Bike keeps shifting by itself!
I've no idea what's going on with my bike. Recently I started getting shifting problems, so I changed the rear cable, and the chain as well because it needed doing. When my bike is on the stand in the garage it shifts fine, but as soon as I try to ride it it keeps randomly shifting! What's going on??
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How old is the cassette ? A new chain and an old block isn't a good mix.0
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Shifting up or down? An old cassette on new chain can give you skipping usually down shifting which is fun, that or your cable tension is a little too high.0
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Ok... I'll take the bait...
http://www.bikeradar.com/forums/viewtopic.php?f=40004&t=13083543&start=20#p201947700 -
When I changed the cable on my MTB a while ago I adjusted it and it just worked, so there is obviously something else going on here.0
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Is it possible the cassette could be worn out already?? As I say I've only had it just over year, but I've been riding it regulary. Surely a cassette should last longer than that??0
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What cassette is it ? Do you favour a couple of sprockets ? How often do you clean the chain ? How many miles do you do ?
Sometimes the chain beds in after a few rides - how many miles have you done on this.0 -
Qube wrote:Ok... I'll take the bait...
http://www.bikeradar.com/forums/viewtopic.php?f=40004&t=13083543&start=20#p20194770Bungle73 wrote:I've been maintaining my own bikes for 20 years................
I probably know a lot more about than a lot of people on this forum.0 -
Probably a faulty quick-link....FFS! Harden up and grow a pair
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Maybe you put the chain on upside down?I don't do smileys.
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Parktools0 -
Fenix wrote:What cassette is it ?
SRAM PG930 11-28T according to the specs on the company's websiteDo you favour a couple of sprockets ?
I've never really thought about it. I just use whatever gear suits the terrain I'm on and the speed I'm at. I guess I usually stay somewhere near the middle, but the ghost shifting is happening pretty much as soon as I pull away.How often do you clean the chain ?
When it looks like it needs it, and when the bike gets cleaned. But the chain only just needed changing. When I checked it a while ago it was fine.How many miles do you do ?
I've done around 1664 miles since I bought it last July.
I haven't even used it yet! I can't even ride the bike atm, because it keeps shifting by itself. That can't be right. I just tried going out on for the first time today, and had to come back home.Sometimes the chain beds in after a few rides - how many miles have you done on this.0 -
I'd give it a ride and see if it settles. Your block shouldnt be worn with that mileage unless its very very dirty.0
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Could be a bent derailleur hanger. With the worn chain there was enough slop in the chain that it wasn't an issue, new chain being laterally stiffer would highlight the issue. Only a guess of course.0
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Have the shifting problems changed in nature since the new chain and cable?[Castle Donington Ladies FC - going up in '22]0
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Veronese68 wrote:Could be a bent derailleur hanger. With the worn chain there was enough slop in the chain that it wasn't an issue, new chain being laterally stiffer would highlight the issue. Only a guess of course.
I'm not sure that could have happened though. And getting that checked and fixed is going be a pain. There are no bike shops around here, apart from Halfords. They all closed down.DeVlaeminck wrote:Have the shifting problems changed in nature since the new chain and cable?
Well the original problem was it wasn't shifting properly at the high end of the block, which apparently is a sign of sticky cables. That's exactly what happened with the MTB, and a cable change fixed it.
Now, as I say, it works fine in the garage, but it keeps ghost shifiting when I try to ride it. That never happened before.
I'm wondering if it's some kind of problem with the chain. Maybe I should have stuck a bog standard Shimano on there.0 -
Does it actually shift to a different cog or does it just skip a link?
You could have issues with the cable and/or hanger - but I suspect as you've been messing about with pins and quick links that you've pushed the pin in and caused one (or more) of the links to be stiff - so it doesn't pivot when it goes over the cassette - then the pressure of the pedal stroke causes it to jump a link - which obviously you notice.
I found that when fixing a chain with the pin - the pin had to be driven through then backed off a bit by swapping the chain link tool around and driving it back out a fraction.
It's easy to check - just jump off the bike and turn the crank backwards - watching the chain for any stiff links.0 -
Good call on the stiff pin. Yes you dont get THAT issue with the Quick Links......0
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I can't really tell. I can feel it skipping when I peddle and sometimes when I look down it's shifted up a gear.
I haven't messed about with any pins. All I've done is put the chain on once, realise it was incorrectly threaded, taken it off, and then put it on again. I haven't used any pins.
I've already spun the chain around looking stiff links and it looks fine.0 -
Maybe you put it on back to front?I don't do smileys.
There is no secret ingredient - Kung Fu Panda
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Parktools0 -
Re quick link - it could be ...
if you've either not attached it correctly or have the wrong one - do your speeds match? because chains are different widths.
anyway - here you go ...how to adjust your gears ....
http://road.cc/content/feature/164256-h ... ign=buffer0 -
I'm thinking I'm going to have to buy another new, Shimano, chain. I've got one laying around, but it's not suitable.
I've been waiting all week through the crappy weather to go out on the bike, and now it's nice it's not working!
I wish I'd just left it now. Before I touched it I could use it, and now it's unridable.0 -
It's the one that came with the chain!Slowbike wrote:Re quick link - it could be ...
if you've either not attached it correctly or have the wrong one - do your speeds match? because chains are different widths.
anyway - here you go ...how to adjust your gears ....
http://road.cc/content/feature/164256-h ... ign=buffer
It's a 9 speed chain on a 9 speed drivetrain.0 -
I think I might try ditching the damn link and joining the chain with a pin, but I'm not sure if that will make the chain too short, and I also don't know if a Shimano pin will work with a KMC chain?0
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I do like your username. Apt.0
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Still sounds like a worn cassette to me.0
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Bungle73 wrote:I'm thinking I'm going to have to buy another new, Shimano, chain. I've got one laying around, but it's not suitable.
I've been waiting all week through the crappy weather to go out on the bike, and now it's nice it's not working!
I wish I'd just left it now. Before I touched it I could use it, and now it's unridable.
i m sure kmc chains are not directional but it would worth double checking this....
Why dont you just refit the old chain? (you can use the quick link that came with your new chain if you ve not a 9 sp pin) if it goes back to how it was, you ll know its a worn cassette, if not, it ll be your new gear cable and subsequent set-up/ indexing.... check the chain is threaded through the RD properly too.
unless your hanger is bent, it would be very odd that a worn cassette would affect all the gears, you d expect at least some to be fine.
Are you sure you fitted the new cable correctly? ie made sure the shifter was in gear 9 - smallest cog- position? and that the cable moves fine in the last loop of outer casing?0
