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Old 07-19-04, 08:38 AM   #1
Portis
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New Chain, Ghost Shifting

I just had a new chain put on my MTB. Everything is fine except under load (hard pedaling) the the chain ghost shifts on the rear cassette. It actually seems to not actually shift but more accurately just try to shift and then fall back on the proper sprocket.

I tried to loosen the rear cable on my ride this morning, but got no luck. I intend to play with it more tonight when i have time. What should i check? Why did the new chain make it do this?

BTW, the bike shifts fine in the stand. LBS adjusted shifting at time of chain replacement. I can take it back to them and will if i can't figure it out. Thanks.
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Old 07-19-04, 10:06 AM   #2
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Originally Posted by Ranger
I just had a new chain put on my MTB. Everything is fine except under load (hard pedaling) the the chain ghost shifts on the rear cassette. It actually seems to not actually shift but more accurately just try to shift and then fall back on the proper sprocket.

I tried to loosen the rear cable on my ride this morning, but got no luck. I intend to play with it more tonight when i have time. What should i check? Why did the new chain make it do this?

BTW, the bike shifts fine in the stand. LBS adjusted shifting at time of chain replacement. I can take it back to them and will if i can't figure it out. Thanks.
You probably need to change your rear cassette. As a chain wears, it wears out the cogs also. A worn cogset will not mesh with a new chain.
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Old 07-19-04, 11:46 AM   #3
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Originally Posted by msantiago1
You probably need to change your rear cassette. As a chain wears, it wears out the cogs also. A worn cogset will not mesh with a new chain.
msantiago1's advise is sound. You can do a visual check of the sprockets to see if they have worn - the teeth begin to look like shark's fins. if this is the case, you need a new freewheel and most probably new front sprockets too.

Also, check to make sure that the cable has good tension. Shift the gearing into the position where the cable is the most slack (usually the lowest gear). Tighten the cable and re-tighten the nut that holds the cable to the derailure.

Good luck.
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Old 07-19-04, 12:05 PM   #4
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Ditto Mike's advice. But for a quick fix, try just turning the adjustment barrel next to the nut that holds the cable. That'll tighten the cable w/o actually having to open it.
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Old 07-19-04, 12:29 PM   #5
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On department store dual suspension "MTBs" ghost shifting can occur due to wear in the sus joints, which allows frame flexing under load. I suppose it can also happen with quality ds bikes but it will be longer before it happens. What type of MTB do you have?
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Old 07-19-04, 12:52 PM   #6
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On department store dual suspension "MTBs" ghost shifting can occur due to wear in the sus joints, which allows frame flexing under load. I suppose it can also happen with quality ds bikes but it will be longer before it happens. What type of MTB do you have?
Trek 4300. I have spoken with LBS guy. He thinks i have worn out those two cogs. He has ordered a new cassette. Hard to believe i wore them out in a little over 2000 miles but oh well. I can see some wear on the two cogs that seem to be causing the problem. (gears 4 & 5 on 8 spd)

Hopefully the new cassette will cure the problem. It seems sort of screwy that i created a problem by trying to avoid a problem. I have always heard that I should replace my chain before it gets too worn. Maybe i didn't do it soon enough but, the bike worked just fine before i took it in.

EVerything is falling apart. Last week i had to have a new BB on my other Trek 4300. I think i need to start doing some of these repairs myself and invest in some tools.

Last edited by Portis; 07-19-04 at 12:57 PM.
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Old 07-19-04, 04:59 PM   #7
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Ranger...to make you fell better I wore mine out in less than 2000 miles. I replaced my chain when my chain wear indicator indicated it was time....oh well. My bike bikes getting a more durable cassette this time.
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