shaft drive bicycle

Discussion in 'Mountain Bikes' started by vlad, Feb 6, 2005.

  1. vlad

    vlad New Member

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  2. triguy98

    triguy98 New Member

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    Looks interesting. Havent seen one. Never ridden one. My one concern would be the strength of the joints were the shaft meets crank and rear hub. Not having seen the bike, I can't say this is a vaild concern, however, on their website, the people who ar emost likely to enjoy their product are soft riders, not true punders. So if you are hard on your gear, like I am, I'd steer clear. If you put out an incredible amount of power, I'd stay clear.



     
  3. vlad

    vlad New Member

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    have no idea how shaftdrive compares to strength of chain drive bikes. I surmise that a company that wants to stay in business would take care to sell more than adequately strong bikes.

    http://www.dynamicbicycles.com/chainless/technology.php

    excerpt:

    Q: How durable is the shaft drive?
    A. Our shaft drive is made of the highest grade aluminum alloy and steel components, and has been independently tested for strength and durability. It has been tested at over 1000 lbs./in of torque – more than 4 times the pressure exerted by an average rider under normal conditions. The shaft drive is also resilient to impacts, and its sealed design makes it weather resistant for all-season use and better protected from adverse conditions such as sand, dirt, water, salt and grime.
     
  4. triguy98

    triguy98 New Member

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    And drive shafts in trucks are perfectly fine for average drivers under normal conditions. But offroad, they can break. I'm not saying theyre crap bikes, but if you ride hard, I'd stay away. I know my "average" rider friend puts out a LOT less power than I do. Wedge the rear wheel into a a funky crack and crank the pedal hard, you can prolly easily exceed four time "normal" torque input.

    Again, the company themselves said the bikes are for normal riders, not hardcore nuts. If I could talk them into giving me one to test, I wager I could break it. I love breaking stuff :D
     
  5. willtsmith

    willtsmith New Member

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    A shaft must translate a vertical rotation into a horizontal rotation and back. The website touts an "internal gearing system". But the shaft has NOTHING to do with the gears. Those hubs are designed to work with chains.

    The thing that will stop shaft drive bicycles from EVER being commonly accepted is:

    a) The aforementioned extra parts ($$$) to translate vertical->horizontal->vertical.
    b) The inability have gears without expensive internally geared hubs.


    Chains are VERY efficient. And they rarely brake on single speed bikes. Chains only have problems when used in conjunction with derailleurs. That's the cheap and VERY efficient gearing solution. No gears, chains work great, no need for shafts.

    Why do automobiles use shafts instead of chains??? Because an internal combustion engine can generate a LOT more power than human legs. That type of HP will easily snap chains.

    There is ONE shaft drive system that I'm interested in. It is the AWD system used in Christini bikes. A pickup near the rear wheel transfers force via shaft , through the top tube, down the fork and to the front wheel. Chains simply wouldn't work for this application.
     
  6. garage sale GT

    garage sale GT New Member

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    I have decided not to buy a shaft drive bike because of the strength issue.

    If the bike has a six inch crank you can generate 1000 inch pounds just by standing on one pedal, if you weigh more than 166 pounds. So you can exceed the rated torque just by pedaling standing up while cresting a hill even if you are out of shape and never ride a bike.

    If you put spd's on it and power up a hill you can probabaly exceed the maximum rated torque by 3 or four times. If something in that shaft drive fails suddenly while you are struggling up a hill, injury is virtually guaranteed!

    Maybe they did not test the unit to failure; maybe it is a lot stronger than the rated value. I won't risk my health on it.

    On that note, does anyone know of a source for chain cases for commuter/foul weather bikes?
     
  7. garage sale GT

    garage sale GT New Member

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    I was in a bike shop today and there was a muddy, knobby tired, shaft drive bike on the repair stand. I did not take note of the brand but it looked like the ones currently on the web, they all look the same to me...from the same factory in Taiwan perhaps?

    Apparently, someone in or around Naperville, IL is trying one out. I just wonder what they weigh.

    The website for one of the companies said their machine was tested to 1000 in*lb of torque, which is very little as I pointed out; however, maybe the company that runs the particular site I saw just doesn't want to stick their neck out.
     
  8. vlad

    vlad New Member

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    thanks for your post.

    I am curious as to the opinion of the owner of the shaft drive bike.
     
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