Chain/gear slippage.

You got Shimano? On my few "attempts" to adjust shimano deraileurs I ended up with some bent screws from the screwdriver...

You can give it a shot but if you see anything like bent threads on the screw that might damage the deraileur I think its best to just bail and let the shop do it.

I allready changed my front deraileur screws with some allen key driven ones from the LBS after they got damaged by some DIY adjusting... I was careful and everything too...

If its not too bad you can maybe "pack" the adjustment with some other repair like a clean and lubrication or flat repair or something...

MotownBikeBoy said:

I wish I were more mechanical. I think this could just be a question of a loosened cable between shift lever and derailleur, right? If not that, any other possibilities? I could just take it to the shop, but I really want to learn about the mechanics and how to repair things if possible.

Describe the problem in more detail. As for "bent" or otherwise damaged derailleur adjustment screws, it's important to know how to pick the right screwdriver and how to use that screwdriver properly. There are different sized screwdrivers for a reason.

Quote: Originally Posted by alienator [IMG]/img/forum/go_quote.gif[/IMG]

As for "bent" or otherwise damaged derailleur adjustment screws, it's important to know how to pick the right screwdriver and how to use that screwdriver properly. There are different sized screwdrivers for a reason.
As are good screws and cheap bad soft ones...

Hi, guys, sorry I didn't get back to this thread. If I weren't 't such an idiot about all things technical I could probably explain it better. Riding along, the bike will suddenly go into a lower (less resistance when pedaling, less power per stroke) gear, the chain slips down one level on the rear sprockets. Hope that makes sense? Anyway, when I first got the bike, after about a week this started happening, I took it back, the tech at LBS said it was due to the cable stretching as it got broken in. He did a quick adjustment and viola, no more problem. This recent bout started after I took off the rear wheel to fix a flat. So, I undid that - I took the wheel off, cleaned and lubed the chain, etc, and so far, no more problem. Maybe something was just a tiny bit out of alignment? See why I wish I weren't such a mechanical idiot?

I can't remember what bike you have, but if the wheel isn't placed properly in the rear dropouts, it can produce misalignment between the cassette and chain line. When ever you remount a wheel after removing it (for whatever reason), be sure that the wheel is seated properly in the dropouts.

The amount of tension in your rear quick release can affect the rear derailleur alignment as well. Stand over the rear wheel and watch the derailleur as you close the QR lever - you will see what I mean.

If you need it, trim adjustment of the derailleur is easy. There is a barrel adjustment on the downtube and also one on the derailleur itself. Put the bike in a gear, spin the pedals a few times and check to see that the derailleur is centered over a cog. It shouldn't take more than a 1/2 turn or so to trim it in.

Thanks again, guys. I'll learn a lot just by asking stupid questions and getting intelligent answers. Alienator, this is my primary bike, the Specialized Crosstrail Pro Disc.