contango 

I recently swapped out the chain and cassette on my 2009 Specialized Tricross Sport.

The old Shimano chain went out and I replaced it with a KMC X9 because I wanted the master link on the chain.

The old Shimano HG50 9-speed 11-32 went out and I replaced it with a Shimano HG61 9-speed 11-32. I would have bought the HG50 but they were out of stock and weren't expected in for a while.

I measured the new chain against the old chain and it was a single link longer, so I took the extra link off before fitting it. So that means I've got 115 links in my chain.

Today I took the bike for its first proper ride on the new parts (a quick spin up and down the street doesn't really count). For a while it was fine but then I noticed that on the smaller sprockets if put a burst of power down on the pedals it jumped at the back. I've never experienced chain skip before but think that's what was going on. It did that in both the outer and middle chainrings. I didn't use the granny ring so can't comment on that.

On the way back I noticed that a couple of times it skipped as I went over a bump in the road. I don't remember if previous skips were related to bumps in the road or not.

Does this mean my chainrings are worn out as well? Or is it more likely that I just need to take another link out of the chain?

For reference the chain now has 115 links, the chainrings are 50/39/30 and the cassette is a 9-speed 11-32.


Edit to add: The old chain was somewhere between 0.5 and 0.75% worn, and I bought the bike used so don't know if it's the original chain or not.

AEO

chain skipping usually only happens when the chain isn't sitting properly on the cogs to start with.
They rarely jump off the cogs they are currently on.

I'm guessing either stiff link in the chain or sticky pawls in the freehub.

contango 

I imagine a stiff link in the chain would cause problems on the smaller sprockets rather than the large ones. Wouldn't sticky freehub pawls give the same problem regardless of the selected sprocket? I'm wondering if the fact it only happens some of the time points more towards a chain issue.

I'll go take a peek at the chain. I'd hope I don't have stiff links already, it only came out of the box yesterday!

BobLoblaw

Stiff links can cause odd, unpredictable problems. That would for sure be the first thing to look at. just pedal backwards and watch the chain pass through the rear D.

When the chain is on the smallest chainring, chain tension is at its lowest and that's when a stiff link will cause most of your problems.

BL

Marauder9

It could be just the link(s) that you touched to install the chain are stiff. The pin might not have been been pushed all the way through to the other side.

HillRider

A stiff chain link is a distinct possibility as is the fact that the shifting might not be spot-on. A change of cassette, even for one by the same maker, often requires readjusting the rear derailleur as the spacing and positioning may be slightly different. I'd try setting up the rear shifting from scratch.

contango 

Erk, setting up the rear shifting sounds like a big job.

I took a closer look at it. From 1-4 (where 1 is the largest sprocket) things seem fine. 5 starts causing problems, and from 6-9 it makes a nasty noise. That was after adding a drop of lube to each roller.

Looking at the chain as it comes out of the upper jockey wheel and into the cassette it seems there are several links that look like they are sticking on the jockey wheel and then jumping into place.

When you're saying "set up the rear shifting" are you talking about adjusting the limit screws or something more fundamental?

FBinNY 

Since both the chain and cassette are new, it's safe to rule out the new chain/old cassette issue. (If either the chain and cassette aren't new, that's the likely issue).

Test for stiff links as follows. press the lower RD pulley forward so the lower loop slackens and sags about 3" in the middle, forming a gentle arc. back pedal slowly and look for links that don't straighten into the curve immediately leaving the lower pulley. You might also feel a tug on the RD cage as stiff links come through.

If you don't see or feel any stiff links, then it's on to other causes, the most likely of which are a bent or bis-aligned hanger, poor RD trim, or possibly the "B" screw adjustment, though that's usually more of an issue on larger sprockets.

HillRider

It's not that difficult and adjusting the limit screws may or may not be needed but doing so is really fundamental. If your chain does have stiff links, that's the first thing I'd fix.

contango 

Looks like the RD needed retuning.

I fiddled with the limit screws, then fiddled with them again, and again, and managed to get it so that I could shift from 1-2-1 and 8-9-8 but still gears in the middle weren't right. So I fiddled with the cable tension a little, then the liit screws repeatedly until eventually it all worked.

I so desperately didn't want to take it to the LBS, not least because I'd bought parts online to save a significant chunk of cash and it rather defeated the point if I then had to take it into the LBS to have them do it properly.

Then for good measure I took it out for a test ride, shifting up and down and up and down and usign all sorts of inappropriate gears for the job and everything seems to work. Hopefully it will stop raining long enough I can take it out for a decent spin soon!

It took me the best part of 2 hours, but next time I'll have a better idea of what I'm doing. Thanks everyone for input.

HillRider

Good, I'm glad it worked out. Park Tools' web site has a huge list of tutorials on various aspects of bike mechanics including derailleur installation and set up. It's worth a visit prior to any job you haven't done before.

dsbrantjr

"Erk, setting up the rear shifting sounds like a big job."
"I fiddled with the limit screws, then fiddled with them again"

Setting up the rear derailleur is not a big job nor is it particularly difficult if you approach it systematically. Fiddling may or may not work out. A reasoned approach will generally yield better, faster results. I recommend that you follow this procedure:
https://www.parktool.com/blog/repair-...nts-derailleur
from beginning to end without skipping any steps. It should take only a few minutes and only require simple tools like a screwdriver and wrench or (ugh) pliers.

contango 

It's not something I'd ever done before so had no idea how to even begin. It seemed daunting when I looked at how many things might need tweaking.

I've got a book on bike maintenance so I started from there, adjusted one and then the other only to find the intermediate gears weren't engaging correctly. From there I adjusted the cable tension and it still wasn't quite right, so I backed off a little of the extra cable I pulled and tried again, and that time it worked.

I should perhaps be a bit more specific in my language - I used the term "fiddled with them" to suggest it took me a few goes rather than randomly twiddling screws in the hope that sooner or later I'd hit the right combination.

That's a good article you linked, I'll certainly refer back to that if I need to adjust again.

LarDasse74

It is quite possible that you will never eed to adjust the limit screws again. If the chain can access the gears at both ends and cannot be pushed off the cassette on either end, the limit screws from now on should be left alone.

contango 

The only reason I can see for needing to tweak them again is the next time I change the cassette.

On reflection I'm wondering if taking off the dork disk made the difference that meant I had to adjust everything again.

dsbrantjr

The cassette should bottom on the freehub, not the dork disc. The difference is probably just fabrication tolerances on the cassette.

contango 

That's what I'd have hoped but did have to wonder if that couple of mm of plastic would have made a difference.

Perhaps if I'd stuck with an HG50 I'd have saved some time, even if that meant not getting it until the end of this month.