Something to kick it off : offroad rollerski's that ROLL

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Cloxxki
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Something to kick it off : offroad rollerski's that ROLL

Postby Cloxxki » Fri Dec 01, 2006 3:53 pm

I bugged the Newgroup with this before.

I've been working on some designs for off-road rollerskis.

I find that even the 2x250mm tires on my Crosskates roll like crap on anything less than pavement. Front wheels get hung up in the slightest pothole, and from self-propelling you're left balancing to prevent head-first crashing.

Siriro offers a road-ski with 4 wheels, paired on rockers.
http://www.siriro-shop.de/assets/big/DQbeweglich_big.jpg

I though to steal that idea (it an't be patented, a very popular setup in autotive and industrial), and combine it with the wheels that are now regarded "off-road" :150mm or 6x1-1/4". Cheap and available, though very overbuilt thus slow rolling.

The rockers reduce the effect of a trail obstacle greatly. A 1cm twig will lift each and of the ski frame (rocket pivot) by only half that. Much less weight is transferred to the front wheel, as it just rolls over, stride or skate should be unaffected.
Furthermore, for the same reasons that speed inline skates prefer 5 wheels over 4, 4 rollerski wheels will roll faster than 2, but quite a bit.
On soft soil, the first wheel will probably indent the terrain a bit, making it easier for the next wheels to follow. It could roll pretty well, all in all.

My aim is to reach similar speeds offroad as ont he same trails with snow. How about off-road summer biathlons? Training in the forrest over fire roads rather than on the road shoulder? Same trail systems as in winter time!

I'm looking for someone who'll work with me on a first prototype. It's a simple design, technologically hardly different from the dozenes of 2-wheelers out there. Who can do this? I can come up with designs and some sizes, but can't draw or work metal.

Image
Image

Even a 3-way rocker system is possibly (unclear pic). Each 1cm twig only raises the frame by 1/3cm, each wheel bears 1/6th of the rider's weight.
Good for weight balance to put on the front.
Image

To get speeds really up there, eventually ligher and thinner tires will be needed. The 150mm tires now on the market are much like tractor tires, hard to tell whether they're pressurized of flat, so rigid. With the weight spread of multi-wheel designs, thinner casings and tread will suffice.
To add lateral stability, a flat tire contact patch might be preferable. Also faster rolling on soft soil. Beace bikers also use wide and flat profiled tires for maximum float, at low pressure.

For heel clearance, the rear wheels may be pushed to the side. most rear one on the outside. Rockers would have a centering spring to ensure preferred landing sequence.

Shoot at my ideas, and help me find someone who can make this!

Suppose this would become a product that was fully evolved, with good high-performance bike-bike tires, light frame, smart dimensions....would you buy it?

Happy skating,

J

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Alpinord
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Postby Alpinord » Tue Apr 10, 2007 9:54 am

Some related links:

http://www.xcskiworld.com/training/rollerguide.htm

http://www.skiroll.it/test/rolski-off-r ... ad-eng.htm

http://www.xcskiworld.com/training/roll ... memade.pdf

From http://rollerskishop.com/faq.php
FAQ: Can I use Pursuits on gravel roads?
No. 100 mm wheels are not made for soft surfaces.


FWIW, I'm a 3d CAD designer and can bang out some drawings when I have time. Sounds like an interesting project. I'm very interested in an offroad option.
Best regards, Terry, SlideWright
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