How do you fix ghost shifting?

have a bike shop tune it up, if it has not been tuned in that long, you will be amazed how well it works when you get it back

Possible that you have a bent derailleur and/or hanger.

Are you getting the bad shifts under stress or just easy riding?

If your chain was worn, your cassette probably adapted to your old chain also. Replacing the chain may have only fixed half the problem. I admit that I'm bad about replacing chains and usually have to replace the cassette at the same time because I waited too long.

Replace the cable, and see what that does for you.

You say you replaced the cables, but did you also replace the cable housing? If not, that's a possible cause of your ghost shifting. Old housing gets gunked up on the inside leading to more friction between the cable and inner part of the housing. As a consequence, the cable won't always necessarily release by the same amount, nor be pulled by the same amount when activating the shifter.

On some bikes, a momentary ghost shift can be caused by compression of the suspension in which the housing segment that bridges the front and rear triangle is pulled (slightly) out of the cable stop due to movement of the swingarm. The routing on your 2002 Mongoose Sommet looks okay though. (Check though that your routing is the same as shown in the picture. If the housing is routed underneath the bottom bracket, then they may be some cause for concern.)

you may just need to turn the barrel adjuster to get the cable tension right, but if you're using a 7 year old drive train then it's probably time for a good tune up...new cassette and cables (brake and shifter) and housings. I wore out a chain in about 6 months and my main cog in 9 months on my stock drive train, and had my rear shifter cable replaced once in that time frame too. it's amazing what a new, well lubed cable will do for your shifting.

a full tune up from your lbs will do wonders for your bike and your riding ability.

I replaced cable/cable housing...

I was guessing that the cassette was worn, but it was only a guess. I'll change it out this weekend and see what happens from there. I'll also double check the cable tension.

Hardwarz

I replaced the chain, cassette, rear derailer and had a pro tune and thats when they told me the hanger was bent. They straightened it out be it didn't shift like new untill I installed a new hanger.

If you bashed the chainrings on rocks you might have also bent the hanger.

the progression is cheap => expensive

In my case, my brand new second hand bike tended to shift a lot during heavy pedaling. I used the SRAM manual for my deraileaur and it turned out the upper pulley, the jockey, was too far from the cassette. Put it closer to spec and voila, no more cringe inducing shifts under load

I did do some other adjustments at the same time but in my case, I think that was the main culprit.

my 05 trance (that i love with all my heart) ghost-shifts like the world is going to end tomorrow. For the longest time, 2W1P monkeyed with it and it would work fine until i got 5 minutes into a ride and it was right back to its good-ol 'ghost-shifting' self.

A recent swap of the cables and i'm doing better, though it does still happen somewhat regularly. I've enjoyed this bike a lot and have ridden her hard as of late and i can't help but wonder if i've tweaked something in a fall. Thoughts?

Re-cabling won't cost much, have the local bike shop do it. #1 cause of ghost shifting is worn or improper setup of cables.

XS NOIZ said:

my 05 trance (that i love with all my heart) ghost-shifts like the world is going to end tomorrow. For the longest time, 2W1P monkeyed with it and it would work fine until i got 5 minutes into a ride and it was right back to its good-ol 'ghost-shifting' self.

A recent swap of the cables and i'm doing better, though it does still happen somewhat regularly. I've enjoyed this bike a lot and have ridden her hard as of late and i can't help but wonder if i've tweaked something in a fall. Thoughts?

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Your shop can check for a bent hanger in under a minute, have them look it over.

Do you have the cable tension setup properly (read the park tutorial if you don't know how)? Assuming it is correct try 1/4 - 1/2 turn on the shifter barrel in either direction and see if that helps. The existing cable could have stretched...

I think the derailuer hanger straightener tool is the most used tool at my LBS. I've been in there twice for that in a couple months time.