Re-using a worn cassette

[Johnmankelow]

When you install a new chain it will slip on a the teeth of a worn gear wheel. Has anyone tried filing the teeth on a used gear wheel to restore the profile and use it again?. Although teeth on a gear wheel are claimed to be hardened it is possible to file a worn wheel and it would also be possible to change the shape on a grinder. If it is possible is it worth doing?.

[CREPELLO]

It's not possible because the wear has now changed the teeth pitch from 1/2" to something more than 1/2".

[Brucey]

I have done this.

It is easy enough to 'dehook' a sprocket (i.e. remove the overhanging part of the tooth) but there are problems....

1) Being accurate; this is really difficult.

2) preventing 'ride up'.

Ride up? Well the rollers on a new chain now bear against a worn part of the sprocket; this has the wrong angle on it. When any chain roller sees a load it rides up slightly, and this then prevents the other links from engaging with the sprocket correctly, almost as badly as if the hooks were still there. This makes the chain jump.

In theory you can regrind the whole tooth profile to avoid this but it is incredibly difficult and time consuming (unless you have a CNC machine...). The only other way of overcoming it is to ride with a new chain on the most worn sprockets for several hundred miles until the chain beds in and doesn't jump under load any more. This is very tedious and just a bit risky; finding out that the process isn't yet complete means a jump, probably at the wrong time, when you are riding out of the saddle, in traffic etc. Any given jump can cause the chain to break. Even if this doesn't happen the chain may be wearing at an accelerated rate.

If you are going to try this I'd suggest using a length of new chain on a chain whip as a 'gauge' to check smooth engagement under load (rohloff make a tool that works exactly like this BTW). The tooth dressing can be done using an angle grinder and/or a dremel tool.

Hours of fun ahead; no guaranteed good outcome....

cheers

[mercalia]

also not worth the bother when u can get good quality quite cheap eg shimano HG41 £8 HG51 for £10, 8 speed

[sreten]

Hi,

Its just not possible. The cassette is toast as far as new chains are concerned.
Read up on rotating multiple chains with one cassette usually 3 chains.

rgds, sreten.

[cycleruk]

What would happen if you turned the sprockets round?
Yes I know they have odd castellations to prevent this but they can be ground to suit.
I have replaced a couple of individual sprockets from other cassettes with success. Obviously depends on which sprocket is worn.

[meic]

If it is a Uniglide cassette then when you turn the sprockets around, you will get a whole second life out of your cassette.

Hyperglide may be worth trying one day but looking at them suggests the chain will just ramp over the teeth.
Though I am sure that an un-reversed £8 cassette will be better than a reversed £100 one so it isnt worth even trying is it?

[Brucey]

.... I am sure that an un-reversed £8 cassette will be better than a reversed £100 one so it isnt worth even trying is it?

quite so. When I've tried this, it has been in the expectation that it probably isn't worth it in most cases. But who knows, if I work out how to do it properly then it may be useful at some point in the future.

It does bug the heck out of me when I have to ditch a cassette because of one or two worn sprockets, and only a few places sell them individually...

cheers

[coast 2 coast]

How many hours have you got that you are willing to spend fiddling around with a file, to create something that will never be as good as a unit that costs less than £30 to buy new?

[meic]

Thirty quid is 5 hours on minimum wage. Getting to 6 hours if you work long enough to pay tax.
A lot more hours than that if it is eating into Tax Credits, housing benefit and Council Tax rebate.

The economic prizes of this country are not shared out equally.

Apart from that avoiding waste is a good thing in itself regardless of the financial concerns.

[reohn2]

How many hours have you got that you are willing to spend fiddling around with a file, to create something that will never be as good as a unit that costs less than £30 to buy new?

Head,nail,on.
I've just bought six Shimano cassettes from CRC,all HG51's two of each different ratio sets,four 9sp and two 8sp,the lot cost £62 delivered,a no brainer IMO.

[reohn2]

Thirty quid is 5 hours on minimum wage. Getting to 6 hours if you work long enough to pay tax.
A lot more hours than that if it is eating into Tax Credits, housing benefit and Council Tax rebate.

The economic prizes of this country are not shared out equally.

Apart from that avoiding waste is a good thing in itself regardless of the financial concerns.

Time is money whatever you're doing,so @ £12 for a 9sp good quality HG51 cassette,which would you rather do,work a couple of hours at your job or filing the teeth on an old cassette that'll never work as well as it did when new?
There are some things not worth the effort.

[meic]

I agree it is not worth the effort because it will not work.

If money is tight then better to buy cassettes at £8-20 each than at £30-190 and try and reclaim them.

[reohn2]

I agree it is not worth the effort because it will not work.

If money is tight then better to buy cassettes at £8-20 each than at £30-190 and try and reclaim them.

The high price cassettes are just lighter than their cheaper counterpart anyway,they don't last any longer IME.

If money is really tight,a cheap 8sp cassette can be made into a 9sp by using a cog and the spacers from the used 9sp ie;if you use 9sp 11/32 cassettes, buy an 8sp 11/30 from CRC@£7.49 split it,use the seldom used hardly worn,32t cog and spacers from the old 9,and you saved yourself £4.50.Do that twice with the same 32t cog and 8sp cassette,and the third 9sp 11/32@£11.99 only costs £3.Begin the 8-9sp cassette cycle again
All prices are at CRC current rates,
Obviously it doesn't work with any cassette combo but it's an example of how savings can be made,if you really try