rec.sport.unicycling · Public discussion

Changeable crank length

Started by brian.slater · · Last activity · 9 posts · 443 views

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rec.sport.unicycling
Published
6 October 2004
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7 October 2004
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brian.slater
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  1. I've just found this 'Crank Arm Shortener'
    (http://www.ride2online.com/figurea.htm#top) and thought it might be of
    interest here. I've not tried it but saw one in the LBS. Price:
    $100USD is the best I saw on-line and in the LBS.

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    brian.slater - Nellfurtiti, the Wonder Cat

    Brian C. Slater
    AKA: Snoopy

    Ok, I am now officially in my normal state of -advanced- confusion.
    Don't try to confuse me, it won't make any difference.

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  2. it's available in the Quality Bike Parts catalog, so just about any LBS
    can order it. they will, however, increase the "Q" factor of your
    cranks.

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    unisk8r - All this for just cross-training?
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  3. Took me a while to figure out how they worked from the dimensions page;
    the assemlby page made it a bit clearer-

    http://www.ride2online.com/assembly.htm#top

    Interesting that they're designed for a different function:-

    "TANDEMS - Crankarm Shorteners are a device that allows an elementary
    age child or short adult to ride on the back seat (the stoker's seat) of
    a tandem bicycle. The Crankarm Shorteners reduce the length between the
    stoker's seat and the pedals. Briefly, the pedal is removed from the
    crankarm, the Crankarm Shorteners installed and the pedals are then
    reinstalled on the Crankarm Shortener."

    ie the adjustment is so those with short legs can use the bike, rather
    than the leverage change that unicyclists would want them for; but, the
    result is the same.

    --
    onewheeldave - Semi Skilled Unicyclist

    "He's also been known to indulge in a spot of flame juggling - but it's
    the Muni that really fires him up."

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  4. brian.slater said:

    *Price: $100USD is the best I saw on-line and in the LBS. *

    That's quite a profit margin... from the designs it looks to be about
    $12 in aluminum stock and 2 or 3 $1 bolts per crank.

    For that much money you're better off buying two sets of cranks and
    swapping 'em out with one bolt each.

    This design might not stand up to the strains induced by trials
    riding... I'm curious, why are you interested in these?

    --
    maestro8 - Mad Scientists for World Domination
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  5. maestro8 said:

    *

    That's quite a profit margin... from the designs it looks to be about
    $12 in aluminum stock and 2 or 3 $1 bolts per crank.

    For that much money you're better off buying two sets of cranks and
    swapping 'em out with one bolt each.

    This design might not stand up to the strains induced by trials
    riding... I'm curious, why are you interested in these? *

    If that's the case, why don't all cranks cost less? Normal cranks use
    even less material.

    Anyway, I don't think anyone would use these for trials. To start with,
    they must be heavier because of the added material used to make it
    adjustable. I have always thought that road use is where adjustable
    cranks are the most useful.

    It took me a while to understand how these cranks work. Now that I
    think I have a grasp on that, I wonder how well they work.

    Daniel

    --
    daino149 - On Vacation - till i find a job

    Check out my pics: www.unicyclist.com/gallery/daino Updated: 04.07.03
    Kaena
    Bugman - "if you are a little left of them, it would seem like they are
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  6. If i remember rightly, Nathan Hoover has adjustable cranks...might be
    worth talking to him about them?

    --
    unicyclistjoe - NZ's 2nd Best Trials Unicyclist

    Well a MOPED or whatever you call it...yeah good one security

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  7. daino149 said:

    *

    If that's the case, why don't all cranks cost less? Normal cranks use
    even less material.

    *

    I bought some 7075-T6 to make some beefy MUni cranks, the same material
    used in the Odyssey Black Widows and Kooka Kranks. The cost for six
    cranks came out to less than $10 per crank.

    In higher quantities, the price breaks might bring the cost down to $6
    or $7 each, unless the manufacturer has the stock cut up at the
    supplier, add (worst case) $1 each there.

    The rest of the cost goes to paying the machinist, renting / leasing the
    CNC machine and covering other overhead. Machinists charge a hefty
    hourly wage, and CNC machines aren't something you can just buy off
    eBay...

    I'd say if people bought cranks like they bought soda pop, we'd see the
    prices on these things plummet. But until then we should just gloat
    that we're (collectively) pushing the edge of cycle sports... we're
    breaking everything the industry is making, so we've gotta pay for them
    to develop better products!

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  8. unicyclistjoe said:

    *If i remember rightly, Nathan Hoover has adjustable cranks...might be
    worth talking to him about them? *

    Yes, he does. However, they cost something like US$500. Bronson Silva
    also has cool adjustable length cranks on his titanium suspension Coker.

    --
    TonyMelton - Skinny butt

    Three new albums added to 'my photo gallery'
    (http://gallery.unicyclist.com/albur10). Check it!
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  9. There is a past thread on some adjustable crank ideas: 'Adjustable crank
    idea' (http://tinyurl.com/2plgy) I like the eccentric crank that Steve
    Howard drew up in his CAD system. It just seems like a neat design.
    It's similar in design to the cranks that Bronson Silva has on his
    Creative Gecko bionic Coker.

    Here's a link to Steve Howard's gallery of two adjustable crank designs
    he drew up: 'Adjustable cranks gallery'
    (http://gallery.unicyclist.com/cranks)

    --
    john_childs - Guinness Mojo

    john_childs (at) hotmail (dot) com
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