Converting to a single chain ring

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Comments

  • Johnny_Cage
    Johnny_Cage Posts: 57
    Err sorry, tripping. I meant Acera, not Deore :oops:

    No I don't have the crankset at the moment. The one I have just now is riveted together, so I can't take rings off, so will need a new one.

    Looking to get a Shimano Acera M361 Triple Chainset Square Taper.

    Don't know what I have at the moment, will need to check - just ordered a BB tool.

    Thanks for the link.
  • bailsofhay
    bailsofhay Posts: 191
    If you have square taper at the moment you will need a crank extractor as well. Do you know what your current chainset model is?
  • The Rookie
    The Rookie Posts: 27,812
    WHAT CRANKSET IS ON THERE NOW we can then find out what width the BB should be.

    Why are you blowing unnecesary money on a new crankset when a used one is a fraction of the price and you can probably buy a better one?
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • Johnny_Cage
    Johnny_Cage Posts: 57
    Don't know what crankset I have now, it is unbranded... I am trying to find out what BB I have.

    A brand new crankset is so cheap, why would I waste money on some old skanked-out thing?
  • bailsofhay
    bailsofhay Posts: 191
    Pics?
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Johnny_Cage wrote:


    A brand new crankset is so cheap, why would I waste money on some old skanked-out thing?

    It's mostly the rings that wear and you're proposing to put a new single specific ring on so if you buy new you're just wasting the new rings that come with it.
  • The Rookie
    The Rookie Posts: 27,812
    £30 when your bike new was probably less than 10 times that isn't cheap. There is a decent Truvativ Stilo on eBay right now, probably won't get any bids that will be about £6 delivered.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • delete_my_account
    delete_my_account Posts: 192
    The Blackspire chainring you mentioned is ramped which makes shifing easier. You don't want to shift with a single ring. You'll want a ring specifically designed for a 1x setup.
    Delete my fucking account.
  • Johnny_Cage
    Johnny_Cage Posts: 57
    MichaelMLFC92 wrote:
    The Blackspire chainring you mentioned is ramped which makes shifing easier. You don't want to shift with a single ring. You'll want a ring specifically designed for a 1x setup.

    What are these types of rings known as?

    How is this one?

    http://www.chainreactioncycles.com/hope-single-dh-chain-ring/rp-prod80578?utm_source=Google&utm_medium=Shopping&utm_name=UnitedKingdom&gclid=CNb8neX_2r4CFUn4wgodW5AAuQ&gclsrc=aw.ds
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    A chainring!

    No ramps.
  • Johnny_Cage
    Johnny_Cage Posts: 57
    I asked what type of chain ring.

    This one looks like a single one without ramps - the teeth look longer.

    What does DH stand for? from Hope Single-DH Chain Ring.
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    You've answered your own question there. DH is downhill - a form of MTB in its exteme - racing down a hill fast.
  • Johnny_Cage
    Johnny_Cage Posts: 57
    So, would that Hope chain ring be suitable? (don't do downhill discipline) is it the equivalent of a middle ring?

    It says it is for 9 and 10 speed, but mine is an 8-speed...

    With that in mind, would a 32t, 34t or 36t be best?

    I would prefer first gear be easy enough to traverse rocky uphill sections, as opposed to flat out speed - though I would still like some decent enough resistance for speed.

    I know I can't have it both ways, being a single-ring setup and all (especially only an 8-speed) but what do you think?

    Appreciated.
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    I think you should just buy another cheap triple.
  • The Rookie
    The Rookie Posts: 27,812
    That ring is fine, as are lots of other cheaper ones, what you DONT want is a middle ring as that will have ramps and pins.

    I'd suggest starting with a 32t unless your riding is in very flat areas when you could go higher.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • Johnny_Cage
    Johnny_Cage Posts: 57
    OK great, 32t sounds right. I had that in mind anyway, but wasn't so sure.
  • Johnny_Cage
    Johnny_Cage Posts: 57
    Right, so I got my crank arms off, waiting on a BB removal tool.

    I will measure the length of the old BB itself, that's no problem - but is the spindle length important to measure on the old BB?

    Won't I need a longer spindle so the ring reaches to the middle position? Therefore, is it pointless to acutally measure the old BB spindle length?

    I have identified that I need a Shimano UN55 Square Taper Bottom Bracket, just needing to find out the correct spindle size. How should I go about this exactly?
  • cooldad
    cooldad Posts: 32,599
    Will be in the tech docs for the crankset. If you're not changing the cranks, the same length as you have now.
    I don't do smileys.

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  • Johnny_Cage
    Johnny_Cage Posts: 57
    cooldad wrote:
    Will be in the tech docs for the crankset. If you're not changing the cranks, the same length as you have now.

    Haven't bought crankset yet, so I will go ahead and get it (Shimano Acera M361)

    I thought the BB size specified in the crankset's documentation would pertain to a triple ring. Will the size still be valid, bearing in mind I will be taking the 3 rings of the crankset and replacing them with a single ring?

    Also, there is two length sizes for the crankset, 170mm and 175mm, what is that - the arm length? What should I go for?
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Yes. Yes. 175 is 'normal'

    Still think you'd be better getting a secondhand something.
  • Johnny_Cage
    Johnny_Cage Posts: 57
    Right, got my BB out.

    It is a 68 width and 122 length.

    Should receive my crankset tomorrow, not bought the new BB yet.

    Looking at the PDF online for the crankset it says the applicable BB is the UN26.

    PDF
    http://techdocs.shimano.com/media/techdocs/content/cycle/SI/Alivio-Acera/SI_0094A/SI-0094A-001-ENG_v1_m56577569830667768.PDF

    The UN26 comes in a 68x122.5 (no 68x122 - 0.5mm out)

    Is the 0.5mm discrepancy ok?

    Will this BB get me to a middle ring placement chainline?

    Thanks.
  • cooldad
    cooldad Posts: 32,599
    Half a mm is fine - not noticeable.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools

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