Mountain Biking - MAYDAY bent rear derailleur!?

Hello all,

I am relatively new to mountain biking; I have owned a couple of bikes in the past but never really put them under any serious stress.

I purchased a MB off ebay the other day, it arrived yesterday and I tried to put it together. Everything went fine up until I got to the point of installing the rear wheel (with a 7-speed cassette on).

The problem is that the rear derailleur (which is actually mount on the bike's frame) appears to be angled towards the weel so that it comes in contact with and falls inbetween the spokes of the weel.

At first, I thought that the derailleur was bent but after closer inspection it looks very rigid and in no way bent. What is definitely bent, is the point of the frame where the rear derailleur is mount on.

Question: If you can recall from your own bikes, is the Guide Pulley directly above the Tension Pulley?? Also, are the two Pulleys of the derailleur 100% parallel to the rear wheel?

Question2: I was wondering how can I possibly fix this... I tried playing around with the B- H- and L- screws but nothing noticable happened.

I'm sorry if the description of the problem was not good enough (my english is not very good) so if you need any clarification please ask!

Thanks in advance, and take care.

The best thing to do at this point is go to your local shop and have them straighten the derailleur hanger. They will most likely use the Park DAG-1 (http://www.speedgoat.com/product.asp?part=42305&cat=330&brand=184) derailleur tool. Without this tool it is pretty much impossible to get it completely straight, especially without having some experience with working on bikes.

The adjusters on the derailleur probably won't help much. If the hanger is not straight your bike will never shift correctly.

Thanks for the reply LowCel; the problem is not just that the bike can't shift, but the rear wheel won't move AT ALL as the Tension Pulley is stuck between the spokes (as I tried to insert the wheel)

Sounds like it is definately time to take it into your local bike shop. Hate to say it, but this is a perfect example of why it is better to purchase bikes from a lbs until you have more experience with them.

Probably damaged during shipping. Did you get insurance on the bike for shipping?

If so, save the box it came in and call the shipping company. They'll send someone out to inspect the damage, then you can make a claim.

UPDATE

It's amazing what you can do with a spanner these days. Hanger's been sorted.

Shifting is the problem at the moment. A gear was not getting in so I ajusted the H and L screws and it shifts fine now, but the chain is not properly alligned with the sprockets so it makes a sound that gives me the impression that the bike is going to fall apart...

Also when I shift the front gear down to the smallest sprocket, the part of the chain going in the Guide Pulley comes in contact with the chain leaving the Tension Pulley of the rear derailleur, I don't know if this is normal but it definitely doesn't look normal.

I think it's a matter of getting the angle of the whole rear derailleur right.

I do enjoy fixing my bike, I am aware that I don't do things properly but I hope that I will manage to get it running flawlessly in the end and that I learn from the experience. I get the tools from my next door neighbour and all information from this forum and google.

Thanks all for replying!

Please go to a bikeshop :rolleyes:

/\ What he said. :D

Take the bike to a good shop and ask them to check your dropout, chances are that it was bend during shipping. They can make is straight using the tool that Lowcel talked about.

Also, contact the ebay seller and let him know what happened. If the frame has a replaceable hanger he may send you one for free, it happened to me and the seller sent me a new one.

If the frame doesn't have a replaceable droput you may be in trouble. The tool works ok but the hanger will not be perfect so you may experience ghost ****fing or just regular shifting problems that will require constant tinkering and after a while figthin it you'll just hope for the frame to break so you can justify a new one.

With respect to your derailleur adjustment. The L and H screws will only adjust the limit of travel meaning that this will only prevent the chain from jumping off from either end of the cassette. You described misalignment of the chain on the sprockets, which must now be corrected with the barrel adjustments. Here is a link http://parktool.com/repair_help/FAQrindx.shtml describing this.

That being said, this is why it pays to have a good relationship with a LBS. I have walked into my LBS asking for help and tips and the guys will always take the time to do a once over on the bike after I've done my own adjustments/installations at no charge. I did my own adjustment of the rear derailleur after smacking it against a rock. Got it to about 95% and went in for a final once over and wasn't even charged for it.

Hey all thanks for the replies!

santiago thanks for the website! I was messing around witht the barrel (there is one on the gear shifters as well as the derailleur) last night but still can't get it right. Shifting is much better, no skips at all BUT THE FREAKING CHAIN COMES IN CONTACT WITH THE SIDE OF THE COGS AND PISSES ME OFF.

The only thing that keeps me from taking the bike to a (not so local) shop is that I will be bike-less for a few days, even if I can't ride it if you know what I mean.

Thanks all again and be good.

Hey all thanks for the replies!

santiago thanks for the website! I was messing around witht the barrel (there is one on the gear shifters as well as the derailleur) last night but still can't get it right. Shifting is much better, no skips at all BUT THE FREAKING CHAIN COMES IN CONTACT WITH THE SIDE OF THE COGS AND PISSES ME OFF.

The only thing that keeps me from taking the bike to a (not so local) shop is that I will be bike-less for a few days, even if I can't ride it if you know what I mean.

Thanks all again and be good.

I don't remember which but one of the barrel adjusters offers minute adjustment and the other offers larger adjustments. I think the derailleur one is the first one to tackle and then you fine tune the one on the shifter itself.

It does sound like the derailleur hanger may be crooked too so that will make the last adustments to make it perfect impossible to get to. You'll have to bite the bullet and bring it into the shop.

Santiago (and LowCel and syklnut and harov and dirtdevil) is right...the L and H screws arent going to fix your problem unless the chain is jumping off the cassette. You should tune the barrel adjuster on the back of the derailleur first. Put pressure on the rear tire as you shift and adjust. If the problem persists while you're riding, you can tune the barrel adjuster on the shifter. If you can, try to be going up a slight incline while you're doing this...it seems to work a lot better for me.
I agree that you should take the bike to a shop and let experienced mechanics take a look at it.

Thanks for the replies, but how is it possible to ride the bike and play with the barrel adjuster at the same time? Another problem is that the derailleur barrel is broken and won't turn at all... but according to parktool.com, the shifter barrel offers the same degree of adjustment as the derailleur barrel, so I guess I might be able to do it anyway?...

I went on a purchased a new rear mech off ebay, Shimano Tiagra, just in case the one currently on the bike has had it...

I'm thinking that if I manage to sort this out then I will learn quite a lot about how the derailleur works and I'll be able to troubleshoot any (most) other problems that arise in the future. This is probably the learning curve for me.

Again thank you all for the time you spend to answer my stupid questions!

Thanks for the replies, but how is it possible to ride the bike and play with the barrel adjuster at the same time? Another problem is that the derailleur barrel is broken and won't turn at all... but according to parktool.com, the shifter barrel offers the same degree of adjustment as the derailleur barrel, so I guess I might be able to do it anyway?...

I went on a purchased a new rear mech off ebay, Shimano Tiagra, just in case the one currently on the bike has had it...

I'm thinking that if I manage to sort this out then I will learn quite a lot about how the derailleur works and I'll be able to troubleshoot any (most) other problems that arise in the future. This is probably the learning curve for me.

Again thank you all for the time you spend to answer my stupid questions!

A) The Shimano Tiagra is a road bike component, it is not designed for a mountain bike!

B) On the barrel adjuster you think is broke and won't turn: Pull the barrel out of the socket and then turn it. The plastic knob is not actually what tightens/loosens the cable, it twists a cam inside that does and you probably need to pull it out to get it to turn..

Thanks for the replies, but how is it possible to ride the bike and play with the barrel adjuster at the same time?

Keep one hand on the bar and make adjustments with the other (talking about the adjuster on the shifter of course).