The "Primus Specification" Willans Silverstone 6 Harness is specifically designed with a shorter shoulder strap between the mounting point and the adjuster buckle for single-seat, open-cockpit cars where:
- The shoulder belt mounting point is very near the drivers shoulders and/ or
- The driver has smaller shoulder and chest size and/ or
- A larger or taller seat
- Other standard harness' shoulder straps "bottom out" and driver runs out of room to tighten the shoulder straps.
The Primus Spec harness is to help position the shoulder adjusters at the proper height. The adjusters need to be at chest level below the frontal head restraint/ HANS device and not too low near the drivers waist. As compared to the standard Silverstone 6 harnesses, the Primus Spec is 4" shorter from the tip of the shoulder mounting tab to the top of the shoulder adjuster buckles. Only 12" of fixed length versus standard of 16".
*To check for whether the Primus Spec or standard harness is best for you, measure distance from shoulder strap mounting point to drivers chest where adjuster buckles are needed in normal seated position with all safety gear on (fire suit, helmet and FHR/ HANS). A simple string can help measure.
Proven by the best where safety is paramount: Willans harnesses have been used by 19 Formula 1 World Champions and in over 250 Grand Prix wins:
- Expiration date: End of 2031.
- Silverstone 6 Single Seater 2/3 L&D LHAND FHR Use Only, FIA 8853-2016, but custom modified by Willans for Formula Race Parts and Primus Racing Parts.
- Choose color via drop down menu. Red, Blue, and Black colors are most common in stock colors.
- Shoulder Straps: The 2"/ 50mm wide shoulder straps (for use in conjunction with a Frontal Head Restraint (FHR) system such as a HANS Device) feature lightweight aluminum "Silverstone" adjusters and have 8mm (5/16") bolt-in endplate mounting tongues sewn in.
- Lap Belt & Sub Straps: The D-ring lap belt and looped sub straps eliminate the lower buckle tab for comfort in cramped cockpits.
- The 3"/ 75mm wide camlock lap belt has no bulky quick-adjust sliders. Length is adjusted when the belt is installed and stays static in length when strapping driver in.
- The D-ring lap belt and looped 2" sub straps each use two 8mm bolt-in mounting tongues to sandwich the belts in place.
- The camlock buckle is permanently attached to the right side of the lap belt, thus the LHAND delineation by Willans.
- FIA 8853-2016 approved.
Willans is the UK's largest manufacturer of competition seatbelts. Their harnesses can be found in everything from top ranking F1 cars to Formula Fords. All Willans harnesses feature military-specification polyester webbing, rotary camlock buckles, and FIA homologation.
* Most racing organizations only allow the use of 2" shoulder straps with an appropriate Frontal Head Restraint (FHR) such as the HANS Device.
Click here to view Willans Fitting and User Instructions.

