Bianchi Nyala chain skipping

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I was in a bike shop today to try to get my bike fixed because the chain skips and its been getting worse. One bike mechanic looked at it and seemed to say it wasn't worth fixing. He said something about getting a new chain, front and rear sprockets and bearings. After spending some time on the internet looking at this problem, I found out about a problem known as chain stretch where the pins and bushings wear out and the chain ends up longer compared to when it was new. I checked for that and other things like derailleur alignment, etc. I tried turning a screw on the derailleur to see if the chain would tighten up, but it didn't help. The derailleur tension is about the same compared to some other bikes I have, so I don't think its that. I made two videos which seems to show the bike has a lot of chain stretch and doesn't line up on the sprockets. I'm going to try to change the chain myself and see how well that works. I checked the chains on three other bikes. Two don't seem to have the problem at all and my 1973 Schwinn Varsity might be developing this problem a little bit, but it hasn't had any problems with a skipping chain and sprockets. The Bianchi Nyala is the worst one. Anyone else here experience this problem?


bike chain appears stretched


chain and sprockets don't line up



Example of bike chain skipping/slipping





More info on chains:
https://www.parktool.com/blog/repair-help/chain-compatibility
 
Most undamaged Bianchis are a bike worth some effort. It may not be cost-effective at professional shop rates, but as a DIY project, why not?

The pros have 'chain checker' tools, but it's easy enough to check for chain stretch with a common ruler. Each pair of pins is 1/2 inch apart. The length across three pins should be one inch, and so on. Detecting wear over that short distance would be very difficult, but what if you measured over 24 links? The longer your measurement, the more exaggerated any error becomes. A badly stretched chain can be very obvious over its full length. The rollers no longer mesh properly with the various sprockets and cause excessive wear on those items, too.

In addition, I'd say from the other video that your shifter adjustment is far out of whack. That alignment is performed by turning the barrel adjusters located at either end of the cable. Cable condition can also result in poor shifting, especially if they're kinked, corroded, or otherwise bound up from age. I tend to clean and lube every friction and pivot point I can find. About the only parts on a bike that can't be lubed are the braking surfaces.

I suggest once you replace the chain, seek out a video that describes the shift adjustment process. I could explain it here, but a visual demonstration is probably the better way to go.
 
The chain came in the mail today and I put it on the bike. It doesn't skip on the lower 2 or 3 speeds, but skips on the higher speeds. The highest speed isn't that bad, though. Maybe it needs a new cassette. I never changed a cassette before.
 
The chain came in the mail today and I put it on the bike. It doesn't skip on the lower 2 or 3 speeds, but skips on the higher speeds. The highest speed isn't that bad, though. Maybe it needs a new cassette. I never changed a cassette before.
Replacing a freehub cassette is a simple process, but one that requires several specialized tools--a chainwhip and a removal key (Park Tool FR-5). Before you jump to that trouble and expense, though, I'd revisit the cable adjustment I suggested earlier. I'm betting it's just a matter of 'tweaking' the cable tension a tiny bit.

 
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make sure the der is set up properly. Align the high and low limits, then adjust the cable. I'd do this before replacing cassette.
 
It may be a freehub cassette or a freewheel cassette, depending on the year and/or if someone changed the OE rear wheel out.

Edit: If the Exxon Valdez drivetrain videos above are of your bike, it is a freehub and for the love of God please clean your drivetrain.
 
Replacing a freehub cassette is a simple process, but one that requires several specialized tools--a chainwhip and a removal key (Park Tool FR-5). Before you jump to that trouble and expense, though, I'd revisit the cable adjustment I suggested earlier. I'm betting it's just a matter of 'tweaking' the cable tension a tiny bit.


If it's only skipping on a few cogs, it could be either the limit screws not set properly, or a bent hanger.
 
The chain came in the mail today and I put it on the bike. It doesn't skip on the lower 2 or 3 speeds, but skips on the higher speeds. The highest speed isn't that bad, though. Maybe it needs a new cassette. I never changed a cassette before.
Probably a worn Cassette/ freewheel ..
New chain on old sprockets will tend to skip especially on higher gears ….
 
Probably a worn Cassette/ freewheel ..
New chain on old sprockets will tend to skip especially on higher gears ….

Yep.

Gee, it's almost as if the guy at the bike shop was right... :rolleyes:
 
Yep.

Gee, it's almost as if the guy at the bike shop was right... :rolleyes:
Looking more closely at those videos, the cogset doesn't look very sharky though *nobody* can really see fine wear through the heavy petrochemical coating.

A common order of business for this whole situation would be:

Check cable tension.

Check high and low derailleur stops.

Check derailleur hanger alignment.

Check chain for wear and replace if needed. Normally a worn chain would indicate the need for a new cogset, but not always.

Check the cogset and/or chainrings for wear. A "sharky" cogset/chainring (teeth are pointy, like a shark's tooth) is an obvious indicator that replacement is needed. If not obviously in need of replacement, look for wear on the edges of the teeth, or even bent teeth.

If the bike shop guy checked all of the above, he probably was right. The fact that he didn't wipe down that cogset to inspect it properly says he may not be right.
 
I bought the bike used for $35. The original gear levers didn't work so I put on another pair that have continuous motion (no click). I've used that system for about 10 years with little skipping. There was some on some gears, but only if I peddled hard. The bike probably needs a new cassette.
 
I'm confused. How many of your rides are suffering this plight? The last two clips you provided are clearly NOT the same bike. Our advice can only be as good as the information you provide. Right now, that's based on grainy video and a very general description of the problem. We've tried to be helpful, but only now, after one week, do you disclose that you've mixed & matched non-original parts. Did you not think that might be important? I guarantee that every member who responded here did so under the presumption that your shifting was indexed.

In this instance, friction shifting isn't a big deal and actually offers some benefits. But it would have been nice to know and may have steered our troubleshooting in a different direction. Is the cassette bad? Quite possibly...especially if you've been riding on it for 10 years with a stretched chain, after buying it for 35 bucks--that sounds like a very tired bike. :rolleyes:

In my first reply, I stated that a Bianchi is worth repairing, and I stand by that. But, if this bike is as rough as it seems, I'd sooner achieve that end using components from a donor bike, than sink a lot of money into brand-new parts.
 
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Thanks for clearing that up. Under the circumstances, I suggest you submit another video clip showing the bike with the new chain installed and allow the members here to re-assess the behavior. There are a few things I see in clip #2 that I do not like, but could have been caused by the worn chain.

Did you remove any links from the new chain when installing it? The reason I ask is it may determine if either of the eBay cassettes can be easily used. Count the number of teeth on the largest sprocket in your existing cluster, then report back what you find. It's usually safe to replace with the same number of teeth or fewer, but more teeth means a larger circumference, and a larger circumference means a longer chain (and sometimes derailleur) is required.
 
Thanks for clearing that up. Under the circumstances, I suggest you submit another video clip showing the bike with the new chain installed and allow the members here to re-assess the behavior. There are a few things I see in clip #2 that I do not like, but could have been caused by the worn chain.

Did you remove any links from the new chain when installing it? The reason I ask is it may determine if either of the eBay cassettes can be easily used. Count the number of teeth on the largest sprocket in your existing cluster, then report back what you find. It's usually safe to replace with the same number of teeth or fewer, but more teeth means a larger circumference, and a larger circumference means a longer chain (and sometimes derailleur) is required.
 
Buddy …. I’ve worked with Bikes for 50 years .., A new chain on old sprockets will skip especially on the high gears ..smaller rear ones ..,
Never mind messing around with set screws and bearings …. Replace the rear sprockets. …. Then test ride it….
 
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