Have I broke my rear mech or shifter?

danlightbulb

Hi all,

On todays very wet miserable ride I tried to change up when I was already in top gear (with all the wet and mud I was sure I had another gear left).

Anyway now I can't change down. When I change down on the shifter the cable just goes slack.

I am about to go and clean the bike down and take a closer look, but any ideas what I may have broken would be useful.

Thanks
Dan

nicklouse

maybe neither.

inspect the cable.

cooldad

What do you mean by up? And top?
Cable generally slackens when you change up - ie to small cog.

danlightbulb

Yeah sorry, I was on big rear cog and tried to change to a higher cog. I guess that is actually a lower gear but i always think of moving 'up' the cogs.

Ive given it the once over with the sponge, and its shifting through the whole range but very stiff on the up (to larger cog) change. Need to spend a bit more time on it its bloody chucking down again. On inspection, the mech had appeared to jam in the top cog position.

I'll give it all a good clean and regrease on a dry day. Is the shifter component user serviceable?

oxocube1

I wouldn't advise taking the shifter apart as from my own experience, some of them can be an absolute pain in the arse to get back together again. I usually squirt some lube into the shifter through the cable hole, that's my idea of a shifter service!

cooldad

Just use big cog or small cog, you are confusing the issue.
Detach the cable from the mech, make sure the mech moves freely - could be something jammed in the spring, then hold the end of the cable move the shifter and see if the shifter works ok. Could just be the cable gunked up - 99.9%* of all shifting problems are cable issues.


*proven scientifically accurate made up statistic.

danlightbulb

Yeah I guess I won't know until I test it properly. I only ask because I did put quite a bit of thumb force into the shifter trying to change to a larger non existent cog, and that's when it stopped working out on the trail.

The Rookie

Just like a car, up means longer gearing (you go 'longer' for one turn of the crank) which is a smaller gear at the back.

Sounds like your cables are gummed up, it will make shifting down (bigger cog) harder and the rear spring mech may not be able to pull the cable to shift up.

Check the cable right at the rear (between last outer and clamp bolt) if that is tight when other cable is loose then it is 100% the cables.