Is this cassette worn??

[robt57]

I'd add 'this user' is a user I am on two forums along with. If he chimes in, I suspect some schooling on this subject to occur.

From a Thread on other forum, and I am posting without his permission. [will remove if asked]. Good info IMO, so I am adding it to this thread.

'this user' sez:

New chain on worn cogs causes the same occurrence at either the front or rear sprocket, but with different symptoms.

With a hooked tooth, the chain rollers occupy a more-advanced position on a worn rear sprocket, due to the missing metal.
On a chainring, the chain rollers occupy a retarded or less-advanced position along the toothed part of the ring.

But, the metal isn't usually missing near the tip of the tooth, and the rollers still have to fall between teeth during engagement, so the rollers will strike the less-worn tips of the teeth on their way to falling between teeth.

It gets worse as the load increases, as the chain elastically pulls slightly forward(rearward) from even it's already-advanced(retarded) position along the rear(front) sprocket, thus causing harder contact with the tips of the teeth.

At the front sprocket, as the chain rollers engage the teeth, the rollers impacting the teeth can be heard and can be felt as a rumble through the pedals as the chain's driving tension forces the rollers past the tips of the worn teeth.

But at the rear sprocket, there is only mere sprung chain tension trying to force the rollers into engagement between the teeth, so as the pedaling force increases, at some point a single roller will hang atop the tip of a tooth and prevent a series of several rollers from engaging at all, resulting in violent slippage followed by engagement as the now de-tensed chain once again resumes engaging the sprocket until the chain again reaches that critical tension.

The fix for either condition is to bevel away the protruding drive/driven-side corner at the tip of the tooth, roughly only a 1mm bevel at about a 35-40-degree angle to the driven edge of the tooth (where the "pocket" wear has formed). This simply lets the rollers follow their hinged arc into engagement without striking the tips of the teeth.

I've done this in minutes using a Dremel stone (without even removing the rear wheel from the bike) with complete success on many hurried occasions.

But on the alloy chainring, a file is the thing to use on the softer metal that would clog a grinding-stone surface.

The OP's pictured Middleburn chainring appears to be just a couple of swipes of a file from having every tooth restored to running quietly with a new chain.

I've probably repaired about 60-70 rear cogs and perhaps a dozen chainrings using the above techniques, and with about a 90% success rate.

A few different rear cogs didn't work out despite following up with a bit more grinding, for whatever reason. I suspect that with a single chain having perhaps worn the cog over a great range of chain stretch, that the wear pocket was bigger than it looked because the hook thus appeared less sharply defined. Somehow there were just a few like this that I couldn't quite fix.

[mtechnica]

Originally Posted by oldpotatoe

If the chain is centered on the cog and it 'skips' under load, that cog is worn out. With all the ramps and cutout and tooth shaping and such on cogsets, it's really 'hard' to look at a cogset and tell if it's worn..In person is tough, via a picture..well...

+1

Replace the chain once it fails the first elongation pin on the chain checker to avoid worn cassettes.

[mtechnica]

Originally Posted by robt57

I'd add 'this user' is a user I am on two forums along with. If he chimes in, I suspect some schooling on this subject to occur.

From a Thread on other forum, and I am posting without his permission. [will remove if asked]. Good info IMO, so I am adding it to this thread.

'this user' sez:

New chain on worn cogs causes the same occurrence at either the front or rear sprocket, but with different symptoms.

With a hooked tooth, the chain rollers occupy a more-advanced position on a worn rear sprocket, due to the missing metal.
On a chainring, the chain rollers occupy a retarded or less-advanced position along the toothed part of the ring.

But, the metal isn't usually missing near the tip of the tooth, and the rollers still have to fall between teeth during engagement, so the rollers will strike the less-worn tips of the teeth on their way to falling between teeth.

It gets worse as the load increases, as the chain elastically pulls slightly forward(rearward) from even it's already-advanced(retarded) position along the rear(front) sprocket, thus causing harder contact with the tips of the teeth.

At the front sprocket, as the chain rollers engage the teeth, the rollers impacting the teeth can be heard and can be felt as a rumble through the pedals as the chain's driving tension forces the rollers past the tips of the worn teeth.

But at the rear sprocket, there is only mere sprung chain tension trying to force the rollers into engagement between the teeth, so as the pedaling force increases, at some point a single roller will hang atop the tip of a tooth and prevent a series of several rollers from engaging at all, resulting in violent slippage followed by engagement as the now de-tensed chain once again resumes engaging the sprocket until the chain again reaches that critical tension.

The fix for either condition is to bevel away the protruding drive/driven-side corner at the tip of the tooth, roughly only a 1mm bevel at about a 35-40-degree angle to the driven edge of the tooth (where the "pocket" wear has formed). This simply lets the rollers follow their hinged arc into engagement without striking the tips of the teeth.

I've done this in minutes using a Dremel stone (without even removing the rear wheel from the bike) with complete success on many hurried occasions.

But on the alloy chainring, a file is the thing to use on the softer metal that would clog a grinding-stone surface.

The OP's pictured Middleburn chainring appears to be just a couple of swipes of a file from having every tooth restored to running quietly with a new chain.

I've probably repaired about 60-70 rear cogs and perhaps a dozen chainrings using the above techniques, and with about a 90% success rate.

A few different rear cogs didn't work out despite following up with a bit more grinding, for whatever reason. I suspect that with a single chain having perhaps worn the cog over a great range of chain stretch, that the wear pocket was bigger than it looked because the hook thus appeared less sharply defined. Somehow there were just a few like this that I couldn't quite fix.

Wow this is really interesting and makes a lot of sense actually.

[fmradio516]

Originally Posted by robt57

I'd add 'this user' is a user I am on two forums along with. If he chimes in, I suspect some schooling on this subject to occur.

From a Thread on other forum, and I am posting without his permission. [will remove if asked]. Good info IMO, so I am adding it to this thread.

'this user' sez:

New chain on worn cogs causes the same occurrence at either the front or rear sprocket, but with different symptoms.

With a hooked tooth, the chain rollers occupy a more-advanced position on a worn rear sprocket, due to the missing metal.
On a chainring, the chain rollers occupy a retarded or less-advanced position along the toothed part of the ring.

But, the metal isn't usually missing near the tip of the tooth, and the rollers still have to fall between teeth during engagement, so the rollers will strike the less-worn tips of the teeth on their way to falling between teeth.

It gets worse as the load increases, as the chain elastically pulls slightly forward(rearward) from even it's already-advanced(retarded) position along the rear(front) sprocket, thus causing harder contact with the tips of the teeth.

At the front sprocket, as the chain rollers engage the teeth, the rollers impacting the teeth can be heard and can be felt as a rumble through the pedals as the chain's driving tension forces the rollers past the tips of the worn teeth.

But at the rear sprocket, there is only mere sprung chain tension trying to force the rollers into engagement between the teeth, so as the pedaling force increases, at some point a single roller will hang atop the tip of a tooth and prevent a series of several rollers from engaging at all, resulting in violent slippage followed by engagement as the now de-tensed chain once again resumes engaging the sprocket until the chain again reaches that critical tension.

The fix for either condition is to bevel away the protruding drive/driven-side corner at the tip of the tooth, roughly only a 1mm bevel at about a 35-40-degree angle to the driven edge of the tooth (where the "pocket" wear has formed). This simply lets the rollers follow their hinged arc into engagement without striking the tips of the teeth.

I've done this in minutes using a Dremel stone (without even removing the rear wheel from the bike) with complete success on many hurried occasions.

But on the alloy chainring, a file is the thing to use on the softer metal that would clog a grinding-stone surface.

The OP's pictured Middleburn chainring appears to be just a couple of swipes of a file from having every tooth restored to running quietly with a new chain.

I've probably repaired about 60-70 rear cogs and perhaps a dozen chainrings using the above techniques, and with about a 90% success rate.

A few different rear cogs didn't work out despite following up with a bit more grinding, for whatever reason. I suspect that with a single chain having perhaps worn the cog over a great range of chain stretch, that the wear pocket was bigger than it looked because the hook thus appeared less sharply defined. Somehow there were just a few like this that I couldn't quite fix.

I worked for an old school bike guy at his shop when I was going to school. i remember him telling me if there was a gear skipping, you can easily fix it by removing a burr with a metal file. sounds like what this user is talking about. Ill check out each tooth carefully to see if i can find anything.

[Mark McM]

Originally Posted by robt57

The fix for either condition is to bevel away the protruding drive/driven-side corner at the tip of the tooth, roughly only a 1mm bevel at about a 35-40-degree angle to the driven edge of the tooth (where the "pocket" wear has formed). This simply lets the rollers follow their hinged arc into engagement without striking the tips of the teeth.

This might be okay temporary fix, but it's probably not a good long term solution. The change in shape of the tooth "pocket" will result poorer chain engagement, and while it may not slip, it will concentrate loads on fewer chain rollers/pins, resulting in faster chain wear.

[robt57]

Originally Posted by Mark McM

This might be okay temporary fix, but it's probably not a good long term solution. The change in shape of the tooth "pocket" will result poorer chain engagement, and while it may not slip, it will concentrate loads on fewer chain rollers/pins, resulting in faster chain wear.

More like a gear the last 500 [200?] miles before you toss it all really.

Anytime a new chain goes on used well used cassette the chain wear will be accelerated IME.

[fmradio516]

yeah and these chains i have arent cheap(i bought two so i can rotate), so maybe i should bite the bullet and get a new cassette.

So Chorus/record(bigger ti cogs) will last longer than a full Ti Super Record?

[thwart]

Originally Posted by fmradio516

yeah and these chains i have arent cheap(i bought two so i can rotate), so maybe i should bite the bullet and get a new cassette.

So Chorus/record(bigger ti cogs) will last longer than a full Ti Super Record?

Or... lots of lightly used Chorus 11 cassettes around for small money.



Buy one and use the steel, more durable 'middle cluster' on the Super Record you have now.

[mulp]

Originally Posted by fmradio516

well its possible I didnt put the spacers in order. I didnt think it mattered, I just stick on the spacers without paying any attention to them. What is the correct order to do this in?

If you look on the pdf that was provided on page 10, assuming im reading it correctly, it goes F, F, R, F from smallest cog to largest.

[robt57]

Originally Posted by fmradio516

So Chorus/record(bigger ti cogs) will last longer than a full Ti Super Record?

Is there a full Ti SR, I thought only top 6 cogs were Ti??

[fmradio516]

Originally Posted by robt57

Is there a full Ti SR, I thought only top 6 cogs were Ti??

sry yeah youre right. 6 biggest cogs are ti. It was hard for me to tell without taking the wheel off, but yeah in better light, i can see there is a difference

[Mark McM]

Originally Posted by robt57

Is there a full Ti SR, I thought only top 6 cogs were Ti??

There were Campagnolo full Ti cassettes for 8,9&10 speed, but only the large sprockets were Ti for SR 11spd. Ti is completely gone for 12spd.

[fmradio516]

Originally Posted by Mark McM

There were Campagnolo full Ti cassettes for 8,9&10 speed, but only the large sprockets were Ti for SR 11spd. Ti is completely gone for 12spd.

Thats crazy. not even on the biggest cogs? What are they doing in its place to sell the SR? Whats makes it special?

[Seramount]

Originally Posted by zap

Ride the bike for a 100 or so miles....and initially take care when in the cogs that skip. There is a chance all will be well and hammer ready after that.

My longevity experience. Record 10 ti/steel cassette. When I installed the third chain I had skip in 2 ti cogs but that went away after a week of riding +/- 100 miles.

This particular Record 10 cassette lasted over 20,000 miles.......and that 3rd Record chain lasted over 12,000 miles..........factory lube and refreshed when needed. Shifting got a little ragged at the end but I think that is pretty decent mileage.

just had the same experience with a DA 10 setup. replaced a chain (10K miles) and it skipped on a cassette with 18K miles. figured the cassette was toast and bought a replacement online...while I waited for it to arrive, kept riding. by the time it was delivered, the skipping had stopped.

[Mark McM]

Originally Posted by fmradio516

Thats crazy. not even on the biggest cogs? What are they doing in its place to sell the SR? Whats makes it special?

This is a good question. According to the 2020 catalog, there are only 3 sizes of 12spd cassettes (11-29, 11-32, 11-34)*. The largest 6 sprockets are in 2 3-sprocket steel monoblocs. The weights for the Chorus version is given as 310g vs. 266g for the Record/Super Record version. The Spare Parts catalog gives the same part numbers for the 6 smallest sprockets for all models, but the Chorus model has different part numbers than the Record/Super Record for the 6 largest sprockets. Maybe the Record/Super Record version has more material machined away for the steel monoblocs?


*There were at least 7 different sizes of 10spd and 11spd cassettes. Despite having more sprockets, the 12spd cassettes have as large or larger size jumps between sprockets than most 11spd cassette.