Off-Topic Monster Truck Specs

Griff747

Well-Known Member
These are a few questions that have been boggling on my mind for a few months, and some of them may sound silly in a way, but I am still trying to learn more about these trucks, so do not go raging all over this thread (or at me). Plus, this could help new Fans learn more about today's Monster Trucks(in a way).

Here are my Questions: What kind of Gear Ratio's do modern Monster Trucks use? Do normal Drivers use Automatic or Manual? If the Truck is a Rear/Middle Engine Desgined Truck, Would switching from parking (or 1st gear) to the next gear, would you have to reverse the way you normally switch gears on a normal car? How does the Rear Steering Work?
 

Smasha

Well-Known Member
Gear ratios are changed all the time (in the transfer case) depending on the event and size of the floor. The transmission is usually a Coan 2 speed trans and is 'semi auto' in that you still shift from first to second etc with your hand, but there is an automatic 'clutch'. I believe the shift pattern is entirely linear, meaning forward once is first, forward a bit further is second, and then all the way back is reverse or some sort of ratchet. The rear steering (and front steering) is hydraulic which means it uses a system of hoses and cylinders filled with oil or hydraulic fluid. The liquid is pumped around by a hydraulic pump which is either run via a belt from the engine, or battery powered. The rear steer is controlled by a toggle switch and the front by the wheel. As the switch is pushed to one side, the hydraulic pump pushes the oil down the hoses you see on the axles and into the steering cylinders, which either extends it or contracts it and thus, turns the wheels. The front steering works exactly the same only it works off an orbital valve which is a fancy name for a system which converts the left/right movement of the steering wheel into oil flowing to the cylinders. Hopefully that answered everything.
 
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Smasha

Well-Known Member
I think they can do a ratio change in about 10 minutes thereabouts (maybe less, not sure). They just have to unbolt the front of the T-Case, slide the new gears in and bolt it up again.
 

KD58

Well-Known Member
These are a few questions that have been boggling on my mind for a few months, and some of them may sound silly in a way, but I am still trying to learn more about these trucks, so do not go raging all over this thread (or at me). Plus, this could help new Fans learn more about today's Monster Trucks(in a way).

Here are my Questions: What kind of Gear Ratio's do modern Monster Trucks use? Do normal Drivers use Automatic or Manual? If the Truck is a Rear/Middle Engine Desgined Truck, Would switching from parking (or 1st gear) to the next gear, would you have to reverse the way you normally switch gears on a normal car? How does the Rear Steering Work?
Most monster trucks have a ring and pinion gear ratio that is usually in the 6:1 range, Foot trucks are 2.73:1 if I'm not mistaken. The planetary gearsets are anywhere from a 3:1 to a 6:1 ratio depending on the planetary. The quick-change gearsets are in the transfer case, and usually take less than a couple minutes to change if you know what you are doing and work well in a hurry. Forgive me if my facts are off but I think the final drive ratio on most race trucks is in the neighborhood of 25:1. I've never really paid attention to that figure, but that's a number I've heard tossed around. Anyone else out there who knows better than me, feel free to pipe up, I think it'd be a neat fact to have in stone, but of course the actual number is dependent on the gearing in the trans as well.

Most monster trucks use a 2-speed "Powerglide" transmission, although it really only shares the name and basic architecture with an old GM Powerglide, the cases, guts, and all that are of course modernized racing products. The transmissions use a torque converter, not a clutch of any kind, to transfer power from the engine's crankshaft into the transmission itself. On most shifters, at least on the 2spd trucks I've driven, the shift pattern begins in "Park". Ratchet the shifter towards the rear of the truck once and you are in "Reverse". Another ratchet lands you in "Neutral". Another ratchet after that lands you in "2nd Gear" or "High Gear". Another ratchet still will bottom out the shifter in "1st Gear" or "Low Gear". When racing, you bump the shifter forward to shift from 1st to 2nd, and the shifter has a lockout mechanism on it to keep you from accidentally shifting into neutral. The C6 transmission that Foot was still using when I started doing some driving for them was a 3-speed, and instead of shifting towards neutral on the shifter, you actually started one click past neutral in 1st gear, then ratcheted two more times for 2nd and 3rd. Some monster trucks might still use a Lenco or B&J type transmission with a centrifugal clutch, but I think the Hall Brothers were probably the last of the stalwarts hanging on to that concept, which was far more labor-intensive and expensive than a 'Glide. I know of no competitive monster trucks today that use any kind of manual transmission/pedal clutch arrangement.

With the motor and trans in backwards, the transfer case has an odd number of gears to achieve proper reverse rotation, so that the whole thing isn't running backwards and that your ring and pinions are turning in the optimal direction and what not.

The front steering is manipulated with an engine-driven pump, sometimes belt driven, sometimes driven off the crank or blower snout, and pumps fluid through an orbital valve at the end of the steering column and down through hydraulic lines into one or more hydraulic cylinders. The rear steering is typically manipulated by one or more electric over hydraulic pumps that force fluid through the same kind of lines the front uses, into a similar cylinder arrangement on the rear axle. Most teams use an electric momentary switch of some kind to control their rear steering, with many teams using one variety or another of a "automatic return to center" switch and cable setup on the rear axle, which basically means when you let off the switch/button, the rear will bring itself back to "straight". Both BIGFOOT and Hall Brothers trucks have a variable settings so that you can drive on full manual, semi-automatic, and full automatic. I drive with mine set to "semi-automatic", which basically means the rear steering stays turned until i manipulate a separate button on the shifter with my thumb to bring the rear steering back straight.

This GoPro video that I took at one of my car crush exhibitions in Canada (for the sole purpose of helping explain rear steering) should help you see, at least in the case of a BIGFOOT truck, how my teammates and I work the rear steering and shift through the gears.

http://www.youtube.com/watch?v=xjxW6CM0HkU
 
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