This derailer shouldn't work but it does!!!

[Fleming]

Let me start by saying that generally I am pretty competent at doing most things on the bike and have been servicing my own bikes for at least 15 years.

 

Until a short while ago I had a 2008 LX rear derailer on my bike that I have never been able to get the shifting 100% right on. No matter what I have tried it always battled on either the upshift or downshift and a little mud would completely throw it out. I know its the derailer because I have tried 2 sets of shifters and its been the same. I have also checked and neither the derailer nor the hanger is bent.

 

Earlier I was trying again to adjust and thought screw it. I have a worn out 2000 model XT derailer in a box somewhere. I am gonna try that. I fitted it and first thing that I saw was how bent the thing is. No matter, a few minutes later and my gears were smoother than they had ever been with the LX. I cant believe it, the thing is so bent it just shouldnt work but it just does and it does it so well.

 

Below is a picture showing how bent the XT derailer is.

 

http://i17.photobucket.com/albums/b69/stuartfleming/P1078680.jpg

[The_Break]

It not your derailler that is bent it is your hanger bracket!!!!!!

 

Either that or your frame is skew.

Edited January 7, 2011 by The_Break

[An3]

I agree - looks like the hanger is bent.

[Fleming]

I thought that too but here is a pic of the LX derailer on the bike that I just cannot get to work.

 

http://i17.photobucket.com/albums/b69/stuartfleming/P1078688.jpg

[DawieO]

Yip, that hanger looks like it is trying to make whoopee with your cluster. Fortunately is is a MUCH cheaper fix than a rear der!

[The_Break]

 

http://i17.photobucket.com/albums/b69/stuartfleming/P1078680.jpg

 

This is what the frame, hanger and derailler should look like. Note the hanger is parallel to the gears. You only need ask your bike shop to bend it straight using a dropout alignment tool.

Edited January 7, 2011 by The_Break

[MattyG]

just machine one yourslef like you did with the brake brackets

[The_Break]

I thought that too but here is a pic of the LX derailer on the bike that I just cannot get to work.

 

http://i17.photobucket.com/albums/b69/stuartfleming/P1078688.jpg

 

Same thing. Clearly bent.

 

I bet your little screw that touches your hanger bracket on your newly fitted derailler is either shorter or longer than on the LX derailler by a good few turns.

Edited January 7, 2011 by The_Break

[Guest Big H]

Make sure you remove the dropout hanger and inspect it for cracks as it is made of aluminium and alu does not like to be bent backwards and forwards. You do NOT want a straightened and maybe weakened dropout hanger to snap when you are on a trail 45km from the nearest civilisation.

[Christopher Brunsdon]

Agree with BigH. Get the current one straightened, throw it into your Camelbak as a backup and get a new one. A good LBS will not charge you, and you anyway need to get your replacement hanger aligned as your frame can be out of alignment.

[LazyTrailRider]

I have to agree with the others here Stu, luckily like they said it's not a biggie to get straightened. I think the LX is probably bent (and cancels out the skew hanger), why is why you can't get it to work... The XT might actually be straight!

[Bspoke]

The hanger bolt in the derailler can get bent just a little and this immediately effects the throw particalary in the middle of the block for an unfathomable reason. You will have to dimantle the top end of the RD to see it . Ive also experienced bent and broken springs at both ends in the older low range models.

Good luck if you dismantle, make sure you maintain a hold on the hanger body if you remove any of the clips/nuts ,or you will spend the day looking for the wayward spring which can travel amazing distant., believe me .