I wrote out a draft for the rules:
World’s Fastest Schwinn Stingray Competition
Frame
Bike must make use of a Chicago built, 1963 1/2 to 1980 20” Cantilever Schwinn Stingray frame. Frame may be shorty style, longer style or Krate style.
16”, 12” and Fastback frames are not allowed.
The frame must be integral to the craft.
The frame may be modified in the following ways:
Frame braze-ons can be deleted. (Kickstand mount, chain guard mounts, fender mount brace.)
Rear dropouts can be made smaller or streamlined, but any dropouts present must be original. Dropouts may have additional holes.
All original frame tubing must be present, including seat post nub.
Frame tubing can be modified in the following ways:
Small holes can be drilled in the frame tubing to allow cables to run through the frame.
Rear frame triangle tubes can be cold set, bent inwards or outwards to accommodate larger or smaller rear wheels, rear swing-arm, low rider position, etc. However, tubes may not be chopped or cut to accomplish this. Cold setting only. From the side the frame must maintain stock lines. Frame tubes may not be bent up or down, as viewed from the side.
Fork
Front fork must be a Schwinn Chicago built Ashtabula or Springer style fork from any bike that said Sting-Ray on the chain guard. This includes Krates, Stingrays, Fastbacks, Midget Stingrays, Runabouts, Pixies, Lil’ Tigers, etc.
Forks may not be chopped.
Forks may have holes drilled to mount handlebars.
Forks may have mounts for handlebars welded on.
Forks may be reinforced with any kind of truss, brazing, extra metal, but the stock fork must remain.
Aero
Front and rear and bottom partial Aero fairings are allowed. However, as viewed from the side, 80% of the original Schwinn Stingray Frame must be visible. 80% of the front fork must be visible, as viewed from the side.
Wheelbase, Swing Arms, Frame Extension
Maximum wheelbase is 50”.
Rear swing-arm or frame extensions may be mounted to extend the wheelbase at the rear of the frame, allowing for lower riding position stability and safety at speed.
Rear swing-arm or frame extender may be of custom manufacture or design, but must be made of steel.
Wheels
Wheels may be no larger than 20”. Smaller wheels may be used.
Wheels may be any material or manufacture.
Front wheel may not have a wheel disc, and must have spokes. No mag or blade wheels.
Deep V rims ok.
Rear wheel may have a wheel disc.
Seat
The bike must have some kind of banana style seat. Seat can be chopped to make it narrower, wider, shorter, longer, etc. It must be a minimum of ten inches long and three inches wide. Seat can be any manufacture of material, or can be custom, but must resemble a banana or solo polo seat in appearance and spirit.
Crank, Pedals and Gearing
Functioning crank, pedals, chain and gearing are not required. Bikes may be gravity powered.
Any cranks, pedals or gearing present may be of any make, type or manufacture.
Power
No added power is allowed. This includes electric or gas power. Only human power and gravity may be used.
Handlebars and Grips
Grips must be Schwinn style. Repro or 80s cushion style Schwinn grips ok.
Any handlebar tubing present must be from a Schwinn that said Stingray on the chain guard.
Chain guard
No chain guard is required.
Any chain guard present must be from a Chicago built bike that said Stingray on the chain guard.
Knee Boards and Pegs
Knee boards may be present to allow for a low riding position. Rear pegs may be present.
Ballast
No more than 25 pounds of ballast external to the bicycle frame may be added to the bicycle. Frame tubes may be filled with material to make the frame itself heavier.
Maximum bicycle weight is 75 pounds.
IGBA Eligibility
Bicycle must be legal for competition with other gravity bikes under standard International Gravity Bicycle Association rules. Bicycle may qualify for either Fairing or Non-fairing classes.
Brakes
Brakes may be any make or manufacture. Bicycle must be equipped with front and rear brakes that can stop the bicycle from 100kph to 0 in 100 meters, as per the IGBA rules. Rim brakes, drum brakes, disc brakes, coaster brakes all ok.
