One of Brian Miller's Web Sites.

Information About Tractor Pulling Sleds and How to Build A Sled

Part 1 - Important Information About Pulling Sleds

Because there are no companies, manufacturers (except for me, if I can find the time) or how-to books available for constructing a pulling sled (also know as "weight transfer machines"), most of them are actually built by an individual in their own private garage from a lot of imagination and parts availability. It greatly depends on a sled builder's preferences and a foreseeable knowledge of the laws of physics on how pulling sleds operate and function. Also, an experienced tractor puller can tell a poorly constructed sled from one that performs with excellence.

To be a successful and competitive puller, the puller must understand the pulling vehicle, and the operation of the sled.

Lots of people say they can't afford a weight transfer sled. But if you look around enough and get to know the right people, you'd be surprised how little it takes to build your own sled. This web site will help, too.

What sets an easy-to-start sled apart from one that is hard to get moving is proper balance. A properly balanced sled is when there's not much weight on the skid pan when the weight box is all the way back, in the rest position. There should be about 300± lbs. of weight on the skid pan. Which makes it easy for a tractor to start the sled. A correctly balanced sled will allow a tractor to gain some momentum (ground speed), before successfully stopping the tractor.

As of how much weight it takes for a sled to stop a tractor, that greatly depends on what type of tractor(s) that will be pulling it. Most sleds have no problem stopping slow moving, stock and lightweight tractors, but a sled will need to be weighted down more or the weight box will need to be placed in a faster gear for the faster and heavier (fully modified) tractors. Multiple gearing to control the speed of the box travel is a must, too. The weight of most sleds for garden tractors and motorcycle engine-powered pulling tractors range from 4,000 to 6,000 lbs., including weights in the weight box. And the weight box itself can weigh anywhere from 200 to 2,000 lbs. But depending on the design of the sled and being there is no "specific weight capacity" to how much weight can be added to the weight box, about all I can tell you is keep adding weight until the sled seems to stop the tractors at a specified distance.

Rule of thumb is, and depending on the type of pulling vehicle, the total weight of the sled needs to be about 5 to 6 times heavier or 500-600% more than the total weight of the heaviest pulling vehicle for the sled to successfully and safely stop the pulling vehicle. And about 2.6 times the total weight of the sled needs to go in the weight box. Meaning if a sled weighs 5,250 lbs, then 2,000 lbs. of that weight will need to be in the weight box, leaving the sled itself weighing 3,250 lbs.. I.E. If you have a 1,050 lb. tractor class, then the total weight of the sled should be about 5,250 lb. If you run heavier classes, then multiply the tractor weight class by a factor of 5 and that should work well. That is what most good sled builders shoot for. In other words, if a garden tractor were to pull an extremely heavy sled, it'll be like a Volkswagen trying to pull a dump truck. And it'll be vice-versa if the dump truck were to pull a Volkswagen and the VW was trying to stop the dump truck. Although, I have seen some good sleds that weighed about 3,500 lbs. work pretty well. Overall sled design, speed of the transfer box, weight transfer box weight vs. the sled chassis weight, pan size, angle of ascent for the weight transfer box, pulling [link] chain hookup point and length all must be considered for best results. The best thing to do is to go to several pulls where there are different sleds. Take note of which ones work well and talk with the operators/builders. They are usually glad to help. I would first figure out the total weight of the sled and start from there.

Being most ATVs are much lighter in weight than most garden tractors, and they don't have the traction as most garden tractors do, an ATV sled needs to be much lighter in weight than a garden tractor sled, one can build it the same except use 3" channel steel framing, one 3- or 4-speed aluminum case transmission, a low-geared narrowed small car rear end with at least a 4:1 ring and pinion ratio, and the rear end on the ground will need to be very high speed (numerically lower; 2.56:1± ratio) with tall tires. The rest can be the same design, length and width as a garden tractor sled that's mentioned here in this web site.

Weight of Various Materials -Precision Electronic Digital Scale

If you don't have a scale to weigh your steel or lead, here's the formula to figure the weight of these metals: (All measurements shown are in inches. And it's best to use a calculator for these, folks.)

When placing permanent weight in the weight box of a sled, try to avoid using gravel, automotive engine blocks, cylinder heads or anything that's porous or has a lot of "empty space" in it. The empty space takes up a lot of valuable room that could be filled with other metal. Therefore, it's best to use solid pieces of steel, cast iron or better yet, lead.

The effectiveness for a sled to successfully stop a high-speed, fully modified pulling tractor depends greatly on where the two "leg supports" (the support posts that goes from the frame down to the skid pan, also known as the "fulcrum point") are positioned on the frame. I've seen many sleds where the two upright posts or "legs" are mounted toward the very front on the frame or midway of the weight box on the frame when it tops out on the sled. Well, this is the WRONG way to build a sled! Because the weight box is transferring very little weight over the skid pan as it reaches the upper part of the frame. If the legs are too far forward, too little weight of the moving weight box plus the rear weight of the sled's frame and drivetrain components will not be transferred over the pan. This will place less overall weight of the weight box plus the total weight of the sled onto the skid plate, reducing the stopping effort. Therefore, a sled will stop a fully modified tractor more effectively when the legs are positioned at the rear of the weight box or slightly further back when the box is "topped out."

Transferring 90% of the total weight of the sled over the skid panTo transfer most of the weight of the sled over the skid pan, don't weld the rear-end (that's on the ground) directly to the frame. Instead, mount some low weight capacity leaf springs on the rear differential to the lower frame. The reason for this is as the weight box travels past the leg supports, the weight of the rear of the sled's frame will rise up slightly and the weight of the frame itself will be transferred onto the pan. It works like a seesaw that has transferable weight on one end. By this design, less weight is needed in the weight box. And to keep the sled's tires from coming off the ground as the box tops out, install a couple of link chains loosely from the rear of the pan up to the frame. Or, install a couple of frame "bumpers." Which are steel posts mounted on the inside front of the pan, going up to the sled's frame. As the box tops out, the chains will tighten up, or the frame will rest on the bumpers, allowing the frame to transfer 90% of the sled's weight onto the pan, with 10% of the weight resting on the tires, which will will remain on the ground. See the animated drawing in this paragraph as an example.

IMPORTANT - After a sled has been setting for a while, it's a good idea to have a large (farm) tractor pull it down the track with the weight box in the fastest gear to remove any rust that develops on the bottom of the skid pan. If this isn't done before the pulling event begins, the first tractor to pull will out-pull all the others by at least 20-30 feet!

When maintaining a sled, be sure to clean out the inside of the pan when the pulling event is over, or during a pull if necessary. If the pan isn't kept clean, dirt accumulation will make the sled heavier to pull and it might rust out in certain areas. Also, be sure to clean the old, dirty oil from the drive roller chains with a power/pressure washer, especially after a dusty pull (when the track hasn't been watered down). Spray the chains with WD-40 or lubricate them with ordinary motor oil. Remember, oil attracts dust. So if the chains aren't kept clean, the dust that's mixed with the oil gets inside the chain rollers, causing the chains to wear or appear to "stretch" overtime. The faster spinning chains will always wear quicker than the slower moving chains. And the reason double chains are used isn't only because they're stronger, they reduce the amount of wear that can take place on the chains and sprockets. Remember, to make the drive chains (and other parts on the sled) last as long as possible, always have the [dirt] pulling track watered down. Before the pull and if necessary, between classes.

Swivel VS. Non-Swivel Skid Pans -

Some people may have different thoughts on this, but in my opinion, swivel (center pivot or "fifth wheel type" of connection) skid pans don't work near as well as a pan having two leg supports. I have noticed that a swivel pan will sometimes cause a high speed tractor to "jerk" side to side while pulling. This is very dangerous and could break something on the tractor or cause the tractor to go out of control and possibly injure the driver. I've seen some tractors have to stop about halfway down the track because the "side to side jerking" gotten so bad. And the track officials would measure the distance where the tractor stopped, too.

For safety, don't make the pan swivel side to side. Attach it to the two "leg" supports and fasten a heavy bolt or pin crossways on each side of the pan and into each leg. Make the pan so it'll "float" with the contours of the track, but not rotate or swivel side to side.

On rare occasions, a swivel pan could cause a [high speed] tractor to suddenly whip to the side severely, and if the weight box is "topped out" when this happens, 90% of the weight of the sled will be transferred directly over the pan, causing the sled to be top heavy. This could cause the entire sled to topple over. This has been known to happen! It's not a pretty sight, either.

So as you can imagine, a pan with two "leg" supports works much better than any sled with a swivel pan. In fact, a sled with two "leg" supports will be much more safe and stable. Plus, the sled will follow the tractor straight down the track, causing no problems whatsoever. Also, if you are thinking of constructing a sled, make the pan so it'll "float" with the contours of track (when the front and rear of the pan can move up and down). And my sled design will allow the frame of the sled to flex, allowing both the tires and pan to have full contact on the ground at all times.

Install a Device on the Sled to Pull the Killswitch on a Pulling Tractor -

To construct a dependable device to pull even the toughest killswitch on a pulling tractor in the case of an emergency, use a 6 volt starter motor (preferably rebuilt or in good condition) that's made for a 1953-1964 model 2N, 8N or 9N Ford farm tractor. When these motors are operated off of 12 volts, they are very powerful. Sometimes a 12 volt starter motor won't have enough strength to pull a killswitch.

Mount the motor toward the front of the sled, and run a minimum 3/16" diameter steel cable with a heavy duty hook w/clip (dog clip) forward of the sled to the rear of the pulling tractor. A wide pulley will need to be made and mounted on the shaft of the motor for the cable. Mount the motor on the sled securely, and it'll be a good idea to use a pillow block bearing on the end of the shaft so it won't bend from the torque of pulling a tough killswitch or when the cable tightens up.

Use a heavy duty 12 volt automotive battery, a starter solenoid to activate the starter motor and a heavy-duty push-button type switch to activate the solenoid. And always charge up the battery before every pull! Click this eBay link if you need a Ford starter.

The basic safety requirements for virtually any pulling sled are as follows:

  1. A rider/operator on the sled at all times, and who is experienced and knowledgeable in the safety of sled operations.
  2. Hydraulic wheel brakes on the sled to stop it.
  3. A red and green light visible at a distance of at least 300 feet. The red light should be activated by a toggle switch next to the operator and by the wheel brakes.
  4. A powerful electric motor to pull the killswitch on the pulling vehicle in case of hitch and/or chain breakage or pulling vehicle goes out of control.
  5. And most importantly, sled operations requires total alertness of the operator while the pulling vehicle is pulling the sled down the track.

Sled Inspection and Certification -

Some years ago, the people in charge of the now defunct NGTPA contacted us about using our sled at their event and they said that first it would need to be inspected and certified. They wanted $200 for the inspection and $500 to certify it. Where this money went, nobody would tell us. Personally, I think it was a scam. I mean, I know my sled is safe and it's been proven to be very safe. I believe that the NGTPA was the only sanctioning body that required that the sleds used at their events were supposed to be inspected and certified. Because they were the only ones who mentioned that to us. And as far as I know, there's no laws anywhere that says sleds must be inspected and certified. And there are no web sites nowadays saying anything about sled inspection and certification.

Part 2 - How to Build a Simple and Functional Pull-Back (Non-Motorized/Self-Propelled) Pulling Sled for up to 1,050 lb. Garden Tractors, ATVs, Motorcycle Engine-Powered Pulling Vehicles and Possibly 1,500 lb. "Small Wheel" Mini Rod Pulling Vehicles
Top of page

I have no pulling sled plans drawn up on paper that I sell. Being there's so many variations of parts and designs that can be used in building of a sled, it's hard for me to suggest exactly which parts to use and exactly how to design a specific type of sled. When I built my sled, I used some of the parts off of old junk cars that I had setting on my property. Of course, I had to purchase certain parts at local salvage yards, too. What I'm getting at is the exact parts that I recommend to use would probably be not be found in your area. This would alter the design of the sled too, because the parts that's used have a lot to do with the functioning of a sled. But then again you may get lucky and find the right parts. I used all Chevy parts in building of my sled with the exception of the narrowed rear end, which came out of a Ford Pinto. The best advice I can offer you is use the information in this web site, use your imagination and do your best. And if you have any questions, you can call or email me and I'll help you in any way I can.

As there are many ways to build a pulling sled, and I believe my plans are the least expensive and most practical way of making it happen. As this type of subject is kind of hard to explain in a web site with no detailed pictures, you must use your imagination. Because I included as much information as I could here, folks. You'll need to have some metal fabrication and welding skills to complete this project, too.

I have no copyrights on my sled design and nobody is infringing upon any anything if they decide to use my plans in this web site to build a sled. I posted this information freely so people everywhere can build their own sled or build a sled to start a new pulling club. I made this web site to help promote the sport of small engine pulling vehicles. Anyone is free to use my plans if they choose to do so.

Also, I have no other pictures, drawings or diagrams that I can post in this web site. I need to work on getting some, though. I know they would help out a lot here.

If you have any questions regarding the construction or operation of a sled, please call me at 1-573-875-4033 or e-mail me at pullingtractor@aol.com and I'll answer your questions as honestly and accurately as I can.

Parts Needed to Build a Pulling Sled and How They Work Together -


ü Start by acquiring two automotive rear-ends:

  1. The first rear end goes on the ground and drives the driveline that controls the weight box. A heavy duty, high-speed (numerically lower; approximately 2.56:1± ratio) rear-end that's also capable of carrying a lot of weight (approximately 4,000 lbs.) is required. The rear end out of a full-size rear-wheel-drive luxury car, 1/2 ton truck or van will work ideal under a sled. The GM 10 bolt 8.5" (1971 and up), 12 bolt 8.875" (car and truck); Ford, Mercury or Lincoln 8", 8.8" or 9" and the Chrysler, Dodge or Plymouth 8.75" (ring gear diameter) rear ends are all heavy duty and capable of carrying a lot of weight. To find the exact gear ratio of a rear end, remove the rear end cover and count the number of teeth on the ring and pinion gears and then divide the bigger number by the smaller number. Another method to figure the approximate ratio is to rotate one axle one full turn and take note of how many revolutions the driveshaft turns. Then divide the number of turns by two. Most automobiles that's equipped with an automatic transmission and the newer automobiles that have a manual transmission have a high-speed rear-end. A low-geared rear-end shouldn't be used in this application because the weight box drive system will require more chain/gear reduction to pull the weight box up slower. So remember, the slower the driveshaft turns, the better. Use of tall tires would also allow the driveshaft to turn even slower.
  2. Or, instead of using the type of rear end above, a front "straight axle" differential assembly with lock-out hubs from an early model 1/2 ton 4x4 truck (Chevy, GMC, Dodge, Ford, etc.) can be used under a sled instead of the rear end out of a rear-wheel-drive vehicle. With lock-out hubs, the driveshaft wouldn't turn. Plus, the transmission to drive the weight box wouldn't need to be placed in neutral when the sled is being towed on the road. It would need to be high speed, too. And the steering would need to be fixed or welded in place and the transmissions in the sled would need to be installed offset for direct alignment of the driveshaft. Click here to read more about towing a sled on the road.
  3. The second type of rear-end will control the weight box and should be out of a small rear-wheel-drive vehicle that originally came with a 4 cylinder engine. An import or compact car/truck rear-end works ideal for this purpose because many of them are low geared (numerically higher; approximately 4:1). A "locked", limited slip or posi-trac rear end will NOT work for this purpose. This rear-end must be narrowed, and installed right-side-up, towards the front of the sled with the yoke facing rearward. It will become the right angle drive unit to control the weight box.
    NOTE: If you don't have the ability to narrow a rear end yourself or can't find a machine shop that's willing to narrow one for you, then the rear end out of a Pennsylvania Panzer, Meteor or Copar garden tractor can be used in a sled. These rear ends are very narrow, have mechanical brakes, and the ring and pinion ratios are either a 3.73 or 4.10:1, making them ideal for use in a sled. These rear ends actually came out of a mid-1950's used Dodge or Plymouth car and was narrowed by the Panzer factory just for use in their tractors. They measure approximately 28" from axle flange to axle flange (where the wheel mounts). They have drum brakes on each axle, too. They were installed upside-down in the tractors for driveline purposes but must be ran right-side-up for use in a sled. When facing the center pinion, the brake assembly on the right axle (driver's side, if installed in a car) must be removed and the flange machined down or an adapter made to accept a small sprocket.

Advertisement:
If you need a narrowed automotive rear end for your pulling sled, please contact me, Brian Miller, at A-1 Miller's Small Engine & Specialty Shop (1501 West Old Plank Rd., Columbia, Missouri. 65203 | Phone: 1-573-875-4033). Please call any day between 12 noon and 8:00 p.m. Central time, and please be patient because I stutter. Email: pullingtractor@aol.com. You can also contact me through Yahoo! Messenger: We are in the process of relocating our shop/business to a much larger facility at 1712 Business Loop 70 East, in Columbia, MO, offering faster service and many more parts & services to our customers! 1712 Business Loop 70 East, Columbia, MO - Google Maps or Map of 1712 Business Loop 70 East, Columbia, MO by MapQuest.

Details include:

  • Chevy, GM, Ford or Import automotive rear end with factory 4:1± ring and pinion gear ratio.
  • Narrow housing as much as possible (axle flange to axle flange).
  • Install a 12 tooth sprocket for a #50 chain on the right axle flange (when facing the center yoke).
  • Install brake drum and brakes with a long parking brake cable on the left axle (when facing the center yoke).
  • Price: $700.00, plus shipping.

Narrowed rear end for use in a pulling sled

Channel Steelü Make the frame of the sled 14-16 feet long. For frame material, it's best to use 4" C-channel iron (steel), because it's strong, lighter in weight and it'll flex with the contours of the track for better pan and tire contact on the track. (You don't want a rigid frame.) Make the frame 4' wide, outside measurement. And for strength to hold up to the tow bar and adjusting rods for the chains on the ends of the frame that connects to the weight box, use 4" x 4" "H" beams.

ü The tires should have at least a 6-ply rating and be 26"-28" tall when fully inflated. Taller tires turns the driveshaft slower. Be sure to always carry a spare tire with you, too.

Weldasprocket® hubü Find a source for some quality #50 and #60 roller chain, with matching sprockets. One source for quality roller chain and other useful items at reasonable prices is Surplus Center, 1015 West "O" Street, Lincoln, NE 68501-2209. Phone: 1-800-488-3407. Web site: http://www.surpluscenter.com. And Weldasprocket® hubs and sprockets works ideal for building a sled. The hubs have set screws and standard keyways. Wholesale Tool Co. (http://www.wttool.com) carries Weldasprocket® hubs and sprockets, and they also carry quality roller chain at reasonable prices. Order your parts online or request a free catalog.

ü Going forward from the rear-end on the ground is a standard length automotive driveshaft that's connected to either a 3-, 4- or 5-speed manual-shift transmission that's facing forward (like in an automobile) with the pilot shaft directly connected to the yoke of the low-geared (4:1 or lower) narrowed rear-end.Fabricated pilot shaft to yoke tubing connector Having multiple transmissions or even one transmission with multiple gears will offer more gear choices to vary the weight box on different track lengths and for different classes of tractors. If using multiple transmissions, it'll be better to position them end to end to reduce the weight box gearing so the box will travel slower. To connect the pilot shaft to the yoke, remove the splined center from an old automotive clutch disc that matches the pilot shaft's diameter and splines, machine and true it up in a metal lathe so a heavy wall steel tubing can be welded to it. Then weld a flange to the tubing and true up the outer part in the lathe. And then fasten the flange to the yoke. But if all you can find is a small, high-speed rear-end (anything higher than 4:1), then a chain reduction (a smaller sprocket welded to the clutch center that's on the pilot shaft and a larger sprocket fastened on the yoke) is needed here instead of the tube connector. The size of the larger sprocket greatly depends on the ratio of the ring and pinion gears in the narrowed rear-end. After testing the sled (with the transmission in the fastest gear; 1:1 ratio) for weight box travel distance, the larger sprocket may need to be changed for the weight box to top out at 300 feet.

ü Weldasprocket® hubA small sprocket (12T, #50) is then welded onto the right axle (when facing the yoke from the rear of the sled) of the narrowed rear-end. It's best to use a Weldasprocket® sprocket for this. The best way to mount a sprocket on the end of an axle is machine the flange down to a "shoulder" for the sprocket to fit on.

ü A drum brake is on the left axle (again, when facing the yoke from the rear of the sled) of the narrowed rear-end using the parking brake cable to engage/disengage the box drive. This brake acts as a clutch, to control the engagement and disengagement of the weight box. It rotates the spider gears, cutting the gear ratio in half. When the brake is locked, the left axle won't turn, but the right one will. Allow me to explain how this brake system works. You know how when one tire on the rear of a car (or on the front, if it's a front-wheel-drive) get stuck in a mud hole or on an icy spot on the road, and only that tire spins, and the other one, which is on a dry surface, does nothing? Well, when the brake drum on the narrowed rear end is in the locked position, this allows the pinion shaft to rotate the other axle, which pulls the weight box forward. With the weight box anywhere on the frame, and when the brake is released, the brake drum spins, allowing the other axle to rotate in the opposite direction, which rolls the box back down. The pinion shaft doesn't turn, because it's locked by the transmission gears. I hope I explained this well enough. And sorry, but I have no pictures how this looks or works. See drawing further down in this web page.
To further explain, the brake acts the "engager" and "disengager" for the weight box. With it engaged and the transmission gears also engaged, the axle on the opposite side of the brake turns, which winches the weight box forward. And when the brake is disengaged, the spider gears in the differential spins, allowing the weight box to row back down on the sled rails.
Also, keep in mind that the brake on one axle acts as a clutch. It won't keep the weight box from rolling back on its own in case the transmission gears were to slip out of gear or if a chain breaks. That's why I put heavy duty chains and locks on the shifters for the transmissions in my sled. I've been using my sled since 1995 and never had anything break or fail on it. You can put a third chain on the weight box and a separate brake if you want, but if you already have heavy duty chains and locks on the shifters, there's no need for it. It'll just be added weight that'll make the sled harder to pull.Ê

ü The small sprocket on the right axle connects upward via chain to a larger sprocket (40T, #50) (this sprocket can also be changed to achieve the desired weight box distance) that's mounted on the end of a 1-1/4" diameter jack shaft (not pictured in drawing), which pulls the weight box forward.

ü Install a (16T, #60) sprocket in the center of the jackshaft. (On my sled, I use two #60 chains that's spaced 2' apart and they're connected to a 1-1/4" diameter jackshaft to pull the weight box forward.) And use a small matching idler sprocket at the rear of the frame. Install an adjusting rod (heat-treated/hardened 1/2" diameter threaded rod to prevent stretching) to tighten the box drive chain. Actually, it's a good idea to install adjusters on all the chains.

Make the wheels minimum 4" in diameter x 1-1/2" wide with a 5/8" center hole. In a metal lathe, machine a 90º "V" groove in the circumference of each wheel.ü Fabricate or acquire four solid steel wheels for the weight box. These wheels should be a minimum of 4" in diameter x 1-1/2" wide with a 5/8" center hole. To fabricate them, use a metal lathe, machine a 90º "V" groove in the circumference of each wheel. Then fasten some angle iron on each sled frame with the angled part facing upward. The angle iron will allow the wheels to stay centered on the rails (prevent weight box side to side "wobble"), and they'll allow the dirt that gets kicked up by the tractors to fall off. McMaster-Carr Supply Company (http://www.mcmaster.com/index.asp) also carry these type of wheels at very reasonable prices. (When accessing McMaster-Carr's web site, type in "v groove wheels" click FIND and the information should come up on your screen.)

ü "Box Hook" to prevent the weight box from jumping off the railsMake a couple of "hooks" from 1/4" thickness angle iron under each side of the weight box to prevent the box from jumping off the rails.

ü Make the skid pan size either 4' wide x 6' long or 6' x 6' square, with minimum 1/4" thickness heat-treated/hardened steel, to last a long time, hold up under the pressure of the weight box and ground scraping. Actually, the best metal to use for the bottom of a sled pan is a tool steel. There are two versions that work rather well. They are AR400 or you can use AR532. Both are used for grouser bars in wood shaving mills and in floors of industrial conveyors, as well as other high abrasion uses. Good stuff, but about $4.00 per lb, but in the long run would be cheaper than anything else you could use. NOTE - the pan will last much longer if it's made of thicker metal. But remember - when replacing a worn out skid pan, the thicker the metal is, the heavier the front of the sled will become. In other words, it'll throw off the balance of the sled. If a thicker pan is installed, the rear-end on the ground may need to be moved forward slightly to regain the correct balance.

ü Make the dust shield on the front of the skid pan a minimum of 2' tall x 4' or 6' wide x 1/8" thickness steel.

ü Make the front lower portion of the skid pan "rounded" or curved upward so it'll slide up and over the dirt. Use a minimum 1/4" thick, 16" in diameter x 2' or 3' long steel tubing. Split the tube equally lengthways in four ways, then butt and weld the two halves together. See drawing for details è

ü Make the length of the leg supports 32" each, when measured from the bottom of the upper frame rail to the inside bottom of the skid pan. IMPORTANT - Be sure to weld some "X" bracing from the top of each leg support to the bottom of the opposite support to prevent them from flexing side to side or collapsing to one side when the weight box is over them.

ü Give the upper frame rails a 4º or 5º tilt so the weight box will roll back with no problem. Use an Angle Finder or a protractor with a vertical level to position the frame at the proper angle. And by having gravity roll back the weight box is the easiest and simplest way of making it happen. It also makes the entire sled lighter. Most pullers like a light-weight sled, especially stock pullers. And remember this - you can always add weight (ballast) to a sled, but taking it off (if it's used to make part of the sled function), is hard to do.

Drawing of a typical pulling sled

To insure that your sled will stop the tractors effectively is connect the parking brake cables on the rear-end that's on the ground to a lever that's mounted toward the front of the sled. When the weight box tops out, it'll hit the lever, activating the parking brakes on the rear-end. Roll the box back, and the brakes will release. Connect the parking brake cables with one long cable. And at the lever, use a V-belt pulley to fasten the cable in so when activated, it'll place equal pressure on each parking brake.

The right way to connect the parking brake cables IMPORTANT! If the rear-end is mounted with leaf springs to the frame, be sure that each parking brake cable, where they come out of the backing plate, are mounted through a strong loop straight in line (on the horizon) with the lower frame, and then go toward the upper front of the sled. If they aim upward directly out of the backing plate, the force of the weight box could momentarily lift the rear-end off the ground, causing the sled to jerk violently several times before coming to a full stop. But if the rear-end is welded directly to the frame, then the cables can be aimed directly toward the upper front of the sled.

How to Shorten Automotive Axles or Adapt Two Shafts Together -

"Pinning" an automotive axle to shorten it This information is for the narrowed rear-end that goes toward the front of a sled, adapting two types of ignition distributors together, and for other projects.

When shortening automotive axles or joining two shafts together, just cutting the axles or shafts in two, and then butting and welding them together don't always work. The reasons are...

  1. The axles or shafts will probably wobble, or if they're not properly braced, they will start to wobble over time.
  2. The weld itself, despite the tensile strength, won't be strong enough if the axles or shafts were to flex under severe strain. Under severe conditions, the weld will crack, and the axle will eventually break.

If the center length of an axle is tapered and isn't thick enough for re-splining, then the only way to shorten these type of axles is by "pinning" them. This method has been proven to work flawlessly for many years and it's exceptionally strong! Although same diameter-length axles can be shortened and resplined, pinning works great for these axles as well.

To prevent torsional twist, the entire length of most OEM automotive axles are induction hardened. This means that only the surface is heat-treated, but towards the center is soft metal. This makes them ideal for drilling into. Pinning an axle retains the surface hardening, retains torsional strength, reduces flexibility (keeps it straight so it won't bend or wobble under strain) and retains the rigidness. This method can also be used for street vehicles, mini-rod pulling vehicles or drag racing.

How To "Pin" An Automotive Axle or Two Shafts Together:

  1. Carefully measure in two places on each axle or shaft to the length they need to be, then make two cuts in each axle or shaft. On axles, for strength and durability, cut 2-1/2" away from the splined end, and for strength, don't cut close to the flange. Cut further down on the axle, away from the flange. Cut (and machine) the axles just like it shows in the drawing above. Discard the center section.
  2. With the flanged end of each axle clamped in a super spacer (with a self-centering 3-jaw chuck) that's fastened on the table of a vertical milling machine, bore/drill a hole 2-3/8" deep into the axle, leaving approximately an 1/8" wall thickness.
  3. In a metal lathe (with a self-centering 3-jaw chuck), turn down the shaft of the splined end of the axle, making a stub that's 2-1/2" long. Machine the stub .003" larger so it'll be a press fit for the drilled hole in the flanged half. Bevel the end of the shafts so the shaft will press in the other half straight and easy.
  4. Using a hydraulic press, carefully press the two halves together, leaving an 1/8" gap for a bead of weld.
  5. Thoroughly weld the two halves together, and grind away any sharp points on the weld so it won't harm the oil seals when the axles are slid into the rear-end housing. Return to previous paragraph. È

If you have a set of automotive axles that's "meaty" in the middle, then doing the above is only an option. Axles that's thick in the middle can be cut off and resplined. You can have Moser Engineering (of 102 Performance Drive, Portland, Indiana, 47371) do it for you. Their web site is: http://www.moserengineering.com, their email address is: rmoser@moserengineering.com and their phone number is: (219) 726-6689.

How the Weight Box Drive System Works -

The narrowed rear-end serves as a right angle drive to control the movement of the weight box. With both transmissions in gear, and as the brake drum (left axle) is engaged or locked, the input (pinion) shaft rotates the right axle (the spider gears will rotate, cutting the gear ratio in half.) The right axle then rotates the 1-1/4" jackshaft which pulls the weight box upward and forward. As the box "tops out," it will bump against a "trip lever" that's towards the front of the sled, automatically and partially releasing the drum brake, causing it to act as a "slipper clutch." The brake will actually lightly slip, maintaining the box at the top. Release the brake lever by a hand-operated lever, and the box will roll back on its own (gravity pulls it back down). To prevent severe damage to the drive components, brackets, frame or any parts on the sled, a trip lever must be located at the rear of the sled too, to automatically release the drum brake when the sled is being pulled back to the starting line (only if the manual release lever hasn't been disengaged). This is extremely important!

The #60 chain connects to the center of the weight box which must be securely fastened. It's a long, looped chain which connects to the jackshaft, to the box, over an idler sprocket on the rear, then it goes back to the jackshaft. A looped chain prevents the box from traveling forward (using it's own weight or momentum) when a fast tractor pulls the sled, then stops suddenly. With a cable, the box will continue to move forward, but it won't do that with a looped chain. A looped chain controls the full movement of the box.

IMPORTANT! When placing the transmission(s) for the weight box in gear, make sure they go fully into gear and it's also a good idea to lock the lever(s) so the gears will stay engaged when the tractor is pulling the sled. Click here to see what happens when the weight box is not placed into gear: Garden Tractor Pulling Video by Æ?Jennifer?Æ - MySpace Video. (You may have to watch it several times. And keep your eyes on the weight box.)

On my sled (Track Master), to move the weight box forward, I'm using two GM (Chevy) transmissions - a late 1950's - early 60's Muncie 3-speed direct-coupled (for the coupler, I used the centers from old clutch discs welded to a pipe) to the pilot shaft of a late 1960's - early 70's Saginaw 4-speed (I used a 4-speed car transmission because the gearing ratios are closer than a 4-speed truck transmission). I'm using just the 2nd and 3rd gears in the 3-speed transmission. Because if I were to use 1st gear also, this will make the box go forward way too fast, requiring more chain/sprocket reductions. And I'm using all 4 forward gears in the 4-speed transmission. When both transmissions are shifted into the fastest gears (2nd and 4th, respectively), this gives the weight box it's fastest travel speed, which would be on a short track and/or for modified tractors. When the 3-speed tranny is placed in 3rd gear, and the 4-speed tranny is in 1st gear , which are the slowest gears, this gives the box it's slowest travel speed, for a long track and/or light-weight stock tractors. A combination of all the gearing combinations in between will give the weight box a total of 8 speeds. The gearing in between are for the middleweight class of tractors or various lengths of tracks or track conditions.
- Brian Miller

IMPORTANT! Older Automobile Hood Springs For trouble free service, make precise measurements, calculations and clean/inspect/repair all parts and drive units before attempting this project. For strength and durability, use only new chains and sprockets. And be sure to install a spring-loaded lever to keep the drum brake engaged, in case the operator's hand slips off the manual release lever while releasing the weight box. The spring(s) will re-engage the brake automatically. Preventing the box from rolling back at full speed, resulting in possible damage to the sled. A couple of hood springs off an older salvaged automobile works ideal for this. Or click this eBay link for: Items matching ( hood springs ).

Towing a Sled on the Road - Return to previous paragraph.

90º Elbow Pipe Fitting IMPORTANT! The type of sled in this web site can be towed on the highway or hauled on a trailer. If you prefer to tow it directly on the road behind a truck, then it'll be a good idea to install a 90º elbow pipe fitting in the rear transmission's oil filler hole to fill it with additional gear oil so the gears on the mainshaft will sling the oil, keeping the internal moving parts well lubricated. This will prevent the risk of burning up the transmission. If additional oil isn't added, the needle bearings on the mainshaft where they go into the pilot shaft housing will most likely burn out. The picture below shows what can happen to an automotive manual-shift transmission that's been towed without additional oil or the driveshaft removed. And of course, place the rear transmission in neutral. Use a padlock to securely lock the transmission in neutral in case you have to stop someplace on the road and some stranger attempts to place the shifter(s) in gear without your knowledge. Also, the sled design in this web page can be towed on the road with a 1/2 ton pickup truck with good brakes. Plus, position the weight box about 1/4 way up on the frame, to add some tongue weight on the tow vehicle.

IMPORTANT! NEVER, EVER tow a sled or trailer on the road without the use of strong safety chains!
If a towed vehicle (sled or trailer) breaks loose from the towing vehicle on the road, safety chains will help prevent a disastrous accident with another incoming vehicle. Or if no safety chains are used, and if you're lucky, all you'll have to do is drag the sled or trailer out of the ditch. And if it's a sled, or a trailer with pulling tractors, hopefully there'll be minimal damage. And in most states in the US, it's required by law to have two safety chains for towing. Safety chains should be crisscrossed, too.

To construct a strong tow bar, make it similar to a 3-point hitch on the rear of a farm tractor. Connect the two lower brackets of the tow bar someplace on each side of the skid pan and then connect the upper heavy wall square tubing of the tow bar in the middle of the "H" beam on the upper front of the sled.

Some further notes about sleds -

When not in use, always store your sled indoors, keep it sheltered or cover it with a drip-proof canvas or cover. (A large boat cover will work.) Because rain water can play havoc on the roller chains, shifting mechanisms and the paint. Keep the skid pan raised off the ground too, to prevent excessive rust from accumulating under it. Take proud in your sled! It'll last for many years and give trouble-free service when properly taken care of.

When or if you're having an indoor pull, remember that most indoor arenas are made of a mixture of sod, sand, a little clay and some dried animal manure. This means that most sleds won't stop as well on this type of pulling surface. So to successfully stop the tractors, you may have to add more weight to the sled, either in the weight box and/or in the skid pan. Always bring extra weights along, at least 1,000 lbs. worth. Because you may, or more likely, will, need them. Especially if the sled's been used a lot outdoors on longer tracks. And to prevent any delays at the start of the actual event, practice pulling a few days before the event to get the sled weighted correctly.

Furthermore, if you're going to introduce automotive-engine mini-rods as a new class, it's best to have a sled that's capable of handling these powerful and faster pulling machines. Most ATV, garden tractor and motorcycle engine-powered tractor pulling sleds are too light, making them too dangerous for heavy, high-horsepower and high tire speed mini-rods to pull. Even if one were to add a lot more weight to a smaller sled, this would be hard on its chassis, tires, ground axle(s), chains and the weight box drive parts. Plus, the pull chain and hook probably wouldn't be strong enough to handle the strain. It'll be like a Volkswagen trying to stop a dump truck going downhill.

By the way - we use a 40" length pull chain. That's pretty much standard for garden tractor sleds. And most mini-rod sleds use a 54" length pull chain (I think). The length of the chain is measured from where it attaches to the front of the sled to the inside of the hook.

IMPORTANT! Use a hook with a safety latch to prevent the hook from jumping out of the hole in the drawbar!

On rare occasions, a high-tire speed garden pulling tractor, and especially a fast-moving mini rod, will "jerk" back and forth when it's about 75%-90% down the track or towards the end of its pull. What happens is when the vehicle is pulling the sled, the sled will be jerked forward slightly, and the jerking force of the sled will cause the pulling vehicle to be jerked backwards slightly. As this happens, there's momentarily slack in the pulling chain, and the weight of the hook could literally jump out of the hole in the drawbar. Nothing will break, the hook will just simply jump out, and the pulling vehicle will launch forward violently at full speed. Now if a killswitch is used on the pulling vehicle and is connected to the sled, as the hook is disconnected from the pulling vehicle, the plug in the killswitch will be pulled, killing the engine in the pulling vehicle. But this doesn't stop the progressive forward motion of the pulling vehicle. If this ever happens, the pulling vehicle could go out of control and crash into a blade-off tractor or even worse, crash into a crowd of spectators or bystanders.

The way to prevent this from ever happening is the use a quality hook with a safety latch attached. See the pictures of this type of hook to the right. This type of hook is available on eBay and perhaps a heavy lifting equipment supply place. Top of page.

Attach the pull chain on the front of the skid pan as low as possible, so the chain (weight box) will place weight on the rear tires of the tractor so they can dig in. If the chain is attached higher up or the same height as the hitch on the tractor, the rear tires won't be able to dig in and the tractors won't be able to go as far.

"Big wheel" mini-rod (with the 18.5 diameter wheels) sleds must weigh anywhere from 8,000 to 10,000 lbs., fully loaded. And the "small wheel" mini rod (with the 26 - 12.00 x 12 tires or 15" diameter wheels) sleds must weigh anywhere from 6,000 to 8,000 lbs., fully loaded. Most ATV, garden tractor and motorcycle engine-powered tractor sleds weigh only 3,500 to 5,000 lbs., fully loaded, making them too dangerous for mini rods to pull, unless extra weight is added in the skid pan to help slow the momentum of the mini rods going down the track.

So please, always think of the sled that's going to be used at pulls first before introducing a new class of heavier, faster and more powerful pulling vehicles! Let's make this a fun sport, not a life-threatening one.

Posted: Feb 18, 2009
From: Rick Davis of Shelbyville, Texas | Phone: n/a | E-mail: outbackcustombikes@yahoo.com
For Sale: PEDAL TRACTOR PULLING SLEDS. I build and sell different types of Pedal Pulling Sleds. A economy one for $129.95 plus $30.00 shipping anywhere in the lower 48 states in the USA. It has a rope driven weight box, All Metal construction, fixed skid plate, painted in any tractor color/colors you want. Top of the line is a Pro Model Sled with Chain Drive and floating skid plate, Diamond plate weight box and side skirts, Has a transmission with forward and neutral gear. It normally sells for $695.00 but now on sale for $495.00 plus shipping to be calculated by destination. Please contact me at my above email address if interested in one or if you want more Information on them. Click here for a picture of the Economy Sled painted in John Deere colors.

Or if you want, do a search on eBay (http://www.ebay.com/), or post a want ad in my web site: FREE Advertisement Posting Page. Thousands of people worldwide read the ads in my web site everyday.

Building a Bigger Sled -
To construct a larger scale sled for mini-rods, pulling trucks and/or large farm tractors, just make it a larger version of the sled in this web site, with basically the same drivetrain but with the exceptions of heavier frame rails (20' long), a bigger weight box (for more weight), a larger skid pan (for more ground/gripping surface) perhaps a bigger narrowed rear end (for less chance of breakage) and a bigger (truck) rear end on the ground. And to make it motorized/self-propelled, position all the drive parts toward the rear of the sled, and position the engine, transmission/reduction drive unit towards the front of the sled. And install two rear ends on the ground. The front one to drive the sled and the rear one to work the weight box.

Don't Be A Cheater!

If you're going to become a sled operator, be a professional one, so all pullers will respect and trust you. I believe that no sled operator should EVER ride the brakes, slip the clutch (that controls the weight box) or interfere with the operation of any tractor while they are pulling! I didn't create this web site so sled operators can cheat for others. I'm a sled operator myself and I know what it's like to be accused of riding the brakes to keep a tractor from going very far. I just want everyone to know that I or any of my backup sled operators do not cheat for anyone whatsoever. Besides, I didn't build my sled to cheat with. I'm not that kind of person. Each and every tractor that pulls my sled pulls it with no interference from me or any of my sled operators.

Measuring the Distances of the Pulls -

The most advanced, convenient, accurate and quickest measuring system for pulling sleds on the market today is the Agri-Tronix Sled Monitor System [http://www.atcindus.com/proddetail.php?prod=1000-6620]). Each monitor requires 12 volts of power, the kit comes with a magnetic pickup coil (sensor) that reads off the teeth on a sprocket which is mounted to the pinion shaft that's mounted next to the driveshaft of the rear end that's on the ground. The Sled Monitor is positioned on the sled, and the Remote Display sits on a table at the announcer's/judge's stand.

But if you don't want to invest the money in the above measuring system, then the second most accurate and low cost method is a measuring wheel device that measures in feet and inches. It's kind of like what the Highway Patrol use to measure skid marks in traffic accidents. The one that works ideal on a sled has a 10" diameter measuring wheel. They're quick and simple to use. It mounts on the left tire of the sled (left side, with a person standing behind sled and facing it). It should be mounted spring loaded so the pressure will be placed upon the tire to prevent it from bouncing or skipping on the tire, which will result in an inaccurate distance reading. It has a reset button to set the footage back to zero at the starting line. You can get a measuring wheel at a construction supply store, a surveying business or look on eBay.

NOTE: The only drawback about using the measuring wheel is (being the measuring wheel is mounted on the left tire), if a tractor were to pull the sled severely to the left of the track, a few inches will be subtracted from the true distance, because the left tire will rotate slower than the right one. And if the sled went to the right, a few inches will be added to the true distance, because the left tire will rotate faster than the right one. But it is better and faster than the old "rope and tape measure" method of measuring the distance.

Brian Miller's Sled Rental and Miller's Sled Building

Professionally-Built Garden Tractor, ATV, Motorcycle Engine-Powered Tractors and Possibly Small-Wheel Mini-Rod Pulling Sleds! We do not build sleds for bigger tractors (yet).

If you're a proud owner of a pulling sled, please send me a picture of it so I can show it off in my gallery!
Pulling Sled Picture Gallery

Linked pages to my parts & services:

A-1 Miller's Small Engine & Specialty Shop

Engine Rebuild Parts, Machine Shop Services, Engine Rebuilds & Build-up and Exhaust Header Pipe Kits

Carburetor, Fuel System Parts & Machine Shop Services

Clutch Parts, Rebuilding & Machine Shop Services

Transaxle Parts & Machine Shop Services

Steering, Chassis Parts & Machine Shop Services

Conventional Ignition, Electrical and Crank Trigger Electronic Ignition Parts and Kits

Brian Miller's Sled Rental and Sled Construction
(Self-propelled weight transfer machine)

Please click HERE, e-mail me at pullingtractor@aol.com or call me at 1-573-875-4033 if you need machine work performed, repairs made, various parts, if your business would like to help sponsor my web sites or if you'd like to make a donation towards my web sites. Please call between 12 noon and 8:00 p.m. Central time, and please be patient because I stutter.

à Return to Main Pulling Tips Page | Please Sign My Guestbook | Return To Previous Page | Classified Advertisements for Garden Pulling Tractors and Related Parts | Garden Pulling Tractor Engine Builders, Parts Suppliers and Service Providers | Brian Miller's Garden Pulling Tractor Picture Gallery | Pulling Sled for Garden Tractors Picture Gallery | Top of Page

Looking for a place to pull your tractor? Then check out this web site: Hot Links for Various Garden Tractor Pulling Clubs and Associations.

© 1996-Present. Designed and maintained by Brian Miller.