I had to get a spoke replaced today so I took the wheel off and dropped it off at my lbs. I picked it up tonight and reinstalled the wheel. Went for a ride and now it seems my rear der is hopping. On every 2nd rotation I can hear it move up and down. It didnt do this yesterday. I got off the bike and cranked the wheel and can see it hopping about every 2nd rotation. The wheel is in the dropouts straight. I didnt wack anything. Not sure whats going on. Also my front Tiagra isnt shifting from little to middle ring, it seems that its just missing. That also wasnt like that yesterday. Not sure what happened. I'm going to have my lbs check it out tomorrow.

Thanks

Hopping could be due to a problem with the jockey wheels. When you removed the rear wheel, did you damage the jockey wheel springs? If so, without adequate tension on the jockeys as applied by the spring, they jockeys will not hold the chain on the cogs, causing the hopping.

For example, when determining chain length, you always want to be sure the jockeys are neither all the way extended, nor too loose so as to allow slack in the chain. So, jockey wheels are critical for a properly fitting chain.

I always work from what I did that could have thrown something out of whack. The broken spoke repair didn't change the hub or cassette, so it has to be the DR itself. I know that removing the rear wheel sometimes causes me to push the lower jockey wheel quite far forward, with the potential of overextending the mechanism creating just such a problem.

Others more experienced will give their opinions, but this seems logical to me.

I had to get a spoke replaced today so I took the wheel off and dropped it off at my lbs. I picked it up tonight and reinstalled the wheel. Went for a ride and now it seems my rear der is hopping. On every 2nd rotation I can hear it move up and down. It didnt do this yesterday. I got off the bike and cranked the wheel and can see it hopping about every 2nd rotation. The wheel is in the dropouts straight. I didnt wack anything. Not sure whats going on. Also my front Tiagra isnt shifting from little to middle ring, it seems that its just missing. That also wasnt like that yesterday. Not sure what happened. I'm going to have my lbs check it out tomorrow.

Thanks

Is the rear wheel in the drops correctly? Make sure the cassette is on tight. If yes to both, try adjusting the barrel adjuster a little either way on the rear deurailleur.

Although that's where the problem is now seen. I think that Shane got it with the cassette. If the LBS replaced a drive side spoke, they had to remove the cassette. Two things could have happened - the cassette was either on properly or was a bit loose originally. Sounds like when they reinstalled it (hopefully tight enough), it changed the orientation of the cassette relative to what the derailleur was formerly adjusted for. With modern 9/10 index systems, it doesn't take much to get out of tolerance. The 'hopping' that you see/feel is the chain in between gears because things are not lining up like they used to. This can cause the front shifting to be off too - if fixing the cassette doesn't fix the front shifting, then all that is required is minor adjustment of the FD cable tension to get that straight.

IMO you're doing the right thing by going back to the LBS - take your whole bike, not just the wheel. If the cassette is installed and torqued down properly, it should take a very minor adjustment of the rear derailleur cable tension (and possibly limit screws) to get things back up to snuff.

IMO you're doing the right thing by going back to the LBS - take your whole bike, not just the wheel. If the cassette is installed and torqued down properly, it should take a very minor adjustment of the rear derailleur cable tension (and possibly limit screws) to get things back up to snuff.

What is the correct torque for a nine speed Shimano cassette? Do you know?

What is the correct torque for a nine speed Shimano cassette? Do you know?It's right on the lockring...

The OP said it happens every two revolutions. If he meant two revolutions of the crank, it could be a tight link in the chain. Most chains are 106 links, so two revolutions of the crank on the 53t means that a stiff link would show up right on time. The cassette replacement sounds like a better theory, but I don't see how it would happen every OTHER revolution (of the wheel?).