Diagnosis - Shifting/Gears Problem

schleckster

Hi folks,

I went out for a ride yesterday and got to the first steep-ish climb, tried to shift down onto the smaller cog on the front cassette, the shifter clicked as it would normally and it sounded as if the it was trying to change gear, but instead the chain wouldn't come off the large cog. This was the second time I'd experienced this. It also wouldn't shift on the flat.

Confusingly, I went out apprehensively for another ride today and all seemed fine, a little clunky/noisy maybe. So, could anyone offer a diagnosis for this, or a way to fix it? I keep the bike religiously maintained, by that I mean anytime it sees rain or damp roads it gets a full clean after and a re-grease. I haven't crashed or knocked it on anything either.

This was with Shimano Tiagra on a bike (Specialized) that's a few months old - I know this is one of Shimano's lower gruppos but surely it should perform better? I'd be interested to know anyone else's experiences with this gruppo. I was going to upgrade to a better set anyway when viable, but now I'm thinking the sooner the better! Thanks all.

ju5t1n

Sometimes gears won't change under pressure, happens a lot on steep hills. Select your chainring in advance and you should be okay

schleckster

That's true, but this happened as I was trying to select it in advance of the hill, as you say, on the flat. Should have made that clear/better expressed myself, sorry.

k-dog

The main culprit this year is muck in either the mech or the cable - under the bottom bracket is the obvious place.

To check that you can change the shifter then check the cable. You should find the cable goes slack along the downtube. That proves that the shifter is doing what it should.

Then undo the cable from the mech. If it moves then the cable is probably gummed up.

If it's stiff then the mech will be gummed up. Give it a good spray with light lube until it's moving again. If its really bad you might have to take it off and soak it in oil or something.

dennisn

I'm going to cast my vote for out of adjustment.

schleckster

Thanks guys for your input, will have a closer look at the cables and mech; like i said there didn't seem to be a problem today after a fresh app of lube, hopefully it's not chronic.

crankycrank

Schleckster + trouble shifting. Anybody see the irony in this? Sorry, I couldn't resist. :twisted:

nolight

Are you sure you are really shifting and not half-shifting? On my 105 shifters, I need 2 clicks to really shift the front gear. 1st small click moves the front derailleur a bit but is not enough to really shift up to the small chainring.

keef66

Were you in a small sprocket at the back? My 105 triple is sometimes hesitant moving to the granny ring up front if I'm at the smaller end of the cassette because the chainline is working against it.