# How To Build a Pinewood Derby Car/Glossary

* Home
* Preface
* Rules
* Block
* Wheels
* Axles
* Assembly
* Physics
* Appendices

## Alignment

    The process of aligning the wheel vertically (camber angle) and parallel to the direction of travel (toe and steer angles).

## Axle Slot

    One of two slots cut in the stock BSA kit block.

## Beveling

    tapering the axle to reduce the contact area between the axle head and the outer wheel hub.

## Balancing

    Wheel modification to achieve an equivalent mass distributed about the hub.

## Block

    The 7 x 1-3/4 x 1-1/4 pine block.

## Bore polishing

    Polishing the inner surface of the hub to reduce friction between the wheel and axle.

## BSA

    Boy Scouts of America.

## Coning

    Modification of the inside wheel hub to reduce hub-to-body friction.

## Center Rail

    On wood tracks, a lane guide that is approximately 1/4" inch tall and 1-5/8" wide that the car straddles to keep it on the track.

## Deburring

    Axles are essentially one-inch nails that have two burrs under the head from the stamping process. A typical axle treatment consists of removing these burrs followed by sanding and polishing.

## Dominant Wheel

    The front wheel that touches when the car is on a flat surface. In a raised front wheel configuration, this is the wheel that is not raised.

## Extended Wheelbase

    The largest distance possible between the axles such that the wheels do net extend past the end of the block: 5-3/4" with the axle holes 5/8" from the end of the block.

## Graphite

    A form of carbon that is found in pencil lead. It is one of the favored dry lubricants

## Grooving

    Notching of axles to reduce the contact area and thus the friction between the axle and the wheel.

## H Tread

    A wheel modification in which the tread is cut with a "H" cross-section to allow contact with the track surface on the inner and outer parts of the tread only.

## Kit

    The Official BSA "Grand Prix Pinewood Derby Kit" with block, 4 axles, 4 wheels and instructions.

## Krytox

    A liquid synthetic lubricant (MSDS)., Krytox oils and greases are perfluoropolyether (PFPE) synththetic lubricants made by DuPont

## Light Wheels

    Wheels that have been reduced in mass, typically by removal of material from the inner side of the wheel.

## Matched Wheels

    Wheels taken from the same mold number.

## Mold

    The plastic injection mold for pinewood derby wheels.

## Mold Number

    The number on the inside of a wheel, indicating the injection mold.

## Moly

    Molybdenum disulfide lubricant.

## Molybdenum disulfide

    Molybdenum disulfide is a dry lubricant similar to graphite.

## Nickel plating

    Nickel plated axles can be polished to a smoother finish than stock zinc BSA axles.

## Notching or Grooving

    Axles can be notched or grooved to reduce the contact area and thus the friction between the axle and the wheel.

## Nyoil

    A liquid synthetic lubricant (MSDS).

## Outlaw Wheels

    Thin wheels machined from a high-performance polymer such as delrin that are typically allowed only in open class races.

## Oversize Axles

    Oversize axle (e.g. 0.091 diameter) axles can reduce wheel wobble. Official BSA axles are 0.087 inch in diameter.

## Rail Riding

    Adjustment of the dominant front wheel alignment to induce a slight steer toward the track center rail to cause the car to hug the rail as it goes down the track.

## Raised Wheel

    One wheel (typically front) raised approximately 1/16 inch on the car body. This wheel is not in constant contact with the track and thus contributes less to the rotational inertia.

## Silicone

    A polysiloxanes organic/inorganic polymer lubricant.

## Speed Axles

    Nickel-plated aftermarket axles.

## Teflon

    The trade name for polytetrafluoroethylene (PTFE) polymer. Powdered Teflon is a common Derby car lubricant.

## V Tread

    A wheel modification in which the tread is cut with a "V" cross-section to allow a single radial point of contact with the track surface.

## Wheelbase

    The spacing between the front and rear wheels from wheel center to wheel center. The standard pinewood derby wheelbase is about 4.5 inches and the extended wheelbase is 5.75 inches with the wheels 5/8 inch from the end of the 7 inch block.