Saturday, December 27, 2008

UPDATE:

We had snow in Seattle, and that's a rare thing. What's more, we had snow for days and days, in sufficient quantities to get out and do some XC skiing. As a result, I had a chance to test out the pulk. One of the pulling designs didn't work, but the other worked fabulously. Here are the summary results.

First off, we probably skied a total of 10 - 15 miles in all sorts of conditions over the 4 days that we had it out and about in Seattle. We had dry, powdery snow; wet, heavy snow; an icy top of freezing rain over powder, and basic ice/slush. In all conditions, the pulk did well. I was able to pull it through the wet slushy stuff, through the icy top layer, up hills, down hills, etc.

  1. Pulling systems - Design 2, using the Burley's bike-towing arm, didn't work. It was fine for pulling on flat or uphill, but as soon as we went downhill a bit, the weight of the trailer pushing downhill towards the skier caused the joint in the pulling arm to bend and drag on the ground. So we scrapped that design, and just used Design 1, which worked like a champ.

  2. Skis - for the skis that I attached to the trailer, I used some old XC skis I found at Goodwill. These skis had fish-scales on the bottom for traction, which I thought would be helpful, but in reality these scales were too helpful as I couldn't push the trailer backwards. Occasionally, if you need to turn around on a trail or back up, it's nice to push the pulk backwards. With the fish scales on the bottom of the trailer, this was impossible, as the combination of the scales plus the weight of the trailer and 2 kids caused the scales to hold fast to the snow. If I do a revision of this pulk, I'll look for some old used downhill skis or XC skis with no scales...

  3. Harness - the harness worked well. If you notice how the carabiners are attached to the harness, you'll see that the carabiners attach to two parts on the harness: 1) some vertical straps that are part of the waist belt, and 2) the horizontal strap that I added to the waist belt. This system seemed to hold up pretty well, even when pulling two kids up inclines. That said, I think this is probably one of the weaker parts of the design, and I'd like to find a better attachment system in the future. I think the thing to do is to attach the poles to the waist harness's horizontal strap using some grommets and a lock nut. More on this later...

  4. Ski attachment system - on our fist time out, we had gone about 200 yards when I looked back and saw that the ski-and-block setup that I had attached to the wheels of the Burley with hose clamps had slipped laterally (picture the ski-and-block system splayed outwards from the wheels) and was dragging on the ground. When I inspected the setup, I saw that the hose clamps were actually not that tight, even though I thought I had tightened them well back in the shop. In fact, what happened was that the tires on the Burley had deflated slightly, since we went from the warm air of the shop to the very cold air of a snowy day outside. And since the tires deflated slightly, and the hose clamps use the pressure of the air in the tires to hold the block-and-ski attachment, the whole attachment came loose. I brought a screwdriver with me, and I used it to tighten up the hose clamps some more. After that initial adjustment, we didn't have any other issues with the ski system.

3 comments:

Warren du Plooy said...

Wow. Great work. Any updates other than the last ones published? I'm going to start building this as soon ASAP. Snow is on its way!

Unknown said...

HI Foliage-

I enjoyed your story. If I ever get to the point of redoing my site to include a section with contributors posting their stories- I would like to include yours. Thanks Ed Bouffard

skipulk@yahoo.com

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