# Rear derailleur rubbing on frame



## jinkler (29 Jun 2015)

I can't seem to figure this one!

As you can see from the photo, the derailleur is rubbing on the frame. I can only assume I've set it up wrong, or I purchased the wrong derailleur? It's fitted to a full-sus 29er.

Any clues please people?


----------



## Yellow Saddle (29 Jun 2015)

jinkler said:


> I can't seem to figure this one!
> 
> As you can see from the photo, the derailleur is rubbing on the frame. I can only assume I've set it up wrong, or I purchased the wrong derailleur? It's fitted to a full-sus 29er.
> 
> ...


May I assume that you've just fitted a new derailer and now this happens?


----------



## Yellow Saddle (29 Jun 2015)

If so then perhaps you tried to place a direct mount derailer like the one above with a standard derailer.


----------



## Cubist (29 Jun 2015)

The frame looks like it has a dropout and mech hanger, so it looks to me like you have put a Direct Mount Mech on a standard hanger. I think that is what Yellow Saddle is saying. What sort of frame is it, and what mech did you buy? I don't recognize it.

Edit. No, that's a standard mount and a standard mount mech, but it's not mounted correctly, see below.


----------



## raleighnut (29 Jun 2015)

Try giving the B screw (the little one by the mounting) a few turns in, that may give clearance.
Also check the chain length (it may be a tad too long)


----------



## Cubist (29 Jun 2015)

Scratch that
If you look at the cylindrical mounting assembly, you'll see a lug sticking out at about 7 o'clock. That's a stop lug which should match up with a straight edge or a corresponding lug on the mech hanger. (nearest to us in this photo:



)

The angle of your photo doesn't help, but the mech is rotated 45-90 degrees too far forwards (anticlockwise) . The cable entry should be more or less vertical. Undo the bolt, loosen the mech and rotate it clockwise so that the lug matches the stop on the hanger. You may need to adjust or even change the cable length.


----------



## jinkler (29 Jun 2015)

Hi all.

The frame is a titus rockstar. It's a newly built up bike (by myself), so yes, it's a new mech, this is the one I've purchased: 

http://www.wiggle.co.uk/shimano-xt-t780-10-speed-shadow-rear-derailleur/?sku=5360449222

So, did I buy the wrong mech?

I'll check out the other suggestions this evening when I get home. Thanks for the help!


----------



## Cubist (29 Jun 2015)

Well, strictly speaking an XT T780 is a touring bike mech specifically, but there's no reason it won't work your gears. The MTB specific mech is the XT M780 Shadow. The shadow design makes the profile of the mech slimmer and therefore arguably safer on the rear. For a bit more money you can get the XT M786 Shadow plus, which has a clutch design to keep the chain taut and reduce flap and slap. 

Rockstar eh? Very nice. Any chance of some pics?


----------



## jinkler (29 Jun 2015)

I can't see a way of turning it onto a lug. Here's a better photo if it helps, and one of the bike!


----------



## Yellow Saddle (30 Jun 2015)

It is still a poor photo but my guess is that the RD has to be rotated anti-clockwise, specifically where the RD attaches to the frame hanger. Have a good look at what Cubist said in the post that starts with Scratch That. I think that's the problem. That ramped notch on the hanger at the RD side is what you have to focus on.


----------



## Motozulu (30 Jun 2015)

Yes same here - it looks like the lug on the mech isn't behind the lug on the hanger.


----------



## Cubist (1 Jul 2015)

jinkler said:


> View attachment 94176
> 
> 
> I can't see a way of turning it onto a lug. Here's a better photo if it helps, and one of the bike!
> ...


 Look at this picture. The stop lug on the hanger/dropout is just to the left of the bolt I'm turning. The triangular shaped lug you can see on the first photo you posted must line up with and act on that stop lug. 




Your mech is 90 degrees too far towards the handlebars. (a quarter turn approx) 

Undo the mounting bolt, and swing the derailleur 90 degrees in a clockwise direction, ie backwards, and line the stop lug on the mech bolt assembly with the stop lug on the hanger before tightening it again. The top jockey wheel should be directly underneath the cogs on the cassette in the big cogs, or just forward of them in the small cogs. not touching the frame like yours is. 
It should line up like this if it has a bridging piece (which should be horizontal)








or this if it doesn't:


----------

