Ghost shifting EVO

[asylum_inc]

Hello everybody.  I have been using the board for a while now ( but not posting) so this is my first offical post!  

Now for the question- I have a 5500c K2.  I am having trouble with 'ghost shifting'.  Are there any tips/ tricks for shifting with a f/s bike?  The chain and cassette have under 100miles.  I am using 9 speed ESP.

I have pics up of the bike - click my www

Thanx

[Di.R.T.]

Describe your ghost shifting.  IS it happening in all gears or specific ones?  does it only happen on bumpy trails when the susp is active or even on flats?

[Mike_Farris]

From what folks on the 855 Heads mailing list have said, you want to run full-length cable housing from the rear mech to the cable stop nearest the bottom bracket.  From your pics, it looks like you've run the cable as originally designed (housing from the cable stop to the swingarm, no housing inside the swingarm, housing from the back of the arm to the derailleur).

I know that this works with World Cup frames, but have no personal experience with the EVO frames... so I can't say that this will work with your frame. Nevertheless, it's worth a shot...  

Good luck!

[asylum_inc]

It only happens on bumpy trails - only while in the middle ring.

[asylum_inc]

I looked at the problem a little closer last night - looks like the swingarm has some play in it at the pivot point.  Is there a way to tighten up the pivot?

[Old Proflexer]

we've had many 'ghost shifting' q's on carbons over the years and each time it seems the cause was just a little different.

if it wasn't doing it before the change, then best to look for the components that were swapped out.

without a more detailed description of the shifting problem it's hard to say - could be anything from:

bad cogs
chain bounce
improper chain length (if it's new) requireing a b screw adjustment
loose derailler
loose derailler hanger
sticky cables
poorly adjusted derailler / barrel adjusters
inadequate cableing at the swingarm pivot making shifts when the bike flexes
etc. etc.

a loose swingarm can be adjusted to specs - may want to do an OP Jiffy Lube and readjust the drop on the swingarm.

any time one puts on new cogs and a new chain, the entire shifting area of the bike needs to be examined and properly adjusted to optimize performance - from chain length, derailler stops, fore and aft tension, all cables are running smooth, adequate play is in the cable housings to allot for bike flex, all parts are tight - yada, yada, yada.

hopefully your chain and cogs are compatable

OP

OP's Jiffy Lube
http://idriders.com/proflex/files/k2pivot.pdf



 

[asylum_inc]

Thanx for the help  I'll work on it over the weekend - hopefully I will get it straightend out.  I noticed the front der post is not very solid on the frame - is there a way to make it more solid?

[Old Proflexer]

you could glue / epoxy it down - it's loose on all 3 of my carbons but holds in place when tension is on the front derailler cable.

a more detailed shifting problem would be nice - is it up shifting, down shifting, which gears - big, small, middle, climbing with or without pressure etc.

OP

[asylum_inc]

OK- here is more info ( I just didn't feel like typing:) )



It only does it under load (uphill) with suspension movement.  I can't tell if it is up or downshifting. It feels like it is skipping all over the cassette - but I am still able to pedal if I back off a little so it must be only a gear away.  I am going to work on it tonight some and ride on sat/ sun/ mon. That should be enough time to get the bugs worked out.  [smiley=bomb.gif]

[Carbon_Angus]

i had a similar episode, but it happened on my 857 SS, hard pedaling, rough, uphills, etc. back off or even backwards pedal a tad would drop it back in place only to happen again. my singulator pulley was kinda chewed up, from something and was causing the problem.

it may be far fetched, but worth a look at your der. pulleys from what you have described. it doesn't sound like a cable problem at all.

good luck

[Matno]

The most common cause of mysterious ghost shifting on the EVO's seems to be the length of the housing between the swingarm and the closest cable stop on the frame. If it doesn't have enough bend in it (about an inch of drop) then it can move when the suspension is compressed, which effectively changes the length of your cable. (It actually pulls out of the "socket" in the swingarm). You can be pretty sure it is something like this if it shifts perfectly when on a bike stand, but ghost shifts every time you ride.
Adding 1/2" to that small piece of housing usually fixes the problem.

Also, make sure your derailleur is perfectly parallel to the cassette cogs. That can certainly cause ghost shifting, and has been known to happen pretty frequently.

[smiley=coolfrown.gif]