Modified Cars

Overview: The modified class is a step up to higher performance racing. The modified class car typically features razor wheels, small diameter axles and extended wheelbases.

*Rule changes for 2010 are listed in red


M1 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) 

M2. Weight: Maximum 5 ounces on scale accurate to 1/10 ounce, or 142 grams

M3. Body Specs:

A. Width - Not to exceed 2 3/4 inches (7cm)

B. Length - Not over 7 inches (17.8 cm)

C. Weight - Not over 5 ounces on scale accurate to 1/10 ounce.

D.  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.

 M4. 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.

 M5. No part of the car body may protrude in front of the starting peg.

 M6. 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.

M7. The following items are PROHIBITED:

A. Springs

B. Starting devices or propellants

C. Electronic or lighting devices

D. Liquids, wet paint, oil, sticky substance, or powders of any kind (other than axle lubrication)

E. Glass or excessively fragile parts

F. Wheel bearings

G. Loose objects on car

H. Magnets 


M8. Modified wheels must conform to the following specifications:

  A. Wheels must be 31mm diameter or smaller.
Wheels 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.

M9. 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.

M10. The wheels must be attached directly to axle and spin freely.


M11. 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. 

M12. Axles must not be connected to any device that mechanically alters rotation and spin.

M13. 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.

WIRL race organizers reserve the right to reclassify or disqualify any car at their discretion.


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