chain slipping?
 

Hey guys,

i've been working on my bike for a while and just replaced the chain and it seems to be sleeping every few rotations from the crank. at first i thought it was a little loose so i checked the length and it was good. Does anyoen know what is wrong and how i can fix this?

and i have another problem,

i took the derailleur off another bike and used it on this one ( a vintage schwinn road, i think it's a deluxe varsity?) and it seems that the derailleur is actually holding against one of the cogs on the cassette so that it won't spin. I'll try to get pictures or a video soon.

Thanks

You might need a new cassette - it is a general rule of thumb to replace both parts of the drivetrain at the same time.

I agree.

I disagree.

So would Sheldon Brown have....

http://www.sheldonbrown.com/chains.html

+1.

Here's Sheldon on chain wear from link above:

Measuring Chain Wear

The standard way to measure chain wear is with a ruler or steel tape measure. This can be done without removing the chain from the bicycle. The normal technique is to measure a one-foot length, placing an inch mark of the ruler exactly in the middle of one rivet, then looking at the corresponding rivet 12 complete links away. On a new, unworn chain, this rivet will also line up exactly with an inch mark. With a worn chain, the rivet will be past the inch mark.

This gives a direct measurement of the wear to the chain, and an indirect measurement of the wear to the sprockets:

* If the rivet is less than 1/16" past the mark, all is well.

* If the rivet is 1/16" past the mark, you should replace the chain, but the sprockets are probably undamaged.

* If the rivet is 1/8" past the mark, you have left it too long, and the sprockets (at least the favorite ones) will be too badly worn. If you replace a chain at the 1/8" point, without replacing the sprockets, it may run OK and not skip, but the worn sprockets will cause the new chain to wear much faster than it should, until it catches up with the wear state of the sprockets.

* If the rivet is past the 1/8" mark, a new chain will almost certainly skip on the worn sprockets, especially the smaller ones.

Try tightening the angle adjuster on your RD. If you're still touching,chances are you need a long cage RD.

well what about the chain slipping? i'm a little confused. sorry.

the chain is brand new, i therw the old one out after i replaced it

You may need a new cassette, too.

If you let your chain wear for too long ... then it's entirely likely that you will need a new cassette.

May want to have the Local Bike Shop ("LBS") verify this for you.

Where does Sheldon say to not change cassettes and chains at the same time? I've read most of his stuff inside and out, including that article, and he just mentions how to tell when you need to change both of them. In my experience, generally chains and cassettes get worn down at the same time, especially if you don't take care of them. If well taken care of you can alternate a chain on one cassette and be fine, unless you constantly ride on just a few gears.

I would agree with you- and if this new chain is slipping on the cogs, it (the cassette) is in all likelihood worn badly enough to warrant replacement.

Okay, okay...forget about the chain/cassette thing until you figure out if you're cassette is compatible with your derailleur. Adjust the tension screw(it's the lonely one up top that presses against the frame). It's adjustment determines if your RD can shift to the largest cog in back. If your RD cage or pulley is hitting the cogs, you'll need to turn the angle screw in until it allows the chain and cage to clear the largest cog without interference. If you get this set properly and your current RD is indeed compatible, I am pretty sure the chain slip will be cured. You may need to adjust the limit screws to dial everything back in. I hope this helps.