105 Rear Derailleur Issues

CaerlyrOsprey

Hi All,

I would really appreciate advice with a mechanical problem I have picked up.

Just got back from a ride and halfway in I noticed that I couldn't change down to the smallest cog on the back. The "click" on the shifter disappeared and the gears wouldn't move. This got progressively worse until only the three largest cogs were usable.

I am planning to take the bike to the LBS as soon as I can, but, would appreciate some advice on what the issue could be, so I don't look foolish in the shop!

Thanks!

Kevin.

47p2

Sounds like your cable has slipped

doug5_10

+1 check that the cable end hasn't shifted out of its cradle in the shifter and become jammed. Check the 'clicks' when free from the cable as well. A good squoosh of GT85/degreaser into the internals to get things moving might help too.

thistle_

Also check that the dérailleur bolt that attaches it to the hanger hasn't come loose.

sungod

also, the cable may have frayed/jammed somewhere

the cage is moved to the smaller cogs by the spring in the rear mech, so if the cable has jammed it'll stop the cage moving outwards

simple test, if the cage is stuck on the larger cogs and you click the shifter all the way to small, the cable should now be slack where it emerges from the housing and runs to the clamp on the rear mech

if the cable is slack, it's the rear mech itself that is stuck

if the cable has tension (it should have a bit due to the rear mech spring) then it's jammed somewhere (or the shifter is faulty)

keef66

Undo the cable at the clamp on the rear mech. Pull on it gently and see if you can feel it moving as you click up and down the gears. Do you get all 9 clicks in each direction? If not, my bet is the cable's fraying inside the shifter. Best replace it before it gets any worse; stray bits of wire are a bugger to remove once they become detached.

patrickf

As above, my bet (as long as the shifter is OK) would be the cable frayed and/or getting stuck.

If your cable had slipped or the bolt was loose then I'd expect your derailleur to shift into the bottom sprockets as a normal RD will naturally spring outwards. You'd then be left unable to shift down into the larger sprockets.

It's not unusual for cables to fray. I've had this happen inside the shifter too, which makes it a bugger to get the cable out.

hstiles

Loosen the gear cable from the rear mech. It should drop down to the smallest cog. You can push on the derailleur to force it into the highest cog. Turn the pedals whilst pushing the derailleur back and forth to verify that it's moving freely and covering the full range of the cassette.

Next hold the end of the gear cable and click through the gears on the shifter. You should be able to feel the cable moving.

From experience, shifting issues are caused by the following, from most likely to less likely

Frayed, dirty or kinked gear cablle
Rusty or clogged cab;inner cable housing
bent rear mech hanger
mud or grease in the derailleur spring
Faulty shifter

CaerlyrOsprey

Thanks very much for the advice. Being mechanically useless, I took my bike in to my LBS and he found the gear cable had frayed inside the shifter.

Problem was easily repaired and bike is working perfectly again.

Cheers for all the help!

Kev

keef66

I thought it sounded horribly familiar.

Glad you're sorted