WIRL Car Class Rules

  Pure Stock

 The Pure Stock Class is closely based on the traditional BSA Pinewood Derby rules and most restrictive division in WIRL racing. Cars racing in this division require stock BSA wheels, the new BSA wheels are accepted), standard axles, and a wheelbase of 4 inches or less.
See Official Pure Stock Rules Here

Pro Stock

The Pro Stock Class is the stock class for advanced builders. The Pro Stock class rules are more lenient than the pure stock class. There is no maximum wheelbase restriction, and different wheel and axle makes are allowed.
See Official Pro Stock Rules Here


 The modified class is a step up to higher performance racing, utilizing razor wheels, standard nail type axles and extended wheelbases.
See Official Modified Rules Here

Pro Modified

A Pro Modified car is the fastest type of legal WIRL car. The modified class car typically features razor wheels, small diameter or "needle" axles and extended wheelbases.
See Official Pro Modified Rules Here


The open class allows any car to run for times. This year for the first time, monthly points and certificates will be awarded. Cars must be gravity propelled and able to run safely without damaging track. Metal, bearings, over standard length or weight, bring it on! WIRL reserves the right to decline running a car in the open division if it is found to be potentially damaging to the track, the car, or other cars. Cars that do not pass specs for their regular class will be run in the open class.

The shared specs for most race classes (except Open Class) are as follows:


The main body structure must be made primarily of wood.

Body Specs:
Width - Not to exceed 2 3/4 inches (7cm)
Length - Not over 7 inches (17.8 cm)
Weight - Not over 5 ounces on scale accurate to 1/10 ounce.
Height- Not to exceed 2 3/4 inches (7cm) *not applicable to Rookie class
Center Rail Width Clearance – At least 1 3/4 inches (4.5 cm) minimum along entire center length of car.
Bottom Clearance - at least 3/8 inches (.95cm) from track. Fender flairs with less clearance are acceptable as long as the center rail width clearance is met.

Body design may be enhanced by adding other stable materials such as plastic or metal. All additions must be firmly attached and conform to the size specifications.

No part of the car body may protrude in front of the starting peg.

There should be an unpainted, unfinished wood surface on the underside of the car at least 1/2 x 1" (12 x 26 mm) to be used for a WIRL car number stamp.

The following items are PROHIBITED:
Starting devices or propellants
Electronic or lighting devices
Liquids, wet paint, oil, sticky substance, or powders of any kind (other than axle lubrication)
Glass or excessively fragile parts
Wheel bearings
Loose objects on car

There must be at least four wheels on the car, however, it is not required that all four wheels make contact with the track surface.

The wheels must be attached directly to axle and spin freely.

Axles must not be connected to any device that mechanically alters rotation and spin.

Lubricants must be dry on the axle at race time. Wet, oily, or greasy axles are not allowed. Over-application of lubricant which results in excessive shedding onto the track is not allowed. Approved lubricants include (but are not limited to) graphite, Teflon, and Nyloil.


Standard Wheelbase: No More than 4 1/2 inches (11.43cm) from center of front axle slot to center of rear axle slot.
Extended Wheelbase: Greater than 4 1/2 inches (11.43cm) from center of front axle slot to center of rear axle slot.
Standard Axles: 
Readily available nail or pin type axles with an overall diameter of no less than .084 " (2.13mm).
Needle Axles: Having an overall diameter of  less than .084 " (2.13mm).
BSA Stock Wheels: Standard issue BSA brand  wheels with 8mm tread.
31-8 Stock Wheels: Maximum 31mm diameter. Tread width no less than 8mm. Must be constructed of plastic, rubber, or polyurethane.
31mm Razor Wheels: Maximum 31mm diameter.  Must be constructed of plastic, rubber, or polyurethane. Wheel hubs may be made of metal, but may never come in direct surface contact with the track.
Drilled Sidewalls: Holes through the sidewalls of the wheels
Hollowed Wheels: A standard stock wheel in which plastic material has been removed from or otherwise modified on the inside of the wheel.

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WIRL rules copyright 2007-2012 and may not be copied or republished without permission
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