Reverse-wearing a cassette...?

[rjb]

I recall Brucey advocated judicious use of a file in those circumstances to restore normal service.

[veloaficionado]

Also, given the trend to reeeeeeaaaalllly wide-range (and freakingly expensive!) cassettes, the wear on the teeth will be unevenly distributed, and unevenly seen on the various cogs, with 42-48-50 teeth cogs exhibiting nearly no wear when your 14-18 teeth cogs will be just about shagged . . . how would you account for that?

I suspect I'll just be religiously swapping chains every 50km, but thanks for your thought experiments. My bwain cogs are turning now . . .

[fastpedaller]

42-48-50 teeth cogs exhibiting nearly no wear when your 14-18 teeth cogs will be just about shagged . . . how would you account for that?

To a large extent the wear is (of course) more on the sprockets that are used more frequently. When using a small chainring the torque is the same (if the pedal is being pushed with the same force), but the force through the chain is higher (than if in a big ring). At the wheel, for a given force in the chain the wrap around of the chain will be on many more teeth of a larger sprocket compared with a smaller one, thus spreading the load/wear over more teeth.

[531colin]

Also, given the trend to reeeeeeaaaalllly wide-range (and freakingly expensive!) cassettes, the wear on the teeth will be unevenly distributed, and unevenly seen on the various cogs, with 42-48-50 teeth cogs exhibiting nearly no wear when your 14-18 teeth cogs will be just about shagged . . . how would you account for that?

I suspect I'll just be religiously swapping chains every 50km, but thanks for your thought experiments. My bwain cogs are turning now . . .

If you want to even out the sprocket wear, you need a really big ring on your triple chainset so that the really big sprockets give useful "cruising" gears.


In reality, the teeth are "damaged" ...ie the tooth profile is changed....by running chains which are so worn that they ride up the teeth, and wear the "wrong" part of the tooth to the "wrong" profile. (because the distance between rollers is increased)

My cassette, photographed year after year, shows that if you change the chain before it alters the tooth shape then you can carry on using new chains on an old cassette without slipping, even though the teeth are worn thin.....because the shape of the tooth on the loaded side is "right", ie not worn so as to be "wrong"

[531colin]

I recall Brucey advocated judicious use of a file in those circumstances to restore normal service.

That would be an interesting experiment; I may have a go, but I have already replaced the rings, and its like a new bike!

[531colin]

..........sorry, erroneous post!

[531colin]

IMG_5501 by 531colin, on Flickr

Same old cassette after yet another winter. I've binned it!

[gxaustin]

I find Brucey's idea of reverse-wearing sprockets interesting as a concept, but I'm much too lazy to deliberately set aside a chain at a particular wear state so that I can put some damaging wear on a cassette and then attempt to re-habilitate the cassette.....much easier to avoid damaging the cassette in the first place!

I'm with you there, Colin. I recently changed my 11sp cassette after about 20,000 miles. It never skipped and would maybe last even longer but I thought 3 years of use was fine. The chain rings are still going fine.
Also I treated my bike to new idlers, bar tape and cable outers, so I changed the cassette too.

[531colin]

I recall Brucey advocated judicious use of a file in those circumstances to restore normal service.

That would be an interesting experiment; I may have a go, but I have already replaced the rings, and its like a new bike!

Early results are encouraging; changing is slick again; just need a couple of long rides to be sure, to be sure.

[LuckyLuke]

IMG_5501 by 531colin, on Flickr

Same old cassette after yet another winter. I've binned it!

What a good innings!

Best wishes,

Luke