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Bike repair advice
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My city is in lockdown so I have no idea when I will be able to get to a bike shop. Hoping to get some advice on how to fix an issue that has just cropped up.

My chain isn't lining up with the cogs on the chain ring as you can see in the pic. If I go below 150 watts it is generally ok, but over that it makes a horrible grinding sound and becomes pretty much unrideable if trying to go at a decent pace.

What is the issue, does something need adjusted, is the chain too stretched out and can I fix this without making things worse? I'm only riding on the trainer, so no danger of hurting myself or anyone else if a bandaid solution fails.
Last edited by: 42point2: Jul 10, 20 5:22
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Re: Bike repair advice [42point2] [ In reply to ]
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No picture, so some basic questions.

1) cable or electronic shifting.
2) inner or outer ring?
3) has this gradually ocurred, or did it happen suddenly? Did you do anything? ;-)
Last edited by: Duncan74: Jul 10, 20 1:01
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Re: Bike repair advice [Duncan74] [ In reply to ]
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Duncan74 wrote:
No picture, so some basic questions.

1) cable or electronic shifting.
2) inner or outer ring?
3) has this gradually ocurred, or did it happen suddenly? Did you do anything? ;-)


Wasn't able to upload the pic for some reason!

1. Cable
2. it happens on both chain rings
3. It happened all of a sudden. A few days ago I first noticed it when there was a grinding sound, thought that it was jumping to another gear. Had a closer look and realized that the chain ring and chain were not lining up properly. When I rode yesterday it was worse and could only ride at an easy pace.
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Re: Bike repair advice [42point2] [ In reply to ]
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1) great, means 99% fixable
2) Odd it's in both but that's good as it narrows options.
3) Even better, sudden things are easier to find as something will be a stop out of where it should be, and not just a cable that's streched over time.


So my initial suspicion with the fact it's both rings is that the front mech bolts are slightly loose and it's catching on the chainring. Check the bolts are tight holding it onto the frame. Dont worry if this isn't the issue as it's part of the problem solving.

Does the mech move in and out when you move the shifter? Ignore how far, just making sure it's moving.

Also, silly things, it's on the rear jockey wheels ok and not slipped off the top one?
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Re: Bike repair advice [42point2] [ In reply to ]
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In the absence of more information it sounds like your derailleur is simply out of position.
Normally that would be due to poor setup, but if it just cropped up having previously been okay, then most likely, someone was fiddling with a barrel adjuster or the derailleur without you noticing, or the front gear cable has moved. I suppose it's also possible the front derailleur got a knock and could be damaged but seems less likely.

Adjusting the front derailleur is a trivial job on a tri bike and only slightly less trivial on an indexed road bike setup. It's far easier to do it yourself than go to the trouble of bringing the bike to a mechanic (even if that was an option). Having the bike on a trainer makes it even easier since it serves as a bike stand. If the groupset is Shimano, I'm pretty sure they provide manuals including detailed set-up instructions, for all their parts, on their website. There are also plenty tutorials on YouTube if you prefer.
Including 10mins to look up and read or watch instructions, the job shouldn't take more than maybe 15-20mins. The second time you do it, maybe allow 3-5mins including hopping on and off the bike to change gears and check it's okay.
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Re: Bike repair advice [Duncan74] [ In reply to ]
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Duncan74 wrote:
1) great, means 99% fixable
2) Odd it's in both but that's good as it narrows options.
3) Even better, sudden things are easier to find as something will be a stop out of where it should be, and not just a cable that's streched over time.


So my initial suspicion with the fact it's both rings is that the front mech bolts are slightly loose and it's catching on the chainring. Check the bolts are tight holding it onto the frame. Dont worry if this isn't the issue as it's part of the problem solving.

Does the mech move in and out when you move the shifter? Ignore how far, just making sure it's moving.

Also, silly things, it's on the rear jockey wheels ok and not slipped off the top one?


The mech seems to be moving fine and the chain does not seem to be rubbing on anything. All bolts seem to be tight and I can't see anything obvious issues with jockey sheels etc
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Re: Bike repair advice [Ai_1] [ In reply to ]
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Ai_1 wrote:
In the absence of more information it sounds like your derailleur is simply out of position.
Normally that would be due to poor setup, but if it just cropped up having previously been okay, then most likely, someone was fiddling with a barrel adjuster or the derailleur without you noticing, or the front gear cable has moved. I suppose it's also possible the front derailleur got a knock and could be damaged but seems less likely.

Adjusting the front derailleur is a trivial job on a tri bike and only slightly less trivial on an indexed road bike setup. It's far easier to do it yourself than go to the trouble of bringing the bike to a mechanic (even if that was an option). Having the bike on a trainer makes it even easier since it serves as a bike stand. If the groupset is Shimano, I'm pretty sure they provide manuals including detailed set-up instructions, for all their parts, on their website. There are also plenty tutorials on YouTube if you prefer.
Including 10mins to look up and read or watch instructions, the job shouldn't take more than maybe 15-20mins. The second time you do it, maybe allow 3-5mins including hopping on and off the bike to change gears and check it's okay.


My bike has been at home on the trainer, no one has touched it and it's pretty unlikely that I knocked against it without noticing.

It is a Shimano groupset, so will have a look the instructions on their website and videos. Hopefully that will sort out the problem!
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Re: Bike repair advice [42point2] [ In reply to ]
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When you say "My chain isn't lining up with the cogs on the chain ring" is it possible you mean the chain isn't hugging the chain ring and is slightly further out than it should be, above the teeth? If so that is probably chain wear.
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Re: Bike repair advice [42point2] [ In reply to ]
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Take it off the trainer and go for a ride.If the problem stops then it may be that you are jamming the bike into the trainer too tightly and that the frame is flexing under load.
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Re: Bike repair advice [OddSlug] [ In reply to ]
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OddSlug wrote:
When you say "My chain isn't lining up with the cogs on the chain ring" is it possible you mean the chain isn't hugging the chain ring and is slightly further out than it should be, above the teeth? If so that is probably chain wear.


It is almost sitting on top of the teeth on the chain ring. Not in the grooves like it should be. You can see a gap between the chain and chain ring
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Re: Bike repair advice [42point2] [ In reply to ]
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42point2 wrote:
OddSlug wrote:
When you say "My chain isn't lining up with the cogs on the chain ring" is it possible you mean the chain isn't hugging the chain ring and is slightly further out than it should be, above the teeth? If so that is probably chain wear.



It is almost sitting on top of the teeth on the chain ring. Not in the grooves like it should be. You can see a gap between the chain and chain ring


So how old is the chain? Normally that is chain wear. They call it chain stretch but it isn't a great description of it. Even if you don't think it's that there is no harm trying a new chain on since you can swap them easily with connect links. You could also just clean and lube the chain then check for stiff links - edit - I mean just to prove it isn't a stiff chain, I doubt it will be. Normally that would be a worn chain that needs replacing.
Last edited by: OddSlug: Jul 10, 20 3:54
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Re: Bike repair advice [42point2] [ In reply to ]
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42point2 wrote:
OddSlug wrote:
When you say "My chain isn't lining up with the cogs on the chain ring" is it possible you mean the chain isn't hugging the chain ring and is slightly further out than it should be, above the teeth? If so that is probably chain wear.



It is almost sitting on top of the teeth on the chain ring. Not in the grooves like it should be. You can see a gap between the chain and chain ring
Are the rollers sitting on top of the teeth (excessive wear), or is it the side plates sitting on top of the teeth (likely a misaligned derailleur).
If the chain is centered on the teeth and it's not engaging properly then the derailleur is not the issue, it's just there to align the chain with the chainring.
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Re: Bike repair advice [42point2] [ In reply to ]
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A chain checker is a really cheap tool and it's always handy. And get some quick link pliers.
Always have your next chain on hand before you need it.
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Re: Bike repair advice [Justicebeaver] [ In reply to ]
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Justicebeaver wrote:
A chain checker is a really cheap tool and it's always handy. And get some quick link pliers.
Always have your next chain on hand before you need it.

I love Wippermann Connex chains. No tools needed for the quick link!

...and the 11SX chains I've been using really do last too!
Last edited by: Ai_1: Jul 10, 20 5:09
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Re: Bike repair advice [Ai_1] [ In reply to ]
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Well without the pic its hard to tell, but it does sound like a work chain.

Essentially each roller wears a little over time, and once youve added togeter a few links the chain gets noticiable longer. you can get cheap chain wear indicators, and they really do the job, well worth having. if youve got a worn chain, it will eventually wear the sprocket to suit, and when you put a new chain on it will slip on the old sprocket, so it pays to chain chains more often epeciially iof you are using expensive sprockets. chain rings are less prone to wear due to the higher tooth count.

https://www.youtube.com/watch?v=Y54ekC8PHB0

As youve found, slipping is usually load related, a chain slip when your out of the saddle sprinting can be a bad thing. bit of a tangent, a freind changed the chain on his tandem, took it for a test ride ( on his own) and it was fine. with two people on it the extra torque made it pretty much unrideable due to chain slip. put the old chain on and it was fine.
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Re: Bike repair advice [JRC] [ In reply to ]
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For some reason I can't upload a picture of my bike, but here's what it looks like, though not as bad. https://bicycles.stackexchange.com/...ing-on-big-chainring

Chain is the original one I got with the bike and has about a year to a year and half's amount of use.

The comments all seem to mention a worn out chainring and/or stretched out chain. I'm thinking it is the chain, as it would be surprising if all of a sudden both chainrings developed the same problem at the same time.
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Re: Bike repair advice [42point2] [ In reply to ]
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i sounds like the chain is shot. If it has worn the cogs, it may skip when you replace the chain, then you have to do the cogs too
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Re: Bike repair advice [42point2] [ In reply to ]
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Go with the chain. It’s the obvious thing and it’s a consumable. It probably will solve it and if it doesn’t you will use it sooner rather than later.

The chain wears faster than the chain ring. So if both were new together the chain goes first.

Someone else mentioned a chain wear tool. Get one and keep an eye on the new chain and replace it before it gets this far.

Don’t over think it. Get a new chain.
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Re: Bike repair advice [OddSlug] [ In reply to ]
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OddSlug wrote:
Go with the chain. It’s the obvious thing and it’s a consumable. It probably will solve it and if it doesn’t you will use it sooner rather than later.

The chain wears faster than the chain ring. So if both were new together the chain goes first.

Someone else mentioned a chain wear tool. Get one and keep an eye on the new chain and replace it before it gets this far.

Don’t over think it. Get a new chain.
Yep, seems like the chain is most likely and, as above, you'll use it anyway!
The fact you said this cropped up suddenly and mentioned the chain not "lining up" with the teeth threw some of us off earlier in the absence of a picture. It will have been gradually worsening but has just become bad enough to get your attention. A chain wear tool like this is worth having: https://www.connexchain.com/...-wear-indicator.html
There's lots of types and any will do, or you can just measure the chain length over a given number of links and compare it with the recommended max link length.
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Re: Bike repair advice [42point2] [ In reply to ]
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Having seen the picture you emailed, then first thing is to give the chain a clean. I am pretty sure that is a major factor in your issues and potentially the sweat landing on it whilst you're training is what's made the issue come on suddenly. There is an issue with the chain not 'bending' properly as you can see towards the top in the photo. Have you any chain cleaner at home?

For trainer use then some very light (dry) lube with a small amount reapplied every 10 hours riding would be good. At the moment it almost looks like you've still got the gunk on that protects the chain in transit ;-)

Can you also please check the back jockey wheels and that the jockey is providing some tension / movement. I'm fairly sure that the jockey will be very gunked up - may not be the cause of this but you need to sort it.
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