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  1. #1
    a litte bit fixed mintyai's Avatar
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    Hollow tech II cranks

    Does anyone out there use hollow tech on the track?

    Why do Shimano have the hollow tech for the roadies, but still only do octalink and square taper for the track?

    Is there a problem with the non-drive side connection of hollow tech, or is it because track riders don't like change? Or could it be something to do with chainline issues and external BB bearings? (I am rocking an ENO which is 46mm - so the other ring of a hollow tech double would be in the right place).
    24" - 520mm wheeled folding fixed :: http://www.minty-ai.net/bike

  2. #2
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    NJS certification is probably part of it.
    The small number of track cranksets sold and the cost of designing a 2 piece one is probably another.
    Chainline issues are fixable you just angle the spider in more. q-factor problems would be harder which is why a megatorque seems easier than a HTII.

  3. #3
    Senior Member Plantmiester's Avatar
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    I doubt Campagnolo has any problems with NJS certification, seeing as NJS won't certify their stuff anyways because they're too busy protecting their national economy (I don't actually have a problem with that). I see the biggest reason being the marginal Q-Factor, which on the track you want to be down to an absolute minimum.
    Velocipede, my blog about biking and bikes.

  4. #4
    manwench
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    I run a set on my track bike, but they get removed for track riding. Only reason is I've been too lazy too adjust the dish on the rear for the wider spacing. Overall I have nothing but good things to say about them(165mm length!) two piece makes clean-up REALLY easy. You can get correct chainline with these if you move the spacers on the rear axle to the left side and re-dish the wheel. Almost forgot, the reason Shimano will/can't make external bearing cranks is NJS and they aren't in the business of making non-NJS track parts. Cartridge bearings are not allowed and new technologies must first be phased in that is to say reasonable time is given for all ranks to test/buy/acquire new items. With all the recent changes who knows we might see them in a few years....


    SAm
    Last edited by seitenryu; 01-03-08 at 03:57 AM.

  5. #5
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    Quote Originally Posted by seitenryu View Post
    Almost forgot, the reason Shimano will/can't make external bearing cranks is NJS and they aren't in the business of making non-NJS track parts. Cartridge bearings are not allowed and new technologies must first be phased in that is to say reasonable time is given for all ranks to test/buy/acquire new items. With all the recent changes who knows we might see them in a few years....

    SAm
    The dura ace NJS track BB has cartridge bearings.

    http://www.businesscycles.com/tbb-shim.htm

    I think the real reason is for NJS certification the cranks and BB needs to be 3 piece, hollowtech is 2 piece.

  6. #6
    manwench
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    Yeah...the needle bearing one came to mind first. Only reason I can think they have allowed it is Shimano has a lot of power/influence over those kind of decisions. Besides PowerCranks or SRM cranks theres not many cranks nearly as stiff as the Dura-Ace 7710. Those and 7600s seem to be the favorite cranks for keirin riders.

  7. #7
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    I should point out that most keirin riders are still using the square taper dura-ace cranks, which are still in production in Japan. The Octalink versions are the favorites of the international level guys because of stiffness. I have heard of two recent studies of cranks that yielded some interesting info. First off I heard it through the industry grapevine that when Sram was doing their testing of cranks when developing Red the dura-ace track crank was used as the benchmark for stiffness (which could be true as it never seems to show up in any published test by any company or magazine). The other study supposedly came from Shimano or the Australian national team and found that external bearing cranks just create to much rolling resistance in track applications. Look at it this way... if the top national federations like AIS and British Cycling pump millions into their track programs and yet still choose conventional internal bearing crank systems they must have a good reason. It's not like they could not just use 130bcd track rings on an existing outboard bearing crank system or simply develop their own crank like Walser did.

  8. #8
    Not-so-Senior Member
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    HT2 cranks spin a lot stiffer than square or octalink/ISIS ones do. I've even had customers in my shop ask if their crank is fitted properly because it's so stiff (like only spinning twice round after a hard push with no chain on them). However, 99% of road racers and probably most MTB racers use them, and track bikes are all about stiffness right?

  9. #9
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    Are octalink BBs NJS? I thought only square taper could be NJS.

  10. #10
    A little North of Hell
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    Quote Originally Posted by Yoshi View Post
    Are octalink BBs NJS? I thought only square taper could be NJS.

    http://www.businesscycles.com/tbb-shim.htm
    [SIGPIC][/SIGPIC]
    XXXI

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