Rear Cassette skips just one cog

[YahudaMoon]

You might need new cables.

this ^^^^^^^^^ changed my rear inner outer cable a few month back, problem sorted

 

[RWright]

I want to see some un-bending!

I don't know if you do or not...it wasn't pretty, still isn't. That is why I would not have felt right using the word straightened.

It works now but I still may just replace the rear derailleur, it is an inexpensive one, I may even move up to a little nicer one.

 

[andrew_s]

A "bent rear mech" that causes indexing problems is usually a bent hanger on the frame rather than the mech itself. The hanger can get bent just by the bike falling over.

On steel frames you use a long arm with a pointer on that you screw into the hanger in place of the rear mech and swing round to check the pointer is the same distance from the rim all round, then heave on the arm to bend the hanger back.
With an aluminium frame you may be able to do the same one or twice, or most frames have a replaceable hanger.

 

[lulubel]

On steel frames you use a long arm with a pointer on that you screw into the hanger in place of the rear mech and swing round to check the pointer is the same distance from the rim all round, then heave on the arm to bend the hanger back.

That's a really useful piece of information. I was wondering what I'd do if the integrated hanger on my steel frame got bent.

 

[kedab]

and this is why i have stopped tinkering and make use of my LBS - i do love to tinker but always end up in a far worse state than i began...too much time in front of computers in my adult life and not enough time falling off bikes as in my yoot when i could pretty much get most things working again

 

[TheDoctor]

I see the problem - it's a Campag mech!!
Replace the groupset with Shimano and all will be well
*hides*

 

[BigonaBianchi]

hide thee well forsooth heretics shall burn

 

[mrandmrspoves]

The cheapest proprietary tool for straightening a bent mech hanger is probably the Cyclo version. Got mine for about £25.
It's basically a long bar with a screw on one end that screws in where the rear derailleur would and a sliding pointer at the other end. Before you use it you need to make sure the rear wheel is buckle free and straight. Then you srew the tool into the hanger until it is tight and rotate it until the pointer is in the 12 O'CLOCK position and adjusted so the pointer is im contact with the wheel. Then rotate the tool so it is at 6 O'clock and again the pointer touches the wheel rim. Then repeat at 3 O'clock and 9 o'clock. Job done

 

[Paul Walters]

I had a similar problem with my Campag equipped Orbea a couple of years back...... my LBS sorted it by replacing the short section of sheathing on the cable between the chain-stay and the derailleur, and by slightly truing the drop-out. Guy in the shop used a gadget like a beam-compass screwed into the drop out, which he rotated around the wheel rim. He measured the offset and was able to bend the drop-out slightly to ensure a uniform separation. Works fine now.

Oops..... bit late posting this...... see its been covered above... so +1 ^^^^^