I just noticed that the rear tire on my GL1000 is cupping on the left side. I've never seen that on a bike before. Is that a indication that my swingarm bearings are toast? I tried wiggling it and couldn't move it. I never jacked it up yet though. What is causing this?
The left side is where you would expect it because of the crown of the road. If everything is tight and the shocks are working OK, it's probably just the type of tire you're using. Some types are more prone to cupping than others.
Normal as mentioned, but low pressure of course agravates the problem and some tire designs are much worse at cupping than others. I always thought it was the road crown too causing more wear on the left than the right, but actually this is not the case. The actual cause is the motorcycle is turning left more than it turns right. As silly and strange as this sounds, think about it and it all makes sense. When you turn left you are on the outside of the road, right you're on the inside. Every turn you take no matter if you're travelling 10mph in the city or 75mph on the interstate is longer left turns than right. This adds up over time depending on how many turns the tires take and can add up to much more wear on the left than right.
Yea, it all makes sense now. I've not noticed this until now. I think it's because I accelerate real hard and wear the centers out real fast usually. This bike, not so much. Plus I just got this bike, so the PO is the person that put the wear on the tires. I've only rode it 250 miles so far. But I plan to at least double that this weekend. I'm going to double check the tire pressure to be sure though. Thanks for the repys!!