Shimano alivio gear lever not catching

[Salty seadog]

Hi all,
Due to injury the bike has been still for 3 months, put some air in the tyres and took it for a quick test today and the gear lever that puts you in a lower gear on the rear occasionaly fails to "connect".... Rather than being a tight crisp change it feels loose and travells about twice the distance as it would on a gear change, then it clicks in on the next push and changes nicely. It is not on every gear change but about 1 in 5-10 or so.

any idea as it was not like this before my lay off? Jagwire cables by the way.

cheer,

ssd

 

[RecordAceFromNew]

Shift into the lowest gear (i.e. largest sprocket at the back), then without spinning wheel or pedal click the shifter in to the highest gear. You will find that the inner cable is now no longer under tension and you are free to release the cable outer from bosses and cable stops, allowing you to slosh the outer up and down the inner, to look for rust/gunge/fray and an opportunity to clean the inner with a green scouring pad / teflon oil or replace cabling if appropriate.

You can do the same with front mech/cabling except you want to shift into the highest gear and then click shifter into low gear. Similarly for low normal / rapid rise rear mech.

 

[Salty seadog]

I'll give it a go but to my mind the problem feels is in the lever housing.

 

[Salty seadog]

To clarify, when this problem happens the gear lever fails to engage inside the housing and simply glides forward twice as far as you would expect during a normal gear change so I believe it is not pulling on the cable at all. There is simply no resistance.

 

[Drago]

What year approximately is the shifter?

 

[Salty seadog]

What year approximately is the shifter?

Sorry Drago, no idea, the bike was bought in 2011.

 

[Drago]

Ah, so fairly new then. I was hoping you wouldn't say 1997-98, whaich was a flaky year for Altus and Alivio shifters.

 

[I like Skol]

I have an 8spd LX shifter from back in the day that does this despite not really being used much over the years. I have tried spraying lube in there and I know the cables are not the problem. It seems to be more likely that the pawls/ratchet mechanism is occasionally passing the first indent and connecting with the next. I suspect a huge spider has crawled in there at some point and its dried corpse is obstructing the pawls

 

[Salty seadog]

without knowing about the inside of the housing Skol, that was basicly my guess, the ratchet is missing a beat, .....didn't consider the insect/arachnid angle though...hmmmm

 

[RecordAceFromNew]

If the issue is in the shifter then chance is it is gunged up inside. Happens often enough due to old grease etc. Open it up (usually one or two small screws, you can check tech doc first by reading the model code underneath, something like SL-mxxx), spray some WD40, clean it up, click up and down a few times ensuring the pawls/ratchets move freely, and chance is it will work like new again. I have never seen one of these things fails completely and becomes unserviceable from normal use.

 

[Salty seadog]

cheers for all the replies all, after having a chat at the lbs his diagnoses is that one of the teeth on the ratchet cog is damaged and the problem will occur when this dammaged tooth presents itself for action...

seems to make perfect sense to me and if that is the case i can live with it at least for a while.