Use flanged bearings, instead of sprockets, for idler pulleys? #16
Description
Two flanged bearings are cheaper than a single sprocket and will probably work better.
The bearings would need to be aligned carefully because they're larger than the 20 tooth sprocket they replace. The side of the belt that attaches to the anchor bolts needs to be straight.
The belt will need a half twist on both sides so that the flat side of the belt rides on the bearings (the bearings don't have teeth).
Look into using an idler pulley kit instead. It's more expensive, but may be more convenient.