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ghostshifting from the middle to small chairing without using a front derailer

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ghostshifting from the middle to small chairing without using a front derailer

Old 03-10-14, 02:27 PM
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ghostshifting from the middle to small chairing without using a front derailer

I knew I'd never run out of new mechanical issues with my bicycle (a Hardrock classic from around 2000), and yesterday during my first ride of the year outside I had a new one that was hard to believe as well as hard to describe. I was in the middle chainring in front and had just shifted down to into 1 on the rear from 2 when suddenly the chain shifted to the small chainring. I shifted it back to the middle ring without shifting the rear derailer, noticed the chain was in the center of the front derailer cage, and then watched the chain shift back to the small chainring. I was able to repeat this several times, and the problem only occurred in this combination of gears. Both the front and rear derailers shift like they should, and the chain would stay where it should after shifting to any other combination of gears yesterday. Recent maintenance included replacing the rear brake arms, pads and cable, replacing the front derailer cable (I switched the brakes years ago so the left hand works the rear brake), replacing the left shift/brake control and changing back to the 26x1.95 tires I use in the spring. I'd previously replaced the right shift/brake control 2 years ago when I replaced the 7 speed cassette with an 8 speed cassette, as well as replaced the original 7 speed rear derailer with an 8 speed Deore. The rear wheel seems centered in the rear triangle, the brakes work fine, and first loosening then re-tightening the rear quick release didn't change the problem. What's causing the problem, and what do I need to do to fix it?
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Old 03-10-14, 03:44 PM
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Originally Posted by no motor? View Post
I knew I'd never run out of new mechanical issues with my bicycle (a Hardrock classic from around 2000), and yesterday during my first ride of the year outside I had a new one that was hard to believe as well as hard to describe. I was in the middle chainring in front and had just shifted down to into 1 on the rear from 2 when suddenly the chain shifted to the small chainring.
That can happen with worn or bent chain rings.

I'd replace the middle ring immediately, because you can go over the handlebars if you're standing with your weight is forward when you get the uncommanded (I learned that one the painful way).

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Old 03-10-14, 04:47 PM
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I've wondered if that's the case. I replaced the cranks about 2 years ago (the frame, fork, and front derailer are the only parts I haven't changed) and the middle ring will skip if I put too much force on it. The large and small rings don't do that, sounds like it's time for another upgrade.
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Old 03-10-14, 04:53 PM
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no motor, Also check the crank arm fixing bolts are tight as there is a slight possibility the crank arm is moving outwards. Is the chain also two years old?

Brad
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Old 03-10-14, 04:55 PM
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Originally Posted by no motor? View Post
I've wondered if that's the case. I replaced the cranks about 2 years ago (the frame, fork, and front derailer are the only parts I haven't changed) and the middle ring will skip if I put too much force on it. The large and small rings don't do that, sounds like it's time for another upgrade.
Because it's skipping on the middle chain ring, that's likely the problem. You can order chain rings seperately.

Brad
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Old 03-10-14, 05:21 PM
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Originally Posted by bradtx View Post
Because it's skipping on the middle chain ring, that's likely the problem. You can order chain rings seperately.

Brad
I paid $30 for my last middle ring. While not cheap that is a lot less than a whole crank set.
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