Araya R200 - Apollo Custom Sport - Specialized StumpJumper
As usual - Sheldon has some help. From his online glossary....
The upper pulley on a rear derailer. This is the pulley that actually guides the chain from one sprocket to another. Shimano jockey pulleys are designed with a "Centeron®" mechanism that allows a small amount of sidewards motion to compensate for imprecise index adjustment.
Since the pulley with the steel insert is slightly narrower than the bushing, which would leave some room for "sideways motion", I gather, that the pulley with the steel insert is the jockey pulley, and should be installed in the upper position.
An hence the other pulley is the tension pulley, and should be installed in the lower position.
Anyone like to confirm this ? I'd appreciate the input.
Vintage Trek, Vintage Diamond Back Mountain Bike, Bianchi Axis CrossBike
I have an XT derailleur sitting here on the table and the upper pulley can indeed be moved backandforth sideways a little. So I think your analysis is correct. On the XT, the top one says "sealed ceramic bush pulley," while the bottom says "sealed bearing pulley". I can't read the writing in your picture, but perhaps your pulleys also have bush vs. bearing labelling on them? Bushing one goes up top.
like 15. my favorite a 1951 schwinn spitfire cruiser. also have a 1959 amf roadmaster, 1962 jch deluxe cruiser among others.
easy. the way you have them in the pict is basically the way they go. the ideler wheel with the metal insert goes at the top of the derailleur, closest to the cassette. the other idler wheel, the tensioner, goes on the bottom of the derailleur. only the first wheel has the extra metal insert in it and the tensioner doesn't need but only the one bearing in it. a little lube on those beariings before you put them all together is a good idea.