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Thread: Derny updating?

  1. #1
    coprolite fietsbob's Avatar
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    Derny updating?

    was looking at the article on Motorpacing, in the current issue of Paved magazine,
    and folks kept up those old bikes with 2 stroke motors, and a moped like pedal scheme.

    had me wondering.. Aprilia did some Fuel cell prototypes, but dont think it went far..
    or in an appropriate direction.

    http://www.google.com/imgres?imgurl=...%3Disch&itbs=1
    given the nature of Keirin Racing on Indoor tracks, a hydrogen fuel cell motor would be so much better.
    because the exhaust is nontoxic.. it's water.. AFAIK burning hydrogen is oxidizing it..

    the niche to fill is a fast enough easily controllable, pace increase.. quiet running machine to lead out racers
    and not having a hydrocarbon exhaust in an indoor Velodrome , just so much better
    Last edited by fietsbob; 12-12-12 at 10:58 PM.

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    Senior Member taras0000's Avatar
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    You can already find very capable electic mopeds to fit the bill. You could make one out of a scrap motorcycle that will do 50mph.
    Taras - :noun. 1. Typically an overweight has-been that can sometimes be seen pootling around a velodrome on an old Look KG 233.

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    coprolite fietsbob's Avatar
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    As a motor-pace rig, the big motor ones, the modification was rider standing Up so as to make the largest possible wind block..

    Dernys were smaller machines..

    the 2 types , some pictures here: http://www.clubbz.com/clubs/galleries/?c=21740

    More An FYI, I got no reason to do any building since there are no Keirin or other paced races to support where I live,
    or can afford to travel to..

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    Senior Member bitingduck's Avatar
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    There was one of these at Home Depot Center for a while:
    keirin PAS. Roger probably still has it but I haven't seen it in a while.
    Track - the other off-road
    http://www.lavelodrome.org

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    Senior Member bitingduck's Avatar
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    There are a bunch of variations of the scooter used in this video around at HDC: electric scooter
    Track - the other off-road
    http://www.lavelodrome.org

  6. #6
    Senior Member bitingduck's Avatar
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    There's also at least one mtb with a hub motor something like this: ebike conversion It's set up to be able to go fast enough for keirin pacing (some of them are speed limited)
    Track - the other off-road
    http://www.lavelodrome.org

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    coprolite fietsbob's Avatar
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    http://en.wikipedia.org/wiki/Derny
    the wheel guards on the rear of the French Originals were there to reduce overlapped wheel crashes, I presume.

    the roller on the back of the high power motors are a couple feet back of the pace bike..

    pacers stand straight up..

    the pacers job is to slowly increase the speed, slowly enough that the pull is not broken by a surge too quickly..

    E Moto's in the LBS, riding any of the pedal-elect's once the motor kicks in they jump up in speed rather quickly..
    Last edited by fietsbob; 12-12-12 at 05:41 PM.

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    Senior Member bitingduck's Avatar
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    Quote Originally Posted by fietsbob View Post
    pacers stand straight up..
    That's just for "Steher's" races (hence the name) -- for a lot applications the driver is seated (and in some of them pedals and in others doesn't): https://www.youtube.com/watch?v=CN9wNTgwTR8. I think in most that I've watched, the guy with the fattest driver wins. If you read the UCI rules, there are even rules for the size of the jacket that the drivers can wear (to prevent them from increasing the draft too much).

    I've paced behind all the bikes I linked to above, and they're pretty easy to stay on as they accelerate. The scooter can get some decent acceleration, but isn't too hard to keep at a reasonable rate so riders can stay on it. The bigger issue with drivers is having a very steady hand on the throttle-- only a few of them are good at keeping the speed very smooth all the way around the track.

    There's also an electric crotch-rocket at home depot center that can go up to 50+ mph. That one can pull away pretty easily.

    None of them have a roller, and I think at least one doesn't have a wheel guard, but I don't know of any crashes from wheel contact with the pace bike in the last ~6+ years. The motorbike at encino has a roller, but I don't think I've banged it more than a few times. I've been behind riders who were hitting it for fun.
    Track - the other off-road
    http://www.lavelodrome.org

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    **sigh** When I logged onto this thread I was thinking this was the sort of update we were looking for.

    scooter_girls_178.jpg

  10. #10
    coprolite fietsbob's Avatar
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    There's also an electric crotch-rocket at home depot center that can go up to 50+ mph. That one can pull away pretty easily.
    dont want to drop the guy off your wheel you are pulling, then you are not doing your job..

    it's how slowly and evenly, can you increase the pace?

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