Mel, you're right. It's a std vs x-ring question. I've used diamond mc chain since the 70's and I think it's probably your best bet for std chain. Why don't you try one and see how it works out for you. If you don't have to adjust it all the time, you're probably set. After all, it was good enough for us back then. Be sure to lube it often though. I lube mine every 100 miles or so while it's warm. If you are perpetually adjusting, think about an x-ring. But x-ring chais are MUCH wider than standard and some people here have had them hit and wear through the transmission case. It has clearance on my 750 K0 and another member here told me he has no trouble on his K1. I think 550's have some clearance issues.