Chain Skipping after Chain Replacement - Cassette replacement?
WARNING: I am fairly certain the problem is the rear cassette needing replacement, but given the cost involved, I wanted to make sure prior to throwing money at the problem.
I recently checked my chain, and it was bad. I don't know what prompted me to check it, I just did. According to the chain measuring tool at the bike shop, it was past the 1% mark (didn't hit when putting it in to check). This is what leads me to believe that my problem is the rear cassette.
I know what worn metal looks like, but I truly have no idea what a worn cassette looks like. Would the pictures above indicate that the cassette is worn? I spent an hour playing with the high and low adjustments, as well as the "B" screw (I think that's what its referred to, its in the second photo). The highest and lowest rear gears work just fine, but the chain skips around uncontrollably in the middle gears.
So, is my assessment correct? If so, are there brands to avoid when replacing it? I'm going to talk with the bike shop on campus about replacing it because I don't have the tools, and the longer this is out of service, the more I wince with pain when I have to get on the MTB.
You have it right, the cassette needs to be replaced. The smallest and largest cogs are the least used so the least worn. The middle cogs are used most and wear most.
I've never replaced a chain and not replaced the cassette. It's just what you do.
Originally Posted by HillRider
Fair enough. Consider this newbie schooled in the nuances of chain care. I've only put 200ish miles on the bike since I bought it, but it was a used bike and I should have known better. I'll get the quote from the campus bike shop tomorrow (cheaper than the LBS, shockingly) and if its much more than it would cost me to buy the spline tool and a new cassette, I'll do it myself.
Originally Posted by kellyjdrummer
You'll also need a "chain whip" and a 10" crescent wrench. You can use a skewer to hold the spline tool for the wrench.
Yep. I have the crescent wrench, and I will make a chain whip out of the old chain though. Thanks for watching out for me though! It is nice to know people are looking out for those who aren't 100% sure what they're doing.
Originally Posted by kellyjdrummer
Not a problem. Be cool.
You'll likely need to adjust your derailleur as well, when you finish.
It's easiest to loosen the cable and reset it as if you were installing a new cable.
Good news bad news. The good news is that the MSU Bike Shop can replace the cassette (parts and labor) for cheaper than I can order a cassette with shipping. The bad news is that this means I won't be expanding my tool collection at this time (not really bad news, I know).
So, tomorrow I'll either drive into campus (work and class) with my bike and have them do it, or I'll strap the rear wheel down to my MTB and let them do their thing. Just have to figure out a safe way of strapping it on.
Thanks again for the tips, and kellyjdrummer, thanks for the idea of treating it as I would a new cable. Adjusting derailleurs is something I'm actually competent with and have done before so this should be good. I'm looking forward to having my bike back in service tomorrow afternoon. Then I'll bust out a good long ride to make up for the days I haven't commuted on it!
Since you replaced the chain, are you sure you don't have a stiff link instead?
Slowly rotate the crank backwards and observe the chain as it runs through the pulleys on the RDER. A stiff link will cause a noticeable "twitch". Takes about 30 seconds to check and doesn't cost anything.
Take tools, rags and patience.
Originally Posted by tekknoschtev
if you have to replace your chain AND cassette, its a fair bet you might need to replace the front chainring(s) as well
Low car diet
Maybe, but chainrings are so much bigger than rear cogs that they can usually last several cassettes/chains. Replace the chainrings only if you discover a problem with a new chain.
Originally Posted by cbchess
Originally Posted by slopvehicle
+1. I've had chainrings last through four or five chain and cassette changes and still run quietly and shift well.
Originally Posted by JiveTurkey
OK, I need help apparently. The MSU Bike Shop is so back logged with flat replacements and their own rental bike repairs that it'd be Monday before they could get to my bike, which I felt was absurd (though I was understanding, I could see they were obviously busy I just didn't want to not have my bike this weekend), so I bought the cassette from them (11-28, the old one was 11-25, if it matters for this problem).
I then went to another bike shop who had the tool (YAY!) and a helmet that fit (double yay, but that's for another post), so I bought the tool and came home to get to work. Dummied up a chain whip from the old chain, got to mucking with the spline nut thingy and in a few minutes had the old cassette off and the new one on.
And it still stutters and skips around! What gives?! It works fine in the highest and lowest gears, but its like its just a little bit off in the middle ones, but not all of the middle ones. It skips up and down more when the bike is flipped over in my living room than it did when I was riding it, but it definitely wasn't quiet like the old chain and cassette, and in a few gears it skips up and down. This is rather frustrating!
So, any tips? Pointers? I've double and triple checked the chain for stiff links - nadda. It doesn't always skip at the same point on the chain either, but its like the chain doesn't seat correctly on the cog and a link pops up instead of meshing properly. It seems rather random, but I'm sure there's a pattern to it that I'm missing. I've adjusted derailleurs before, but never with STI shifters (if it makes a difference).
Thanks in advance!
Shorten the chain. Make sure it is at minimum tight on small front and rear. (Small both.) Hard to know without being there.
Actually, it's funny that the shops are backed up with flats, since they take less time to repair than the time it takes to drive the bike to the shop. 'Lotta new bikers, 'eh?
Last edited by kellyjdrummer; 09-03-08 at 05:16 PM.
kellyjdrummer, I can completely understand the "Hard to know without being there" thing. If the following pictures and (admittedly dark and low-res so likely useless) video don't get me any more pointers, I'll be taking it to the LBS.
Your tip did help me though - I realized that perhaps the old chain was the incorrect size (I did buy the bike used after all) and therefore when I matched the new to the old one, I was making a mistake, so I resized it using the small-small method, and below is where I'm at (turns out I was a few links too short before). May be note worthy, but now it doesn't shift up or down, it just seems to miss meshing with a link here and there whilst pedaling, and it is noticeably less prevalent when I'm on the bike and riding, but still present.
This is the first time I've ever replaced a chain where I had to remove the old one, size the new one and put the new one on, and its the first time I've ever even THOUGHT about replacing a cassette. I've only ever had to replace one chain and the LBS sized it for me and I just used the master link. This time, I still utilized the master link but resized myself.
Here are some shots of the rear derailleur, though I'm not sure if they help at all.
And here is a link to the video of me shifting, on the middle chain ring, down all of the gears and then back up. The video turned out much darker than I thought, and its resolution is poor because I shot it with my point and shoot camera - couple that with the compression of youtube and I'm not sure if its of any use but its worth a shot and might point out something obvious to someone who knows more about what they're looking at.
Oh - and to anyone who thinks I'm upset about this, FAR from the truth. This 1) got me to buy new tools (what geek/nerd doesn't love new tools), 2) got me to learn how to do the work myself and 3) has quite satisfied my tinkering desire for the last couple days. Also, if I can't figure it out, at least I gave it my best effort before giving in - which is something I try to do with everything!
I have had similar problems with my chain skipping, and have replaced everything except the rear derailluer - that may be next. You said you checked the size of the chain - for length I presume. What you may want to look at is if the chain is the correct "width". Nowadays, the chain width is different, i.e. a 10 speed chain is typically narrower than a 9 speed or 8 speed chain.
Check the specs on what size chain you bought, and compare that to how many cogs you have on your rear cluster. It looks like you have a seven speed from your pics.
paw888, thanks for the tips. I did solve the problem though (HORRAH!). Fortunately, it wasn't the derailleur, rather it was "user error" I didn't completely follow through with the advice above by pretending to replace the cable, and I just got back from doing just that - and VIOLA! It works. It looks like I needed to pull the cable about 1mm further than it was before.
So, tomorrow I commute again!
Thanks everyone for the valuable advice, and thanks again for putting up with my newbie tendencies. Now that I have a better idea of what I'm doing, I could probably do this faster - but here's to hoping I've got many worry free miles ahead of me!
Respectfully, I would say that's just what you do. Others may find no need to replace a cassette when replacing the chain. I see how the shifting works with the new chain, examine the cassette and go from there.
Originally Posted by kellyjdrummer
Back to Biking
I'm curious, because I'm dealing with a very similar problem on a recently rebuilt bike....
Tightening the cable to the rear derailleur stopped the chain from skipping in the middle cogs? I could see it fixing a skip in the largest cog, but not in the middle.
Why do you think this worked?
Steve (hey, I'm Steve too ) I can't say for certain why it worked. One of the symptoms I was noticing is that the chain line wasn't exactly perfectly aligned with the rear cogs and that left them rubbing in some configurations meaning they'd ramp up or down depending on the position. The only thing I can think is that it was off by just enough that this solved it, and I had the upper and lower limits set properly so they were the stopping point not the cable tension, leaving the largest and smallest cogs in working condition.
That's my best guess.
Blue Light Special
I can't believe nobody has mentioned www.parktool.com yet. See the links on installing a new chain and adjusting a rear derailleur. The symptom of clean shifting at one extreme and loose shifting at the other could mean you need to adjust the "B-tension" screw on the rear derailleur. Usually this needs to be set only once, but see parktool and the link below for details on how to set this screw so you can confirm it's in the right place. If everything is working now, it's probably best to leave it alone. Otherwise, look up your rear derailleur model on
and look for the installation manual, it also has instructions about setting the screws on the rear derailleur. Basically, there are two screws right next to each other on the parallelogram part of the RDER - those are the high/low limit stops, which you don't need to touch if you were able to shift into the highest and lowest gears on the cassette. There is another screw under the big screw that attaches the RDER to the frame - that is the B-tension screw. The details for adjusting the screw, you will find in the links above.
Last edited by kmart; 09-04-08 at 10:40 AM.
Originally Posted by KrisPistofferson
I just left East Ridge Bikes and asked them while I was there about the 'b' screw and they said likely not. Incidentally, the 'b' screw doesn't attach the mech to the bike. It sets the front to rear tension, moving the guide pulley away from or towards the cog set.
I think the chain is too long. In the YT vid, the cage is slightly visible, but it doesn't swing much, forward to back, through the shift, top to bottom, which indicates that the chain may be too long.
Also, it appears that for a roadie, the cage may be too long, considering the idle pulley isn't visible in the video.
One more q....
Does the chain skip cyclicly, as in once in every trip around, or is it arbitrary? If it is cyclical, it's a sticky link. If so, bend the chain sideways, 'to and fro' at the sticky link. Bend it extremely, almost to the point of damage. If not, it's likely too long.
Actually, I go two chains per cog set, normally. I ride a lot of mud and dirt, so I grind a lot of steel all year.
Originally Posted by RockyMtnMerlin
tekknoschtev, here's a site you may want to get to know. Lot's of great videos, the best being "Why WD-40 is never a good thing."