8-speed chain skipping on a 9-speed cassette

[Number_35]

Hello all! I'm hoping that one of you faithful and helpful BITOG cyclists can give me some good advice.

My wife and I are planning to leave tomorrow for our annual Minnesota cycling trip. I have a happy dilemma in that both my '02 Rocky Mountain and '04 Giant Iguana mountain bikes are in good shape now, and I'd be happy to take either on this trip.

However, as part of the pre-trip inspection yesterday, I checked my wife's Giant Iguana (c. '07) and found the chain to be really stretched - way beyond 1%. I picked up a new 8-speed chain yesterday, and installed it this afternoon. We went for a short ride to test our bikes, and the new chain was skipping badly. I figured it was 'new wine in old wineskins' and that I should have changed at least the cassette (rear sprocket) and possibly the front drive. To my surprise, when I went to remove the cassette I found that her bike has a 9-speed cassette, not an 8-speed like my bikes.

This makes me wonder whether the problem is in my using a wider (8-speed) chain on a 9-speed cassette, rather than wear to the cassette gears and/or chain rings. I'll definitely change the chain to a 9-speed, but wonder whether it would be prudent to change at least the cassette too.

Hoping to hear back ASAP from anyone who knows more about such things than I do! Thanks in advance!

 

[andyd]

What if you shortened the original chain by a link and got the right chain later?

 

[Number_35]

Andy, it's not the chain length but the width of the individual links that (may be) the problem.

 

[wwillson]

If the chain is the same, which many 8 and 9 speed chains are, then look for wear (shark toothing) on the cassette. Every time I replace a cassette, it's because I've put a new chain on and the chain skips on a worn cassette.

 

[Number_35]

Typically chains up to and including 8 speeds are one width, but above that the chains get narrower. I'm guessing that the chain is slightly too wide, and is skipping as it gets caught intermittently between the different cassette gears.

But you're right, it's very likely the cassette and front chain rings are also worn.

 

[tcp71]

8speed chains are wider than the 9s. It is catching on the beggar sprocket up. Get a 9speed chain, but I suspect with a chain stretched that much, a new cassette is in your future. Chainrings generally work fine and don't need replacing.

 

[Number_35]

Thanks, I'll pick up a (correct, 9-speed) chain tomorrow and a new cassette tomorrow. Will report back!

 

[AZjeff]

If nothing else put the old chain back on. Odds are extremely low that it would give you problems since it wasn't when you checked it.

Had to laugh because you violated one of our rules when we were racing bikes, do not do maintenance the day before an event or ride, nothing good comes of it. Trust your regular maintenance, lube and adjust a little bit and go ride.

Have a great trip!

 

[Number_35]

Ha, so true!!!

I considered reinstalling the old chain, but it's so stretched that I don't have a lot of confidence of it.

My closest LBS opens @ 10:00, so I'll pick up the correct chain, and a cassette just in case.

 

[NYEngineer]

The stretched chain is not meshing with the now deformed cassette. Once both parts are new all should work well. May need a chain ring as well.

 

[Number_35]

The knowledgeable young fellow at my LBS thought (as I did) that neither that cluster or the chain rings looked too bad, so I went with the new chain only. It's pretty smooth now, with no skipping.

Thanks all for your input.

 

[Surestick]

Originally Posted by andyd
What if you shortened the original chain by a link and got the right chain later?


Assuming you're not trolling...
The issue with a stretched chain isn't that it's too long, it's that the pitch of the chain (the distance between the links) has increased due to internal wear.

A 9-speed chain is narrower than an 8-speed so that is likely the issue, however, if the old chain was really worn it's likely the cassette and chainrings are toast too and a new chain would skip anyway.

Luckily, if the parts are available changing everything out is easy.

 

[JLawrence08648]

Change the chain, then adjust the cable!!! If it skips, you need a new cassette. I buy Sram 950 26 tooth, sometimes 28t.

 

[Number_35]

I spoke too soon ... Day 1 of our cycling holiday in Minnesota was good, with us riding the Walker-Cass Lake section of the Heartland Trail, which was pretty flat. Even so, my beloved complained of the new correct (9-speed) chain skipping under load. (We also rode the Mi-Gi-Zi trail around Pike Bay, near the town of Cass Lake, which was hillier, and the skipping was worse there with more need of the lower gears.)

Anyway, we drove down to Baxter/Brainerd the next day to ride the Baxter-Crow Wing State Park section of the Paul Bunyan trail, and stopped at Easy Riders bike shop in Brainerd and picked up a new 9-speed cassette (Shimano 11-34, the same as the old one). I recommend the shop - friendly & knowledgeable staff, and they had my part (which the first shop we tried didn't). I had tools with me and changed the cassette out in the parking lot. The staff invited me in and allowed me to use their GoJo pumice/citrus hand cleaner afterwards.

Anyway, per my wife the bike was flawless after that (which was good, as that day and the next two involved some steep climbs).

So, lesson learned - if a chain is that badly stretched, just bite the bullet and change the cassette at the same time.