Set up by three individuals Niki Smart, Jay Brett and Nick Mynott, SUB is a small
company in southern California that caters to clients who want individual specialised
vehicles. Their first vehicle, G1 a three wheeler is an evolution of work done by
Niki Smart years earlier on the "One-up" that sat in London's' Millennium dome.
G1 is a ground up build, demonstrating the company’s ability to produce, not just
one, but a series of fully functioning, innovatively packaged vehicles that are road
legal and that could be used in a day to day scenario as well as being pushed hard on a track.
The original One-up concept was 'An Engineering Aesthetic'. The project was about the
design beauty that purely engineered forms posses from their focus on performance and
efficiency. Smart looked a lot at castings and fabricated suspension parts as well as WW2
battleships and especially submarines. The idea was to be as minimal, without being a bike:
one seat, three wheels and a small engine. His original used a 600cc Honda CBR located behind
the driver. The resulting longer wheelbase (2.7m) made for a rear biased weight distribution.
The track was 1.6m. While similar in concept, G1 makes use of a tight packaged V-twin to
reduce the wheelbase to 2.3m (same 1.6m track) and to achieve a 50/50 weight distribution.
The 50% on the rear wheel and 25% on each front creates a dynamic, stable platform.
A major aspect of the project was to design and build a vehicle with aesthetic appeal -
a single seat, lightweight, high performance machine ideal for quick runs through canyons.
The project was never about straight-line speed or acceleration. More important was to create a
vehicle that handles predictably and controllably and is engaging and fun to drive, while keeping
the project within a manageable budget and time frame.
So Why Three Wheels?
Even the sportiest of cars on the market seem unnecessarily big with much unused volume and weight.
If you spend the vast sums of money that most exotic performance cars cost, the last thing that
you want when pursuing the ultimate performance and efficiency is to put your friend next to you,
destroying your power to weight ratio and upsetting the balance of the car. The idea of a single
seater seems logical for the ultimate in performance, even for the road.
In the automotive world, the notion of using three wheels where four would do is often received
with wonder and mistrust. It's usually employed as a sales pitch for vehicles that are generally
odd or dubiously functional. The discussions for and against are largely based on issues of
visual and dynamic stability, with the thinking that there is something missing (usually the
forth wheel). The aim of this project was not only to build a vehicle that overcomes some of
the stigmas of three wheeled vehicles, but to surpass them and to exploit their advantages in
an exciting and desirable product.
Some points of the project philosophy:
By using a 1000cc-motorcycle engine, efficiency is ensured (40 to 50mpg); because of the
light, compact engine and gearbox, and because the unit has been specifically designed to
propel a small mass as opposed to the engine and drive train in a conventional car
designed to propel an average mass of 3000lbs.
A major surprise is the use of motorcycle tires. This was to get the right tire contact
patch area distribution as well as weight distribution, with minimum tire frontal area
and rolling resistance. As the Morgan three wheeler demonstrated, you can attain high
cornering speeds on narrow tires. While it was easy to find a rear tire with the
required contact patch it was difficult to find front ones. However Avon builds a
tire for the cruising market where they have widened the tire by splitting the conventional
tire down the centre and added a spacer. Available in a choice of widths, the Avon’s
have the desired contact patch and are designed and built for the weight of the vehicle.
They have low rolling resistance and frontal area, to aid overall efficiency, and
lend the vehicle a unique aesthetic quality.
The low centre of gravity makes life easy for the suspension. Long double wishbones
at the front act through pushrods to inboard spring-shock units. At the rear, twin
trailing arms act through a pushrod to a transverse mounted spring-shock unit. In
such a light vehicle using rose joints throughout and needle bearings in the rockers
minimizes suspension stiction. With a single tire at the rear, the front suspension
system controls all of the roll. To minimize pitch under acceleration and braking,
the front and rear geometry has a low, central, instantaneous pitch centre. This
geometry also increases chain life by eliminating chain snatch.
Building the prototypes
The cornerstone of the project was to balance the weight of the engine with the weight
of the driver. The new package allows the vehicles to achieve a weight distribution of 25%
on each front wheel and 50% on the rear.
A low centre of gravity and minimal polar moment of inertia provide a stable but agile
vehicle. Both recreational and sports driving will benefit from its responsiveness and
nimbleness and it does not need power assisted steering or braking; so improving feel
and reducing component complexity.
Quick steering response is a by-product of reduced mass and low polar moment of
inertia, not on the number of wheels or how they are configured. A typical three-wheeler
is lighter and has approximately 30% less polar moment than a comparable four wheel
design. The yaw response time is the time taken to reach steady-state cornering after
a quick steering input. This is around 0.30 seconds for a softly sprung four-wheeler.
Four wheel sports cars will respond in about half that time. For a well designed
three-wheeler, it's as little as 0.10 seconds, which is a third less than a
high-performance four wheel car's typical 0.15 seconds.
A benefit of using three wheels is to qualify the vehicle as a motorcycle and not
a car, provided that the gross weight falls under 1500lbs.
Consequently the vehicle does not have to comply with the level of legislation that
a car has to. This typically means registration and road taxation.
As a motorcycle the vehicle can travel in the car pool lane on freeways, even with just one person.
Each individual brought a complementary skill set to the project. Smart is a
designer, and fabricator whose résumé includes work on the Aston Martin Vantage
concept and the ultra-light weight Ariel Atom sports car. Brett's background of
Industrial design and his ten-year involvement in film and automotive concept
vehicle construction lends the project his expertise in fabrication and program
management. Mynott, a digital modeller, has an extensive background in automotive,
product design and engineering and has worked on the construction of 6 concept
and race vehicles within the last 4 years. The combination produced the expertise
in design, modelling and build required for the project, the overlapping skills
creating an effective team.
Advanced 3D surfacing software was used to model the entire car from the ground
up. From initial suspension geometry in wire frame to the completed wishbones
uprights and wheel arches, all modelled and animated through its full range of
motion. The computer enabled the team to design, refine and simplify each component,
reduce costs and simplify assembly all before committing to production. In it's
element as a tool for building and checking interference, fit and assembly the
computer was used to speed production, reduce errors and produce a higher
quality at a reduced costs to the team. Throughout the build phase, modifications
were updated in data and the physical models continually checked against the
digital model to ensure tolerances were met. Co-ordinate geometry machines and
white light scans ensured that all the space available was utilized to best effect,
giving a finished product that is tightly packaged, of minimum weight and has a
formula feel. Once surfaced and highlighted, the body tools were CNC cut to
produce highly accurate low cost re-usable moulds. A complete cross section of
tooling from plaster, foam and clay to composite epoxy and even rapid prototype
parts were used. Composite parts were oven cured before being finished and
painted. Great importance was given to materials and finishes, from the powder
coated two piece custom made forged wheels to the black phosphate finish of the
steel bolts that hold the aluminium alloy uprights together. Everything was given
the same degree of consideration and importance to ensure a coherent high quality
finish. The result is three fully functioning road legal custom built vehicles that
were delivered on time, on budget and to a very high quality. Vehicles that have s
ince driven over 1000 miles each with only suspension and spring rates needed to be
What's it like to drive?
The three cars are each individually fitted to the customers with custom seats and
floor mounted pedals positioned to cater to their range in size; from 6 foot 8inches
tall, to 5 foot 10 inches. The car uses a modified motorcycle wiring loom and the
gauge pack is carried through as well, with everything functioning including the
fuel level meter. The indicators and lights are positioned around the gauge pack
within easy fingertip reach without having to take our hands off the wheel. Each
car is fitted with a four point anti-submarining harness and uses a cut off Momo
steering wheel for better gauge visibility. The cockpit walls are high giving
the formula car feel while rear visibility is good due to the positioning of the
mirrors. The gear stick is mounted close to the steering wheel on the firewall
that separates the driver from the engine which maintains the 6 speed sequential
box form the TL1000R. The steering is quick with one complete turn for lock to lock.
The brakes are strong and progressive giving good feedback. Driving on the road
you are smaller than most cars and much lower to the ground. You feel like a race
car driver because it has super bike-like speed and formula car handling. The ability
to see the wheels further enhances the formula feel of the vehicle with the ability to
place the wheels right on the curbs through corners. It all combines to create an
unbelievably fun and unique experience.