Author Topic: Bike chain slipping  (Read 4391 times)

unpolloloco

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Bike chain slipping
« on: August 05, 2013, 08:31:46 AM »
I have a 10-year-old Trek hybrid that I picked up off of Craigslist for a steal a while back that is giving me some problems now when I'm pedaling hard.  The pedal will move a quarter turn or so occasionally with no force, like the chain is slipping or has slipped off of the back cassette. 

My question is: how do I identify if this is a chain issue, a cassette issue, or a derailleur issue without taking it to someone to check out?  Everything looks fine at a first glance (nothing is obviously worn or broken), but something probably is!

Greg

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Re: Bike chain slipping
« Reply #1 on: August 05, 2013, 09:03:16 AM »
My wife just went through this problem on her bike, used several days a week for commuting.

Chains stretch, which wears out the gears.  Look at your gears and compare the ones that look like they get a lot of use to the ones that never get used.  They should all look the same but you'll probably notice the used-looking gears have larger spaces between them, and that the gear teeth are smaller and rounded off.

The gears will likely need replacing, and the chain too of course. Bring money.  In the future, you have to replace the chain when it starts to stretch to prevent it wearing out the gears, which cost more.  Bike shops can measure chain stretch, I'm sure there's a way to do it at home as well.

mpbaker22

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Re: Bike chain slipping
« Reply #2 on: August 05, 2013, 09:55:25 AM »
rule of thumb is each chain link should be an inch.  If you start a ruler at a reference point on one link, you should hit the same reference point on the 13th link, 12 inches later.  If it's off, especially by more than a mm or 2, you're chain has stretched as Greg says.

Even if the chain hasn't stretched, the teeth could be rounded off as Greg suggested.  I'd specifically check for rounded off teeth as checking the chain is a proactive strategy that should be taken before slippage begins.

jradc

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Re: Bike chain slipping
« Reply #3 on: August 05, 2013, 10:05:58 AM »
I am a volunteer at a community bike co-op, and this is a common problem that people come in with. It has several possible issues:

1) Maybe nothing is worn out, but the chain is slack. When you look at the chain, is the bottom of it super slack? Do you normally pedal in the smallest front chainring? If so, I recommend trying out a different front chainring to take out some of the slack. Occasionally you see a chain which was not correctly sized, but that is rare.

2) Maybe the chain is worn out. The ruler method mentioned above is good. Another good solution is to shift into the largest chainring and then attempt to pull the chain away from the ring with your hand (sorry, you get dirty). If the teeth and chain are fitting tightly together, then you won't be able to pull it much at all. If the chain is worn out, you might be able to see a little daylight in between.

3) Maybe the chainring is worn out. Do you always pedal in the same front chainring? If so, there's a decent chance its worn out after ten years (I personally ride 90% in the middle front chairing, so I have this issue). You can inspect the chainring to see if the teeth appear "sharper" on that ring than the others, that means its worn out. Sometimes you can replace just one chainring, depending on the type.

4) Other stuff: maybe the chain isn't slipping at all - occaisionaly seen rear wheel ratchet slip for example.

Good luck.

unpolloloco

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Re: Bike chain slipping
« Reply #4 on: August 05, 2013, 11:36:28 AM »
Thanks for the advice!  I'll check things out tonight and see.  The issue I have is that I bought this bike a year or so ago (put on a few hundred miles since then - so not that much!) but don't know how much it had been used before me.  This issue's only popped up recently.

I just don't want to put in $$$ to have a bike shop fix it when I can probably unload this back onto craigslist with the issue disclosed for about the same as I paid for it, then turn around and buy another similar one for slightly more $$ (bought the bike for about the same price as the minimum service cost is at most bike shops in my area!).  DIY is highly preferred in this case!

MilwaukeeStubble

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Re: Bike chain slipping
« Reply #5 on: August 05, 2013, 05:56:11 PM »
If DIY is that preferered, try re-greasing the chain.  I've had a similiar problem that was miraculously solved with chain grease before, it's cheap to do, and it probably needs to be done anyway.

You can also try adjusting the derailleur with a screwdriver (there should be a couple adjustment screws down there, you want to move the derailleur closer to the frame (probably:). Basically as the bike ages the cables which control the gears (and brakes) will stretch and the derailleur will move to its right.  If your chain sometimes overshoots the top gear this is probably why.  I don't think this would be the cause of your problem but I'm sure it's somehow possible, and again it probably needs to be done anyway.  (Note: if your not willing to tinker with this, and you haven't had problems shifting gears don't bother doing this adjustment.  It can be a royal PITA to get the adjustments right)

jawisco

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Re: Bike chain slipping
« Reply #6 on: August 05, 2013, 07:10:35 PM »
Your chain is too long.  If this has been going on for a while, you probably will need a new rear cassette and a chain, but if it has only been happening a short while, you can probably just replace your chain and you will be fine.  It has to happen anyway, and it is pretty inexpensive to change it and see if the slippage keeps happening. 

If you can DIY, you can replace your cassette for low cost as well. Either way, it is probably a fine bike that has treated you well so far and likely will be low cost to maintain going forward. So rather than buy and sell on craigslist (which takes time), spend that time to learn a little bike DIY and get to know your bike.

ralay

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Re: Bike chain slipping
« Reply #7 on: August 06, 2013, 06:05:13 PM »
Replacing chains and (to a lesser extent cassettes/freewheels) is a routine part of maintenance for a well-ridden bike.  I'm car-free and can wear out a chain at least once a year.  If you plan on riding a lot, you're not really going to escape the problem of routine drive train maintenance by reselling the bike.  If your town has a bike co-op you can probably use all their tools for free or next to free.  If not, you'll need:

Parts:
chain to match your bike (single speed or 6/7/8/9 speed, ~$10)
cassette/freewheel with same number of cogs as your old one (~$20)

Tools:
chain breaker (<$10, single or multispeed, better value as part of a multitool)
lock ring/freewheel removal tool (~$6 must match your cassette/freewheel manufacturer)
chain whip (~$10, sometimes comes a as a pedal wrench or lockring/freewheel remover combo, this is semi-optional but sure makes life easier)

If it were me, I would spend the $50, watch some youTube videos.  Find out the difference between a freewheel and a cassette, how to break and reconnect a chain, and how to unscrew and rescrew a freewheel/ cassette lockring.  That's it.  You won't have to sell your old bike at a discount and you won't have to shop for a pristine new one that won't have this problem (in its first year).  You'll also be able to reuse the tools for this and other routine bike problems.  My 2 cents anyway, if your problem is indeed a worn chain/cassette which is very common.


unpolloloco

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Re: Bike chain slipping
« Reply #8 on: August 08, 2013, 10:09:00 AM »
Replacing chains and (to a lesser extent cassettes/freewheels) is a routine part of maintenance for a well-ridden bike.  I'm car-free and can wear out a chain at least once a year.  If you plan on riding a lot, you're not really going to escape the problem of routine drive train maintenance by reselling the bike.  If your town has a bike co-op you can probably use all their tools for free or next to free.  If not, you'll need:

Parts:
chain to match your bike (single speed or 6/7/8/9 speed, ~$10)
cassette/freewheel with same number of cogs as your old one (~$20)

Tools:
chain breaker (<$10, single or multispeed, better value as part of a multitool)
lock ring/freewheel removal tool (~$6 must match your cassette/freewheel manufacturer)
chain whip (~$10, sometimes comes a as a pedal wrench or lockring/freewheel remover combo, this is semi-optional but sure makes life easier)

If it were me, I would spend the $50, watch some youTube videos.  Find out the difference between a freewheel and a cassette, how to break and reconnect a chain, and how to unscrew and rescrew a freewheel/ cassette lockring.  That's it.  You won't have to sell your old bike at a discount and you won't have to shop for a pristine new one that won't have this problem (in its first year).  You'll also be able to reuse the tools for this and other routine bike problems.  My 2 cents anyway, if your problem is indeed a worn chain/cassette which is very common.

Perfect - Thanks a bunch everyone!  Looking at the cassette, it's very worn (probably had a bit more usage than I thought it had when it bought it).  I'll replace that and the chain once I gather all the parts required.  A $50 repair on a $150 bike is much more palatable than a >$200 one (bike shop route)!

PantsOnFire

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Re: Bike chain slipping
« Reply #9 on: August 08, 2013, 02:51:36 PM »
Stop.  You never really mentioned whether you could see the chain slipping.  Before you try this or that, or buy anything, use your eyes.  If the chain isn't visibly slipping over the teeth of the rear cogs or front chainrings, then your problem is most likely inside the freehub and a new chain, cassette, chainrings, etc. won't do a thing to help you. 

NVDee

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Re: Bike chain slipping
« Reply #10 on: August 09, 2013, 04:10:20 PM »
Word of wisdom here
Stop.  You never really mentioned whether you could see the chain slipping.  Before you try this or that, or buy anything, use your eyes.  If the chain isn't visibly slipping over the teeth of the rear cogs or front chainrings, then your problem is most likely inside the freehub and a new chain, cassette, chainrings, etc. won't do a thing to help you.

Checking the freehub engagement before you do anything.