The cars : Sinclair C5 development story

Predicting the future – 25 years too early

Sinclair C5

Suggest buying a Toyota Prius and people will smile then nod approvingly. It’s cool to be seen to be doing your bit for the environment by buying an alternatively-propelled car. But tell those same friends that you always hankered after a Sinclair C5 and they will merely snigger and consider you rather strange for doing so. Strange, then, that Sir Clive Sinclair produced 12,000 C5s in nine months, and it took Toyota a whole lot longer – and cost rather more.

Sir Clive had already given the public accessible future technology. Though it was a Casio or Texas calculator that ultimately graced the executive desk of the 1970s, it had been the Sinclair pocket calculator of 1972 that started the ball rolling. Almost ten years later, the kit-build ZX80 led to the creation of the swish looking, ready-made ZX81, which truly kick-started the home computer revolution in the UK. In short, Sinclair Research was the UK’s Apple of its generation – giving the market exactly what it wanted, even though (customers) never knew they needed it.

The C5 was no different – except it was a quarter of a century premature.

Providing the spark – the Electrically-Assisted Pedal Cycle Regulations 1983

Boffins at the UK Transport and Road Research Laboratory configured this new legislation, the Department of Transport rubber stamped it. Sinclair then exploited these new rules to the max, ruthlessly.

Simply any ‘electrically-assisted cycle’ constructed to these regulations had to weigh less than 60kg, contain an electric motor rated at (no more than) 250W and meet British standard pedal cycle braking specifications.

So, if Sinclair could meet these specifications anyone over 14 could legally ride a C5 without need for any licence, insurance or road taxation (or a protective helmet – a socially outrageous concept 25 years later).

The secret factory

Sinclair C5Of course, it’s hard to share a vision without a physical product – or hard cash. The Electricity Council had previously funded £5.5 million pounds of research grants (£2.3 million alone to the Lucas/GM electric van). However, Sinclair’s funding for the project came via a 10% sale of Sinclair Research Limited and, according to a report in The Engineer magazine, a total of £12.9m from Sinclair’s own funds. Having secured the funding, a production line was sought.

Originally, Sinclair’s aim was for the C5 to be the foothold of a whole range of electric vehicles, so when an option on the ashes of John Z. DeLorean’s Northern Irish facility,came up Sinclair voiced an interest. Sitting idle was a purpose-built vehicle assembly line embracing many modern production methods at a knockdown price with a workforce and Government backing to boot. At the same time Sinclair Vehicles Limited (SVL) was established, based at the University of Warwick Science Park.

Early in 1984 the seemingly well-informed Engineer magazine claimed an announcement was poised (for the ashes of DeLorean), though ultimately an arrangement could not be brokered. Undaunted, the Welsh Development Agency stepped in: Hoover (the American vacuum cleaner conglomerate) had a modern facility in deepest Merthyr Tydfil with space and workforce to spare. With a planned production volume of 200,000 vehicles a year, Hoover became interested enough
to spend £100,000 on a satellite factory within the existing complex.

Starting with six members of staff in a sealed room, the project was sworn to secrecy, such that the only scoop prior to launch was six months later in November 1984, when the Mail on Sunday published a story. In fact, all parties involved in the project treated it with the kind of security normally reserved for a new car launch. Hoover staff trial assembled 100 C5s prior to full production, pulling them apart before reassembling. Potentially 50 C5s could be produced per line per hour – with a capability of a massive 8000 C5s a week…

The other advantage of Hoover’s involvement with the project came in the form of 19 service centres, 400 Engineers and recommend six monthly servicing of the C5. A healthy contract on 200,000 projected vehicles.

Where there’s a Wills, there’s a way

While Sinclair had an engineering aptitude, it was from the electronic rather than production background. However, an opportunity presented itself in the form of a casualty from the DeLorean debacle – Barrie Wills. Wills had a sound background in automobile lost causes – apprenticed at Jaguar, part of the team behind the Leyland National, Managing Director of Reliant before joining the board of DeLorean – all in the space of 20 years.

Wills was understandably sceptical of an electric car, but agreed to meet Sinclair regardless – despite being Delorean’s longest-serving employee, the Receivers were in control of the Belfast factory. Wills had a good relationship with Lotus in Hethel (so much so he would eventually father the front-wheel-drive Elan) and became the bridge between Lotus and Sinclair.

Formula One design

Sinclair C5

Development had already begun at Ogle Design (Tom Karen’s design house responsible for the Scimitar and the Raleigh Chopper cycle amongst others). Sinclair, aided by Tony Wood Rogers, had a spent a year with Ogle honing the prototype, but the design was faltering and getting heavier – 100kg, then 150kg. So, when Wills arrived in March 1983, Ogle and Sinclair curtailed their association and transferred development to Hethel – home of Lotus.

At Lotus, brothers Brian and Colin Spooner examined what they had inherited: a design study with a set of regulations. Although the design was reworked by Lotus (dropping its drag co-efficient of friction from 0.95 to 0.6), Sinclair employed a young graduate fresh from the Royal School of Art’s Industrial Design course – Guy Desbarats. Desbarats revised the design and added flush wheel trims, in addition to a small boot tweaking the C5’s Bond Bug-esque rear pillar.

Hethel’s chassis design gurus set to work on the pressed steel chassis. The design had many parallels with the humble ski – great torsional strength made by two pieces of pressed steel joined in a sandwich, whilst giving enough flex to create a suspension effect. Over 19 months, the design was tested extensively – not just at Lotus’s Hethel test track, but at the Motor Industry Research Association (MIRA) test facility. The C5 was subjected to every surface and test condition bar the famous banked oval. Uniquely, the C5 crash testing found that no injury was likely in a collision simulation up to the C5’s maximum speed (15mph).

For a little piece of competition pedigree, the Bugatti Owners’ Club even opened up Prescott Hill Climb so Lotus could put development miles on the C5!

Though originally sceptical of the whole commission for Sinclair, ultimately the Spooner brothers were won over – to quote Colin ‘It is a remarkably stable vehicle, it performs very well, and it’s safe. It is neither a toy or a plaything.’ To quote Brian: ‘The C5 is an extremely reliable piece of engineering, which I am convinced, will in time become even more sophisticated.’

The C5 also aided other automotive technology – its electronic display unit was created by AB Automotive Electronics. The next electronic display from AB would be the ‘Tokyo by night’ instrument cluster of the forthcoming Jaguar XJ40

Body moulding Maestro

Chassis and body was elegantly conceived

At launch, it was established that the C5 had the world’s ‘Largest, mass produced injection moulding’. A bold claim and backed up by the UK industry big-hitters. ICI supplied the white/grey pigmented plastic polypropylene – any scuffs or scratches just revealed the same hue – with Linpac manufacturing the two-piece shell. The practice involved injection moulding the upper part of the shell complete, and moulding the lower part complete.

Then a ‘tape’ would be placed between both halves of the shell whilst in a jig. The last stage was to ‘cure’ this tape by passing an electric current through it, effectively fusing the two halves (of the bodyshell) together. The total time taken for this process was just 70 seconds. A year earlier, in 1983, one of the first uses for this type of assembly was seen in the Austin Maestro – both its front and rear Bokan bumpers were moulded this way…

While the moulded bodyshell waited, the assembly of the chassis began – wheels, tyres, bearing and steering were fitted. With the electric DC motor installed, further electrics (lights) are fitted to the complete shell before it clothes the rolling chassis. Just like a new car, the virgin C5s were rolling road tested on a special jig – which replicated a 12 stone body weight – before being rolled into cardboard packaging for transport direct from the line to waiting trucks.

Energy crisis

As owners regularly found out, battery technology had kind of stalled. In reality, until the mobile cellular telephone became common place ten years later, battery technology was not massively removed from the turn of the century. Undaunted, Sinclair made the most of what was commercially available – his personal belief being that once electric vehicles became popular, battery manufacturers would up the ante and pay for the development themselves.

Joe Caine became Sinclair’s battery man. An ex-employee of Chloride, he contacted Sinclair by letter; one successful CV application later and he had his own lab in Bolton complete with £10,000 of testing equipment. In conjunction with Oldham Batteries, he developed a battery which withstood Sinclair’s remit 300 charge/discharge cycles. In four hours, a C5 could be 80% charged, in eight hours 100% charged. Because the C5 weighed 30kg and the battery (a 12V 36ah item) 15kg, it meant a spare could be carried and still not exceed the 60kg maximum of the new regulations.

Meanwhile, Wood Rogers had found his first suitable electric motor – originally envisaged for a truck cooling fan. However, the Bosch item was replaced by an Italian item, unfortunately from a company that also manufactured washing machine motors – something the press quickly picked up on…

It was hoped that a 20-mile range was possible from a single charge, boosted by using the ‘push and coast’ system of driving. Quite simply you accelerated, eased off the (electric) throttle, coasted then accelerated again.

The launch

Sinclair C5
Sir Clive Sinclair was bullish about the C5’s prospect at its launch (Picture: Planet Sinclair)

Sinclair Vehicles launched the C5 on Thursday, 10 January 1985 at Alexandra Palace in London. (Home of the first TV transmission in November 1936 by the BBC). The following day, the C5 made the front page of most national newspapers, followed by the invitation for the public to try the C5 over that weekend. Over 100 Electricity Board showrooms had a C5 on display to tantalise consumers.

Sinclair and Wills were upbeat during the press conference in which six C5s burst out of packaging on stage and circled the arena. A development film then showed the C5 being tested and, amongst the more sensible sales patter, rather bizarrely Wills informed the journalists present that the seating position was based upon that of the Ford Capri! The press pack also made much of the fact that the driver’s eye level in traffic was comparable to the Mini, but with a turning circle two thirds of Mini’s – not an amazing boast.

It was anticipated that over 100,000 vehicles could be produced in 1985, creating 200 jobs, and that as of 10.30am that day (during the press conference), it was confirmed that precisely 2507 C5s had been constructed so far. It was announced in addition to Hoover’s maintenance back up electrical retailer Comet had won the contract to handle replacement battery sales, with Woolworths additionally waiting in the wings. The Royal Society for the Prevention  of Accidents was represented too, assuring the press of the C5’s safety and handing out fact sheets.

Sinclair C5
Initial road tests soon revealed C5 shortcomings – drivers felt vulnerable in mixed traffic
Sinclair C5
Sir Clive Sinclair cut rather a dash at the launch of the C5 – but it was no quantum leap

The advertising plans for the new C5 were outlined, the main thrust of the £3m advertising campaign being TV commercials (even though the UK had just two commercial stations at the time.)

‘Imagine a vehicle that can drive you five miles for a penny; a vehicle that needs no petrol, just a battery; and that takes the press of a button to start, the squeeze of a lever to stop. That needs no licence, no road tax, and you can drive it whether your 14 or 40. A vehicle that costs just £399. The Sinclair C5 is a new power in personal transport. The Sinclair C5. £399. Want to buy one? Or simply want to read all about it? Just dial 100 and ask for free phone C5 – NOW.’

Persuasive stuff indeed. Final thanks were given to all the companies who had supported the project, then the floor was open to questions before the obligatory test drives. The overall response was all rather favourable – so, what went wrong?

The dream discharges

Sinclair C5
Somehow it all looked rather exciting…

Despite claimed orders approaching a 1000 units for the first week, and 5000 sales for the first month after launch, in reality approximately 7500 C5s were sold by Sinclair Vehicles – an impressive figure were it not for the additional 4500 unsold C5s.

Though available direct (with a crafty £29 delivery charge added to the £399 retail price) by the summer of 1985 Comet stores were offering C5s with free delivery. On 13 August, Hoover announced it was to cease production of the C5 due to the stock pile of unsold units. A last ditch attempt by Comet to retail the C5 at a slashed price of £139.99 (delivered to your doorstep) in September did little to stop the Receivers being called on 12 October.

Total debts at the point of liquidation were £6.4m, (Hoover’s debt alone standing at £1.5m). In an effort to recoup some cash the remaining 4500 C5s were sold by the Liquidators but, as manufacture was outsourced, nothing much else existed to offset the debts.

There are many theories to the downfall of the C5, but perception and price remain the two fickle favourites. Worthy as electric transport was in 1985, the world was not ready to save the planet – but it could justify a front loading video recorder with remote control, or a compact disc player. If you needed personal transport, a new bicycle was just 20% of the C5’s purchase price, and people didn’t stare at you on your way to work.

Therein lied problem number two – possibly the reason behind the C5’s downfall. Nobody dared be seen struggling to propel a C5 uphill with articulated trucks inches from your torso. Combine that with quizzical stares and finger pointing of the bemused general public and your pool of purchasers narrows considerably.

Sadly, the C5 was a visionary idea that just appeared in the wrong century.

Sinclair C5

Sinclair timeline 1958-1986

1958 Leaves school and becomes Editor of Practical Wireless

1961 Formed Sinclair Radionics

1962 Microamplifier – smaller than a half-crown. Joins MENSA

1966 Microvision TV (£99.95). Chris Curry joins

1968 System 2000 complete hi-fi system

1972 First calculator – Sinclair Executive (£79.95)

1973 Cambridge calculator (£29.95) Nigel Searle joins

1976 Company loses £335,000. NEB buys a 43% stake for £650,000

1977 Collapse of calculator market. NEB injects further £1.9m.

1978 £2m loss. First microcomputer designed and sold to Newbury Labs. Emerges two years later as the New Brain.

1979 Sinclair splits from NEB. Sets up Science of Cambridge with Chris Curry. Curry splits off and sets up Acorn. Sinclair sets up Sinclair Research.

1980 ZX80 (£99.95)

1981 ZX81(£69.95)

1982 Spectrum launched 16K (£125) 48K (£175). 300,000 ZX81s sold. Turn-over up to £30m

1983 Spectrums sell at 12,000 week. Microdrives (£49.95). Sinclair is The Guardian’s Young Businessman and is knighted in the Queen’s Birthday Honours. Flat Screen TV (£79.95)

1984 QL (£399). Turn-over up to £77m. Flotation of 10% values Sinclair Research at £134m. Spectrum Plus (£179)

1985 C5 launched by Sinclair Vehicles. Cash crisis at Sinclair Research. Maxwell steps in, and out. £10m raised by sale of Spectrum to Dixons

1986 Spectrum 128 (£179). Amstrad takes over computer business. Sinclair moves on.

Words: Andrew Elphick Pictures: unless otherwise indicated.

Andrew Elphick
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  1. It wasn’t a stupid idea- but certain aspects of the design were not thought through.

    For example, the low ground clearance meant that although the driver’s head may have been on the same level as a Mini drivers (the real thing- certain Bini model’s drivers are eye level with artic truck drivers…); but the fact that the vehicle was so short and because the driver sat as far back as possible- they were simply invisible to truck drivers. It could have sorted that quite simply by using a lightweight rear mast that curved over the driver’s head like a scorpion’s tail with lights and hi-viz markings.

    Another issue was that cycle tracks were only just coming into being in the UK in the 1980s. And early tracks were often very badly designed. For example, where I lived in Cheltenham, a disused railway track was surfaced with loose limestone chippings and turned into a cycle route. Problem being, that to access it you needed to get round a ‘slalom’ style gate presumably in order to deter motorcyles, yet this restricted access to standard-form bicycles, descriminating against wheelchair users, double buggy pushchairs (unless the occupants decamped), tandem riders, trikists, etc; whilst in wet weather the surface deteriorated into a soggy mush, and any cyclist without mudguards ended up wearing a reddish brown stripe on their clothes.

    A C5 could not have accessed such a facility.

    Still, these days it would probably make more sense with better access to cycle tracks- but its appeal would be limited to those with access to these.

  2. One fan site I found seemed to think the C5 would have done better if marketed as a simple “fun” car rather than as a commuter vehicle.

  3. Apparently, the C5 had at least one famous owner – Philip Oakey of The Human League (quoted in Smash Hits, 1986): “I went out on it three or four times at four in the morning so no one would see me. This lady asked me if I was an invalid.”

  4. Andrew and matthew thanks for the photos and infomation. I always fancied one!! Maybe a ebay purchase. I can take it down the cap and horse. Can I drink and drive? Andrew as you have a vast knowledge of these, have you got one? At least this massive plastic or fibreglass rocket will get through small holes and alleys. Well I could be like delboy in salford and paint it yellow!! they will called me grandad rocket man….. lol

    Thanks again guys your the best? Also thanks Keith for all the storys you a a ledgend!! Are you having a AR online meet up?

    Berny rover 216sli in red!! but now want a 25!!

  5. Well you younger guys may not want to be seen driving one of these about but when you get to my age and your plastic knee is wearing out and its a struggle to get around one of these looks a lot better than a mobility scooter……….. Plus I think it would look good outside my bungalow keep up the interesting posts guys

  6. It’s just too low down. I ride a motorcycle to work and I could imagine how much more dangerous it would be if I was too low down to be seen.

  7. They should have given it a camouflage scheme and stuck a few stickers on it – it works for Morgan

  8. I moved to holland, and because of the excellent cycle path network I decided to buy one for work.
    The problem is the speed. It is so slow. But with a 24v conversion and a 3 speed sturmey archer hub. It should reach 30mph, better than the standard 15mph.
    Very much ahead of its time i my opinion. And if the uk wasn’t so backward with its building of cycle lanes. It might have had a chance.

  9. I cycled one of these things from John O Groats to Lands end in 1985 sponsored by a midlands motor dealer, or more like pushed the dam thing up every hill we split belts burnt out the crude drum brake on the downhills. We got in the Guinness Book of Records Though.

  10. Speaking as a dutch Sinclair C5 user, sorry guy’s, The Sinclair C5 was absolutely made for the Netherlands. Practical all roads have seperated smooth bicyclelanes. Whe have no mountains, hardly any hill. Still drive it on a daily basis. Populair modifications in Holland. 7 gear for the bicycle part of the C5 combined with hand throttle instead of the original on/of button , so you can choose to hybride. Pedal or engine. The original 1 gear for the bicycle part is, because it is to small, not practical for that pedelac principle.



  11. Relatively speaking Sinclair was the Apple or Google of its day – combining technology with sleek contemporary design. Their calculators and watches made the competition from the likes of Texas and Casio look cheap and cluncky. All seemed set fair until the C5 came along. This one product killed the company stone dead. I hear that both Apple and Google are entering the car market – as is Dyson. Hopefully they will understand that clever engineering is all well and good, but if it makes the user look like a complete idiot it aint going to sell!

    • It suffered from being launched just after a Christmas, & promoted as a commuting car, when if they had waited until the spring & marketed it at a fun car things might have been different.

      A while back I was reading someone written by someone who bought one when they were discounted & said it was fun zipping around in parks, & almost everyone he had let have a go in it agreed.

    • Er, I seem to remember batteries in Black Watches overheating, the QL computer was released with a bit of motherboard sticking out the side, and the less said about plug in tape drives the better…. The mini TV’s weren’t that brilliant either. At least the Texas and Casio stuff worked and was reliable. Sinclair was extremely innovative but production engineering (and lack of investment finance) did for it.

      • That’s right the thinking was (mostly) right but the production seemed hit & miss, even when sub-contracted to Thorn EMI, Timex, Ferranti & Polaroid.

        Sinclair’s earlier radio kits were a challenge to correctly assemble, thanks to the PCBs being heat sensitive & using “out of spec” semi conductors.

      • Agreed, his products had the same issue as a lot of British cars on this site, of being really innovative but launched before they were ready…

  12. FWIW, the BBC4 Phil Jupitus programme History of the Future:Cars has a piece near the end on the C5 including a recent interview with Sir Clive and colour drawings of the proposed C10 hard top 2 seater and fully enclosed C15 which actually look quite good.

  13. The launch campaign for the C5 was massive, “seemingly money no object”. For a fraction of the £399, you could buy a good quality bicycle capable of 10 mile journeys without too much effort from the cyclist

  14. Real shame he went off at a tangent and made this thing. If he’d stuck to what he was good at we would all have Sinclair smart phones today

    • Some of Sir Clive’s projects were hit & miss, depending on how appropriate they were to people’s lives at the time, along with the build quality & the amount of investment.

      Even when he had something selling well it wasn’t long before the established electronics companies caught up.

    • If you had a Sinclair smartphone the battery would last 30 minutes, it would have enough memory for 20 numbers as long as they were fewer than 8 digits and if you plugged in the charger cable while the phone was on the CPU would be damaged. But it would be cheap.

  15. Ahead of its time? Er, no – this type of vehicle will probably never sell, eg compared to a safer/larger/longer range/more practical SAIC/Wuling Mini. Interesting piece in a paper yesterday that Clive, somewhat arrogantly, never did market research – that actually explains a lot as to why some of his products failed. Possibly surprisingly he didn’t write an autobiography and nobody appears to have done a biography of him – bit of a gap in the market there?

  16. The Sinclair C5 is of the category known as a Recumbent HPV, Alex Moulton made tests of such cycles in the late 1950s, a Freddie Grubb recumbent, and again in the late 1980’s, in each case he concluded the conventional riding position of a cycle is superior solution and closed his studies

  17. I think it is wrong to think of Sinclair Research as the British “Apple”, I think it is better to think of Acorn in this role.

    My reason for this is that Acorn sold like Apple sold products that were premium in both their engineering and quality they were always “reassuringly expensive”. Sinclair Research products were very much engineered down to a price point and whilst it bought success, their products were heavily compromised by this.

    Other reason is that the reason Sinclair Research were making computers was because of Chris Curry, who led the design of their first computer the Mk14. Clive Sinclair did not see much potential with it and his refusal to authorise a follow on product was why Chris Curry moved on to create Acorn with Herman Hauser. It was only then when Clive Sinclair recognised that it was the Mk14 that was bringing the cash in that he directed his team to build the ZX80 the first computer under £100.

    Whilst it showed Sinclair brilliance in bringing a £100 computer to market, you got a much more powerful and useable machine with the £170 Acorn Atom.

    Today’s mobile world owes a lot more to Acorn thanks to their development of the ARM processor that they designed to avoid the need and expense of a cooling fan and as a result has a very low power demand that has made battery powered handheld devices a practical proposition. Ironically Apple who had helped fund Acorn’s development and productionising of the ARM processor was able to use its share of the ARM spinoff business to fund its mover into mobile devices in 2002.

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