51 Re: Rear wheel modification - K1200 or K1100 on the K100? Mon Sep 16, 2019 6:17 am
beachcomber550
active member
chris846 wrote:Seeing as this thread is (still) about the possibilities of fitting wider rear wheels to a K, I'll add this because some future reader might find it useful.
The 5-spoke (best looking wheels ever) rims fitted to the K1200 are a common choice. They can be hard to get hold of, compared to the very similar looking wheels fitted to boxers from the same era. Most times though, people find they can't use boxer wheels for two reasons: boxer wheels have disc mounting posts cast onto the spokes (Ks don't - the disc is sandwiched between the wheel and the hub), and boxer wheels have too much left offset (sometimes described as 'A' and 'B' wheels - is this to make up the space for the 'missing' disc?)
Well, the problematic extra offset on a boxer wheel can itself be 'offset' by leaving out the k series disc, and using a boxer disc mounted on the wheel. I did this with a 5" boxer rim (there are 5.5" options out there too) and, with a bit of adjustment to the swingarm pivots, it was possible to get the left offset down to just 3mm.
This itself isn't without a bit of grief; the boxer disc has a smaller OD, but a boxer rear caliper is correct for this, and (in typical BMW style) fits straight on the caliper mounts on the bevel drive (K & boxer bevels are very similar). I had to shift the caliper and disc over to the left (spacers on the caliper, machined a bit off the disc mounting posts) but this was to clear a wider, non-standard shock, dunno if this would be necessary with a standard shock.
Yes Chris timely advice / warning. I went down that route as well when I was investigating all the options 10 years ago ! For some reason [?] the Oilhead 5 spoke Wobblies were cheaper than the Kay wheels. Maybe as much as 25%. There was no research already done back in the day that I could refer to - so platforms such as this are invaluable to peeps today who might not want to be in the "let's all be different together" club.
I think the answer to this debate [?] is that those who have obviously tried out this format and come to the conclusion that in their view handling is compromised [ Ben Kingham still there ? ]will not want to repeat their experience and those of us who like to tinker and experiment - will.
Did I ever mention fitting the Wire spoked GS wheels to my Kay ............ probably best not to go there.