Crank query

Discussion in 'Cycling Equipment' started by jaybeex2, Apr 21, 2012.

  1. jaybeex2

    jaybeex2 New Member

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    Ive been given an old Raleigh Criterium 12 racer to restore, its totally in bits, the question i have is (and it maybe a daft one), one side of the crank is longer then the other, is this the chain side, or the other side?

    Cheers
    John
     
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  2. alienator

    alienator Well-Known Member

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    For the vast majority of the people, both crank arms are the same length. There are a very small number of riders who have used crank arms with different lengths to account for one leg being shorter than the other. Which side has the shorter crank arm depends on the rider who had it before. You should be using crank arms of equal length, unless you have a serious leg length discrepancy.
     
  3. CAMPYBOB

    CAMPYBOB Well-Known Member

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    one side of the crank is longer then the other, is this the chain side, or the other side?

    Do you mean the crank spindle/axle? If so, the longer side is the drive/chain side (right side of the bike).
     
  4. jaybeex2

    jaybeex2 New Member

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    Thanks Campybob thats as i thought thanks for the confirmation

    John
     
  5. CAMPYBOB

    CAMPYBOB Well-Known Member

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    You are welcome! Good luck rebuilding that classic old Raleigh.

    I have an 1975 International MK II in the stable. They were nice-riding frames.
     
  6. alfeng

    alfeng Well-Known Member

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    That would seem to be logical, but I believe that it's not accurate.

    AFAIK, both JSI & ISO cranks which have asymmetric tapers have the LONGER side on the non-driveside.

    BUT, it's really not a serious issue with either a non-cartridge or cartridge bearing BB other than the inconvenience of removal & reinstallation when you find that the offset of the crankarms are not offset the same from the bike's centerline.
     
  7. CAMPYBOB

    CAMPYBOB Well-Known Member

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    http://sheldonbrown.com/bbsize.html

    Alf, see Sheldon's chart(s).

    I could be wrong...it's been known to happen before! /img/vbsmilies/smilies/biggrin.gif

    JIS models show right side/drive side as longer.

    Japanese Bottom Bracket Spindles, Traditional Cup And Cone Type [​IMG]

    Size
    Code Shell
    Width D Length
    Overall A Length
    Left End B Length
    Middle C Length
    Right End Symmetrical
    Equivalent 3H 68 113 30.5 52 30.5 113 3K 68 117.5 32 52 33.5 119 3P 68 119 32 52 35 122 3N 68 120 32 52 36 124 3S 68 121.5 32 52 37.5 127 3T 68 123 32 52 39 130 3NN 68 124 36 52 36 124 3U 68 124.5 32 52 40.5 133 3TR 68 133 42 52 39 130 3RR 68 136 42 52 42 136 5N 70 122 32 55 35 125

    It's been a few years since I installed a Square taper spindle, but I do remember that if you got it in backwards, the chainrings would be drawn tight up against the chainstay! /img/vbsmilies/smilies/mad.gif

    Some are probably longer on the left side to account for the adjustable cup protrusion...guessing. The obvious answer is just to see how deep the adjustable cup threads in and to check the chainline.

    Ultra Torque has made me braindead!

    Kind regards,
    CampyBob
     
  8. alfeng

    alfeng Well-Known Member

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    The apparent inconsistency in square taper spindles is ONE reason that I heartily embraced the Shimano Octalink BB shortly after it was introduced!
     
  9. alfeng

    alfeng Well-Known Member

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    BTW. It's not that I want to suggest that your experience was anomalous, but when Sheldon Brown stated 'Substituting the 'symmetrical equivalent' bottom bracket will preserve the position of the right crank and chainwheels, but the left side will often wind up farther out." it seems to reeforce MY belief that Sheldon Brown wasn't always correct ...

    Because, it is hard to believe that Brown was more concerned with the offset of the chainrings relative to the center line of the bike rather than having the crank arms centered by using an appropriately wide BB spacer driveside IF he truly believes that the non-driveside of the spindle is shorter.

    BUT, alas, with the asymmetric Shimano cartridge, square taper BBs which 'I' have it seems as though the long side was the non-driveside ...

    [*] ... three of my square taper Campagnolo cranks (a C-Record, a Thron, and a Mirage) have the long side of the offset on the non-driveside, too.

    And, installng one of the asymmetrical Shimano crankarms which I have on a symmetrical spindle will result in the non-driveside arm being closer to the bike's center line AND shimming a symmetrical cartridge will only result in the non-driveside being even closer to the center line.

    [*]BTW. I do know that at least one of Shimano's (?) cartridge BB installed from the non-driveside. I pulled one from a 90s vintage Trek that I have ... its non-driveside was longer than the driveside, too.

    FWIW. The problem which you may have encountered could have been a consequence of using too short a BB spindle for the specific crankset -- there seemed to be lack of consistency in the depth of the receiving taper (as evidenced by the numerous spindle lengths which Brown tabulated) ... and, THAT could have resulted in the chainrings being too close to the chainstay.

    Maybe, maybe not!?!

    Regardless, gotta love the belated symmetry which Campagnolo brought to their Record/Chorus cranks & their 102mm spindles + the fore mentioned, symmetrical Shimano Octalink BBs.
     
  10. 531Aussie

    531Aussie Well-Known Member

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    Ah yeah, those were the days: stuffing around with tapered axles..,..trying to 'guess' which length ya needed. And every time ya took ya cranks off and on, they'd go on the spindle further, so the FD had to be re-adjusted. Well, it did with me, coz I am (or I was) a Newton Head. Even worse, when I was flat broke a long time ago, I used to buy used Shimano BBs for my Chorus cranks, because the Shimano stuff was much cheaper and easier to get. From what I've been told, Campag had a slightly different taper to Shimano, so, each time I rammed the Chorus cranks on a Shimano axle, the cranks would 'stretch'. One day, i put the old cranks on a Campag axle, and they just about flopped around. Also (jee, this is turning into a bit of a ramble :) ), the Campag auto extract bolt set-up on some of their cranks, coupled with me putting them on a Shimano axle (with it's larger and/or sharper-angle taper) meant that the cranks would sometimes come loose!! :) So i would sometimes ride with a 7mm alen key (and they ain't exactly the easiest size to get), so I could keep checking the cranks.

    And don't get me started on non-cartridge BBs. Arrrgh! What a pain they were!!! Someone will probably come on here and say that a properly-adjusted and perfectly-lubed Record or Dura-Ace loose-ball, cup and lockring BB was a thing of beauty, whose smooooothness hasn't been anywhere equaled with modern BBs -- well, you can have them. Ha :)

    Kids today! Sheesh! They dunno how good they've got it. :) ...and they all probably get their bike work done at a fancy shop.
    'Back in my day', my dad used to make me 'learn' by doing my own repairs. Try telling a 13-year-old kid that he can use vulcanized tube patches "easily". :) HA! That's all gold from me.
     
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