by simondo3333 » 19 Jan 2010 10:08
Difficult to determine without seeing it.
I've never used a workstand but I AlWAYS do a lap of our village and take a multitool with me so I can tweak on the go following any cable or drivetrain part replacements. It has to be set up for being ridden. Being turned by hand just isn't the same.
Firstly, it sounds like the lower limiter screw needs checking. The cage might be travelling too far and causing chain rub.
The cage should sit just off the inner side of the chain without any rub or interference.
Look up any of the "how to's" on the web. It should be a 2 minute job.
Failing that - worn drivetrain parts or a trashed bottom bracket will cause shifting problems upfront and only whilst riding with weight on the cranks being the main factor.
A longshot, but could you have knocked the derailleur alignment out since it was on the stand? Check the derailleur bracket/band bolt to make sure its tight as the cable tension when shifting will twist it causing poor shifting.