How much "play" should a rear derailler have?
 

I am having trouble getting my rear derailleur adjusted. I just built the bike using my 10 year old Dura-Ace components. The rear derailleur worked fine on my last bike. While adjusting the derailleur with the chain removed, I noticed it (the deraileur) had a small amount (2-3mm) of lateral play. Maybe it's always been that way, but I can't really say for sure. Some pertinent facts:
1. The rear derailleur was taken off the other bike, cleaned and then stored all winter, so I don't think I damaged it in any way in the process.
2. Chain has just been replaced and cut to an appropriate length, and there are no stiff links.
3. chain skips upwards (to bigger cog) when applying heavy pressure to the crank.
I'm wondering if either the cable is too tight or my derailleur hanger is mis-aligned.
I've been messing with this for a couple of weeks on and off, and it's starting to bug me.

Any ideas would be appreciated. Thanks, Gino

How much "play" should a rear derailler have?

Sure it should have a little play - but don't let it think it should play all the time. Sooner or later it's got to get down to some work. After all - all work and no play makes derailleur a dull boy.

Sorry - I know I'm not helping - but at least I've bumped your thread to the top so that someone who knows what they're talking abou can help you.

That's hilarious, thanks for the laugh. I forgot to add-that derailleur has been watching way too much tv and hardly ever eats any vegetables. Maybe it just got lazy on me. Any other ideas? gino

Could be a slight bit too much cable tension, amongst other possibilities. Might be worth taking the bike to your LBS to have them check your der. hanger alignment. If you used a new chain, did you also install a new cassette?

Thanks Waldo, the cluster has a lot of miles on it. I'm gonna see what happens when I loosen the tension a bit first. Then, I'll have the alignment checked. lastly, I'll buy a new cluster. I'm probably overdue for a new one anyways. Thanks for the advice. I can't beleive you're from Barrington. I ride through your town all the time. We're neighbors, actually. Thanks again, Gino