So, I just replaced the grips on my Triumph.
These are supposed to be for 7/8" bars, and the left one fit fine. I didn't bother to check before I installed them if the left and right were different sizes, figuring that if I attempted to put the throttle-side grip on the left, it would just be way too big and I'd notice. But then the throttle side grip was very difficult to install, I had to heat it up to get it to stretch over the throttle tube.
So I now suspect both grips are 7/8" and I just stretched one. And obviously now the right side grip is literally larger in diameter than the left, since I think they are the same thickness.
I guess I never bothered to check if the Oury grips on my GS are also like this, but a quick check seems to tell me maybe they are the same, the RH grip is 1/8" or so larger in total diameter than the LH grip due to being stretched over the throttle tube.
Am I wrong in expecting motorcycle grips to be made so both sides, when installed, should be the same diameter? And that the throttle size grip should have an appropriately larger inner diameter than the LH side? Or if I'm not entirely wrong, how do I tell whether grips I order are going to be the correct size? The original Triumph grips were obviously made to be the same diameter left/right and to fit the throttle tube.
I am only out about $9 for these not-perfect grips so I'll not mind ordering another pair. Just annoyed that they make them this way.