# Knackered cassette?



## stevenb (27 Aug 2007)

I recently bought a 2nd hand bike off ebay.
Now it was good enough to buy. I have had to change a few bits and clean it up loads. However, after noticing the chain was totally shot I bought another...a SRAM one with Powerlink...in the meanwhile I'd ordered a set of spare wheels as Merlin Cycles were doing a great offer for a pair of Deore V-brake hubs ont Mavic XM117 rims the s/s d/b spokes for £50...bargain. So I had a new Deore cassette fitted by them and I fitted my Schwalbe slick tyres to them. Commuting/road riding wheels sorted. I fitted them and the bike road perfectly with slick gear changing.
Yesterday I went to put my off-road wheels back on....I'd cleaned up the cassette and noticed it looked worn. However...I thought I'd give it a go. I set off and as soon as I stepped onto the pedals the whole drive train slipped. I checked all was ok...but same again...slipping. 
I refitted the slick tyre wheels and the bike rode perfectly.
Is it my old cassette that is causing this...or is it the freehub on my Off-road wheels? I'm hoping it's the cassette.....that's what I've ordered online...
Sorry this thread is long winded....


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## Steve Austin (27 Aug 2007)

if it slips in every gear its the freehub, if it slips in a few gears it is generally speaking the cassette. try it on the larger sprockets on the cassette, they are less likely to slip, so you might be able to see if its the cassette this way.

It can be the front chainrings that cause slipping too, as well as stiff links in the chain.

I would go with trying a new cassette. Old cassettes don't always look that worn, but won't work nonetheless.


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## stevenb (27 Aug 2007)

Cheers for that. I noticed how little wear there is to the larger cogs so I'll give it a whirl. 
Thing is, when I bought the bike and rode it with the knackered chain and cassette I did 4 miles without a hitch and then 22 miles with no probs......so I'm thinking the new chain has shown up the worn cassette....
If it is my freehub then I'll have to order one from Chain Reaction. I hope I can fit them with the freehub tool I have.


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## stevenb (27 Aug 2007)

That was easy...just tried the off-road wheels again....used the higher cogs at the back.....not a dicky bird....must be the cassette. It can't be the middle chain ring as I have no probs at all with my road wheels. Oh well...sorted that one out.


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## andrew_s (27 Aug 2007)

Chains and cassettes wear together, so a new chain will normally slip on an old cassette, even though the old chain worked fine. If you don't want to buy a new cassette, you have to change the chain before things have worn too far.

There are 3 basic strategies for replacing chains:
a) use the same chain and cassette until it stops working properly, then replace the chain and cassette, and possibly one or more of your chainrings.
 check the chain for wear fairly frequently, and replace just the chain at a point before things have got so worn that a new chain will slip.
c) buy a cassette and 3 chains, then swap the chains every 4-500 miles or so (chain1, then chain2, then chain3, then back to chain1 again). Keep going until things stop working.

For option (, you can use a measuring tool like those from Rohloff or Park, or you can measure 20 links of chain. On a new chain that's 10". If the old chain measures less than 10 1/16", then you can put on a new chain with no problems. If the old chain has worn so than 20 links is 10 1/8", a new chain will still work, but there will be some wear on the cassette that means the new chain will wear a little quicker than it would on an unworn cassette.

Whether you pick (a), ( or (c) depends on the relative prices of the chains and cassettes you use, and how much faff you are willing to go through to reduce the cost.
As a rough guideline, if I leave the same chain and cassette on until they die, I get 7,000 miles use. If I want to put a new chain on the old cassette, I have to change chains before about 1,200 miles use. I picked option (a).
Note that these numbers will vary considerably, depending on how clean you keep your transmission, and how wet and gritty your roads or tracks are.


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## Steve Austin (27 Aug 2007)

is that 7000 off-road miles andrew?

i would be very happy with a 1000 MTB miles for a chain and cassette. I generally get more than this btw


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## stevenb (28 Aug 2007)

I will keep that in mind for the future....but as I bought it like it then I expected it to be this way.
Cheers for the info guys.


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