The Racing Glossary

1099-NEC

Form 1099-NEC is the information return a business files with the IRS, and sends to you, reporting nonemployee compensation it paid you during the year — money for work or services you did as a non-employee, such as a car owner paying you to drive or a shop paying you to set up cars.

Ackermann

Ackermann is the steering geometry that makes an RC car's inside front wheel turn at a sharper angle than the outside wheel, so toe changes as the wheels turn. It's adjusted at the steering rack.

Actual Expense Method

The actual expense method deducts a business vehicle's real operating costs — gas, oil, repairs, tires, insurance, registration, licenses and depreciation — multiplied by the business-use percentage, instead of claiming the IRS standard mileage rate.

Aero Push

Aero push is a car going tight in another car's turbulent wake — the leading car strips downforce off the car behind, so the trailing car won't turn and pushes up the racetrack. Clean air cures it.

Anti-Squat

Anti-squat is how strongly the rear suspension geometry resists the back of the car settling under acceleration. Anti-squat is the rear counterpart to anti-dive at the front, and it is a geometry number, not a spring or shock number.

Appearance Money

Appearance money is a payment a promoter negotiates in advance with a specific driver or team to bring the car to a given event, paid for showing up and racing regardless of where the car finishes.

Bead Lock

A bead lock is a ring bolted through a race wheel that clamps the tire's bead against the rim so it cannot unseat, which is what lets a dirt racer run low air pressure. Rules vary by class.

Birdcage

A birdcage is the bearing housing that rides on a dirt car's rear axle tube, free to rotate around it, carrying the radius rods and the shock and spring mounts that locate the rear suspension independently of housing rotation.

Blinky (Zero Timing)

Blinky is an RC speed control mode running zero electronic timing advance, with boost and turbo both off, named for the LED that blinks to prove it. ROAR requires blinky mode in several stock classes.

Blue Groove

Blue groove is a dark, polished lane worn into a dry dirt track where laps have packed and rubbered the surface. Dirt oval racers usually mean the grippiest line; motocross and RC racers usually mean a slick one.

Blueprinting

Blueprinting is building an engine to exact, verified dimensions rather than to production tolerance — measuring and equalizing every clearance, volume and weight so each cylinder and each rotating part matches the next.

Bonus Depreciation

Bonus depreciation is an extra first-year depreciation deduction on qualifying business property, applied automatically unless you file a statement electing out, and taken after any Section 179 deduction but before regular depreciation.

Boost and Turbo Timing

Boost and turbo timing are electronic timing advance an ESC adds by software, on top of the motor's mechanical timing. Boost comes in progressively; turbo dumps in extra at full throttle. Blinky classes ban both.

Bump Steer

Bump steer is the front wheels steering themselves as the suspension moves through travel, with no input from the steering wheel. It comes from tie-rod geometry that does not match the control arms.

Bump Stop

A bump stop is a compressible spacer on the shock shaft that the suspension runs into near the end of its travel, acting as a second, progressive spring that stiffens that corner and limits how far it compresses.

Camber

Camber is the tire's lean from vertical, viewed from the front of the car, measured in degrees. Negative camber leans the top of the tire toward the chassis; positive camber leans it away.

Caster

Caster is the fore-and-aft lean of the steering axis — the line through the upper and lower ball joints — viewed from the side, in degrees. Positive caster tips the top of that line rearward.

Claim Rule

A claim rule lets an eligible competitor buy a rival's engine or component for a fixed price set by the rulebook, right after the feature. It caps spending by making an expensive advantage purchasable.

Consi

A consi is the consolation race that gives drivers who missed transferring out of their heat one more shot at making the feature, with only the top few finishers advancing to the back of the field.

Contingency Money

Contingency money is a manufacturer award paid to a racer for finishing at or near the front while running that company's product and displaying its decals, earned automatically on results rather than negotiated as a sponsorship deal.

Corner Marshal

A corner marshal is a racer posted trackside during a heat they are not driving in, whose job is to right crashed cars and clear the racing line, stepping onto the track only after a caution is called.

Corner Weights

Corner weights are the four numbers a race car reads sitting on four scale pads — the load carried by each individual tire. Left-side percentage, rear percentage and cross-weight are all calculated from those four readings.

Crate Engine

A crate engine is a complete engine bought assembled from the manufacturer and raced as delivered. Circle-track versions like GM's 602 and 604 use special bolts and serialized tags to prevent modification, and the seals must stay intact.

C Rating

C rating is a battery's claimed discharge capability expressed as a multiple of its capacity: multiply the two and you get amps. A 5000mAh pack labeled 100C claims 500 amps continuous — the manufacturer's claim, not a measured figure.

Cross-Weight

Cross-weight is the right-front and left-rear corner weights added together and divided by the car's total weight, expressed as a percentage. Above 50% is wedge; on an oval, more cross-weight tightens the car.

Cushion

The cushion is the ridge of loose dirt pushed to the outside of a dirt track by cars running laps. Drivers lean into it for extra bite, and it moves and shrinks all night.

De Minimis Safe Harbor

The de minimis safe harbor is an annual tax election letting a business deduct low-cost tangible property immediately instead of depreciating it — up to $2,500 per invoice or item for a taxpayer with no applicable financial statement.

Depreciation Recapture

Depreciation recapture is the rule that turns gain on a depreciated business asset back into ordinary income — up to the depreciation allowed or allowable — when you sell the asset or business use drops to 50% or less.

Differential

A differential lets an RC car's driven wheels — or its front and rear axles — turn at different speeds through a corner. Gear diffs are tuned with silicone fluid; ball diffs are tuned by tightening.

Drag Brake

Drag brake is the braking force an electronic speed control applies automatically at neutral throttle, standing in for engine braking. Most ESCs set it as a percentage from 0 to 100, where 100% holds the car on an incline.

Droop

Droop on an RC car is the amount of down-travel a suspension arm has — how far the wheel can drop below ride height before the suspension tops out. It's limited by a downstop screw.

Durometer

A durometer is a gauge that measures how hard a tire's rubber is, read on the Shore A scale from 0 to 100. Lower numbers mean a softer compound; higher numbers mean harder.

ESC (Electronic Speed Control)

An ESC, or electronic speed control, is the electronic unit between an RC car's battery and motor that converts the receiver's throttle signal into motor power, and also handles braking, reverse, and low-voltage cutoff.

Feature

The feature is the longest and last race of the night for a division — the main event that pays the purse and the championship points everything earlier in the program was fighting to line up for.

Final Drive Ratio (FDR)

Final drive ratio (FDR) is how many turns the motor makes for one turn of the wheels on an RC car, calculated as the internal transmission ratio multiplied by spur teeth divided by pinion teeth.

Form 1099-K

Form 1099-K is the information return that payment apps, online marketplaces and card processors file with the IRS, and send to you, reporting the goods-and-services payments you received through that platform during the year.

Forward Bite

Forward bite is the rear tires' ability to put power down and drive the car off the corner without spinning. It's traction in the direction of travel, as opposed to side bite, which is cornering grip.

Fuel Cell

A racing fuel cell is a flexible bladder inside a metal container, packed with foam, that replaces a stock gas tank to keep fuel contained in a crash. Bladders carry a dated certification label.

Gear Mesh

Gear mesh is how deeply an RC car's pinion engages the spur gear, set by sliding the motor in its mount. Team Associated's check: the spur should rock back and forth without moving the pinion.

Green-White-Checkered

A green-white-checkered is an overtime restart used when a caution falls near the end of a race, restarting the field under green so the race finishes with a lap run at speed instead of under caution.

Handicap Lineup (Handicapping)

A handicap lineup starts the best recent performers at the back and the slower or less consistent cars at the front, ordered by a track-kept handicap value built from finishes in previous races rather than by qualifying speed.

Head-and-Neck Restraint

A head-and-neck restraint tethers the helmet to a support worn on the driver's shoulders, limiting how far the head snaps forward in a crash. Racing devices are certified to SFI spec 38.1, which carries a five-year recertification period.

Heat Cycle

A heat cycle is one pass of a race tire from cold up to operating temperature and back to cold. Each cycle permanently changes the tread compound, and racers disagree on what counts as one.

Heat Race

A heat race is a short qualifying race early in the program that sets the feature lineup — the top finishers transfer straight to the feature, and everyone else drops to a consolation race.

Hobby Loss Rule

The hobby loss rule is the IRS standard under Internal Revenue Code Section 183 that denies business deductions to an activity not engaged in for profit, treating the activity's income as taxable while disallowing the activity's expenses.

Home Track

A home track is the speedway where a racer runs the weekly program every week and builds cumulative track points toward that track's championship, as opposed to the specials and touring dates scattered across the rest of the schedule.

Hot Laps

Hot laps are the short at-speed practice session that opens a race program, run in groups before qualifying so drivers can scrub in tires, check the car, and feel out the track surface.

Instant Center

Instant center is the point where the extended centerlines of two suspension links cross — the pivot the wheel is momentarily swinging about. Move the links and the instant center moves with them.

Invert

An invert is a rule that reverses the front of a starting lineup by a set number, so the fastest qualifiers start behind slower ones and have to pass their way forward.

Leak-Down Test

A leak-down test pressurizes a cylinder at top dead center and reads what percentage of the air escapes, showing whether rings, valves or the head gasket still seal. With 100 PSI in, 90 PSI out is 10% leakage.

Lift Bar / Pull Bar

A lift bar is the rigid rear torque link on a dirt Modified or Late Model. A pull bar does the same job but carries a spring, puck or Belleville washer stack, so the bar can give under load.

LiPo Battery

A LiPo is a lithium-polymer battery pack, the standard power source in electric RC racing. Cells run about 3.7–3.8V nominal and charge to 4.20V each — 4.35V for high-voltage packs — and must be balance charged.

Listed Property

Listed property is a tax category of assets that lend themselves to personal use — passenger automobiles, pickup trucks, SUVs, aircraft — and it carries stricter recordkeeping and a more-than-50-percent business-use test than ordinary business equipment.

Locked Rear End (Spool)

A locked rear end has no differential action, so both rear tires are driven at the same speed. A spool is the purpose-built version; welded carriers, automatic lockers and limited-slips are looser relatives often lumped in.

Loose

Loose is when the rear tires lose grip before the front tires, so the back end slides out and the car rotates more than the driver asked for. Racers also call it oversteer.

Marbles

Marbles are pieces of shed tire rubber and loose track material that collect outside the racing line and are slippery like toy marbles. Drive through marbles at speed and the car gives up grip instantly.

Motor Timing

Motor timing on a brushless RC motor is how far the sensor endbell is rotated relative to the rotor, advancing when each winding fires. More timing adds RPM and heat; less timing runs cooler.

Motor Turn Count (T) vs kV

Turn count is how many times wire is wrapped around each stator pole of a brushless RC motor, written as a number plus T. Fewer turns means higher kV, more RPM and less torque per amp.

Panhard Bar

A panhard bar is a lateral link that locates the rear axle side-to-side under the chassis. Its height sets the rear roll center, so raising or lowering it changes how fast the car transfers load in a corner.

Participant Accident Insurance

Participant accident insurance is accident-medical coverage a racetrack or sanctioning body carries for competitors injured at an event. Underwriters write it on either an excess or a primary basis, so the terms come from that policy, not from law.

Passing Points

Passing points are championship or lineup points awarded for positions gained during a race, added to finish-position points, so a driver who starts deep and moves forward can outscore a driver who led from the pole.

Per Diem (Standard Meal Allowance)

Per diem, which the IRS calls the standard meal allowance, is a federal daily meal rate set by travel location that a business traveler may deduct in place of actual meal receipts when away from home overnight.

Pinion Gear

The pinion gear is the small gear on an RC motor's output shaft, held by a set screw. It drives the spur gear, and its tooth count is the primary adjustment racers use to change final drive ratio.

Pit Pass

A pit pass is the paid, per-person credential that admits a driver or crew member to a racetrack's restricted pit area. Everyone going through the pit gate buys one, and it comes with a liability release you sign.

Points Fund

A points fund is money a track or series sets aside for the end of the season and pays out on final championship standings, separate from the purse paid at each individual race.

Points Race

A points race is any event whose finish is added to a championship standing — track, regional or national — as opposed to a non-points show that pays a purse but leaves the standings untouched.

Provisional

A provisional is a rulebook-granted starting spot in the feature for a driver who did not race their way in, awarded on criteria such as series points standings and almost always starting at the tail of the field.

Purse

A purse is the total prize money a track or series posts for a single race or event, divided among the competitors by finishing position according to a published payout schedule.

Pyrometer

A pyrometer is the tool you use to read race tire temperatures. A probe (needle) pyrometer pushes a tip into the rubber to read internal temp; an infrared gun reads only the cooler surface.

Rainout

A rainout is a race program cancelled or cut short by weather before it counts as complete, sending the track to a rain check, a rain date, or a makeup show, and deciding whether points and purse get paid.

Rear Steer

Rear steer is the rear axle sitting or moving out of perpendicular to the chassis centerline, so the back of the car effectively steers itself and goes tight or loose with no input from the driver.

Redraw

A redraw is a random draw among the top heat race finishers for the front rows of the feature, so a driver who won a heat might pull the pole or might pull sixth.

Ride Height

Ride height is how high the chassis sits at rest, measured from a level floor to a fixed point on the frame at each corner. You set it with spring collars or jack bolts, and changing it moves cross weight.

Rod Bolt Stretch

Rod bolt stretch is the measured elongation of a connecting rod bolt as it is tightened, read with a stretch gauge and taken to the bolt maker's spec in thousandths of an inch, because elongation is clamp load.

Roll Center

Roll center is the pivot point a chassis rolls around at one end of the car. Its height relative to the center of gravity sets how far the body leans and how load moves across the tires.

Rollout

Rollout is the distance an RC car travels along the ground for one full revolution of the motor, calculated as tire circumference divided by final drive ratio.

Sanctioning Body

A sanctioning body is the organization that writes and enforces the rulebook for a class or series, licenses tracks and members, sets race procedure, and keeps the official points standings.

Schedule C

Schedule C (Form 1040), Profit or Loss From Business, is the IRS form a sole proprietor uses to report the income and expenses of a business, producing the net profit or loss that carries to Form 1040.

Section 179

Section 179 is the Internal Revenue Code election that lets a business deduct the full cost of qualifying depreciable property in the year that property is placed in service, instead of recovering the cost through depreciation over several years.

Self-Employment Tax

Self-employment tax is the Social Security and Medicare tax a sole proprietor pays on net earnings from self-employment, at a combined 15.3% rate — 12.4% Social Security plus 2.9% Medicare — on top of income tax.

SFI Rating

An SFI rating is the specification number on a safety part's certification label showing which SFI Foundation test standard it passed — 3.2A for driver suits, 38.1 for head-and-neck restraints, 16.1 for driver restraint assemblies.

Shock Dyno

A shock dyno is a machine that strokes a shock at controlled speeds and measures the force it produces, plotting compression and rebound damping against shaft velocity so a damper can be verified, matched or compared over time.

Shock Oil Weight

Shock oil weight is the viscosity rating of the silicone oil in an RC shock. It's labeled two ways — "wt" (weight) and cSt (centistokes) — and thicker oil slows suspension movement.

Shock Rebound

Rebound is the damping force a shock makes as it extends — how hard it resists the spring pushing the suspension back out. Compression damping is the other half, controlling the shock as it collapses.

Side Bite

Side bite is lateral grip at the rear of a dirt car — the rear tires' ability to hold against cornering load, as opposed to forward bite, which is traction in the direction the car is travelling.

Slick

Slick is a dirt track that has lost its moisture — a hard, dusty, gray surface where tires skate instead of digging in. Grip drops sharply and the fast line usually moves up.

Slipper Clutch

A slipper clutch is an adjustable friction clutch between an RC car's spur gear and the drivetrain, tensioned by a spring and nut, that lets the spur slip under sudden load instead of shocking the gears and tires.

Smash Number

A smash number is the load, in pounds, that a coil-over spring is holding when it's compressed to a specific shock center-to-center length — for example, 606 pounds at 18.250 inches on a Late Model.

Spark Plug Reading

Spark plug reading is inspecting a used plug's insulator, ground strap and threads under magnification to judge air/fuel mixture, ignition timing and heat range from the colors and marks combustion leaves behind.

Special

A special is a one-off, big-money race outside a track's weekly points schedule — a touring series date, an open show, or a crown jewel event — that draws outside cars and pays far more than a regular Saturday night.

Speedweek

Speedweek is a compressed block of race nights run at several different tracks in one region under one series banner. More than one series runs an event called Speedweek, so the name alone does not fix the dates.

Spring Rate

Spring rate is a spring's stiffness — the force it takes to compress it one inch, written in pounds per inch. A 400 lb/in spring needs 400 pounds to move one inch, 800 pounds to move two.

Spur Gear

The spur gear is the large gear an RC car's pinion drives, mounted to the transmission — sometimes on a slipper clutch or, on a 4WD car, a differential. Its tooth count sets final drive ratio with the pinion.

Stagger

Stagger is the difference in circumference between the right- and left-side tires on the same end of the car. A bigger right-side tire makes the car want to turn left on its own.

Standard Mileage Rate

The standard mileage rate is the per-mile figure the IRS publishes each year that a taxpayer may use to deduct the cost of operating a vehicle for business, in place of tracking and deducting that vehicle's actual operating expenses.

Sway Bar

A sway bar is a wire bar that ties an RC car's left and right suspension arms together at one end of the chassis, resisting body roll in a corner. Thicker wire means more roll stiffness.

Tacky

Tacky is a dirt track with moisture still in it — a wet, sticky racing surface that holds the tire and lets cars dig in. Racers also call it heavy or black.

Take-Off Tires

Take-off tires, in racing, are used race tires pulled off a car with usable life left and resold cheap. In the consumer tire market the same phrase means near-new tires with under 50 miles on them.

Tech Inspection

Tech inspection is the official check that a race car is safe to run and legal for its class — safety gear, weight, tires, engine and bodywork — done before racing, after the feature, or both.

Test and Tune

A test and tune is a practice-only session a track schedules outside its race program — no heats, no points, no purse — where teams shake down a car, break in parts and try setup changes.