Chain idler project
Regarding the Sonic chain tube problem, (something an ex-machine shop teacher would be interested in), the whole idea of a metal chain running thru a plastic tube just doesn't compute. Yes, I'm old fashioned and very self-reliant. Though I don't have all the machine tools I had when I taught, I still can 'make do'. I was occasionally throwing the chain on my LWB. The thought of spending $85 on the idler from Linear was abhorrent, so I fabricated one using an old rear derailleur, some scrap aluminum, and using the kickstand bracket as the mounting point. (I use the kickstand also). I don't know the anatomy of the Sonic that well from memory, since I have only seen them up close a couple of times, but can't something that uses a caged roller accomplish the same thing as the tube, and offer less resistance? My idler doesn't add any resistance, and keeps the chain in perfect alignment. Due to the spring tension of the 2 rollers, it adjusts for changes when I shift on the rear cassette. Anyway, just an idea.
Any questions email Charles Gaffen
Just click on the thumbnail for full size picture.