My Rear Derailleur rubs on the spokes.?

Question

My Mongoose XR 200 Rear Derailleur rubs on the spkes when I am in 1st gear. It also goes onto the side when in 1st gear, near the wheel. WHY? Does anyone know how to fix this? Any webpages with pictures? thanks

Answer 1

This is a simple fix and you should not use 1st gear until you fix this. You can badly damage your spokes and derailleur.

Your derailleur has 2 screws on it. They limit how far the derailleur travels on the low and high gears (largest and smallest cogs) Your problem is exactly what it prevents. Turn in the low setting screw until you can shift to the large cog well but it doesn't travel past it into your spokes. The high works the same way. This should never change once set so you may have dropped the bike on the derailleur and bent the hanger or cage in causing this. You may be able to bend it out OK. If not time for some new parts.

Answer 2

Most of the posted answers are pretty close. First, there are four possible reasons that this is happening. Not two. The first, and most likely, is that the derailuer throw is maladjusted. This adjustment is made via two limiting screws. The adjustment will be on the, "low range screw", or, "L"; and you will need to tighten, or screw this in about a 1/4 a turn at a time until your problem stops. This adjustment is more accurate if you remove the chain-tension spring pressure from the adjuster screw, while making your adjustment.. The second, the derailuer itself is bent. The third possibility is that the derailuer hanger (MOUNT) is bent. The fourth, and least likely is that the derailuer pivot bushing is worn out.

This last is a common problem on more affordable bicycles. At a certain point, the quality of this bushing can be so low, that the derailuer won't operate right, even if brand new. At any rate, grab the derailuer where it bolts to the frame. Whether that mount is part of the frame, or it is just another piece, doesn't matter. If you can move the derailuer around on its pivot very much at all, have this issue addressed by a professional.

Answer 3

First, try adjusting the low limit screw on the derailleur:
http://www.parktool.com/repair/readhowto.asp?id=64
If that doesn't fix it, or it fixes the rub but the shifting isn't clean, then you've either bent the derailleur or the derailleur hanger. Take the bike to a shop to find out if the frame needs to be re-aligned or if the derailleur needs to be replaced.

Answer 4

Your deraillier is bent. Look at the derailier from the rear. It should be vertical. If it is not, it's bent. Normally, you just need to bend it back, but that depends upon where the bend is. Take it to a bike shop in the first instance. You might try:

www.parktools.com

for their how to sheets.

Note: some answers have stated that you need to adjust the HL screws. Possible, in which case you might want adjust the L screw. That said, you would also notice that your chain jumps off of the sprocket quite regularly. Try this option first, but I would check to see if your derailier arm is bent before adjusting screws.

Luck

Answer 5

If the derailleur is attached to the frame with a hanger; in all liklihood the hanger is bent. You can try to bend it back with your hand or get it replaced.

Answer 6

you are able to alter the positioning of the derailleur there could be 2 screws someplace on it (many times outstanding next to eachother), that in case you loosen or tighten the two one it is going to shift the derailleur in one direction or yet another, wish this helps.

Answer 7

To add to M R .... the adjustment screw you are looking for usually has a letter "L" next to it.