Cable groove in the body of the rear derailleur

[mezzanine]

Is it common for this grove where the cable gets bolted down by the bolt and hooked washer to show signs of wear?

Any tips to avoid this or is it normal as the derailleur shifts through the gears. I've seen the same wear on V-brake arms where the cable gets clamped down and over time the material of the actual arms is badly worn. This can't be right can if surely the cable doesn't move and shouldn't permanently wear away on the component. I know this is wrong but makes me wonder if it would be better to bolt the cable under the bolt head instead to protect the main body of the mech.

 

[adroitstif]

A photo would help but I think what you're looking at has really got to be a deliberately-made cable guide groove rather than something accidental that's been worn away over time. The cable would have to saw back and forth many hundreds of times to wear a groove in smooth aluminium and I can't see how that could have happened either in a brake or a derailleur.

 

[mezzanine]

Thanks adroitstif. I think some slip upwards while in the deliberate groove perhaps but still works fine just makes it look a mess when you inspect it to lube the bolt which is what I was doing.

It's for a RD-M750. Just been looking at this article and it says there's a particular way to position the hooked washer for the XT rear derailleur see last picture at bottom of article - https://artispin.wordpress.com/hubbubs- ... -solution/

I've been running it just how they originally shipped from Shimano but maybe rotating it 90 degrees will secure the cable better

 

[foz]

Re:

Any groove where the cable clamps is deliberate. there is no need to change the clamp - the article uses a different to clamping method to change cable pull and let campag shifters work with Shimano mechs. Unless you use this combination, the only thing you will gain is gears that don't work

 

[Woz]

Ditto. A factory designated or an additional home made groove will never wear if the cable is properly clamped.