Trekinetic: Reinventing the wheelchair

It's light, ultra-stylish and works on all terrains. David Wilkins meets a visionary British engineer who has turned wheelchair design on its head

Back in 2000, Mike Spindle was going on holiday when his family's flight from Luton was delayed. In the crowded airport lounge, Spindle noticed a "cool, good-looking lad" in a wheelchair and was struck by the jarring contrast between the fashion-conscious teenager's hair and clothes, and the staid, traditional design of his wheelchair. He immediately vowed to produce something better and started sketching ideas for radical new wheelchair designs on the back of his boarding pass.

Eight years later, the result is little short of revolutionary. How many British entrepreneurs or inventors have completely transformed an established, mature product and, by extension, the market for that product as well? Most of us can probably only think of one, James Dyson, who came up with the bagless vacuum cleaner; perhaps there should be an honourable mention for Trevor Baylis and his wind-up radio. But now it may be time to add a third name to the list, Spindle, the man behind the remarkable Trekinetic wheelchair.

The most obvious difference between the Trekinetic wheelchair and conventional designs is that it is built around a moulded carbon fibre seat to which the other main components are attached; older chairs use a tubular steel frame across which canvas is stretched to form the seat. But the Trekinetic wheelchair incorporates not just one major innovation but half a dozen, each the subject of a separate patent filing; collectively, they turn established thinking about wheelchair design on its head.

The world's most modern wheelchair didn't, of course, spring fully formed from the mind of its inventor to the wheelchair dealer's showroom. It was the result of six years of intensive development, involving 14 separate prototypes and hundreds of drawings and minor modifications. Apparently insurmountable technical challenges were overcome by Mike Spindle's faith engineering's ability to solve everyday problems. Spindle worked largely alone and without official help, funding the project from his own resources and those of his small Uxbridge-based engineering company.

The Trekinetic story begins in 2000. Spindle's company had invested heavily in a computer numerically controlled vertical machining centre, a sophisticated piece of equipment capable of automatically producing complex parts from solid materials, using data fed from CAD (computer-aided design) drawings. But his contracts to supply tooling to British carmakers were drying up as the manufacturers reduced their UK production or sourced their tooling overseas. Orders from Formula One teams provided some respite, but, by 2000, Spindle realised that he would have to design his own products, exploiting his company's expertise in precision machining, in order to keep his plant running. It was then that he had his inspirational moment at the airport.

One break with traditional wheelchair design made by the first prototype was to move the smaller wheels, or castors, from the front of the chair to the back, which immediately meant it was less susceptible to tipping backwards. Pressed aluminium side panels replaced the steel tubing of conventional chairs.

A second prototype, mocked up in plywood, was used to explore ideas such as incorporating a windshield to protect wheelchair users from the elements, but the next big change came with the third prototype, which demonstrated the principle of attaching the main wheelchair components to a strong seat, in this case an adapted aluminium racing-car seat. It was also the first prototype to have three, rather than four wheels; two large wheels at the front for propelling the chair and a single castor at the rear. With this design, all of the wheels usually remain in contact with the ground, even on an uneven surface. Drum brakes were also adopted; these had previously been used as parking brakes on wheelchairs, but on the Trekinetic chair, they could be used on the move.

The ninth prototype, produced in 2003, adopted a carbon-fibre seat for the first time. The wheelchair had so far been developed in secret, but Spindle felt this design was worth showing to a focus group of doctors, nurses and wheelchair users. This exercise showed up one of the great strengths of the design – its cross-country ability – but also some weaknesses. When Spindle demonstrated how to fold the chair using both hands in a standing position, for example, the wheelchair users immediately demanded something simpler.

One wheelchair user from the focus group, Robin Gibbons, a former Royal Navy diver, continued to provide valuable feedback over the remaining three years of the chair's development. It was Gibbons who pointed out that the three-wheel prototypes had poor directional stability and were unsteady at speed. Spindle solved the first problem by developing a mechanism that automatically and gently locks the rear castor into the straight-ahead position when travelling in a straight line and releases it when the wheelchair is turned. The answer to the second problem led to the development of the "Varicam", a device allowing users to splay, or increase the negative camber of, the main wheels when required, but also to return the wheels to the upright position in order to pass through narrow doorways; all done by simply twisting a bar under the seat.

It was also discovered that the chair performed better while moving with the seat mounted low, in a reclined position, but this change met with resistance from users, who wanted to sit upright when stationary. The solution was to incorporate an adjustable gas strut similar to those fitted to office chairs, that, as well as providing some cushioning, allowed the seat angle to be adjusted.

The final big step came when, at a cost of £50,000, the company tooled up to produce a purpose-designed, carbon-fibre seat which the production wheelchairs would use in place of the adapted go-kart seats on the prototypes. The tooling was ordered in April 2006, just in time to allow the first chairs to be produced for display at the Mobility Roadshow exhibition in June 2006.

But before Spindle could show the chair with confidence, he needed to get the Government's Medicines and Healthcare products Regulatory Agency (MHRA) to give it their seal of approval. This was only granted after a series of rigorous procedures, including a "strength and fatigue" test, which involved dropping the wheelchair 6,666 times. Spindle also used one of his visits to the MHRA at Blackpool to prove the chair's suitability for beach use.

The response to the first Trekinetic chair – the "all-terrain" K2 – was highly positive. A favourable online report by the BBC produced heavy website traffic and 400 email enquiries; most were from wheelchair users or from companies interested in the chair's commercial possibilities, but many were expressions of appreciation from architects, engineers and designers.

Some chairs were sold directly as a result of the show, but Spindle decided the best distribution channel would be carefully selected dealers prepared to invest in stock for display and demonstration purposes – crucial for an advanced product selling at the same price as the best conventional wheelchairs, about £3,000. The current network consists of 14 dealers in the UK, Belgium, the Netherlands and Australia, and, combined with direct enquiries from countries where the company is not directly represented, produces about five orders per week.

Spindle believes his current production set-up could handle 20 chairs a week, roughly the current capacity of the moulding process used by the supplier of the carbon fibre seats, although he is already considering a move to larger premises. Production of precision-machined parts stays in-house and most other components are supplied by about 25, mainly local, companies. Spindle believes the capabilities of the UK engineering sector are underestimated and finds that British companies can often use their expertise to beat the pricing of Chinese suppliers.

Spindle sees considerable scope for future expansion. interest has been bolstered by the recent introduction of the GT-3, a white "street" version of the Trekinetic chair with smooth, low rolling resistance tyres, and the company is still not officially represented in the American market, although there are hundreds of solid expressions of interest from the US. It is clear that he will not rest until he has achieved his ambition for Trekinetic to "be a major player in the global mobility scene".

The user's verdict

James Foster, 36, right, who works for GE Money, has been using his Trekinetic K-2 wheelchair for 18 months. He was one of the first customers.

"The Trekinetic is an awful lot faster than a standard wheelchair and a lot better once you get off paved surfaces as well. I'm always camping, fishing and kayaking and I'd never get to some of the places I go without it. In a conventional wheelchair you are always looking down at the ground, taking care to spot possible obstacles such as stones or tree roots, but in the Trekinetic, you don't need to bother. The drum brakes are great for holding the chair back and steering it when going downhill. The chair is good at getting over kerbs, as well; with the large wheels at the front, you don't need to use the "wheelie" technique you would in a normal wheelchair to get the small wheels over the kerb. It also helps break down a lot of barriers. People won't normally approach someone in a wheelchair but everywhere you go in the Trekinetic, it leaves a wake of turned heads and quite a few people come up to ask you about it. At the Isle of Wight Festival last year, I could hardly move because of the interest in it. I for one wouldn't go back to using a conventional wheelchair."

The expert's verdict

Jonathan Hollins, medical device product consultant

"While many wheelchair users are now experiencing improved quality of life in areas ranging from building access to sporting opportunities, when it comes to wheelchair design, they can often feel like second-class citizens. It is therefore great to see companies tackling the engineering and design challenge of creating an innovative and fit-for-purpose wheelchair. Of course the design must be modern and stylish, but not at the expense of performance, weight, durability and its ability to support the medical needs of the wheelchair user. For many users the choice of wheelchair comes down to two key points – price and pressure care. A wheelchair is a precisely engineered piece of clinical equipment, often the result of years of expensive R&D. The price of the wheelchair I believe represents good value for money in terms of the style, innovation and practicality it affords. In terms of pressure care, inherent design features, including an inclined posture angle, will provide latent benefits. Combined with the use of specialist pressure reducing cushions, users should experience a new dimension in wheelchair mobility. The wheelchair looks like it has managed to break the mould."