MnHPVA Meeting
July 10th 2002
Meeting Report: Dave Polaschek & Mark Stonich
Photos: Mark Stonich and Denis Diekoff
Click thumbnails to read details and see more and/or larger images.
Coming Events
HPRa Races in Chicago and Kenosha this weekend - Dave & Tim going, they think. Pictures later.

Midwest Recumbent Rally in Stevens Point WI is the first weekend of August. Only an extra 58 miles to swing by Stevens Point if you're going to World Championships.

World Human Powered Vehicle Championships August 5-11 Brantford Ontario, an hour or two past Detroit. Tim Dunsworth will attend and photograph the machines and events for a slide show this fall.

Aug. 16th - 18th HPV racing in Sparta WI, including HP boats and Ice Racing on an indoor hockey rink Cancelled

Because he expected Carl's drive discussion to take up most of the meeting, Mark had discouraged people bringing much for show-n-tell.

Fortunately, new guy Hugh Johnson rode to the meeting on his Rans Rocket, with custom, under-seat mounted, pannier racks.

Streamlined Shell Project
Tech Talk; Unconventional Pedalling Systems

Carl Gulbronson asked to use this meeting for a discussion of unconventional drivetrains. Linear, elliptical and arc segment pedal paths, plus varied crank lengths and non-round chainrings. Carl has an exercise machine that has conventional pedals and has shallow, near-linear, arcs for your arms. (Sounds like it would be confusing, but feels natural to use. Mark) He's looking at going after the 1/4mile drag race record, and wants to investigate using as many muscles as possible.

Unfortunately, Carl couldn't make the meeting and the only other Linear drive advocate, Mike Wheeler, didn't have anything ready do show.

Jon Sharratt and Mark Stonich brought books on, and illustrations of, antique bikes, showing that such drive systems have all been done before, but keep getting "reinvented".

Jon brought a lever drive system from the 1980s, including a dual freewheel hub. Mark showed pictures of a similar, but more sophisticated system on a Levocyclette from 1905. The 1905 bike had 10 speeds, but the '80s system had only 4.

Tim Dunsworth showed a mock up of the KingCycle K-Drive . Lots of extra mechanical resistance, but an elliptical pedal path that allows a smaller fairing. Tim also showed slides of unconventional drives which he had taken at HPV World Championship events over the past several years.

  1. Linear drives using cables and one-way clutches
  2. Reciprocating arm drives of several kinds
  3. Elliptical path drives using long slider arms off a regular crank
  4. K-drive style elliptical drives using chains or gears.

Lately there has been much experimentation with Shorter cranks on recumbents. Some feel they are more efficient, others are finding "shorties" to be kinder to the knees. (I'm currently riding bents with 175, 170, 160 and 153mm cranks. If my knees hurt, I know I'm using the longer cranks. Mark)

Most people are trying 145-160mm for 'bents, although some Germans are trying 110s. Standard length for uprights is 165mm to 175mm. Short cranks on uprights only work for short people, or those who never stand up (Sheldon Brown). Packaging advantages on 'bents, especially with fairings. Shorter crank means moving seat back, and your knees stay out of your line of sight. Lots of trikers have gone short.

People assumed 10% shorter cranks would mean 10% faster spinning and 10% lower gears. But some of them, including Mark Stonich, find that you don't need to actually gear that much lower, as your legs can put out more force because they are straighter and have better leverage. Mark also thinks he can spin more than 10% faster. So between these two factors he finds that he shifts less often. Paradoxically, this seems to mean that short cranks allow wider spacing between gears, combined with not needing quite as wide an overall range. This is good for Mark as, to save weight, his new bike will only have two chainrings.

Crank Shortening
Sibley Bike Depot
Andrew Koebrick President of the MN Bicycle and Pedestrian Alliance, ( formerly YellowBike) give us a talk about their group. They've got a lot of "stuff" (90 auto-bikes, 600 tires, etc.) at Sibley Bike Depot, plus a couple warehouses of other bits. Would be interested in supplying us with parts, stock, and perhaps working space, some frre the rest at bargain prices. "We'll give away frame stock, even good stuff. Just please come get it." Not only do they get clunkers, they get overstock from bike industry, so they'll have brand new old-model stuff, some even still in boxes! Check them out at .

Click here to read a posting Andrew sent us with more info, including their new, and much expanded hours.

Andy Singer, Ken Avidar (local bike cartoonists) have an art exhibit up right now for the Art Crawl, so that's another reason to stop by soon.

Art Cars Parade on 4th of July was pretty interesting. Do we want an MNHPVA presence next year? (Art Bikes?)

Is the group interested in the State Fair Parade? We need to apply soon if we want to be in it.

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