I should clarify my previous statements:
I originally responded to the query regarding Perry's mounts for an airhead BMW. My first hand experience was not encouraging. On the other hand, Perry has been mounting sidecars longer than I have and he has many satisfied customers. We mounted this hack maybe 15 years ago and I don't know if it is the same as what he is using now.
My remarks about BMW frames were based upon both personal experience and the widely held reputation BMWs of that era have for being flexible and for frame failure. BMW manuals for these bikes specifically state the frames are lighter than the earlier /2 and are not adequate for sidecar use. You do not need to look far to find anecdotal evidence to support that position. I believe this weakness can be addressed with a proper subframe. That is my opinion, not necessarily fact.
Pam I was speaking about my experience with Mike's bike, not your experience with your bike. There are lots of variables and it is not surprising experiences and opinions will differ. I don't know how you mounted your sidecar or where the attachment points are. I am very happy to hear that it is working well for you. In my opinion the R90 is one of the few really pretty bikes BMW has built. Some would consider it collectible. If it were mine I would not risk damaging the frame with clamps or by welding on it. It is possible to bolt mounts to an airhead without a subframe, but even this I would be reluctant to do. A subframe allows you to better position the bottom mounts and re enforce the bike frame fore and aft and from side to side.
Depending on the use, among other things, a year may not be enough time for damage to become evident. My KLRs broke after several seasons hard use which include classes on bumpy ground, dualsport rallies, a few tipovers and daily commuting. I discovered the damage after jumps with a passenger aboard and some high speed washboard. . I really think though, that the damage was cumulative. Even if you only ride on the street a substandard mount will eventually result in damage or failure. In my opinion.
But please understand me! I am not calling your rig substandard, nor am I saying Perry's mounts are no good. I'd have to have them in front of me. Besides, I am not an engineer. I am just a guy who has messed around with a few of these things. What I have posted are just opinions and worth no more than what you paid for them :-)
Originally Posted by pampine
Barry, I'm trying real hard to do just that.
I know that RedMenace's KLR rigs take a lot of heat; and I wasn't being absolutely critical of his rigs, only relatively in the context of criticizing my BMW rig. Or, more to the point, of seemingly disregarding completely my experience with said rig. See, polite discourse at least allows for the possibility that my rig was a very good one.
Also, I said that it was possible that your "subframe" for old BMWs might be exactly what they needed if their frames failed, and not the $2,000+ overkill that I see here day after day. I readily admit that the new, almost frameless BMWs, need such "overkill." And the fact that I reiterated someone else's request for better photos meant that I was considering DMC's solution if/when I hang another sidecar on my ancient Beemer. About the last thing I'd want to do is endanger life and limb by trying to build something myself, plus I don't much like working metal.
All that other stuff just got in the way; so I was trying to tell you how I got it out of the way for my business. And now I'm really irritated that I apparently find it necessary to explain myself.