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              About Us

              Grinnall Specialist Cars is a centre for innovation and radical sports car and motorcycle trike design, and home of the Scorpion-III, a BMW motorcycle powered 3-wheeler cycle car, and Scorpion-IV, a 4-wheeled big brother to the III powered by a turbo-charged Audi motor. Grinnall also specialise in making three wheeled motorcycle trikes currently based on the Triumph and BMW motorcycles. Please go to grinnall cars for further information on the Scorpion-III & Scorpion-IV.

              Brief History

              For three decades, Mark Grinnall has headed a team of talented designers, engineers and craftsmen who have dedicated themselves to providing top quality performance on wheels.

              The company’s reputation was first made by its extensively reworked and refined conversions of the Triumph TR7 and TR8. By the early 90’s some 350 Grinnall TR8s had been constructed. In 2006 The Triumph Register acknowledged the Grinnall TR8 as a marque in its own right, and has compiled extensive history files on the vehicles.


              New concept needed

              In 1991, in search of a radical but affordable high performance concept, Mark Grinnall turned towards his passion for motorcycling, and his hand to an innovative three-wheeler, which unlike any of its illustrious ancestors would be high-tech, mid-engined and rear wheel driven. This was to be the first in a family of unique, niche-market sporting vehicles. The Scorpion-III made its debut in 1992 when it was featured in CAR magazine, an article written by a young Colin Goodwin. Interest in the S-III exploded in the mid 90’s, with the breathtaking featherweight being featured in dozens of magazines worldwide.


              The S-III is still in production over 20 years after its launch. This is testimony of the design quality and pleasing aesthetic. Using an online Yahoo social forum a global network of owners share their interest in the cars and experiences, with organised events and tours in the UK, Europe and the US. Trouble shooting discussions develop and an archive of history has been compiled to assist owners with cars some of which are over 20 years old. Full factory back-up guarantees all parts and service are available for machines new and old.


              The latest S-III model features the state-of-the-art BMW 1300cc 4-cylinder motor from the K1300S motorbike. With 185bhp, wider track, billet uprights, stiffened rear suspension and many other new features, this machine is lots of fun and very rapid. With 460bhp per tonne this little cycle car is guaranteed to upset Ferrari drivers, and can still return over 50 miles per gallon.


              The next stage in the company history was to create a four wheeled version of the S-III. Development of the Scorpion IV began in June 1998. Research had confirmed the plan was the right one. At motor shows and demonstration days up and down the country at BMW Motorrad dealers – and via our website – a significant number of prospective customers, and some Scorpion III owners too, had been asking us to produce a four-wheeler. They wanted a little more interior room, and even more performance, mainly for the growing track day market. Since that time, several more vehicles destined for this niche have appeared – and some have disappeared. Possibly one of the most successful arrivals is Simon Saunders’ skeletal Ariel Atom.


              Scorpion-III designer Steve Harper (SHADO) was again commissioned to style the S-IV to the same ‘form follows function’ design brief, and maintain a clear family relationship between the two.



              Findings from the research and development of the highly-acclaimed Scorpion-III went into the building of the new Scorpion-IV chassis; a space-frame structure which is remarkably rigid, yet respectably light. The front suspension is a development of that which works so well on the Scorpion-III: Unequal length double wishbones in oval tubing with inboard coil springs over custom made gas dampers, with adjustable camber and castor. At the rear, long, super-stiff longitudinal links give superb handling and camber control without compromising the vehicle’s distinctive styling.


              Exhaustive trials of possible power-trains included Rover K-series, Honda VTEC and Fiat 20v turbo – all fine products. Eventually however, we decided to use the incredible Audi/VW 20v turbo unit, which makes 225bhp in standard form and up to 500bhp after the tuning wizards have done their stuff. The slick Getrag 6-speed gearbox compliments this superb motor perfectly.



              In 1999 work began on the first of our motorcycle derived moto-trikes – with a single front wheel. For us the obvious starting point for a great trike was the BMW R1200C – a machine that had the twin advantages of BMW’s tele-lever front suspension and shaft drive. Launched in 2000, this has been a constant seller for us.


              To the Grinnall Trike collection were added the BMW R1200CL, the Montauk, the sportier R1150R, and in 2005 the Triumph Rocket 3 based trike – the R3T. This has been a wonderfully successful machine, and makes probably the best moto-trike on the planet. Continuing with Triumph a new moto-trike will soon be launched based on the fabulous Triumph Thunderbird 1600 and 1700. This new machine will herald the beginning of belt/chain driven trikes to be rolled out of Grinnall’s R&D department in the future.



              See latest news for future developments

              In 2013 we purchased a 2 acre former agricultural site on the outskirts of Stourport-on-Severn, Worcestershire (post code DY13 0TF). We would like to express our gratitude to WFDC planning department and committee members for granting planning permission for a new factory and retail showroom facility. Phase One is well underway, and will open in March 2015.


              The new site will allow the expansion of our moto-trike range, and finally enable full production of the Scorpion-IV. Re-organisation and production conformity will also allow us to comply with EU regulations and thus EU Certification of Conformity (COC), opening up huge sales potential within the EU. Neither production of the S-IV nor COC for the 3-wheeled vehicles were possible from the old site.

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              In 2015 we will be recruiting new staff in the assembly shop and sales. Interested motorbike engineers with an eye for detail and build quality are invited to register their interest via email with full CV.

              New Products

              They say in the automotive industry if you are not innovating you are going backwards. We are constantly developing and improving the entire Grinnall range. All the company’s original designs are highly evolved, but we listen to our customers and constantly strive to improve what we do.

              Scorpion III – K40

              The latest Scorpion III is powered by the amazing BMW 1200cc and 1300cc K-series engines. Power outputs are 170bhp and 185bhp respectively, giving the little S-III a power to weight ratio of over 460lbs/ton.

              The latest motor signals a break from tradition for BMW, as it is transversely mounted like most Japanese motorbikes. The centre of gravity is very low which improves safety at higher cornering speeds. The new motor also has a dry sump, which eliminates oil surge.

              There is now a choice of engine management systems. The Grinnall option eliminates the use of the CANBUS system used by BMW. Our plug-and-play system is very simple to install and it’s no longer necessary to connect the BMW computer for the engine install or servicing.

              Handling is sharpened by a new wide-track front footprint (120mm/4in wider), that uses new aluminium billet uprights. Steering feel is improved with a new adjustable steering column which is fitted with sealed needle roller bearings.

              The S-III is now offered in the latest colours including MICA paints and bespoke custom paint jobs.


              Scorpion IV – production re-starts in 2015

              This fire breathing monster was mothballed for several years due to lack of factory capacity and the resounding success of the R3T trike. However, the move into new premises in the spring of 2015 will enable production to re-start. We are currently developing a revised S-IV rear suspension that alters the rear camber in corners, thereby improving rear end grip. More information will appear here during the next few months.


              Research And Development

              R & D Partners

              Recognising that we are a minnow in automotive production terms and that we cannot be expert in every field, we have worked (and will continue to work) in partnership with some of the best engineering and test facilities in the UK and Europe in order to optimise our innovative designs.

              We are currently working with Steve Everitt, concept designer and builder of the Venom GT supercar as well as dozens of other notable automotive projects. Steve is currently involved in several developments for Grinnall which will be rolled out over the next few years.

              Sales and Servicing

              We offer full customer sales and support. We have a delivery service for sales vehicles, and collection and delivery on all servicing and repairs. For owners within theUK, repairs are carried out at the factory.

              Our delivery driver is a young retired fireman who is reliable and takes pride in his work.


              Within the E.U.

              Deliveries within the EU can also be quoted for by request.

              Export Worldwide

              For export orders outside the EU such as the USA or Australasia, we use the services of DSV. Kits or whole vehicles can be shipped to anywhere in the world. Individual are provided upon request.


              We carry a full stock of spare replacement parts for all of the Grinnall range. Items are dispatched the same day where possible. Export spares are sent out immediately if in stock. No part is too large or too small.


              Grinnall Cars are keen to meet like-minded, enthusiastic people with relevant experience who would like to join the company. If you are someone who has a keen eye for detail, takes pride in their work, and needs a challenge in life, then please apply by emailing your CV to mark@grinnallcars.com

              Current Vacancies

              We are always on the lookout for keen potential employees for our Assembly Department. The work involves assembling new vehicles as well as picking kits, stock checking, servicing and repairs.

              In 2015 following the move into new premises, we will be recruiting staff in assembly and sales. Interested motorbike engineers with an eye for detail and build quality are invited to register their interest via email with full CV. For more information please email your enquiry mark@grinnallcars.com

              We may also have other opportunities coming up in welding, laminating and painting, so if you would like to join the Grinnall team please contact us.

              In 2015 we will be recruiting new staff in the assembly shop and sales.

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