2026 SOUND OF THUNDER RULES
​​​​​​​& REGULATIONS

• BEARS Formula One: Purpose built race bikes and technically advanced production sport bikes. 661cc - Open capacity, fuel, and tyres.

• BEARS Formula Two: Pre 2006 production-based sport bikes 550cc - Open capacity.

  • Plus the following specific models: APRILIA: RS660, Shiver 750. BMW: F800. DUCATI: 848, Monster 821, 937, Supersport 937, 950. KTM: Superduke 790, 890. MV AGUSTA: F3 675, Brutale 750. TRIUMPH: Daytona 675, Street triple 675, 765, Hinkley twins. Pump fuel, Open tyres.

  • Note: F2 bikes may enter F1 if eligible but cannot enter both classes.

• BEARS Formula Three: Purpose built race bikes and production sport bikes: Four stroke, 501 - 805cc 2 valve multis & singles. 401 - Open 4 valve singles. Plus APRILIA: RS457. Two stroke, 0-350cc multi. 0 - 600cc singles. Open fuel & tyres.

• Lightweight (F4): Four Stroke, 0 – 500cc 2 valve multis & singles. 0-400cc 4 valve singles. Two Stroke, 0 – 350cc air cooled singles, 0 – 250cc air cooled multi’s & water-cooled singles, 0 - 125cc water cooled multi’s.

• BEARS SuperStock: Production based bikes. Original engine chassis & suspension layout. Modifications are permitted providing original concept and design are retained. E.g. a twin shock suspension may be altered to a box section swing arm but not changed to mono shock etc. Pump fuel only. Open tyres. Two classes.

  • Limited – Four stroke 0-750cc 2 valve multis & singles. 0-600 4 valve singles.

  • Open – Four stroke 751 – Open 2 valve multis, 601- Open 4 valve singles. Shaft drive multis may have 4 valves per cylinder but limited to 1000cc​

• Best of British: Open to any motorcycle manufactured in Britain. British engine and frame or frame of non Asian design. Open fuel, open tyres. Three classes run concurrently:

  • 0-750cc

  • 751cc-Open

  • Hinckley (All Triumph motorcycles 1991-present)

• Heritage: Any tubular steel construction frame with non upside down forks, must have twin rear shock suspension, one mounted each side of rear swing arm. Shaft driven bikes with twin or single shock must have rear shock absorber mounted beside differential. Open tyres, open capacity engine, air cooled, open fuel, carbureted and non-belt driven valve gear.​​

• Moto-Euro: Any bike manufactured in mainland Europe. (i.e. no British bikes) European engine and frame or frame of non Asian design. 401cc – Open water cooled 4 valves per cylinder twins. 601cc – open capacity all other machines. Open fuel, Open tyres.​​

• Milwaukee Iron: Open to any Harley Davidson, Buell or EBR. Frames must be of non- Asian design. Open Fuel, open tyres. Two classes run concurrently. 2V (max 2 valves per cylinder), 4V (max 4 valves per cylinder).

• BEARS Classics: (Non Championship Class) Non Asian design, pre 1972, no disc brakes, treaded tyres. Frame and suspension must resemble this era. Two classes run concurrently:

  • 0 - 500cc

  • 501cc - Open.

• A call to riders to prepare will be made 5 minutes before the pit lane opens.

• A call to riders to assemble at the dummy grid will be made 2 minutes before pit lane opens.

• Pit lane will be open for 1 minute and will then be closed with a barrier across the lane.

• Once Pit Lane is closed, any late arrivals will be required to start the race from a Pit Lane start. This will be at the discretion of the CoC, who's decision is final. The Rider will be held in Pit Lane and only released after the field has passed the pit exit road or a point deemed safe by the Clerk of the Course.  

- Control Tower 1 x Starter, 1 x Spotter (COC)

- Dummy Grid 1 x Grid Marshal

- Small tower trackside 1x Marshal (Checkered flag )

- Start line 1 x Red Flag Marshall (double as spotter)

- Track Grid 4 x Grid Marshals (double as spotters)

• Riders will receive one warmup lap once released from the dummy grid, and then stop for the red flag on the starting grid.

• Once the grids are formed the grid marshal(s) will, when confident the grid is ready to start, lower their yellow flag to indicate to the red flag marshal to move off the grid, only if they are also confident. When the red flag Marshal reaches the inside of the track the riders are deemed to be in the hands of the starter.

• These grid marshals (now spotters) as above are to always remain vigilant for stalled riders or riders expressing concern with one or both arms raised.

• If any marshals notice a rider/s with raised arm/s or have any other concern, they are to raise and wave their yellow flag to draw to the attention of the starter and the other marshals, all marshals are to raise and wave their yellow flag at which time the starter will abort the start procedure.

• Start light sequence. The red lights will come on and when the red lights go out it is the start of the race. If at any time the start is aborted the orange lights will start flashing and all marshals will raise their yellow flags.

• The red flag will be held out until the grids have been settled and deemed ready to start, at which time the riders will be back in the hands of the starter controlling the lights.

Notes.

• It will be at the discretion of the Clerk of Course if the grid receives a second warm up lap prior to starting if there is a hold up.

• Start procedure is to be part of the riders briefing and a sperate briefing for the Start Marshals.

• At the conclusion of racing riders should slow and continue around the track to assemble under direction of the flag marshal at the slip road at Flag point 3 (Hairpin).

• Once released by the marshal riders shall proceed directly to the track exit at turn 11 (Sweeper).

• Bikes returning to the pits must not use the pit lane to enter garages.

• At the conclusion of racing riders should slow and continue around the track to assemble under direction of the flag marshal at the slip road at Flag point 3 (Hairpin).

• Once released by the marshal riders shall proceed directly to the track exit at turn 11 (Sweeper).

• Bikes returning to the pits must not use the pit lane to enter garages.

Friday 20 Feb 2026

Practice:

• 4 x 20 minute sessions (Groups TBA)

Qualifying:

1. Lightweight

2. Heritage

3. MotoEuro

4. BEARS Classics

5. Superstock Ltd

6. Superstock Open

7. Best of British

8. Milwaukee Iron

9. BEARS Formula 3

10. BEARS Formula 2

11. BEARS Formula 1

Saturday 21 Feb 2026

• Tyre scrub 10min

1. Lightweight

2. Heritage

3. MotoEuro

4. BEARS Classics

5. Superstock Ltd

6. Superstock Open

7. Best of British

8. BEARS Formula 3

9. Milwaukee Iron

10. BEARS Classics

11. Lightweight

12. BEARS Formula 2

13. BEARS Formula 1

14. Heritage

15. MotoEuro

16. Best of British

17. Conti Cup - Bracket Race

18. Bracket Race - Dependent on Time Available

19. Bracket Race - Dependent on Time Available

Sunday 22 Feb 2026

• Tyre scrub 10min

1. Superstock Open

2. BEARS Classics

3. Superstock Ltd

4. Milwaukee Iron

5. BEARS Formula 3

6. BEARS Formula 2

7. BEARS Formula 1

8. Heritage

9. MotoEuro (European GP)

10. Best of British

11. Lightweights

12. Superstock Open

13. Superstock Ltd

14. Milwaukee Iron

15. BEARS Formula 3

16. BEARS Formula 2

17. BEARS Formula 1

18. Flying Farewell - North vs South Invitational