Cassette and spacer query

venster
venster Posts: 356
edited January 2008 in Workshop
I want to buy a 9 spd cassette for my spare wheel to use on a trainer. Do I need a spacer, or not, with 9 spd.

It's to go on a bog standard Bontrager wheel from a 2006 Trek 1200.

If I do, does the cassette normally come with a spacer ?

Comments

  • Gussio
    Gussio Posts: 2,452
    When I put a 9 spd Shimano Ultegra cassette on a Mavic hub I needed a 1mm spacer between hub and cassette. The spacer came with the hub. Without the spacer, the cassette will not be tight.
  • aracer
    aracer Posts: 1,649
    That spacer is only required for Mavic wheels. With a Bonty wheel, you should need no spacer at all for 9-speed.
  • venster
    venster Posts: 356
    Thank you :)
  • giant_man
    giant_man Posts: 6,878
    Another question and excuse me for invading your thread venster, but why is it some bikes, admittedly the lower end ones, have a plastic 'protector' (plastic disc a little bigger than the largest cog) behind the cassette? Is this for the same reason as having a spacer ie it acts as a spacer?
  • cee
    cee Posts: 4,553
    giant mancp wrote:
    Another question and excuse me for invading your thread venster, but why is it some bikes, admittedly the lower end ones, have a plastic 'protector' (plastic disc a little bigger than the largest cog) behind the cassette? Is this for the same reason as having a spacer ie it acts as a spacer?

    I have a specialized Hardrock fro gnashing around the woods. It ame with an 8-speed setup.

    I recently changed it to a 9. The freehub body was exactly the same, but I had to remove the plastic protector.

    As far as I can tell, this plastic disc has two uses.

    1. It acts a s a spacer for the more compact 8 speed cassette,
    2. It would stop the chain being shifted into the spokes of the rear wheel.

    When I removed it, I must admit I was a little nervous about the chain obiterating my rear wheel, but I have had no issues since, so :roll:
    Whenever I see an adult on a bicycle, I believe in the future of the human race.

    H.G. Wells.
  • giant_man
    giant_man Posts: 6,878
    yes i was thinking the same think myself cee, ie. stop the chain being in contact with the spokes of the wheel. And I am also guessing that it depends on which wheel it is?

    You never see any 'quality' wheels on decent bikes with this plastic protector.
  • venster
    venster Posts: 356
    I would have said the same, protect the spokes.
  • andy_wrx
    andy_wrx Posts: 3,396
    The plastic disc is a spoke protector.
    It protects the spokes against the chain going over the largest cog and into the spokes, which it will chew-up and ruin.
    If you set-up your rear mech limit screws so that the chain won't over-shift, you don't need it, but I guess it tends to be fitted by the manufacturer because many bikes aren't looked after and set-up/maintained properly.

    It looks ugly and is a mark of a newbie, so many people or bike shops remove it, also persuading themselves they're also saving themselves a few grams :roll:

    I bought some new Ksyriums recently and was amused that they came with said protector fitted - I can't imagine anyone riding Ksyriums using it.


    Back to original question - you won't need any spacer to fit 8sp or 9sp onto a Shimano 8sp/9sp/10sp-fit hub, which your Bonty will be.
    You will need a spacer to fit a 10sp Shimano cassette though, which comes with the cassette, as the 10sp is narrower than 8sp or 9sp
    The other post about Mavic needing a spacer is because a Mavic hub is a Mavic M10 hub rather than a Shimano 8sp/9sp/10sp-fit hub, so you need the Mavic spacer to fit 8sp or 9sp Shimano cassette.
    - and if you fit 10sp Shimano cassette onto a Mavic M10 hub, you need the Mavic spacer *plus* the Shimano 10sp spacer.
  • aracer
    aracer Posts: 1,649
    andy_wrx wrote:
    I bought some new Ksyriums recently and was amused that they came with said protector fitted - I can't imagine anyone riding Ksyriums using it.
    Don't see why not - it's hardly as if it's possible to make Ksyriums any less aerodynamic :twisted:
  • steowen
    steowen Posts: 59
    I'm also thinking of 'handing down' my Ksyrium Elites from my 10 speed Ultegra summer steed to my 105 9 speed winter bike.

    So Andy_wrx, have I under stood you correctly; As it's already a Shimano cassette on a Mavic hub I will have the Mavic spacer fitted but will also have the Shimano 10 speed spacer fiited too – Therefore once I've removed the 10 speed cassette all I need to do is remove the Shimano spacer and attach the 9 speed cassette?
    All that glitters is probably glass
  • John.T
    John.T Posts: 3,698
    Yes.
    My Fleet.
  • steowen
    steowen Posts: 59
    Cheers John.
    All that glitters is probably glass
  • andy_wrx
    andy_wrx Posts: 3,396
    Yes.
    You should find you have two spacers (big washers !) fitted - the Mavic one is the thicker of the two which you should keep, the Shimano one is the thinner of the two and you need to remove.

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