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Thread: Slipping Gears?

  1. #1
    Senior Member LessEverything's Avatar
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    Slipping Gears?

    When I pedal really hard, like say I start going up a hill in a mid gear. The chain, gear something slips, it goes "cr-chunk" and then catches. I have extremely strong legs, a couple years back when I was playing college f-ball I leg pressed 1400 pounds, squatted 700 and could dunk a basketball at 310 pounds. I am I just being too tough on the bike or is there something wrong with it.

  2. #2
    Senior Member DieselDan's Avatar
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    Maybe it is time for a new chain and cassette
    Bikes use brakes to stop.

    If your bike has breaks, don't ride it.

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    The Site Administrator: Currently at home recovering from a couple of strokes,please contact my assistnt admins for forum issues Tom Stormcrowe's Avatar
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    That wouold be my thought as well. If you generate that much torque, you are going to eat chains and cassettes.....nature of the beast!
    on light duty due to illness; please contact my assistants for forum issues. They are Siu Blue Wind, or CbadRider or the other 3 star folk. I am currently at home recovering from a couple of strokes. I am making good progress, happily.


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    Senior Member DieselDan's Avatar
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    Two extreme examples:

    Me: 800 miles on a chain and freewheel on a Diamondback MTB that I used exclusively as a commuter when I lived on Hilton Head Island and never drove my car.

    Machka: 8,000 miles on a Shimano Sora drivetrain. Granted she is a small woman that spins on flat Canadian Prairies most of the time.

    Most of my riding peers get 1200-3000 out of a chain and cassette. I measure mine twice a year and change when needed.
    Bikes use brakes to stop.

    If your bike has breaks, don't ride it.

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    Senior Member barba's Avatar
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    There are a few other possibilities, besides a worn chain and cassette (though that is a good bet). It could be that the adjustment of the rear derailleur is off a bit, if you are lucky. Adjusting the cable tension is an easy and cheap fix.

    Has this always happened with this bike? How heavy are you? If you have a frame with a good deal of flex in it, your weight can cause the cable running under the BB shell to be pulled a bit as frame flexes. This can cause "ghost shifting".

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    check the derailleur adjustment first. You may need a new cassette or chain, but it might just be that the adjustment isn't dead on. A twirl of a barrel adjuster might be all it needs.
    Leg strength is important, but it's kind of self-limiting. You can't actually put much more force on the pedals than your body weight, because there' s nothing to push against. If your leg comes down strongly, you'll lift up out of the saddle. You can get a little more by wrestling the bars, but it's a fraction of the total, not a multiple of it.

  7. #7
    Senior Member brodie's Avatar
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    i would think you need a new chain at the least. i had the same thing happen and,put on a freewheel and chain- problem solved.

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    Senior Member LessEverything's Avatar
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    To answer everyone's questions.

    Yes it shifts on its own sometimes about the same times and situations as the slipping. I have only owned the bike two days (its used). I am 375, sexy and nimble like a ballerina.

  9. #9
    Neil_B
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    Quote Originally Posted by LessEverything View Post
    When I pedal really hard, like say I start going up a hill in a mid gear. The chain, gear something slips, it goes "cr-chunk" and then catches. I have extremely strong legs, a couple years back when I was playing college f-ball I leg pressed 1400 pounds, squatted 700 and could dunk a basketball at 310 pounds. I am I just being too tough on the bike or is there something wrong with it.
    It's cross chaining, possibly. Do you have a triple? It's a problem with triples. My Trek Navigator has that problem, and it's usually when I'm climbing and change gears quickly. Don't mash while changing gears.

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    Senior Member Terrierman's Avatar
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    1. Small chain ring in front = lowest two thirds of the gears in the back.
    2. Middle chain ring in front = middle two thirds of the gears in the back.
    3. Big chain ring in front = highest two thirds of gears in the back.

    If you are riding that way and still have the problem (which I assume is on the rear) the most likely culprit is a rear derailer (RD) that is slightly out of adjustment. There is a tensioning nut on the shiift cable where it fastens to the shifter on your handlebars. It will also have a locknut on it. Loosen the locknut and thread the tensioning nut out a couple of turns and see if that solves your problem. 50-50 or better chance it will. If the tensioning nut is already way out, try threading it back in. You can mess around with it and get the shifting way off and then bring it back to where it needs to be. Having the bike on a rack (I hang mine on the travel rack) while adjusting and pedaling with your hand and shifting helps. If that doesn't cut it, take the bike to a decent shop and ask them to check the RD for proper adjustment and while they are at it, check chain for excess wear, and if it is shot replace it. Also have them check the cassette on the back and the chain rings on the front. Hopefully they are not shot too, but if they are, you will have to replace them along with the chain. Unless the bike has seen some serious use, that is not likely. But it is a good reason to keep your chain clean and lubed and also to check the chain now and then to make sure it is not worn and damaging the cassette and chain rings.

    Good luck.
    It's all downhill from here. Except the parts that are uphill.

  11. #11
    Senior Member LessEverything's Avatar
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    I am totally learning so much thanks to the members here. You guys rock.

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    Senior Member Caincando1's Avatar
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    Quote Originally Posted by LessEverything View Post
    I have extremely strong legs, a couple years back when I was playing college f-ball I leg pressed 1400 pounds, squatted 700 and could dunk a basketball at 310 pounds. I am I just being too tough on the bike or is there something wrong with it.
    Holy smokes, you could easily break even the best components. So once you get the bike tuned, you will want to spin the pedals with a high cadence. If you mash the pedals you will break stuff. This stuff just wasn't designed for guys like you. That doesn't mean you cann't get thousands of miles out of a bike, you will just have to take it easy.
    2006 Trek Pilot 1.0
    2005 Trek Navigator 300

  13. #13
    Neil_B
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    Quote Originally Posted by Terrierman View Post
    1. Small chain ring in front = lowest two thirds of the gears in the back.
    2. Middle chain ring in front = middle two thirds of the gears in the back.
    3. Big chain ring in front = highest two thirds of gears in the back.

    If you are riding that way and still have the problem (which I assume is on the rear) the most likely culprit is a rear derailer (RD) that is slightly out of adjustment. There is a tensioning nut on the shiift cable where it fastens to the shifter on your handlebars. It will also have a locknut on it. Loosen the locknut and thread the tensioning nut out a couple of turns and see if that solves your problem. 50-50 or better chance it will. If the tensioning nut is already way out, try threading it back in. You can mess around with it and get the shifting way off and then bring it back to where it needs to be. Having the bike on a rack (I hang mine on the travel rack) while adjusting and pedaling with your hand and shifting helps. If that doesn't cut it, take the bike to a decent shop and ask them to check the RD for proper adjustment and while they are at it, check chain for excess wear, and if it is shot replace it. Also have them check the cassette on the back and the chain rings on the front. Hopefully they are not shot too, but if they are, you will have to replace them along with the chain. Unless the bike has seen some serious use, that is not likely. But it is a good reason to keep your chain clean and lubed and also to check the chain now and then to make sure it is not worn and damaging the cassette and chain rings.

    Good luck.
    Did you have to replace the chain or cassette on your Navigator, and if so, after how many miles? I have nearly 1700 on mine.

  14. #14
    Senior Member Terrierman's Avatar
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    My navigator is still running fine. It's got about 1400 or so on it. Proud to say it is on loan to a friend of mine in Arkansas, who is about the same age I am and who also wants to get himself in better physical condition.
    It's all downhill from here. Except the parts that are uphill.

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    I had the same problem on my mountain bike. It started on the smallest cog and proceeded up the cassette. The guys at the LBS weren't sure what it was. We replaced the cassette and it hasn't happened since. I did notice when the cassette was off there was some where on the tabs of the rear hub. It's going to be a matter of replacing worn out gear more often. You are just going to have to live with it.

  16. #16
    Senior Member Wogster's Avatar
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    Quote Originally Posted by LessEverything View Post
    To answer everyone's questions.

    Yes it shifts on its own sometimes about the same times and situations as the slipping. I have only owned the bike two days (its used). I am 375, sexy and nimble like a ballerina.
    Well, I would find a good LBS, and get them to do a basic tuneup, with a new to you bike, it really should have a good going over by am experienced mechanic, they will tell you what (if anything) needs to be replaced, and get everything else nicely adjusted properly. With a bike shifting on it's own, it's usually a cable way out of adjustment, or a cable that's not running smoothly in the housing. Even if you plan on doing your own repairs, I would get a bike looked at by an experienced mechanic the first time. With gears slipping, it's usually a worn chain and/or cassette (freewheel), I would think your problems could in fact be both, a bike that you buy used, that has one of these problems, either wasn't taken care of well, or the owner was planning on getting a new one, and didn't do required maintenance on the old one.

    Fortunately these problems are usually fairly inexpensive to fix.

  17. #17
    Senior Member Bill Kapaun's Avatar
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    I sometimes have that problem if I haven't completed my down shift(s) properly when coming to a stop. I have friction shifters, so it's not difficult to get somewhere in between gears.
    I shift down and spin the cranks slowly when stopping, even though I'm not "pushing".
    EDIT- I mainly have the problem when I have to make an unplanned, abrupt stop.

  18. #18
    Senior Member Terrierman's Avatar
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    The mystery shifting leads me to think its most likely a slightly out of adjustment RD probably due to cable tension.
    It's all downhill from here. Except the parts that are uphill.

  19. #19
    Senior Member ken cummings's Avatar
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    Quote Originally Posted by Tom Stormcrowe View Post
    That wouold be my thought as well. If you generate that much torque, you are going to eat chains and cassettes.....nature of the beast!
    How true, how true, how painfully true. This AM I stomped on my pedals at a green light and the worn chain fell off of the worn chainring and the big ring chewed into the back of my calf. Eight holes of various sizes. I am a big horse of a rider, former weight-lifter, and have a few sprockets with teeth broken off and broke a crank arm once. First time the bike bit back. Replace what you can.
    This space open

  20. #20
    Senior Member munski1968's Avatar
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    RD or cassette???

    Im also having this problem on my 2007 Fuji Crosstown 2.0 Hybrid. The bike was originally bought as a commuter, but I got layed off back in Oct. Since then I've joined a bike club, and am putting a lot of miles on it weekly. I'm also a Clyde. I weigh about 300 lbs. (dropping quickly though). I used to play football in high school, and also have very strong legs. This causes me have a tendency to over torque instead od spinning going up the grades. Is this really bad for the gears? I try spinning, but I just feel more comfortabe in a higher gear, and using a little more leg power when climbing. Is this a bad habit I need to try to get myself out of? Spinning in a lower gear just doesn't feel comfortable. Also, I haven't made the transition to clipless pedals, and still use platforms. I'm also getting that clanking noise when climbing, and downshifting. I usually stay in the saddle when climbing, but my legs are now strong enough again where I'm starting to stand on the pedals while starting a climb. I was on a 40 mi. ride yesterday, and a few times when I stood up on the pedals the clanking was so bad it sounded like the steel frame was going to split in two?? Does anyone think this problem might just be a RD adjustment, or have I over torqued where the cassette might be bad? I plan on taking it to my LBS for a tune-up (I get free lifetime tune-ups), but they're closed today for Presidents Day, and they're still on winter hours, and will be closed tomorrow too.
    Last edited by munski1968; 02-16-09 at 01:27 PM.

  21. #21
    triathlete? roadie? MTB? caelric's Avatar
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    I'm a big, muscular guy (210 lbs, 5'11", 12% BF) and I weightlift, and while I don't squat 700 lbs, I squat quite a bit, with strong legs. I recently had slipping problems, only in the middle chainring, and when I took a look at it, the middle ring was worn down a lot more than the big and small (small was almost pristine...) As soon as I got it replaced, no more problems, at all. New crankset (and new chain and cassette, but they were just worn out, and had nothing to do with my middle ring slippage)

    So, the whole point is that even for big muscular guys, it's not your strength that is the problem, it is worn out equipment.

    Oh, I am replying to munski1968, not the original poster, from back in 2007...
    Go Fast By Any Means, my triathlon/motor sports blog

  22. #22
    Senior Member munski1968's Avatar
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    Quote Originally Posted by caelric View Post
    I'm a big, muscular guy (210 lbs, 5'11", 12% BF) and I weightlift, and while I don't squat 700 lbs, I squat quite a bit, with strong legs. I recently had slipping problems, only in the middle chainring, and when I took a look at it, the middle ring was worn down a lot more than the big and small (small was almost pristine...) As soon as I got it replaced, no more problems, at all. New crankset (and new chain and cassette, but they were just worn out, and had nothing to do with my middle ring slippage)

    So, the whole point is that even for big muscular guys, it's not your strength that is the problem, it is worn out equipment.

    Oh, I am replying to munski1968, not the original poster, from back in 2007...


    Yeah, saw that after I posted it. I started a new thread lol

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