Originally Posted by The Jerk
Researching tires a bit and looking at the Bridgestone BT-45. The original rear tire size according to the owner's manual is 130/80-18. Apparently the BT-45 doesn't come in this size (or motorcycle superstore just doesn't carry it). So what are people going with? The 120/80-18 looks like the closest option even though by my calculations it would cut sidewall height by 8mm.
EDIT: Im dumb. I didn't even look at the V-rated version of the tire. They do have the 130/80-18 size in the V-rated version. I certainly don't need V-rated rubber on a W650 but it's only a couple bucks more to get the right size so I'll probably just do that.
I know on car tires the ratings do make a big difference in handling.
The higher the speed rating, generally the stiffer the sidewall, so better handling.
Probably the same for bike tires.