Overview: 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, standard axles, and a wheelbase of
4 ½ inches or less.
The main body structure must be made of wood.
Car is eligible to race for a 12 month period
from registration date. (Example: a car registered in November 25th, 2007 is
eligible to race until 12 midnight on November 25th, 2008)
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)
E. Center Rail Clearance –
Cars must clear the center rail which is 1 3/4 inches wide by 1/4 inch tall
along the entire center length of car.
Wheelbase – No More than 4 1/2 inches from center of front axle slot to center
of rear axle slot (11.43cm)
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
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
Loose objects on car
BSA wide wheels are required for the stock racing category. Outer wheel
surface may be lightly sanded, shaved, or polished to remove surface
imperfections and mold casting burrs, but must not be reshaped in any way in
an attempt to lighten the wheel, minimize tread contact or alter aerodynamics.
The fluting and other BSA markings on the outside wheel area must remain
following wheel modifications are PROHIBITED:
Rounding of wheel edges
Grooving, H-cutting or V-cutting
Altering of wheel profile
Narrowing the tread surface
Hollowing, sanding, or otherwise removing or modifying plastic material
from inside the wheel
Filling of wheel surface with any type of material
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.
Nail or pin type axles are allowed with an overall diameter
of no less than .084 inches (2.13mm). Some polishing and/or modification is
allowed as long as overall diameter is not reduced.
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.