Ghost shifting. AARRRGGH!

[1FG rider]

I've been able to get rid of ghost shifting on my past bikes but this one has me scratching my head.

First of all - Niner RIP, new chain, shifts fine on the bike stand but chain starts jumping when I'm on the bike.

I've noticed that when the suspension is compressed, the derailer moves just slightly to the inside of the cassette, most likely the culprit as far as I can tell. I've played with the barrel adjuster but since the suspension/chain tension is constantly varying, I'm having problems getting the chain to stay in one gear when I'm riding.

Any ideas anyone?

[dubjay]

The derailleur shouldn't move during suspension movement, so if it is, maybe a cable is binding somewhere?

And how worn is your cassette? Maybe it's not mating up well with the new chain?

[mtnbikerfred]

If the "b" adjustment screw (the one that sets how far back the deraileur hangs) is set so the delraileur is too close to the cogs, the top idler can hit the cogset when the suspension compresses. Check that.

[scottay]

Longer cable housing pieces/ sections or use full length housing to troubleshoot?
.

.

[tkblazer]

sounds like a good reason to ride the ss

[b-40]

check the cable that goes from the main frame to the swingarm that is the most likely place, i had this exact problem on my Ibis Mojo when i first got it, every thing looked perfect but come to find out that the cable housing from the main frame to the swing arm needed to be as short as possible when the suspension was un weighted, as soon as i shortened thet piece, BADABINGA
problem solved no mor ghost shifting

[1FG rider]

Originally Posted by tkblazer

sounds like a good reason to ride the ss

I knew someone was going to bring that up!

[92se-r]

shimano?

[2wheel_lee]

Addition to what's been said above, replace the cables and housing, and make sure to use only Shimano SP-41 housing.

[1FG rider]

Originally Posted by 92se-r

shimano?

All SRAM stuff

[ransom]

Make sure that your cable housing is long enough so it does not bind while the bike is in it's farest travel position. To short of a cable will cause the derailure to move while in the farthest travel position.

[slowSSer]

Originally Posted by mtnbikerfred

If the "b" adjustment screw (the one that sets how far back the deraileur hangs) is set so the delraileur is too close to the cogs, the top idler can hit the cogset when the suspension compresses. Check that.

a 2nd to this motion. not many people know what the b tension screw is or why it's there, but it plays a key role for a few parts of your drive train including chain tension, pre-load of the dérailleur spring, and distance in between the cassette and upper pulley.

it usually takes a good wrench to know exactly what/how to adjust it and why.

as far as the dérailleur moving when the suspension is in motion, is there a section of housing that's too short somewhere? this was a HUGE deal when I was running cables on my seven as there is one "bridge" of housing from the front triable to the rear due to the suspension.

Originally Posted by ransom

Make sure that your cable housing is long enough so it does not bind while the bike is in it's farest travel position. To short of a cable will cause the derailure to move while in the farthest travel position.

ya beat me to it!

[Pho'dUp]

Bent derailleur hanger?

[SDstumpy]

Originally Posted by 1FG rider

I've been able to get rid of ghost shifting on my past bikes but this one has me scratching my head.

First of all - Niner RIP, new chain, shifts fine on the bike stand but chain starts jumping when I'm on the bike.

I've noticed that when the suspension is compressed, the derailer moves just slightly to the inside of the cassette, most likely the culprit as far as I can tell. I've played with the barrel adjuster but since the suspension/chain tension is constantly varying, I'm having problems getting the chain to stay in one gear when I'm riding.

Any ideas anyone?

I had the exact same problem. RR The most frustrating ride ever!

Did you recently have the cable housing replaced? I had this exact same problem on my stumpy. The housing that runs under the BB to the chainstay was cut too short. Every time I got on the bike the housing would stretch would explain the derailler shifting in. Just make sure ther is ample housing under the BB to alow for full compression of suspension.

[1FG rider]

Originally Posted by SDstumpy

I had the exact same problem. RR The most frustrating ride ever!

Did you recently have the cable housing replaced? I had this exact same problem on my stumpy. The housing that runs under the BB to the chainstay was cut too short. Every time I got on the bike the housing would stretch would explain the derailler shifting in. Just make sure ther is ample housing under the BB to alow for full compression of suspension.

I knew I wasn't the only one to post this same problem, but the search button doesn't seem to work.

I did replace the cable but not the cable housing from the top tube to the seat stays. Housing looks pretty short there.


Don't remember the housing being that short when I first got the bike though.

Thanks for all your ideas

[DBD]

Here is how the cable should look (Some how yours was/is shortened)

[92se-r]

Way too short.

[Shu]

I recently had a similar problem and they had to rebuild my free hub....it was dry/dirty and there was just enough play to cause the cassette to move...I would go to solid cable housings regardless(just my preference)

[slowSSer]

Originally Posted by 92se-r

Way too short.

totally agree- even at a relaxed suspension there should be bends in that cable housing- i think we found your issue!

these internets are wunnerful, arent they?

[jeffj]

Originally Posted by SDstumpy

I had the exact same problem. RR The most frustrating ride ever!

Did you recently have the cable housing replaced? I had this exact same problem on my stumpy. The housing that runs under the BB to the chainstay was cut too short. Every time I got on the bike the housing would stretch would explain the derailler shifting in. Just make sure ther is ample housing under the BB to alow for full compression of suspension.

I've seen this section of housing cause ghost-shifting numerous times. It would be the first place I would check.

EDIT: Looks like you found the culprit.