Atc front ski setup question.

[frankydodo]

Hey guys ! Just a quick question for you. Last year a saw a post on 3ww where a member ( can't remember who ) built a really nice setup for a front ski on his 200s.

I might have time this year to make one ! But my only question was for the axle.

Normally you have the axle that goes through the wheel hub that has bearings and a collar in it.

But in that picture

you see the axle going through a square steel tube i think. Is it ok to do it like that or maybe it would be better to put a round steel tube for the axle part that is just the size of the axle?

What honda did for their yeti kit back in the 80s?

Thanks!

[fabiodriven]

That's Scootertrash's bike. I don't think the shape of the tubing would matter that much personally. Honda had nothing to do with the Yeti kit, Yeti was the manufacturer of the kit.


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[Scootertrash]

This might get a bit long winded, but I'll answer your questions and provide some additional information on why I designed this like I did.

I used the Yeti ski design as the basis for my ski. Their design looked sturdy and I liked their design. I didn't have one in hand to use as a pattern so I came up with my own design. I also incorporated some elements of snowmobile ski design into my kit.

The axle tube is my own design, I slid a piece of seamless round stock inside of the square tube and welded it in. I had to ream the round tube to 15mm to fit the axle. I wanted a strong axle tube that wouldn't bend and fit snugly on the axle. The axle is greased before it's slid into the ski kit to help prevent rust. The 2 square tubes that form a "V" are there to mimic how the weight is placed on the axle when the rim and tire are on the bike. The bearings ride toward outer portions of the axle when the tire is installed, and the "V" helps transfer the weight to the outer ends of the axle. The square tube also allows me a bigger contact patch for welding the axle tube to the mast, or main rectangular tube.

For mounting the ski, I used a ski spindle from a Polaris snowmobile. I cut the spindle off of the mounting block for the ski, then I profiled the end of the mast to fit the mounting block and welded it on. The nice thing about using a mount from a sled is that the mount block prevents the ski from pivoting too much, and it has a grease zerk for keeping the pivot bolt lubed since that is basically the "axle" for the ski to pivot on.

Now for the additional info:

I designed my ski to maintain the rake of the fork tubes like the Yeti kit. If you look at snowmobiles they also have rake built into the ski spindles. Must be for a good reason or they wouldn't have designed it that way, so I maintained that design standard. The upper cross members keep the ski frame from pivoting on the axle. The frame does not need to pivot on the axle and I think it's a bit unsafe for the ski to have the ability to pivot backwards completely and fold under the wheeler. A few years ago we were doing some snow riding and a friend of a friend had a similarly designed ski. He hit a snow drift and the ski pivoted back stopping the machine it's tracks and sending him over the handlebars. He didn't get hurt and it was rather funny at the time, but that incident was always in the back of my mind when I designed this.

My ski frame is designed to transfer any weight to the outer ends of the axle just like the bearings in the hub of the rim.

You'll see some ski kits that look like this:




All the weight of the wheeler is concentrated on the center of the axle in a narrow spot, I feel this could lead to bending of the axle. It might be fine, but I prefer to play it safe. Hence my "V" design.

Disclaimer:

I do not have an engineering degree nor am I a college graduate. All I have is my diploma from the school of hard knocks, a smidgen of common sense, and a garage full of hand tools, welders, grinders and a refrigerator full of liquid intelligence. I try to build all of my creations to be safe and sturdy. I don't cut corners or cheap out on stuff, I always try to do it once and do it right the first time. YMMV

[frankydodo]

............

[tripledog]

Liquid intelligence, lol. Well it did make Bud wiser...

[Name Brand]

I wonder if a check cable from the front of the ski to the top of the 'mast' would be a good way to stop over rotation.

Scootertrash; How do you like the '4Snow' tires? Are they the 25x12x9?