perhaps the only mild criticism would be they're all different sizes, however, no big deal for us. The issue isn't tyres, but the rear wheel set up on this paralever version of the four cylinder K (1989). At time of purchase the rear bevel drive bearings were identified as something to keep an eye on. Indeed, a set of bearings were already on board. Uncertain as to how many occasions these bearings had been a problem, but replacement had been done just prior to purchase. Unfortunately, 3000 miles into our ownership, the large bearing in the bevel failed. The cage had disintegrated, but fortunately we had stopped before anything else in the bevel drive was damaged. Repair was undertaken and the K was soon back in action. However, a frequent eye is kept on the rear end, checking for play and oil levels, just in case. The BMW has not done massive miles altogether (40,000 plus). The issue here is trusting the set up, so much so that we have embarked on a radical amendment to the rear end to provide additional support by making the swingarm twin sided. A BMW steel swingarm and bevel off an R1200C is the basis. A 165 x 15" tyre is the rubber of choice at this stage on an alloy car wheel. Any thoughts out there ? Firstly, about the reliability of the single sided BMW rear end. Plus, experiences and ideas about possible amendments. A key question might be regarding the possible effects on the single sided configuration according to whether the sidecar is mounted on the left as ours is, or on the right.