Getting the indexing right

[RichardB]

Hoping someone can offer some advice. It's my electric commuter bike, which has 1 x 9 gears, with a Shimano Deore rear mech and an Alivio shifter. The gear shifting has never been 100% right, even from new. I took it back to the dealer, who spent a while with it and improved the changing, but now (18 months and 1400 miles later) it is worse then ever. Sometimes it doesn't shift, others it shifts two gears at a time. Sometimes nothing happens, and then it shifts all by itself 30 seconds later, but with no noise to indicate it has been misaligned. Watching it on a workstand, from gear 9 (smallest) one press will do nothing, then it will change correctly until 3, then one more press skips 2 and goes straight to the biggest sprocket. Same going the other way. In use, I can always find the gear eventually, so the bike is useable, but it would be great to have it working properly. My first thought was a sticky mech or cable, so I lubed and worked the mech (wasn't sticking at all) and removed, cleaned and lubed the last curve of the cable from the rear stay to the mech. The cable seems completely free and smooth. I put the cable back with a small amount of slack, got the bike on the stand and tried to get it adjusted using the barrel adjuster. Try as I might, I can't get it so that one press of the shifter = one gear up or down. I have gone from ridiculously tight (no ninth gear) to completely slack, and every click of the adjuster in between, but all I seem able to do is move the fault around. My MTB has an ancient GS100 mech, and I can get this to index perfectly, so I am hoping it is not a lack of skill. Everything is lined up correctly, nothing seems broken or bent, chain is well lubed and shows no measurable wear. I'd be grateful for any ideas.

 

[Ajax Bay]

Has the cassette got an identity eg HG-number? Has the chain been changed since you bought it new with a 9sp chain on?

 

[RichardB]

I'm not with the bike at the moment, but the spec in an advert on the web says the cassette is a Sunrace 13/32. Does that help? Cassette and chain are manufacturer's original. Thanks for responding.

 

[Tim Hall]

Seeing as the problem occurs when changing to a larger sprocket (assuming you've got a normal mech ) I think stiction is unlikely to be a cause (and you've eliminated it anyway). I'd look at mech alignment as a starting point.

 

[lpretro1]

Try a slightly longer piece of gear outer at the rear mech end - it may just be a little too tight of a curve round the the rd

 

[RichardB]

Seeing as the problem occurs when changing to a larger sprocket (assuming you've got a normal mech ) I think stiction is unlikely to be a cause (and you've eliminated it anyway). I'd look at mech alignment as a starting point.

Maybe I wasn't quite clear (I was trying not to write War and Peace, basically), but it does it changing to smaller as well. Sometimes no change, or delayed change, or misses a ratio. I didn't remove the whole cable, just the rear axle section, so when I next get some time I will take the whole cable out and clean/lube. There's no reason for the mech to be misaligned - no impacts to that area, and it's protected by a sodding great metal guard - but I will give it a more careful check. It certainly looks vertical from the rear, and moves perfectly parallel.

Try a slightly longer piece of gear outer at the rear mech end - it may just be a little too tight of a curve round the the rd

Good point, hadn't thought of that. It is fairly tight, come to think of it. And the problem has been there since new. Hmmm.

When the dealer 'fixed it' on the first free service, he took quite a long time and said something about adding or removing spacers to get the chainline better. I didn't question it, as it was certainly improved, but it has deteriorated over time, which makes me think it is a corrosion/lubrication issue rather than alignment, which shouldn't change over time unless there is damage or wear. However, the 13T sprocket is very close to the dropout. The chain isn't touching the seatstay, but you couldn't get a fag paper between them when it is on the smallest. That looks slightly 'wrong' to me. I'll certainly have a closer look on my next free day at all of these points. Then I'll try a new chain and cassette. Thanks both for the input, much appreciated.

 

[steveindenmark]

Richard. Try asking the question on Pedelecs.uk. The guys on there know everything about Electric bikes and are happy to help. We used to use it all the time when we had our Electric bikes.

 

[Globalti]

Change the gear cable outer. Water and dirt have got in and the steel reinforcements have rusted up.

 

[Karlt]

Does sound like a rear loop issue to me. I'd replace it.

 

[RichardB]

Richard. Try asking the question on Pedelecs.uk.

Fair point, although in my experience there is much better expertise here on the purely mechanical stuff. The rear mech and cable are standard Shimano and nothing to do with the battery or drive system. They are just the same as on a normal bicycle.

Change the gear cable outer. Water and dirt have got in and the steel reinforcements have rusted up.

Does sound like a rear loop issue to me. I'd replace it.

Looks like we have agreement here. I did remove, clean and lube the rear loop, and it seemed fine, but renewing that sounds like the best way forward for now - with a longer loop of outer as per lpretro1's comment above. That will be the weekend now, I suppose.

Thanks for the help, guys.

 

[the_mikey]

As above with the addition of being mindful of the rear derailleur alignment, check the derailleur or derailleur hanger isn't bent, that will also cause gear shifting issues.

 

[RichardB]

As above with the addition of being mindful of the rear derailleur alignment, check the derailleur or derailleur hanger isn't bent, that will also cause gear shifting issues.

As above, there are no obvious issues, but will have a closer look at the weekend. Thanks.

 

[Globalti]

Take the bike along to a LBS and get the alignment checked; you might be surprised.