Gary Hieber checks out the concrete surface at Shangri La II Speedway. Charlie Lawrence puts

 his Slingshot sideways during the Mid Atlantic, New Hampshire, Empire Tour Weekend. Peter G. Photo 2009

SPEEDSTR OFFICIAL RULES

1. All cars raced must be supplied by the manufacturer, Speedway Entertainment. Serial Plates will be in place.

2. Absolutely no structural modifications (welding, cutting, additions or brackets). The bodies must remain as supplied by the manufacturer and must fit the templates. All bends, rolls, and holes must be within 3/8 of an inch of the certified SpeedSTR^TM body.

3. You can adjust your car anyway you want but don’t cut, grind, or weld any components.

A. Coil Spring adjustment

B. Pan Hard height

C. Rear axle offset

D. Tire Stagger

E Coil Spring 100, 150, 200, 250 lbs.

4. Tires: All tires must be Goodyear Tires, purchased from authorized dealer.

A. Only allowable tires on the front.

1. Dirt Tires—22.0 x 8.0 x 13, part # D2520, D2355

2. Pavement Tires—22.0 x 8.0 x 13, part # D2432

B. Only allowable tires on the rear.

1. Dirt Left Rear— 27.0 x 10.0 x 15, part # D2514, D2336

2. Dirt Right Rear— 28.0 x 11.0 x 15, part # D2377

3. Pavement Left Rear— 26.5 x 8.0 x 15, part # D2462

4. Pavement Right Rear— 27.0 x 10.0 x 15, part # D2602

C. Pavement Tires can be used on dirt.

D. No grooving dirt tires.

E. Siping of Dirt Tires is permitted (Keep in mind, if your tire prep causes the tire to lose it's required Durometer requirements the tire will be deemed illegal and confiscated by Speedway Entertainment regardless if it is new.

F. Grinding of Tires is Permitted, NO Grinding with the "Bed of Nails" type Grinding Wheel.

G. NO Tire Softeners

H. Right Rear pavement tire can be grooved to 2 inch blocks.

5. Wheels: All wheels must be purchased from authorized STR dealer.

A. Wheels must maintain size and width, front wheels 13x7, LR 15x10, RR 15x13.

B. STR approved beadlocks allowed on all 4 corners.

C. No Bleeders.

D. Wheel covers allowed on all 4 corners, individual track rules may override certain wheel covers.

E. No welding or reinforcing of wheels.

6. Lugnuts: 1” steel Lugnuts only.

7. Car Components: No titanium or carbon fiber. All bolts must be solid steel.

8. Clutch: STR approved steel pressure plate and disc (8.5” diameter) with approved aluminum flywheel. All cars must self start and pull out for all events or will start in the rear of that event.

9. Front Axle: No cutting or welding of front axles. Must be purchased from an authorized STR Dealer and made by Speedway Entertainment.

10. Body: Bodies must be used as supplied by manufacturer.

A. Must be within 3/8” of template.

     B. Min. thickness .040 Max thickness .050 aluminum.

C. 2 1/2” wicker bill allowed between nose and hood.

D. All panels must be in place at start of event.

E. Top wing must use STR mount bracket.

F. Manufactures approved contour and angle.

G. 1 1/2” STR wicker bill allowed on rear of wing.

H. Grill must remain open at all times to stock size.

11. Lettering: Driver’s name must be on visor, contingency decals must be in specified locations.

12. Brakes: Wilwood calipers only.

A. Fronts must be Dynalite singles, LR regular Dynalite.

B. RF caliper may be removed for dirt races only.

C. 3 brake rotors must be on cars at all times.

D. Any brake pad may be used.

E. 1’ bore master cylinder only.

F. All steel braided brake lines.

G. RF shutoff allowed.

14. Engine:  Must be STR, Mopar manufactured and sealed by Speedway Ent. All components must be purchased from authorized STR dealer.

      A. Only allowable adjustments: Sparkplugs, Timing, Main pill, Barrel valve, Valve springs, Shims, STR straight nozzles only. Any stack length, Straight stacks only, Cam timing, Intake port may be matched 1 1/4” from flange, No other items can be done to improve airflow.

      B. All engines must be returned to Speedway Ent. with seals in place.

C. There will be a $250.00 fine for each seal removed.

D. Speedway Ent. has the right to claim any engine at any time to completely evaluate.

E. Any components found illegal will not be returned and loss of all points

to date.

F. No oil additives  

G. All replacement parts must be original  2.4 Mopar.

H. No grinding, polishing, lightening, changing size, or location of any part.

15. Fuel System: STR 1 15/16  Hilborne Fuel Injection components only supplied by dealer . No additives including fuel lubes, fuel must pass water test.

16 Air Filter: K&N part number RD 0620 only. Outerwear's allowed. All 4 filters must be in place at all times during competition.

17. Gauges: Only allowable gauges are Oil pressure, Water temp, Oil temp, and Tach. No other monitoring devices allowed.

18. Shocks: Only allowable shocks will be STR stamped Bilstein 1030, 3535, 4020.

19. Springs: STR Springs only (no modifications)

A. Length 11 1/4” 

B. Spring rates: 100, 150, 200, 250 only.

C. Spring rubbers allowed.

20. Battery: Must be 12 volt dry cell type only. Size 9x7x7, 1” tolerance.  

21. Car Dimensions: Chassis must have serial number plate in place at all times.

A. Radius rods must be stock length.

B. Wheel base min 72” max 74”.

C. RR hub offset max. 11 1/2” from outside chassis to inside RR wheel.

D. 3” min ride height.

      E. RF offset max. 13 1/2” measured from outside chassis to inside RF wheel.

F. Engine must remain in stock location.

22. Gears: Solid steel, no holes. 

A. Min. thickness 1”

B. 433 ring and pinion only.

C. No modifications.

23. Torque Link: Must be tethered.

24. Pinion Angle: Max. 1 degree up.

25. Safety: Speedway Ent. Does not enforce any safety issues. Track safety rules will be the default in all instances.

All bumpers, front axles, etc. must be STR certified. Components must remain the exact dimensions and thickness of the original. Steel or aluminum rod ends will be allowed.

All chassis repair must be performed by Speedway Ent.

26. Weight: Minimum car weight after race with driver must be 1400 lbs. All weight added must be bolted at rear of chassis to tabs provided.

27. Fuel Cells: Stock STR fuel cell as supplied by manufacturer. Stock location, no adding of divider baffles.

Contingency decals must be in place.

SpeedSTR^TM  manufacturer reserves the right to reject any car from competition with penalties .

All protests must be in writing to Speedway Ent.

Speedway Ent. Is not responsible for any race track procedural rules. It is the racers responsibility to participate in all driver meetings.

28. Traveling to Race: If you do not travel and attempt to compete in a race event the following race event will only be $600.00 to win, so do you best to travel to each and every SpeedSTR race event.

Basic Set-up

1.Great set-ups: are done by trial & error. Keep good records.

2. Chassis Height:

            Dirt:                 LF - 3 1/2                   RF - 4 1/4

                                    LR - 4                          RR - 4 3/4

            Pavement:      L Side - 3                   R Side - 3 1/2

More height=more side bite and less forward bite

Less height=less side bite and more forward bite.

3. Tire Stagger :       Dirt 3” - 5”, Pavement 3” - 5”

4. Tire Pressure:

            Dirt:                 LF - 10 - 12 lbs.         RF - 12 - 14lbs.

                                    LR - 4 - 6 lbs.             RR - 7 - 10lbs.

            Pavement:      LF - 10 – 12 lbs.        RF - 16 - 18lbs.

                                    LR - 8 - 10lbs.            RR - 18 - 22lbs.

More air in rear tire loosens car up, use air to work with stagger.

5. Rear Panhard Height: Higher loosens entry and tightens exit. Lower tightens entry and loosens exit.

6. Wheel Weights:   Dirt                  10 lbs. LR wt.

                                    Pavement       10 - 20 lbs LR wt.

7. Right Front Inset : 2” - 5”, Measure by running string across the outside of the RR tire and stretch it to front tire. Measure distance from string to outside of front tire.

Greater the measurement the looser the car

Smaller the measurement the tighter the car. 

Example: This can be adjusted by moving your wheel on the axle or by trailing or leading the RR.

8. Toe-out: should be set at 3/16” out.

9. Front Axle : Make sure front axle is square. Measure from crossbar back to axle.

10. Caster: 3 - 5 degrees

11. Front Radius Rods: Must be bind free.

12. Be sure all suspension parts are lubed and bind free

14. Coil Springs:

            Dirt:                 LF - 150 lbs.              RF - 150 lbs.

                                    LR - 100 lbs.              RR - 150 lbs.

            Pavement:      LF - 150 lbs.              RF - 200 lbs.

                                    LR - 200 lbs.              RR - 250 lbs.

Soften corner for more bite.

15. Shocks:

               Dirt:                 LF - 35/35                  RF - 35/35

                                    LR - 35/35                  RR - 35/35

            Pavement:      LF - 40/20                  RF - 40/20

                                    LR - 35/35                  RR - 35/35

Maintenance......

SpeedSTR’s are real race cars and must be treated as such to be competitive. If you are unsure about anything posted in this manual, contact a certified dealer for assistance.

Cars must maintain a clean appearance at all times. This will assist your maintenance program.

All moving parts such as rod ends, throttle linkages, etc. must be lubed with WD-40 or equivalent. All grease fittings should be greased every race.

Make sure all nuts and bolts are tight after every race.

With your 2009 rules book there will be a suggested routine maintenance checklist. Feel free to make copies and use after each and every race.

OFFICIAL 2010 ONLINE

SLINGSHOT by TOBIAS RULE BOOK

1. Coil Spring Adjustment
    
2. Pan hard height
    
3. Weight ballast. No liquid or loose weight allowed. No weight allowed inside exterior or interior side rails. Add-on weight cannot be outside of cockpit and must be secure.
    
4. Rear axle offset. Cars must be 2 wheel drive at all times.
    
5. Tire stagger is up to individual preference
    
6. Coil spring rate 60, 80, or 100 lb. allowed. Mix or match corners.

• 16-650 and 18-950 minimum Durometer reading 60 (estimated)
• Front asphalt minimum Durometer reading 65 (estimated)
• All cars checked must be within 4% of each other. Example: If all cars Durometer at 62 your tire cannot be more than 2.84 lower than that.

Air Pressure : 12 lb. Minimum right rear for cars 790 lbs. and over.18 lb. Minimum for all others 760 and over. Air will be checked prior to events. Juniors RR will remain at 15 lb.

Air must touch rubber of tire (NO LINERS). If inner tube is used it also must touch tire rubber. Only 1 valve stem allowed in RR wheel.

• The 16/650 tire is the only allowable tire on the front.
• Tires allowed on the rear are ,18/9.50,18.5/8.5 (Saw tooth) and 16/6.50.
• Asphalt tires may be used on any track surface.
 

• NO welded reinforcement on any wheel will be permitted  at all. RR wheel cannot be reversed . Valve stem outward.
• 1/4” bolt on Bead Protectors allowed.

• No modifications to engine. No oil additives.
• The only allowable adjustments are idle, speed jets, valve lash, carb jets, valve springs, valve seals, retainers, spark plug and flywheel timing.
• All replacement parts for Model 35 must be original Briggs & Stratton manufactured engine parts. (No grinding, polishing, lightening, changing size or location of any part).
• Only KNRD-0720 Air Filter allowed or exact equivalent. No open tops.