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AXIAL RC Crawler Glossary
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A
3-Link Suspension
Suspension design using three links to attach the axle assembly to the chassis and allow for movement. A track bar is usually required to keep the axle properly centered. The 3-link design is typically used for front suspensions and when the steering servo is mounted to the chassis. Learn more here.
4-Link Suspension
Suspension design using four links to attach the axle assembly to the chassis and allow for movement. Learn more here.
60/40
Type of weight bias setup with 60% of weight forward of the midway point and 40% rearward of the midway point. Can also be used to describe unequal suspension link length front to rear.
Ackerman
Steering geometry providing different steering angles on the inside and outside front tires while turning. When Ackerman is used, the inner tire will have more steering angle to accommodate the tighter arc it travels.
AMS
Axle Mounted Servo. Designates steering servo is mounted on the axle. Sometimes SOA (Servo On Axle) is used but is not the preferred RC term as it can be confused with the full-size term indicating a Spring Over Axle swap. Learn more here.
Anti-dive
Suspension geometry configuration that limits how much the front end dives during braking.
Anti-squat
Suspension geometry configuration that limits how much the rearend squats under acceleration.
Approach Angle
The angle created between the forward-most portion of the vehicle and the bottom of the front tires. The greater the approach angle, the steeper an obstacle can be before it strikes the front of the vehicle.
Articulation
Suspension movement. Articulation usually refers to the amount of suspension travel allowed by the suspension design and setup, or an axle's ability to move vertically — left wheel up, right wheel down, or vice versa — relative to the chassis. Learn more here.
B
Beadlock
Type of multipiece wheel that clamps the tire's bead in place insead of using glue. The 1/10 MV19 1.9 is an example of a beadlock wheel.
BEC
Battery Eliminator Circuitry. With BEC, you don’t need a separate battery to power your on-board electronics. BEC voltage can often be adjusted using devices such as the Spektrum ESC Programmer V2 to send more or less power to servos or other electronics.
Boat Sides
Chassis plates that are angled, like the sides of a boat, from the rocker panel area to the skid plate. Boat sides increase climbing ability in some situations. The vehicle can lay onto its side to slide up and over rock ledges.
Bobbed
Shortened truck bed.
Brass
Components made from brass alloy. Due to its higher weight compared to aluminum or plastic composites, brass is used to lower a crawler’s center of gravity.
Brazing
Joining two metals together using solder. Unlike traditional welding, brazing doesn't penetrate the metals.
Breakover Angle
The maximum angle of an obstacle that a vehicle’s center section can clear without contact. Unlike ground clearance, breakover angle is impacted by the vehicle’s wheelbase.
Bump Steer
Steering deflection when the suspension is compressed.
Button Head Screw
A screw or bolt with a rounded head. While generally having shallower tool engagement, button head screws are smoother and offer less exposure of the screw. This is an example of a button head screw.
C
Camber
Viewed from above, the angle of a tire’s top surface relative to how it leans toward or away from the vehicle’s centerline.
Camber Gain
The increase in camber angle as the suspension is compressed.
Cap Head Screw
A screw or bolt with cap head with socket receptacle above the mounting surface. While generally having deeper tool engagement, socket head screws have significant exposure of the screw head. This is an example of a cap head screw.
Caster
Viewed from the side, the angle of the steering kingpin relative to how it leans toward or away from the front of the vehicle.
C-channel
Modeled after full-scale truck chassis design where frame rails are shaped like a C or [. A C-channel chassis design reduces frame flexing and increases the precision of suspension movement.
CG
Center of Gravity. This is the vehicle’s balance point, where all weight in all directions is concentrated. The higher that chassis components sit above the wheel axles, the higher your vehicle's CG will be. Arranging components for the lowest CG possible provides the most stability. A high CG may cause rollovers in tight turns.
Clocked
Means that a component, usually part of the drivetrain, has been rotated to provide better alignment.
CMS
Chassis Mounted Servo. Designates steering servo is mounted on the chassis. Learn more here.
Comp
Short for competition. Any type of rock crawling competition, but usually an event specific to navigating courses with gates. You can find comps using the Axial Event Calendar.
Cone
Item used as course or gate marker. Two cones make up a gate. Cones can be made from cut tennis balls, but purpose-made gate marker sets are available.
Crab Walk
Also known as crab crawl. In this 4-wheel steering configuration, the front steering and rear steering turn in the same orientation. The vehicle is then able to move in an angled direction.
Cutting Brakes
System that allows the driver to lock individual brakes in order to stop one wheel and then use the other wheels to drive the vehicle, thus pivoting around that locked wheel.
D
Damping Rate
The rate at which a shock is compressed and rebounds as the vehicle runs over uneven ground. By using shock oils of different weights and/or different pistons, you can change the damping rate to best suit the terrain.
Departure Angle
The angle between the rear-most portion of the vehicle and the bottom of its rear tires. The greater this angle, the steeper an obstacle can be before the rear makes contact.
Differential
The mechanism on a vehicle’s axle that, when cornering, lets the outer wheel travel at a faster rate than the inside wheel. Learn more here.
Dig
See Front Dig.
Dollhouse Truck
A scale truck that is loaded with authentic details and favors realism before performance.
Dovetail
When the narrowed tailgate of a truck bed creates angles bed sides.
Drag Brake
Brake force automatically applied when throttle is not being applied.
Drag Brake Rate
Drag Brake strength setting. On Spektrum Firma Smart speed controls, Drag Brake Rate can be adjusted using the Spektrum ESC Programmer V2.
Drag Link
Link that connects steering servo to steering link/tie rod or knuckle.
Driveshaft Phasing
Installing driveshaft so that the yokes are aligned. This reduces vibration.
Droop Setup
Suspension setup where shocks are compressed when vehicle is static.
Dual Protocol
Radio technology that allows a component (receiver or transmitter) to work with more than one type of 2.4GHz protocol. The Spektrum SR315 receiver is a Dual Protocol receiver that is compatible with SLT 2.4GHz and DSMR®. This means it will work with a transmitter such as the Spektrum SLT3 and the Spektrum DX5 Rugged.
Dual Rate Springs
Shock and spring setup using two springs per shock to achieve two different rates. The Pro-Line 1/10 Pro-Spec Scaler Shocks use a dual rate setup.
E
ESC
Electronic Speed Control. Device that controls a vehicle’s speed and braking.
F
Flat Head Screw
A screw or bolt with a flat head. While generally having shallower tool engagement, flat head screws offer no exposure of the screw but requires a countersunk accommodation. This is an example of a flat head screw.
FMM
Forward Motor Mount. A drivetrain setup where the motor is mounted forward of the center skid plate and not mounted directly to the transmission on the center skid. This design creates a desired forward weight bias and, depending on the design, a lower CG. The Axial SCX10 Pro uses a FMM design.
Full Droop Setup
Suspension setup where shocks have no external springs and are fully compressed when vehicle is static. On a full-size vehicle, full droop can refer to a shock that is fully extended to its maximum downtravel.
G
Gate
Two cones arranged on a course to designate where a vehicle must travel.
GTG
Get Together. A non-competitive gathering for crawling or a trail run.
H
Hard Body
Hard plastic body, typically molded out of ABS plastic, but many also be 3D printed. Hard bodies typically have more details but are heavier and less durable. The SCX24 2021 Ford Bronco has a hard body.
HoG
Hand of God. The act of using your hands, instead of a winch or tow strap, to move or assist a scale truck.
Hypoid Gears
Type of spiral bevel gears.
I
IFS
Independent Front Suspension. Front suspension design that allows the wheels to move through their suspension cycles independently of each other.
Initial Brake
Brake strength setting at the initial part of brake application. On Spektrum Firma Smart speed controls, Initial Brake can be adjusted using the Spektrum ESC Programmer V2.
Inrunner
Common electric motor design where motor output shaft spins inside the motor can. The motor’s magnets are attached to the shaft. The wire windings are inside the motor can. Inrunners are typically thinner in diameter but longer than outrunners.
J
Jounce
Suspension uptravel that generally refers to sudden, and even sometimes harsh, movement.
K
Knuckle
Outer portion of axle that supports wheels and allows for steering.
Kv
A motor rating that indicates RPM achieved per volt applied. The higher the Kv rating, the faster the motor.
L
Linear Rate Spring
Coil spring with a constant rate of resistance through its compression and rebound ranges. Linear springs use the same diameter wire with equal coil spacing throughout the spring.
Link Riser
Device that raises upper link mounting points. Sometimes known as RULR or Rear Upper Link Riser.
Locker
Device that eliminates differential action by locking the axles together, providing 100% of the available torque to the wheel with traction. In RC, spools are often referred to as lockers, but true lockers operate as differentials during normal use then lock up either automatically or via driver control. Spools offer no differential action at all.
M
MOA
Motor On Axle. Axle design that has a gear box and motor built as part of one assembly.
N
O
Offset
Wheel offset refers to a wheel's mounting hex in relation to the wheel's centerline. Zero offset is when the mounting surface is directly inline with the centerline of the wheel. A larger offset, also known as negative offset, provides a wider vehicle track width, and a smaller offset, also known as positive offset, means a narrower track width.
Outrunner
Electric motor design where motor output shaft is attached to motor can. The motor’s magnets are attached to the inside of the spinning can. Outrunners are typically much shorter than inrunners.
Overdrive
Gearing that is higher (faster). Often, in rock crawlers, the front end will be overdriven. This improves climbing in that it increases front wheel speed and helps prevent the vehicle from wanting to pull itself over backwards on ledges and climbs. It also slightly improves cornering. Overdrive can be obtained with a SCX10 III or UTB10 Capra using upgrade portal gears. Axial AR45, AR45P, AR44, and Pro45 axles can be overdriven using upgrade ring and pinion gears.
P
Panhard Bar/Link
See Track Bar.
Pitch
The size of a gear's teeth per inch of gear diameter. A 32-pitch pinion gear has larger teeth than a 48-pitch gear.
Polycarbonate
Thermoplastic used in numerous industrial applications and used to mold lightweight, flexible RC bodies. In RC, polycarbonate is thin and clear. It can be screened at the factory or spraypainted. Lexan is a brand name of polycarbonate. Not all RC bodies are molded from Lexan brand polycarbonate.
Preload
Used mostly to adjust vehicle ride height, measurement of spring compression at full extension. Preload is typically achieved via a coilover adjustment collar on a threaded coilover shock or via preload clips on a smooth coilover shock. Preload does not increase spring rate.
Progressive Spring
A spring designed to change rate as its compressed or rebounding. Progressive coil springs are usually created by using closer coil spacing at one end of the spring.
Q
R
Rebound
The opposite action of shock compression. Rebound is also a measure in shock setup indicating how much a shock expands on its own when compressed without a spring.
Ring Gear
Gear in axle that is driven by the input pinion gear.
Rock Bouncer
Tube framed vehicle made for extreme hill climbs over rocks and rough terrain. The Axial RBX10 Ryft is a scale rock bouncer.
Rock Light
Light mounted inside the fender well or on the chassis that is designed to point down and illuminate the terrain. The Multi-Color LED Rock Lights With Controller is a complet set of rock lights that are designed for the Axial SCX10 III.
RPM/Throttle Match
Design in ESC that increases RPM to match throttle input as load is placed on motor. On Spektrum Firma Smart speed controls, RPM/Throttle Match can be armed or disabled using the Spektrum ESC Programmer V2.
RTR
Ready to Run. Vehicle that arrives fully assembled and with electronics installed.
S
Servo Winch
Servo either modified or factory configured, such as the Spektrum S7110 Low Profile Servo Winch, to function as a recovery winch.
Sidehill
Steep off-camber terrain.
Sintered
Powdered metals that are heated until they bond and form a solid.
Solid Axle
An axle that connects the wheels from each side by one solid assembly. Also called straight axle. Both portal-equipped and standard axles are still straight axles.
Spool
A solid piece that serves as a replacement for a differential and permanently locks the axles.
Spur Gear
Larger gear driven by smaller pinion gear, which is attached to motor.
Standard Axle
A straight axle without portals.
Sway Bar
Device that links the left and right sides of the suspension and helps prevent body roll. Also known as anti-roll bar.
T
Toe Angle
Viewed from above, the angle the tires point in or out. Tires pointing perfectly straight have zero degrees of toe.
Track Bar
Suspension bar that locates an axle assembly in a 3-link setup. The Track Bar keeps the axle properly centered.
Track
Sometimes referred to as Track Width. Measurement of the width of a vehicle from the center line of each wheel. Sometimes overall width is listed as track width.
Trailing Arm
Type of lower link, typically rear, that often includes a lower shock mount.
Triangulated Links
Upper and lower links arranged in opposing angles that prevent the axle assembly from shifting side to side. Triangulated links eliminate the need for a track bar.
Truggy
A truck with the rear bed and frame section removed and replaced with tubing. While not a true truggy, some RC truggies replace the bed with a cage but retain the stock frame rails. A truggy is also a race vehicle with truck sized tires on a buggy layout. Race truggies are typically 1/8 scale.
Tuber
Vehicle with a tube framed chassis, such as the Axial UTB10 Capra or RBX10 Ryft.
TVP
Twin Vertical Plate. Chassis design that uses two opposing side plates as the main structure of the chassis. The Axial AX24 uses a TVP design.
U
Underdrive
Gearing that is higher (faster). In rock crawlers, the front end will often be overdriven. This improves climbing by reducing rear wheel speed and helping to keep the vehicle from pulling itself over backwards on ledges and inclines. It also slightly improves cornering. The Axial SCX10 Pro has a built-in selectable underdrive.
Universal
A driveline coupling in a driveshaft or axle that allows increased range of motion. Also known as a U-joint.
Unsprung Weight
All weight below and unsupported by the vehicle's springs. Typically Unsprung Weight consists of axles, wheels, and tires.
V
Viscosity
Thickness (and resistance to flow) of oil. In RC, "weight" is typically used over viscosity to describe different thicknesses of shock fluid.
W
Weight
See viscosity.
Weight Bias
Weight balance favored towards one end or the other. Crawlers typically use forward weight bias.
Wheelbase
Measurement of the length of a vehicle measuring from center of front wheel to center of rear wheel.
X, Y, Z
