I have the BMW ribbed sport grips on my 2002 ST1100 and the throttle assist would not lock in place against the rubber grip. I went to the local ACE Hardware store and purchased a 15/16" ID nylon snap-in bushing and fit it in the end of the rubber grip between the grip and the plastic throttle tube so the outer part of the nylon bushing is what locks against the throttle assist. Works like a charm and I am out a whole $0.85 for the bushing. I have attached a photo of the bushing. I looked at several different options but this one works great. BTW, I have both the throttle assist Kurakyn 6285 and clutch side 6288 and paid about $95.00 total new on eBay. My bike came with a Vista Cruise throttle lock that was in the way of the starter lever. These look 100% better and it's a much cleaner setup. I have not noticed an increase in vibration with the lighter weights either, which was a big concern.