Bicycle Mechanics - chain skipping problem

I have recently replaced my chain, rear cassette, front middle chain ring and yet the chain skips. This only happens when the chain is on the front middle chainring and about the 5th cog on the cassette. Can't figure out why. I think my cable and gear adjustments are quite precise. For some reason this only happens based on the gear that I mentioned above.

Do I need to also change my pulleys on the derailler?

Oh, one more thing. The skipping happens when I apply greater amounts of pressure on the cranks (while standing up on the peddles).

Any suggestions or comments would be appreciated.

I had the exact same problem. You don't want to hear this but in my case it fixed itself. Mine was bad enough that I actually crashed (in front of the kids) I was going to take off fast, showing off, and kawomp my 250 pounds went flying. I didn't get hurt but I was pissed off big time. I replaced the chain and that helped a little but it still did it exactly as you described. It hasn't done it in several months though. Now that I think about it I haven't really gotten out of the seat and jammed on the pedals lately... this flat Island is well... flat, especially compared to Montana.
Doug:confused:

As others have said, I think your chain is worn out. Look at the big sprocket up front (i.e., chainwheel) and pull on the chain at the 3 o'clock position (i.e., farthest to the right). If the chain rises higher than half the height of a sprocket tooth, your chain is worn out.

When you go to your LBS to get a new chain, also pick up a manual on repairing a bike. Even the cheapest one has some initial value to get you started.

Thanks Cadillac and Dougmt for your comments.

Dougmt, you are right. "The problem will solve itself" is something I didn't want to hear. But thanks for your comments anyhow.

Cadillac, I will inspect my chain like you mentioned. But like I said, the chain is pratically brand new. It is possible that the chain is defective. I guess I'll have to ask a LBS to check and see.

Thanks guys for your help.

klam - also take a look at the Barnett's manual on der adjustments. I seem to recall there was a mention about differences in adjustment when standing on the pedals.

FWIW I run SRAM XOs on my rig and there was also a periodic 'skip' when I was on the middle chainring and cogs 4-5-6 on the cassette. Changing 6-5 would sometimes 'bounce' on 4 before shifting back to 5. I 'cured' that by changing the barrel adjuster position on the 9spd shifter. So far, it's worked ok and I've not had any problems elsewhere.

When the chain skips or slips, it only does so in that gear. It doesn't jump to another gear as mentioned by Bokkie.

Another thing just popped in my mind. Could it be my freehub? I understand its quite rare for the freehub to go. But then again, if it slips, why only in that one gear.

Leads me to believe it must be a cog/chain issue.

klam - just thinking aloud to myself here. Have you installed a different cassette to what was fitted previously? I think I also read that some ders are only compatible with certain cassette gear ratios. Someting on the lines that the der will work with a cassette if it is 11T-34T for example, but might not work completetly successfully if it has a different set of ratios?

Have you tried tweaking the hi/lo screws a fraction of a turn to see if that helps? I guess if you have different ratios on the cassette that would imply the diameter of some of the cogs might be different, and in theory, might need an adjustment to the chain gap?

You probably know more than me about all of this so apologies if I'm off base.

Hey Bokkie;

I replaced an older xt cassette with a brand new Xt, so techically, there should be no compatibility problems.

I have tinkered with the adjustment barrels on the derailler aswell as from the shift pods. This has not been successful so far.

BTW, If I new what the heck I was doing, then I wouldn't be using this forum at all. No worries.

I'm almost out of ideas.

When you've got the bike on the stand and you rotate the pedals slowly, does it skip then or only when pedalling fast? I guess if there was a 'sticky' chain that you might see the effect it has when it runs on the cog that skips, but then again, I'd expect that on other cogs as well?

Your der hanger is straight?

Front der cage runs parallel-ish to the chainring and is spaced correctly (I think it's usually about 1mm or so)?

Sorry, I'm just about out of ideas. Time for someone else to chip in with something more profound than my limited suggestions.:)

ya, when bike is on stand, no skipping. Only when I "hammer" on the peddles while peddling.

Did inspect all links on chain. Seems to be fine.

Derailler looks straight(eyeballing).

"back to the drawing board."

Check to see if something is jammed between sprocket 4 & 5 or 5 & 6.

The dumb question has to be asked... this is new? It didn't do it before "chain"ging the drivetrain?

The only other possibility I know of, that hasn't been mentioned is BB flex stretching the cable just enough to cause problems when hammering. If the problem is new with the new drivetrain, I suspect you might cure it with some slight derailleur adjustment tweaking.

Otherwise, your sprint has gotten much stronger, or your frame has cracked. ;)

good one Roadbuzz. I don't think its my pistons(legs). Just getting over a broken ankle about 2 months ago, so the legs are still weak.

the bb flex could be looked into. Thanks

maybe a stiff link?

For kicks, compare the newly installed middle chainring and see if it is possibly installed "backwards". there are alot of little things going on with the new equipment that is not obvious.

I have the same problem - only when I stand and power though. I'm usually in the middle chain ring and near the last gear. It's not the chainring, it's as if the chain just slips along the one gear - chainring, cassette and chain are new.

I came close to crashing a few times.

I wouldn't be surprised if there's a problem with an incompatible cassette. Perhaps a 9-speed spacer was installed? It's a possibility-especially if it was built cheaply in china....
It's also possible that they sold you the wrong chain...

believe it or not, I think I have solve the problem, if not by fluke, then by luck.

I fiddled with the adjustment barrel on the grip shifts and managed to stop it from skipping.

Just went on a 45 min short ride and tried to encourage the skipping. IT DIDN'T SKIP.

Thanks to all those who reponded with your suggestions.

Well, I don't have a 9 speed and I have messed with the adjusters for months. There is no chain alignment noise at all. On a rack it's shifts smoothly with no noise.

Well, I don't have a 9 speed and I have messed with the adjusters for months. There is no chain alignment noise at all. On a rack it's shifts smoothly with no misalignment noise.

it doesnt sound like its a gearing setup problem, but you need a new chain, after long amounts of use especially in stiff gears, it will stretch very slightly, most of the time adjusting your gears will sort it, but after a while you just need a new chain.