I have been giving serious thought to building one of these ATV sleds for the county fair, and any other ATV events we may get together, along the lines of an ATV rodeo, with barrel racing, and drags. These sleds are few and far between, but I did manage to find this gem of information on the web. The drive system for the cart is the most difficult part of this project, and this guy's version is pretty involved, though obviously very sturdy. Check it out, then check out my idea for using a chopped up old dirt bike, suspended from the sled, to drive the cart.

Sled Pull Info


I had an idea for a drive system for the cart that might be a little easier than what this suggests. I am thinking of using a big dirt bike rear wheel and suspension with the drive chain connected to a large sprocket welded to the alternator side of the crankshaft, with the top end and connecting rod(s) removed. A cover could keep dirt out of the hole left by the missing cylinder. Then the Primary drive, clutch, gearbox, to regular output sprocket would give furthur gear reduction to drive the cart . This would give me a 5-speed transmission and cable operated clutch. I could use an ordinary trailer axle instead of a car rear end, and there would be no right angle drives or special machine fabrications. The whole rig could be suspended in front of the trailer axle and raised for transport. Multiple clutch cables from the top and bottom of the cart track, and for an alongside operator would control the cart.
When I was on Junkyard Wars last year as part of the Metal Medics, (Our "expert" flipped our boat in the Powerboat Episode) Our competitors used a shaft drive BMW motorcycle as a complete powertrain set in an upside down camper shell. It was the tortoise and the hare. We were way fast, but never finished. Anyway, I thought the idea of using a complete powertrain was a great idea, we had fabricated nearly everything. Their idea of using a complete motorcycle powertrain gave them a huge time advantage.
I think a good size two stroke dirtbike should be able to handle the loads involved. As proposed I may not need much additional gear reduction, the primary gears in the motor itself are about 3 to 1. The rear wheel/sprocket set up is to my advantage, with the smallest rear sprocket and largest front sprocket I can find. I can pick up a junk dirtbike cheap and cut away everything I don't need. A low rpm big bore should have the needed beef to handle the loads.
I am figuring the distance traveled by the cart at 12' compared to the distance of the sled at 240 feet being 1 to 20. With a drive ratio of 1 to 4 at the rear wheel, a primary drive ratio of 1 to 3 and a gearbox ratio of anywhere from 1 to 1, to 1 to 4, I should be right in there with a reasonable gear selection for different length events.
...The rest of the sled seems easy compared to the drive system for the cart. This may just be a way to recycle some of those old bikes out there.
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Dam boy you have your work cut out...I didnt there was that much to them things.good luck

 

fourlix

I have a pull shed here in Maine, we travel around the area and sometimes pull in Canada. Some advise, make it rugged, our sled weights 10,000 lbs and is simple. After lots of trail and error, we have simplified it to one gearbox, a 25:1, that goes through a clutch, then runs a winch, we make all of our right angle with the pull cable not the gearbox. We have ours designed so we take counter weight off the back and put onto the front plate as the classes get higher.

Some of the bigger bikes and modified bikes can pull as much as pick-up trucks, so make it safe.

If I can help let me know.

 

nice idea!
the site said they'd build one complete for $3K and you get to pick the color! one will be ready by spring '03.

that sounds like a good price for all the aggrivation involved. plus, the guy already built a bunch of them.

if you charge enough per pull, you'll get your $$ back in no time!

i WISH they had a sled pull in my area. i'd kick butt all over the place every weekend with my 700 and 26" Outlaws!![img]i/expressions/face-icon-small-smile.gif[/img]

later,
-MT

 

There's also a club in northern Minnesota who built a really nice custom sled. Do it right, and you'll have a blast....you'll also be very busy.

Ken

 

For more cool info on ATV pulls check out these sites, http://www.geocities.com/teampullaris/
http://members.tripod.com/atvpullers/