Crash Course: Getting Your Feet Wet in Diesel Truck Pulling
To outsiders, the sport of truck and tractor pulling may seem a bit odd, even boring. After all, there is no side-to-side or one-on-one competition like there is in oval track or drag racing, but rather each driver takes his or her turn pulling the sled as far as possible, with the furthest distance taking the win. However, for those involved in this 90-year-old pastime it’s an addiction that never ends. Just when it feels like you’re about to take the sled for a 100-mph ride, the gigantic weight-transferring contraption pulls you to a grinding halt. It is here, in these last few feet (and even inches), where the winner is usually determined—and it places more stress on the engine, transmission, driveline and axles than you could ever imagine.
As with any growing sport, there are always newcomers at any given event. Thinking of trying your luck at that upcoming county fair or fall festival? From making sure your truck’s equipment is up to the task, to which gear you should be in, to knowing what to expect from start to finish, the following guidance is designed to help ensure you get the most out of your first trip down the track.
Before You Hook… Here’s What You’ll Need
A Proper Pulling Hitch
The hook point for the sled will be at your truck’s receiver hitch, but you need to source your own hitch before the big day, or plan to borrow one. The hitch itself needs to have a 3-inch diameter opening, at minimum, in order to accommodate the hook that’s linked (via chain) to the sled. If you’re going to be pulling all summer or regularly in the foreseeable future, invest in an adjustable hitch. A lot of truck pullers like the adjustable units from Big Hitch Products. They are available for both 2-inch and 2.5-inch receivers and have 12 different height settings. This is ideal for achieving the maximum hitch height allowed in your class, which is typically 26 inches, but on some occasions can be lower. Hitch height and location are everything in truck pulling.
Eliminate Axle Wrap
During the course of a pull, the engine’s torque load can overcome your rear suspension’s ability to keep the rear axle in place. When this happens the differential rotates, forcing the pinion angle to tilt upward. This is known as axle wrap and it can lead to catastrophic driveline carnage if you don’t add traction bars, which essentially tie the axle tubes in with the truck’s frame and stop the axle from wrapping and the leaf springs from twisting. Note: If traction bars aren’t allowed in the rules at your particular event, don’t remove them in order to pull. Without traction bars (and with the engine under big load) tremendous stress is placed on the U-joints, driveshaft and even the leaf springs. Add in some wheel hop and you’re practically begging for driveline breakage.
Blocked Rear Suspension
As the weight of the sled transfers forward, it places more and more tongue weight on your truck. When this happens the rear suspension compresses while the front suspension unloads, which means you lose hitch height and the front tires can’t dig as effectively as you need them to. This costs you precious feet during the course of a pull. One way to stop this from happening is to eliminate suspension travel by blocking the rear suspension. In classes that require a certain amount of rear suspension travel (say 1 inch), many pullers install adjustable stops, such as what’s pictured above. However, rigid or limited travel rear suspension isn’t always permitted, so it’s always best to make sure you check with the sanctioning body or event host on specific rules for your given pulling class.
Pick the Right Tire
Traditionally, the tire of choice in truck pulling has been all-terrains. However, in recent years mud terrains have shown promising results (especially Nitto’s Mud Grappler). In most pulling classes the maximum tire diameter is 35-inches and must be DOT-approved. To widen your tires’ footprint and take as big of a bite out of the dirt as possible, always air down the front tires. Most truck pullers find the sweet spot between 20 to 30 psi. Out back, it’s best to keep the rear tires as rigid as possible, so leave considerably more air in them (or don’t adjust rear air pressure at all.)
Pick the Right Gear
Now that you’ve got the right tread under you, it’s time to choose the correct gear in the transmission to pull in, along with selecting the which side of the transfer case you need to be in (4-Hi or 4-Lo). First things first, decide on a combination that allows you to build optimum ground speed before running out of rpm (this is roughly 22 to 25 mph in most street truck type pulling classes). In any application, running in direct (1:1) in the transmission and 4-Lo in the transfer case is easiest on parts. Unfortunately, for lower horsepower trucks this isn’t always possible. In those instances you can drop down a gear in the transmission and run 4-Hi. Some common automatic transmission and transfer case selections for hot-running street trucks are: Second gear start then shifting to third gear and 4-Lo (’03-’07 Dodge/48RE), Fourth gear and 4-Lo (’01-’10 GM/Allison) and first gear and 4-Hi (’08-’10 Ford/TorqShift). Some common manual transmission and transfer case selections for 700hp trucks are: Fourth gear and 4-Lo (’94-’98 Dodge/NV4500), second gear and 4-Hi (’03-’05 Dodge/NV5600).
Front Suspension Tips
It’s long been proven that GM’s independent front suspension can compete with (if not outperform) the solid front axle suspensions found under Fords and Rams, but the key thing to remember on ’01-newer GM HD trucks is to leave the torsion bars alone. Cranking them up (usually to clear larger tires) changes the angles that the CV shafts and tie-rods operate at, and they are always at their strongest when functioning in a straight line. Also, do yourself a favor and add tie-rod sleeves. For ’05-newer Ford owners, the factory coil spring/radius arm suspension is known to produce violent wheel hop when hooked to the sled. For beginners, the most affordable way to take this out of the equation is to route a heavy-duty ratchet strap around the cross member and axle tube on each side of the truck and tighten them up.
When You Hook…
When you show up to pull, you’ll have to tech-in (primarily to inspect the turbo, check any necessary safety equipment and inspect hitch height), roll across a portable scale (to make sure you’re within the class maximum) and pick your line down the track (which is done by moving the cone behind the sled when you’re on deck to hook). Once you’ve backed up to the sled and are attached to it, creep forward to take the slack out of the chain. After that, it’s time to watch for the official at the end of the track to give you the green flag. He’ll wave the red one when it’s time to let off the throttle at the end of your pull.
Leaving the Line
For diesel pickups, and depending on what power level you’re at, along with what kind of condition the track is in, you will want to build a decent amount of boost pressure before you leave the starting line. This is accomplished by power-braking the truck until it feels like it may push through the brakes (which might not take a whole lot with the transfer case locked in 4-Lo). If you get the sled moving smoothly and all seems well within the first 100 feet, stay in it. If the truck hops or doesn’t feel right out of the hole, let out of it immediately and coast—do not hit the brakes or the sled may tag you from behind. At most truck pulls, you’re allowed a second attempt so long as you let out of the throttle before the 100-foot mark (although sometimes it’s 75 feet).
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