How will I know when my rear cassette needs replacing?

Discussion in 'Bicycle Mechanics and Repairs' started by Bigtallfatbloke, 24 Apr 2008.

  1. Bigtallfatbloke

    Bigtallfatbloke New Member

    ...and the front chain rings come to that. I hav edone iro 4000 miles on this thing and I am off to ride the length of Germany in July. Should I replace the cassette before I go? I have no idea if it needs a new one or not, or how long I should expect to get out of it? It is a shimano supplied on new Dawes galaxies.:biggrin:
  2. Dave5N

    Dave5N Über Member

    When you stand on the pedals and nadger yerself on the top tube!
  3. OP

    Bigtallfatbloke New Member

  4. Twenty Inch

    Twenty Inch New Member

    Behind a desk
    Broadly speaking, if the distance between teeth is 2x wider than the teeth are high.

    You can measure your chain stretch too. 10 links = 10 inches. If it's more than that, the chain needs replacing, which means the cassette does too.

    Anyway, you've answered your own question - get it done before you go to Germany.
  5. If you replace your chain on a regular basis your cassette and rings will last a decade or more.
  6. If it starts jumping is a good sign. I'd replace the cassette and chain, though I very much doubt you'll need to change the chainring yet
  7. I've never heard such drivel !

    yes - quite possibly - but only if you do a few hundred miles a year.

    It all depends on how many miles you do and in certain circumstances how you change gear (changing gear 'gently' - by backing off the pressure when chainging gear - will increase cassette life. Altho this isn't always possible in a racing scenario).

    Oh and also using a decent chain lube..............
  8. 02GF74

    02GF74 Über Member

    ^^^^ that is never right.

    Dunno where I got the number from but once 10 links measure 127.6 mm, the chain is worn - I believe the rule of thumb is 1% longer than a new chain.

    If you catch the cain at this length, you can run 3 or more chains on the same cassette, otherwise the cassette is too worn and a new chain will jump on it so you need to replace the cassette too.

    Annoying part is that you'll find it jumping only on 3 or 4 gears but you cannot buy them spearately (shimano I'm talking about).
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