chainring doesn't fit crank :(

Discussion in 'Beginner's Area' started by tawfer, May 17, 2006.

  1. tawfer

    tawfer New Member

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    I am attempting to build a trials bike out of parts, mostly everything is working fine so far, but...

    I bought a 22t chainring to connect to my truvati hussefelt (probably spelled wrong) cranks. Anyway, both have the same pattern (4 bolts) but the radius of the chainring is smaller than that of the cranks. I was looking on webcyclery.com and they have 'cogs' opposed to 'chainrings' should I have gotten a cog for the front? I can post pictures if this description doesn't make any sense. Thanks
     
  2. muddyfox

    muddyfox New Member

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    Nope. Cog is completely different. You need to measure the bolt circle diameter of your cranks and get a chain ring with the same bcd.

    * its easy with 4 bolt. just measure from centre of 1 hole to centre of opposite hole.
     

  3. justfuzzit

    justfuzzit Member

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    yeah or u can prolly find a chart or something online. thats printable.

    or just go to a bike shop. 99% should be able to help u out.
     
  4. tomacropod

    tomacropod Rum Pig

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    you're aware that there are two sets of bolts on a 4-bolt (such as truvativ hussefelt) cranks? One is a 74mm bcd and the other is a 104mm bcd. Unless you have a chainring designed for a shimano XTR 4-bolt (which is different, and alone in being different) then it should fit. I suggest you get another ring from your LBS - they should have shimano/truvativ/etc.

    - Joel
     
  5. PJL

    PJL War is Peace

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    Actually it is 64mm and 104mm for all non-XTR cranks.
     
  6. tomacropod

    tomacropod Rum Pig

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    ^^ yes, sorry, 64mm. I was getting confused with 74/110. Fucking numbers.

    - Joel
     
  7. goose

    goose New Member

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    I'm pretty sure there's also 4 bolt, 58mm BCD. I remember looking into it a while ago. It is possible to buy a 20T 4 bolt chainring, as I was lookin to go 20/18, but that 4 bolt 20T ring is 58mm BCD, so it won't fit truvativ/raceface/fsa 4bolt. The smallest I've found that you can get for those is 22T:( I bet you have a 58mm BCD 4 bolt ring! Such a pain!
     
  8. tomacropod

    tomacropod Rum Pig

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    never heard of a 58mm 4-bolt. 58/94 is the "compact" 5 bolt standard, now sadly leaving us.

    - Joel
     
  9. goose

    goose New Member

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  10. tawfer

    tawfer New Member

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    On my cranks, there is only 1 set of holes....I'm guessing the 104mm. Sorry I'm new to this stuff, what is LBS? and just out of curiosity what are cogs for?
     
  11. goose

    goose New Member

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    LBS = local bike store

    cogs are the gears on the hub/cassette, on the rear wheel, chainrings are the gears on the cranks.

    hussefelt cranks will have 1 set of threaded holes that accept a 64mm BCD chainring (22T), and one set of through holes that accept a 104mm chainring. You've probably got a bashring on the 104mm holes.
     
  12. tomacropod

    tomacropod Rum Pig

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    I've never heard of a crankset which has only the 104mm holes but given the target market of the hussefelts it wouldn't surprise me if one had come out.

    the smaller set of holes don't go right through the crankarm like the bigger ones, they're only visible (and accessible) from the inside of the crankarm (next to the frame's seattube).

    I read toosicks's posts on t-o.com - I'm sure they exist but I'm equally sure they're never been used on any modern, mass produced mtb crank.

    - Joel
     
  13. tawfer

    tawfer New Member

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    Well, i dunno why the cranks i got happened to be different than all others....but, here they are

    You can see flat ovals where the holes should be....but alas they are not there. Should I just buy a different set of cranks to fit the chainring? I might try to drill the holes out myself in my school's machine shop.
     

    Attached Files:

  14. tomacropod

    tomacropod Rum Pig

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    eureka! Cheap bastards truvativ...

    - Joel
     
  15. goose

    goose New Member

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    That's no good. I bet those are the 'DH single' or 'Singlepeed' hussefelts. That's a shame. I suppose you could find a good trials gearing if you ran, um, 32/28. You'd get excellent chain and drivetrain life:)

    I don't know if you want to drill the holes yourself. It's likely those holes are drilled while the ISIS interface is being machined on a CNC, so their concentric to within the mills tollerances. If you drill them, that prolly won't be true... A good alternative is some FSA v-drive extreme arms, now called Maximus, apparently, for 63 bucks online... as a suggestion.
    http://www.go-ride.com/prod_cranks.html
     
    Last edited: May 22, 2006
  16. tomacropod

    tomacropod Rum Pig

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    check ebay for used cranks. Personally I think that the (somewhat) old 58/94 compact 5 bolt is the best mtb bolt pattern, you can go down to a 20t ring and the bashring isn't too big. Threshold make/made an awesome ring for 94 bcd. Raceface turbine cranks are probably available quite cheaply. eg:

    http://cgi.ebay.com/L-K-RACEFACE-FO...244079316QQcategoryZ56193QQrdZ1QQcmdZViewItem

    http://cgi.ebay.com/SHIMANO-XTR-Cra...244010007QQcategoryZ56193QQrdZ1QQcmdZViewItem

    http://cgi.ebay.com/New-Raceface-Ev...243472250QQcategoryZ56193QQrdZ1QQcmdZViewItem

    http://cgi.ebay.com/Raceface-Turbin...242968116QQcategoryZ56193QQrdZ1QQcmdZViewItem

    too nice for trials:

    http://cgi.ebay.com/Raceface-carbon...242806837QQcategoryZ56193QQrdZ1QQcmdZViewItem

    a piece of bashring history:

    http://cgi.ebay.com/New-bash-Guard-...242855291QQcategoryZ56193QQrdZ1QQcmdZViewItem
     
  17. goose

    goose New Member

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    i agree, compact cranks are great. I wish I could go down to 20T

    g