Gear indexing problem

chrisaonabike

I have Tiagra, 50/34 and 12-30. The bike is a year old, but the chain and cassette were replaced in July, so only a few hundred miles ago.

Until about two weeks ago, shifting was perfect in every way.

Then I noticed that sometimes I'd click once to change to the next biggest rear cog, and nothing would happen at the back. A second click would make the change happen, sometimes two.

So a bit of googling and youtubing later, and I had a go at adjusting the cable tension with the knob at the mech end of the cable. I haven't touched anything else at all.

If anything, it's worse - I can get it to shift to bigger sprockets one click at a time, but it won't then release back to the smaller ones reliably. And if I release the tension a bit so that it changes to the smaller sprockets one by one, it won't change back to the bigger ones again.

It's pretty clean, and well lubed.

Cheers for any suggestions!

nicklouse

sounds like the typical gunked up cables. too much friction in the system.

chrisaonabike

nicklouse wrote:

sounds like the typical gunked up cables. too much friction in the system.

That makes sense, thanks.

Is it practical to remove, clean and relube?
Or should I replace?
Inner only or both?

keef66

Last time I had symptoms like those it was because the inner cable was starting to fray inside the shifter. Easy to replace the inner if you catch it in time; a right bugger if you leave it till you have stray strands of wire lodged in the guts of the shifter.

You can check it without undoing anything:-

With the chain on the largest sprocket, downshift all the way but don't turn the pedals. This will release enough cable tension to allow you to free one end of an outer from it's stop on the frame, This will give you even more cable to play with. Now you can pull the brake lever and push the inner cable back towards the shifter so you can have a good look at the nipple end and check for deterioration.

Quicker and easier to do than it is to describe...

chrisaonabike

keef66 wrote:

Last time I had symptoms like those it was because the inner cable was starting to fray inside the shifter. Easy to replace the inner if you catch it in time; a right bugger if you leave it till you have stray strands of wire lodged in the guts of the shifter.

You can check it without undoing anything:-

With the chain on the largest sprocket, downshift all the way but don't turn the pedals. This will release enough cable tension to allow you to free one end of an outer from it's stop on the frame, This will give you even more cable to play with. Now you can pull the brake lever and push the inner cable back towards the shifter so you can have a good look at the nipple end and check for deterioration.

Thanks so much, it's all frayed to buggery at the shifter end but not yet actually with stray ends lying around AFAICT - I'd never have thought of looking there till it actually broke.

I am now the proud owner of a new inner cable and a Park Tools cable cutter, courtesy of my LBS (= local Giant store) And with my 10% discount since I bought the bike there it wasn't even any more expensive than at Wiggle.

So unless I CBA to do it tonight, instead of my planned 60 miler in the morning, I shall have a relaxing coffee and a bit of cable fettling

Cheers again.

chrisaonabike

Update: all fixed! New cable in place, gears go up, gears go down. Simple enough job, but surprisingly satisfying to have done it myself.

Thanks again for your advice, guys.

keef66

You're welcome!

I've been doing quite a bit of faffing about with cables myself of late. Couple of months ago I moved all the stuff off my racelight Tk to a CR1-SL. Now I've just moved it all back again and I've been fitting some second hand Tiagra stuff to the CR1. Managed to somehow get the nipple of the LH gear cable jammed in the shifter when trying to set up the front mech. Initially thought I'd been sold a duff shifter, but then realised that some part of the outer must've been inadequately seated when I first tried to shift into the big ring, and the resulting lack of cable tension unseated the nipple. Heath-Robinson arrangement of cable ties required to pull the brake lever back and inwards while I went fishing with a pair of needle-nosed pliers to retrieve the jammed nipple. When I finally managed to extract the thing I couldn't for the life of me thread the new cable through the shifter. Left it for 2 days (busy weekend) and when I tried again it went through at the second attempt!

Flushed with success I then went to fit a slightly longer bit of brake outer at the rear caliper on the Tk (I'd shortened it when that kit went on the CR1) and one strand of the inner got caught when threading it back through the barrel adjuster on the caliper. I've chopped off the stray strand so it's not catching anywhere, but I really need to replace the inner now

gozzy

keef66 wrote:

When I finally managed to extract the thing I couldn't for the life of me thread the new cable through the shifter. Left it for 2 days (busy weekend) and when I tried again it went through at the second attempt!

I know that failure. Every time I change cables on 9 speed Tiagra the LH gear cable will not go through in less than an hour. Unless, as you discovered, you then leave it for a day or two, then it's straight through. Insanely frustrating.

keef66

Gozzy wrote:

I know that failure. Every time I change cables on 9 speed Tiagra the LH gear cable will not go through in less than an hour. Unless, as you discovered, you then leave it for a day or two, then it's straight through. Insanely frustrating.

This too is 9 speed Tiagra; first time I've worked on it, maybe it's a 'feature'. On the successful attempt the cable went in so far and hit the customary obstruction, then I pushed the brake lever inwards which seemed to take the cable with it and out the other side. Then I clicked the smaller lever to ensure it was back in the small ring position before locating the nipple and tensioning the cable.

TBH now it's working I'm pretty impressed with it. Thought it would be somehow more agricultural than the 10 speed 105 I'd been used to, but on the maiden ride in the dark last night I couldn't tell the difference.

StillGoing

Had similar experience fitting 9 speed Tiagra to someone's bike. Right shifter somehow got the cable jammed in the mechanism after it jumped the guide meaning they only had 7/8 gears depending on what mood it was in. Took some faffing around to get it out and could see no reason why it had been able to jump the guide. Thankfully it hasn't done it again since I refitted it all for him.

chrisaonabike

I thought I'd resurrect my thread from 11 months back since I've just replaced my rear gear cable again, with exactly the same problem as before - all frayed to buggery at the shifter end, shifting not surprisingly completely borked.

All good again now, though.

Just wondering, is 11-12 months a typical length of time until it frays where it goes round the ratchet on the shifter? 10 speed Tiagra if that's relevant at all.

desweller

Grease or otherwise lubricate the cable in the shifter. If it fails like that again then it's fretting on something in use.

maharg22

My generic Shimano front mec keeps rubbing against the chain despite constant adjustment and tweaking.

keezx

There is only one solution: buy a Campa left shifter. 8)

Old_Timer

Chris, my LBS recently mentioned flushing out the shifters regularly, say 2 or 3 times a year, depending on your riding and the amount of wet weather riding you do. When my SRAM Rival get sluggish I take a can of WD-40, or some penetrant, and soak the assembly down until the fluid runs out clear. then I use a light weight lube spray to keep things moving freely. The grit and moisture can build up in the shifters and wear down cables pretty quick if you are in a wet area and ride in the elements a lot. I think the UK fits the wet area part, and from what I've read of your posts you do some rain riding at times. Just a thought that may help your cable wear issues. Cheers.

chrisaonabike

Old_Timer wrote:

Chris, my LBS recently mentioned flushing out the shifters regularly, say 2 or 3 times a year, depending on your riding and the amount of wet weather riding you do. .....and from what I've read of your posts you do some rain riding at times. Just a thought that may help your cable wear issues. Cheers.

Cheers for that.. I'd have to confess that I've never lubed the cable at the shifter end. I don't do that much wet weather riding, but it got a hell of a soaking on the RL100