Heres another cool thing. This is a urethane idler turned from a skate wheel. Has dual U.S. made bearings. Its much quieter and Im sure more durable that the stock plastic one. Was only $8.99 in various colors on ebay. There is no sleeve between the bearings so you have to run a lock nut on the inside to keep from crushing the bearings. Not a big deal at all.
I like how that looks mounted to seat post tube, looks very durable.
I make the idler/tensioner wheels from skate board wheels, I use high quality bearings and I use bearing spacer between the bearings which prevent crushing the bearings, I do leave my rollers larger diameter for better contact area, I sell mine for $12.00 shipped anywhere in lower 48 for free with an axle bolt, nuts and washers.
The price I charge, mainly just covers wheel & hardware parts, postage, packaging and about $3 for my labor.
I haven't advertised much on here, but a few members here have got one from me and as far as I know they're still working great just like all of mine are.
Again, nice looking set up there cannonball2