Rear derailleur replacement query

muran

I have a second hand Carerra Kraken (2010 model I think) and am having a little difficulty in using my full range of gears. I have adjusted both the front and rear derailleur limit screws to get the best range of accessible and usable gears but still they catch. Either the chain catches on the front or it rubs a little on adjacent cogs when in certain gears at the rear.

I think this is down to a slightly bent or worn rear derailleur and am considering replacing it (SRAM X5). The two cogs are not directly in line when looking from behind the bike, as I understand they should be. My query is whether the hanger part that attaches to the frame comes with the derailleur or is this a separate part? I am not sure if this is the part that is at fault or the derailleur itself so ideally want to ensure I will be replacing both.

Also, I see the derailleur comes in medium and large cage size - any ideas which I would need?

Thanks

nicklouse

Sounds like a bent mech hanger.

Don't forget not all gears are always useable.

See the FAQs for gear use.

supersonic

The hanger is part of the frame, so will not come with the mech.

You would need long cage if running a triple chainset.

But I don't think a new mech will cure the problem - seems to me like cable drag and adjustment issues. Do check the hanger is straight though ie the derailer jockey wheel cage should hang vertical with no twist.

muran

Thanks for your replies.

nicklouse wrote:

Sounds like a bent mech hanger.

Don't forget not all gears are always useable.

See the FAQs for gear use.

Sure, It's not when I am cross chaining that I get the problems (which I don't do). It's when on say the middle chain ring at the front and the 2nd or third largest at the rear that I get the catching with adjacent cogs. Also struggling to get the two smallest wheels at the rear when on the front middle.

I though it was the mech hanger but can't be sure.

supersonic wrote:

The hanger is part of the frame, so will not come with the mech.

You would need long cage if running a triple chainset.

But I don't think a new mech will cure the problem - seems to me like cable drag and adjustment issues. Do check the hanger is straight though ie the derailer jockey wheel cage should hang vertical with no twist.

I am sure the hanger on mine is a separate piece - it's certainly not moulded as part of the frame and is a totally different colour. Certainly looks like a separate part. Am I right in thinking they are separate on some?

The jockey wheel cage definitely twists as the two wheels are not directly in line and there is also play at the pivot point where it attaches to the hanger.

I have tinkered with the think to get the best our of it but I'm struggling a little now. Reluctant to take to a bike shop as I don't want them telling me I need all new parts and being new to this game, who am I to judge otherwise?

Wondering what I should do next ...

supersonic

It's a seperate piece yes, but comes with the frame, not mech. They can be bought from many places, but has to match the frame.

Definitely sounds like it is bent slightly (or the mech, or both), and the cables sound sluggish too.

muran

Any ideas what I can expect to pay to have someone in the know look at it / set it up?

Also, should it be obvious if the mech hanger is bent - easy to test?

supersonic

Need a careful eye! There are tools that show it, or can fit a mech you know that is straight.

New hangers are £10-£20. A shop would charge £15-20 to fit it, a mech and adjust gears. New mech a further £25 or so.

Or just try and bend it back ;-). But clean those cables out first!

muran

Thanks for your thoughts. Being second hand I don't know what the history is and how much hammer it has had so I guess cable renewal / replacement would be a good idea anyway. Now to find a decent guide

muran

Just thought I would let you know that I replaced the front shifter cable and spent most of the afternoon fine tuning the front and back derailleur to get the best results. Hoping that it's time well spent - will know when I ride it next!