PULK Sled

I love gearing up! And, this year I have a new addition---a one-year-old son. Anyway, I've fashioned together a prototype for a child's Pulk sled and was looking for some input from others who have pulled/built one for themselves. This one is built primarily for the tracks, but I do plan on going off track over easy/moderate terrain---we have to get a little nuts---but nothing remotely dangerous. Anyway, What do you feel is the most important aspects of a Pulk, other than safey, and how might I achieve this? (let's call this a brainstorm, so don't hold back!) Also, do you see any serious design flaws in this sled that I may have overlooked? We'll ski with him mainly in the Snoqualmie area, but the Methow is also a destination this year---if it makes any difference. Oh, and the kid weighs about 26 pounds (the sled weight is about 11 pounds, as-is). Thanks for your input! dave Oh...click on the following link to view. www.ofoto.com/PhotoView.jsp?Uc=8bmb9ci.1...&photoid=76383007506

I have a sled in the works that shares many similarities to your design:<br><br>1. Similar starting kids toboggan (I used the "Beast" model which doesn't have the molded handles but seemed to have thicker plastic.)<br>2. Same basic idea of sawed off Goodwill nordics on wooden posts to provide tracking.<br>3. Rigid, sectional traces connected to salvaged framepack hipbelt.<br><br>Let me tell you some of my trials and tribulations with this setup last year. If I were an engineer, I might term them 'project setbacks', or, more optimistically, 'design inputs'.<br><br>My first idea with the traces was that I was going to use PVC conduit, with the idea of putting some deliberate 'give' into the system that would help flex out some of the stop-n-go jerk that inevitably happens when you try to diagonal-stride while pulling something heavy. Also, I thought it would be good to provide 3 degrees of freedom at the sled-trace attachment to make it easier to get around corders. These ideas actually worked really well for something that is perfectly flat, like the Keechelus / John Wayne trail. But, as soon as even small hills were introduced, like on even the green Methow trails, this system no longer worked. The sled will race you, and when it does, those degrees of freedom both in connection and in flex of the traces become dangerous because the sled is able to get out of line and in fact can get completely around you or at least try. No good!<br><br>I can't tell what you've done exactly with the sled-trace attachment from the pix. But what I am going to do this year is copy the design of the KinderShuttle, which I rented last year and used in Methow with moderate success. Its attachment has the traces fit into a rigid U shaped piece. The U shaped piece is then clamped onto the top front of the sled (and probably stays there for transport). Plus all these parts are metal: steel or aluminum. Result is that you have only the single degree of freedom up-down. Sled can't get around you. And this isn't as constraining as you might expect. It's actually easier to get good control when maneuvering this once you get used to it. It's jerkier, but getting a safe system is more important.<br><br>What the KinderShuttle didn't have is runners; it was just a flat drag box and I didn't like that (did have slight raise in plastic that helped it track, but to me it seemed like the main way that it tracked was by inducing enormous drag). Granted this was in soft conditions, but on a day where you're willing to cart a one year old around in the winter air soft conditions might be pretty common. I think that runners are a good idea. They mark up the snow a lot less. And if you do it right, you can set these runners at track width. However, that's not as straightforward as you might think. For one thing, track width (space between tracks) is not a universal standard; different groomers seem to vary by a couple inches or so either way. Also, there is track depth to consider. To be a good xc citizen, and in order to make the runners worthwhile, the posts need to be just a little higher than that depth of the track. This too can vary. Unfortunately the combination of the height and width constraints when trying to set the runners for a track makes the sled more tippy than I'd like. My 4 year old likes to lean and fidget and she tipped herself over more than a few times. I have yet to solve this problem. I might put some kind of wacky outrigger ski on, at an angle to arrest the tip.<br><br>The best answer to this last problem might be to just set them wide and don't even go in the track and just stay in the skate lane like you'd have to with most of the other commercial kid pulks anyways. (Yours look like they might be that wide.) But I like the efficiency of being able to diagonal in the track and won't give up on the idea of making a track-capable pulk without a few more iterations of design such as trying to lower just a bit, or deliberately splaying the ski runners outward just a tiny bit.<br><br>I like your cover design. That's another project for this season and I am not sure yet how I'm going to do it. Probably arced PVC sections with a few forced bends, and stormwindow grade sheet plastic with vent holes punched, but I'm not sure if I have a good idea for how to get a zipper into the design or how to connect the 3 plastic pieces if I go with a sidewalls-plus-topsheet construction like most of the commercial sleds have.

Ahhh...the traces were the most challenging part of this project. What I did to combat the play between the sled loops and the traces was to attach bungees between the sled and the first trace section (closest to the sled). This does two things (i believe, becuse I haven't actually tried it) 1: reduces the play upon takeoff and inbetween (uphill) strides; 2: cushions what play there is so it's not so jerky. I tried several methods of crossing the bungees and found that a double twist works okay...but a twist is necessary. <br><br>However, I have come up with a new trace design altogether using 1-inch pvc, bolts (washers and nuts), and a propane torch...the sled loops are eliminated (and I like the idea of traces sliding into some sort of bracket system) I want to actually bolt the traces onto the hip belt (mine is also salvaged from an old frame pack) This would give it vertical movement and practically eliminate the horizontal movement at the hip belt. <br><br>The conduit frame surrounding the front 3/5's of the sled has helped to increase the torsinal rigidity of the sled(and it braces the cargo hold so not all of the weight is on the sled floor)...the sled will probably tip before it could ever catch up to the skier...I don't know if that is good or bad? <br><br>do you have pics, wolfs? I can only imagine your sled...and my imagination can get out of control sometimes.<br><br>Now, about that cargo hold and cover:In the front the hold is screwed into the skis through the sled. In the back it is being lifted ever so slightly above the sled floor by being bracketed to that conduit cross beam. Inside I have the blue matress pad foam (2 layers) and a hip belt to secure the kid. The inside cover is a Kelty kid cover for a kid backpack and it serves as the poles to lift the outside (plastic cover) which is an original Baby Jogger cover...at least that is what I've been using it for..It has the Jeep logo on it and it came with a jeep logo diaper bag, believe it or not. It has served us well for a year now.

I have used my pulk for two kids now. <br><br>I did not use ski runners, maybe some sacrifice there in drag, but the plastic seemed to slide just fine. Probably the biggest challenge in soft snow is tipping and thin ski runners might accentuate that problem. The skis reduce the effective width of the sled making it potentially more tippy. Unless the weight in the sled is very well placed and centered, the narrow skis will want to sink on either one side or the other. And with a kid, the weight will never be centered. As soon as they fall asleep, and they always do, the head will fall one way or the other!<br><br>The weight of the payload, therefore the seat, should be as low as physically possible. Tipping over is a drag for both the skier and the kid. The higher they sit the farther they will fall in a tipping event and also the steeper the angle they will tip. What would be a simple tip to the side now becomes and almost heads down plunge. Even small kids quickly begin to doubt the sanity of the adult if they repeatedly get dunked in the snow.<br><br>I added nearly full length aluminum runners (L-bar tapered to reduce drag) to the bottom to prevent side slip while side slabbing. This sort of works to a point, but in fact I think if I had it to do over, I would have added runners to just the last third of the length of the sled. The reason is that the runners do resist the turning of the sled. With the runners just on the last third, they will act as a pivot in turns. I think that some sort of runners that cut into the snow are absolutely necessary if anything but flat conditions are skiied and/or hard or packed snow encountered.<br><br>The whole harness/attachement configuration is a real engineering challenge. They seem so straight forward on paper then when you get the thing out on the snow.... With solid direct rods, when you turn, the rods actually stress the sled into turning the opposite way and can tip the sled. If you cross the rods the forces work in the opposite direction but you loose control in other ways. With just loose cords or bungees there is no control on the downhill and it becomes an excersise in survival, not much fun.<br><br>Shussing downhills is great fun on the pulks and kids love it, so I prefer the solid connection. I used nested pvc pipe as an "axel" through the front of the sled. The nested pvc is used because the stuff is really brittle and breaks. I use extra long fiberglass X-C ski poles for the link to me and the harness and they are attached to the pvc axel with very sturdy rubber plumbing hose (about a foot or so long). PVC pipe is too flimsy for the attachement. The hose is pinned to the ski poles and fits tight under tension to the pvc. This connection is not to be trusted alone and I back it up with a nylon rope that is pinned to the ski poles (and are nested inside the rubber tubing) and are threaded into the pvc axel. The axel is open in the center (within the sled) so that the rope from each side is then tied off to permanently attach the poles to the sled. The hose ends are then attached to the axel on each side of the sled. The rubber hose allows for some shock absorbtion while maintaining a reasonable degree of control. The waist harness is a surplus from a frame pack, and the attachments here also allow for some freedom of movement. <br><br>I like to have the waist harness fairly loose so that when I make a sharp turn I can let the harness slide around my waist. This reduces the torque on the system which tends to force the sled to tip over. It also allows the sled to follow me in a more natural arc.<br><br>

I own a Kindershuttle so I can comment on what I like and don't like about it. I looked at Dave's sled photos but I'd have to go and use the sled to have any real feedback on that design.<br><br>Overall I love the Kindershuttle. It's very safe. It has a built in roll bar so if/when the sled flips your child is protected. The harness is a five point harness that attaches to the bottom of the sled. Even if you roll it completely over the child remains attached to the sled. It has a complete enclosure with a large window for viewing and a small mesh window that has a cover on top to help ventilate on sunny days<br><br> Suze is right that it is slow in soft snow. We generally skate ski with it so that hasn't been an issue for us. We find that it tracks great even on the hair pin turn coming down from Windy Pass at Hyak. A friend borrowed it for skijoring (skiing with dogs) and found it didn't work for him. He had problems with one side dropping into their tracks as they broke trail in deep snow while the other side rode high. As a result their little one was always on an incline and the sled was pushing up too much snow.<br><br>The waist attachment system works great. We keep it loose so our hips can rotate while we are skating.<br><br>We've used it mostly for skate skiing. My wife has used it at Hyak on their closed days skinning up and then tele'ing down. We tried to use it once backcountry towards Source Lake in the springtime but had problems with it tipping on sidehills. <br><br>It weights 12lb total and packs down flat. It's not cheap - similar to a pair of skiis. But it gets us out skiing and as they say in the ads - priceless.<br><br>Good luck with your project!<br>

We also own a Kindershuttle. I was looking to build something a year ago, but looked at what well used pulks were going for on E-bay and came to the conclusion that they hold their value so well I'd get a good chunk of my $$ back out. Different strokes.....<br><br>We mostly use it on set track, but went back country quite a bit last spring including overnighters. It felt good to have the fuel bottle and tent off my back and in the rear of the sled. <br><br>Looks like you built a nice set-up.<br><br>I'd make sure the roll-bar system is stout. Our sled went over twice last year, once at a very low speed and once at a pretty good clip. In both case the 5-point harness did a great job and my one year old son just looked up at me like "Wow, this is different". Our center of gravity looks to be significantly lower than your set-up, hope it works out for you.<br><br>When going down packed cat tracks it's suprising how much the pulk chatters. For the skier our knee flex is taking up all the small stuff, the pulk doesn't have this dampening. My only thought is you could replace the wood blocks connecting the sled to the ski's at the front end. If you used a stiff rubber block you might be able to absorb some of the small stuff.<br><br>My one peeve about our pulk is that the window covering is clear. I would much prefer something darker to protect my son's eyes. Hopefully this year he'll like his sun glasses better. If you could find a dark cover for your pulk I'd definitely go that way.<br><br>Please let us know how how it works once you get on snow.<br><br>-Kev <br>