Rock Crawling Rules

Rules of Participation

2.8 size tires or smaller

Dual motors 1/10th scale 540 or 550 size or single 1/10th scale motor

Maximum Li-Po battery is a 3s single pack

Maximum of 10 cell NiMh battery

Points Structure (starting with 100 points)

Roll over and self-recovery= -1 point

Hit trail marker of gate= -5 points

Pick up or replace position of vehicle= -10 points

Off course= -5 points

Using Reverse= -1 point (infinite reverse if hauling a trailer)

Class Definition

1.9 Scaler- (frame railed style vehicles)

1.9 wheels

Any tire allowed cut and/or modified

Standard wheelbase for model +/- 5mm

Full body or cab truck

2.2 Scaler– (frame railed style vehicles)

2.2 wheels

Any tire allowed cut and/or modified

Standard wheelbase for model +/- 5mm

Full body or cab truck

Comp Crawler 1.9 (class not limited to competitions, it is a class)

Stay within participation rules. Other than that, this class is open.

Comp Crawler 2.2 (class not limited to competitions, it is a class)

Stay within participation rules. Other than that, this class is open.

Comp Crawler 2.8 (class not limited to competitions, it is a class)

Stay within participation rules. Other than that, this class is open. ..

*Crawling Director has final interpretation of rules and may find it necessary to make any applicable changes.


2 CLASSES – Non scoring event – more for fun

Stock Class

Absolute stock truck

Stock ESC

Stock motor

Total weight limit of truck no more than 10lbs

Tire size does not matter

Everything else will be considered modified

Mod Class

Anything with modified motor/esc

Any weight

Any tire

General Pulling Rules

Battery limited to 3 Cell no bigger

All vehicles must have a hitch for pulling on their vehicle, 2” max height for the hitch

Rules can change or modified on the day of the event per the event director depending on circumstances

Scale pulling event is not for pulling specific trucks (we will have a pulling day where you will be able to use your specific pulling trucks and be scored)

If there are any questions before the event you can contact GaryJenn Dixon on Facebook or leave a name and number with the hobby shop and we will have Gary get back to you ASAP.

If you would like your truck to got to tech before the event we can make arrangements to do so.

After the first event we will take suggestions on how we can make the pulling event better for you.

Crawler Terms defined by RC Crawler Magazine

1.9 A competition or scale crawler that runs on 1.9 inch wheels.

2.2 A competition or scale crawler that runs on 2.2 inch wheels. The USRCCA’s most popular competition class.

Ackerman An adjustable bell crank steering system that consists of two posts connected by a bar. This bar is also referred to as a drag link.

Articulation An axles’ ability to move vertically-left wheel up, right wheel down or vice versa-relative to the chassis.

Bead lock A type of wheel; two rings are bolted together to clamp a tire bead between them and the wheel rim.

BEC Battery Eliminator circuit.

Bind “Bind” can refer to a couple of things. One is to bind a transmitter to a receiver that runs on a 2.4Ghz frequency rather than an AM or FM signal.

Binding can also be some kind of resistance in the drive train or suspension. If the joints in a drive-shaft are bent too far they can bind when trying to rotate.

Camber The angle of the wheels/tires in relation to the ground when viewed from the front and rear of the vehicle. Zero camber means that the wheels are vertical at 9 degrees (perpendicular) to the ground. With negative camber, the wheels lean inwards towards each other, and with positive camber the wheels leaning outwards and away from each other. As a rule, having slight negative camber is good, but be sure that both wheels lean at the same angle. Avoid having positive camber (wheels lean outwards away from each other).

Center of Gravity (CG) A vehicle’s balance point. The higher you chassis components sit above the wheel axles, the higher your vehicle’s CG. Having a high CG may promote rollover in tight turns. For the greatest stability, arrange your vehicle’s components so that it’s CG is set as low as you can get it.

Clocked A word that indicates that a component-usually part of the drivetrain-has been rotated to provide better alignment.

Course An area on which crawlers compete; it’s marked by a series of “gates” through which drivers must navigate their crawlers.

Comp Abbreviation for competition.

Constant Velocity Drive (CVD) A driveshaft with a ball-type setup that functions like a universal driveshaft. Although “CVD” is an MIP (Moore’s Ideal Products) trademark, it’s now commonly used to describe any driveshaft of this type.

Damping Rate The rate at which a shock is compressed and rebounds as the vehicle runs over uneven ground. Most RC kits now have shock absorbers filled with silicone fluid/oil. Without this, shocks would be too bouncy and wouldn’t be of much benefit. By using shock fluid oils of different weights (viscosities) or using a different type of shock piston, or both, you can alter your cat’s dampening rate to suit the terrain and your driving style.

Differential This transforms power from the input shaft to the output shaft. The differential, or “diff,” is used to alter the speed of the outside wheels of a vehicle’s going through a turn to rotate the faster and travel farther than the inside wheels. For rock crawling, most drivers lock out the diff action.

Dig A feature of the drivetrain that allows a driver to engage only the front or rear axle while the other axle is left to freewheel or is locked. When the front axle is being driven, this is “front dig.” When the rear axle is driven, it’s “rear dig.” Dig is used to negotiate tight turns and avoid reverse penalties.

Droop A feature of a suspension type that, when a vehicle is stationary, is fully compressed. Articulation with a droop suspension design comes from the axle dropping, or “drooping,” away from the chassis.

Dual Rates A switch that regulates the transmitter control input sensitivity. This is a useful function for many beginners, who tend to over control their vehicles.

E-clip A small metal retaining clip that resembles a washer with a section removed and is used to keep hinge pins and other types of shaft in place.

ESC Electronic speed control. An ESC regulates throttle control using it’s very efficient electronic components.

EPA Endpoint adjustment. A radio function that adjusts the length of a servo’s throw in either direction.

Exponential Rate Servo travel that is not directly proportional to the degree of control input. A negative exponential rate makes the control response milder around the servo’s center (neutral) point, but it becomes increasingly stronger as the input approaches 100%.

Gates Two markers identify the “gates” on a crawling course. The gates may be marked by arrows on the rocks or halved tennis balls, etc., but crawlers must pass between them to continue on the course.

Glitch This is the result of the radio interference; it’s a momentary lapse in signal transmission. External sources that cause glitches include overhead power lines, but consistent glitches are most likely the result of something in a vehicle such as the sort of metal-to-metal rubbing you might find with control linkages.

Inner Axle A part of the drivetrain that transfers power from the differential to the wheels.

Lexan A clear, plastic-like material that is vacuum-formed over molds to create RC bodies. They are painted on the inside so that the paint is not scratched off on the rocks.

LiPo Lithium-polymer; in RC, it’s a type of battery.

Locknut A nut that has a nylon insert that grips the threads of a bolt or a shaft to prevent it from loosening. Widely used on axles and in other areas where nuts must secure but may have to be removed frequently for maintenance or repair.

mAh Abbreviation of milliamp hour; it indicates how long a power source such as a battery will operate.

Milliamp A rating for batteries; the higher the Milliamp rating, the lunge the battery will provide power. Currently, most RC batteries range from 1500 to 800mah (milliamp hours).

MOA Abbreviation of Motor on Axle.

NiMH Nickel-metal hydride; NiMH cells do not have “memory” but offer a slightly lower voltage than nickel-cadmium (Ni-Cd) batteries. For average enthusiasts, they need less maintenance.

Offset as in “wheel offset.” Refers to a wheel’s mounting hex in relation to the wheel’s centerline. A larger offset provides a wider vehicle footprint (stance), and a smaller offset means a narrower footprint.

Outdrive Shafts that exit the differential on either side and transmit driveline power to the drive wheels using an axle shaft or a universal driveshaft.

Parallel Wiring A wiring method that ensures a constant voltage and current in a circuit. Wiring two of the same batteries in parallel will result with the same voltage but twice the capacity of a single pack.

Peak The point at which a battery no longer accepts a charge. Past this point, energy is converted to heat that is potentially hazardous and can damage your battery pack.

Peak Charger When the battery has peaked, this type of charger reverts to a maintenance charge rate that considerably decreases the likelihood that the battery will be damaged.

Pitch In RC, “pitch” refers to the size of a gear’s teeth per inch of diameter a gear has. A 32-pitch pinion gear has larger teeth than a 48-pitch gear.

Series Wiring A wiring method in which batteries are wired to increase the available voltage.

Servo-Reversing A radio function that allows drivers to reverse the output of the servo. This is useful when you switch your radio system between vehicles that may have servos in different places of orientations.

Stub Shaft Also called a “stub axle” or “wheel axle,” it’s the drive axle that’s inside the steering knuckles.

Super Class The largest class of rock crawlers recognized by the USRCCA. Vehicles usually comprise parts from th Tamiya’s Super Clod Buster.

Sway bar A heavy wire that’s run across either or both of the front and rear suspension arms. It is designed to keep equal down-pressure on the left and right when going through turns. When the outside edge of the vehicle is pushed up going through a turn, the sway bar pushes down on the inside edge to keep the tires on the ground.

Turnbuckle An adjustable link with conventional threads on one end and reverse threads on the opposite end. It enables driver to adjust their vehicles without having to completely remove the link.

TVP Twin vertical plate.

Wheel Axle The part of the axle drivetrain on which a wheel is mounted.

USRCCA United States Radio Control Crawler Association.