Ebay Aluminum Wheel Spacers
I bought a set of these from user XXBILLETXX from ebay in mid-2011 for a 2002 Grizzly 660 with the mindset of using stock lightweight rims while widening the stance for added stability. They seemed to be well designed and fit their purpose. I bought the 1" version. They came with 4 spacers, 16 washers and lock nuts to bolt them to the stock hubs, and 16 wheel studs. The spacers were threaded for the studs to screw in, and in order to properly install them, you need to use some good loctite. The way they thread in, when you tighten lugnuts from one end, you are essentially backing the studs out the opposite direction. Without loctite to hold them in place, you would just back the studs out of the spacer from the rear as you tightened the lugnuts down.
In stock form with stock wheels/tires, the Grizzly measured about 43 3/4" wide, this improved to 45 3/4" with the spacers installed. Total weight for the set of 4 was 9 lbs, so figure the spacers weight in at around 2.25 lbs each.
I sold these last week after having bought a new set of rims/tires which will have their own offset, and would take away the need for the spacers. For what its worth and some comparison of spacers vs. offset aftermarket wheels, the front track of the Grizzly with STI C7 wheels and 25x8-12 Bear Claw HTR's improved to around 47.5" wide.
In my opinion, for a narrow quad like this, the spacers were a good low cost alternative to widening the stance and gaining some stability. A definitely plus for anyone wanting to continue running stock rims.