After many years cycling I've finally decided I need to get a good understanding of how it all works. Mostly prompted by a recent cycling trip to Italy where my partners bike had a few problems that I was only partly equipped to deal with.
Having just stripped down the rear derailler (shimano) on my Trek mtb and then put it back together again I can't get the undexing to work. I don't suppose this is a new subject, but I couldn't turn anything up via search.
I can engage all the cogs (although a couple rattle) but the main problem appears to be the fact that in bottom gear the jockey wheel is hard up against the cog. It wasn't like that before I took it apart!
The steps I went through to adjust were 1) with cable unclamped (and in top gear on gear shift) checked high and low screws against cage position. 2) Pulled cable taut and clamped. (Not sure whether what position the tension adjustors should be - I've tried full on and off and somewhere between). 3) gears would mostly work top to bottom, but with the jockey wheel problem on the large cog. 4) resorted to random twists of the tension adjustors - to no avail.
Any help would be greatly appreciated - I don't want to have to visit the local bike shop at this early stage!
After many years cycling I've finally decided I need to get a good understanding of how it all works. Mostly prompted by a recent cycling trip to Italy where my partners bike had a few problems that I was only partly equipped to deal with.
Having just stripped down the rear derailler (shimano) on my Trek mtb and then put it back together again I can't get the undexing to work. I don't suppose this is a new subject, but I couldn't turn anything up via search.
I can engage all the cogs (although a couple rattle) but the main problem appears to be the fact that in bottom gear the jockey wheel is hard up against the cog. It wasn't like that before I took it apart!
The steps I went through to adjust were 1) with cable unclamped (and in top gear on gear shift) checked high and low screws against cage position. 2) Pulled cable taut and clamped. (Not sure whether what position the tension adjustors should be - I've tried full on and off and somewhere between). 3) gears would mostly work top to bottom, but with the jockey wheel problem on the large cog. 4) resorted to random twists of the tension adjustors - to no avail.
Any help would be greatly appreciated - I don't want to have to visit the local bike shop at this early stage!
I fail to understand the point in taking a derailer apart. Seeing and undrstanding how it works does not require that.There is a thing called the B tension adjustment that controls jockey wheel to cog distance. Random twists and mindless fiddling will likely never get it right. www.parktool.com has the drill in the repair section.Start at the beginning. I also assume you also assembled the pulleys in the correct positions. There is a top one and a bottom one.
Originally posted by boudreaux I fail to understand the point in taking a derailer apart. Seeing and undrstanding how it works does not require that.There is a thing called the B tension adjustment that controls jockey wheel to cog distance. Random twists and mindless fiddling will likely never get it right. www.parktool.com has the drill in the repair section.Start at the beginning. I also assume you also assembled the pulleys in the correct positions. There is a top one and a bottom one.
The Park Tool web site has good instructions. I would also recommend the books "Zinn and the Art of [Mountain/Road] Bike Maintenance" by Lennard Zinn. They are very well written and seem to be targeting someone such as yourself. Maybe reading the book will replace the urge to disassemble your bike!
As far as your current problem, I haven't the foggiest notion, sorry. Good luck!
After many years cycling I've finally decided I need to get a good understanding of how it all works. Mostly prompted by a recent cycling trip to Italy where my partners bike had a few problems that I was only partly equipped to deal with.
Having just stripped down the rear derailler (shimano) on my Trek mtb and then put it back together again I can't get the undexing to work. I don't suppose this is a new subject, but I couldn't turn anything up via search.
I can engage all the cogs (although a couple rattle) but the main problem appears to be the fact that in bottom gear the jockey wheel is hard up against the cog. It wasn't like that before I took it apart!
The steps I went through to adjust were 1) with cable unclamped (and in top gear on gear shift) checked high and low screws against cage position. 2) Pulled cable taut and clamped. (Not sure whether what position the tension adjustors should be - I've tried full on and off and somewhere between). 3) gears would mostly work top to bottom, but with the jockey wheel problem on the large cog. 4) resorted to random twists of the tension adjustors - to no avail.
Any help would be greatly appreciated - I don't want to have to visit the local bike shop at this early stage!
