I am a fellow clyde and am a bit more of a clyde than you. I have it on good authority which is very high up the shimano food chain that you should have no problem at all. I run only shimano wheels which includes 2 sets of ultegra wheels for my cross bike and one set of dura ace wheels that I have had on my road bike now for over 5 years. There has only been one truing done in the 5 years and it was barely out at all. I'm 270 and I haven't had a problem. And regarding the R500's I have had those wheels as well with no problem what so ever. Shimano Wheels are very durable in my opinion and per my experience. Hope that helps.