Myths vs facts

Tall tales about the C5

A washing machine motor! Invisible to lorries! Sold a handful! The C5 has gathered stories for forty years. Some are true, some are half true, and some started as jokes.

1. MythThe C5 had a Hoover washing-machine motor.

   FactThe motor came from Polymotor, an Italian subsidiary of Philips, which the press kit said made motors for aircraft and marine uses, including gyros and torpedoes. Sinclair press kit, 1985 Adamson and Kennedy say it came from the less glamorous end of Polymotor’s range: a modified washing-machine motor. Adamson and Kennedy It also says the motor was first meant to drive the cooling fan of a heavy lorry. Hagerty UK, 2025

2. MythHoover, or Lotus, designed it.

   FactIt was built under subcontract at Hoover’s plant in Merthyr Tydfil, South Wales, where production had begun in early November 1984. Sinclair press kit, 1985 The press kit said the C5 was designed by Sinclair and developed and tested by Lotus Cars. Sinclair press kit, 1985 Hagerty’s 40th-anniversary piece credits Ogle Design with the C5’s look, Exeter University with refining its aerodynamics, and Lotus with the final detailing, the last prototypes and the testing. Hagerty UK, 2025

3. MythThe pedals were only for show.

   FactThere were no foot controls. The pedals were there because the law required them; they could add range and get the driver home with a flat battery. Sinclair press kit, 1985 The 1983 Regulations let a tricycle count as a pedal cycle if it weighed no more than 60 kg, had pedals that could propel it, and had no motor except an electric one of no more than 0.25 kW that could not drive it above 15 mph. 1983 Regulations Sinclair User found that on a dry, level start a couple of turns of the pedals were enough before the motor cut in, but pedalling was needed on steep hills. Sinclair User, March 1985

4. MythIt did 15 mph.

   FactThe 1983 Regulations let a tricycle count as a pedal cycle if it weighed no more than 60 kg, had pedals that could propel it, and had no motor except an electric one of no more than 0.25 kW that could not drive it above 15 mph. 1983 Regulations The AA recorded a top running speed of 12.5 mph. Adamson and Kennedy The government’s road research laboratory found it was in effect a one-speed machine under power, at about 20 km/h. TRRL report, 1985

5. MythIt was an electric car.

   FactUnder a new 1983 law it counted as an ‘electrically assisted cycle’, so anyone aged 14 or over could drive it without a licence, road tax, compulsory insurance or a helmet. Sinclair press kit, 1985 At the launch Sir Clive began by saying what he was not announcing: a conventional car. The C5, he said, was ‘the first stage on the road to an electric car’. Adamson and Kennedy

6. MythLorries simply could not see it.

   FactIn tests by the government’s Transport and Road Research Laboratory, lorry drivers could not see a standard C5 just in front of the cab, and there was a blind spot just to the cab’s nearside. TRRL report, 1985 By night, with 5-watt lamps and a white body, it was relatively easy to see. TRRL report, 1985 The laboratory concluded that the C5’s overall record on the road might be similar to a pedal cycle’s: better in some respects, poorer in others. TRRL report, 1985

7. MythThe cold killed the battery.

   FactSinclair’s spokesman said the battery lost 8 to 10 per cent of its efficiency at zero degrees, and more below freezing. Sinclair User, March 1985 The AA’s test on its usual suburban course gave a typical range of ten miles, about half the claim; on a cold day in poor conditions the battery went flat after 6.5 miles. Adamson and Kennedy Sir Clive later admitted January had not been the best time to launch, as the batteries tended to give up in cold weather. The Guardian, 2021

8. MythIt was banned in the Netherlands.

   FactA Dutch transport authority ruled that the C5 was not suitable for Dutch roads in its present form, asking for better brakes, more reflectors and the mast as standard. Adamson and Kennedy Planet Sinclair’s summary says it was banned outright in the Netherlands. Planet Sinclair Yet by 1996 many resold C5s had gone to the Netherlands, where they suited the flat cycle paths. The Independent, 1996

9. MythHardly anyone bought one.

   FactIts catalogue says 14,000 were produced at Merthyr but only 4,500 were ever sold. Science Museum Group The National Motor Museum says fewer than 9,000 had been sold by the end of 1985. National Motor Museum In 1996 Maurice Levensohn announced that he had sold nearly 7,000 C5s, at up to £700 each, which he had bought after the venture collapsed. The Independent, 1996

10. MythNobody wanted the leftover stock.

    FactMany unsold C5s were eventually sold for less than a fifth of the original price. Hagerty UK, 2021 In 1996 Maurice Levensohn announced that he had sold nearly 7,000 C5s, at up to £700 each, which he had bought after the venture collapsed. The Independent, 1996 In 2014 a fully working C5 cost around £650 on eBay. BBC Future

The washing machine motor

Every source agrees the motor came from Polymotor, the Italian maker. Sinclair’s own press kit stressed the firm’s aircraft and marine work; Hagerty says the motor was first meant for a lorry’s cooling fan; two Guardian pieces and Adamson and Kennedy link it to washing machines. The Guardian’s 2021 obituary goes further, with a “modified Hoover washing machine engine”, and we found no 1985 source that says the motor was Hoover’s.

Hoover’s part was building the C5 at its Merthyr washing machine factory. That is probably how the motor story picked up the Hoover name. We call the motor a Polymotor design whose origin is disputed.

What did it cost to develop?

Sold, built and left over

Figures for C5s built run from about 12,000 to 15,000, and for C5s sold from “a few thousand” to 17,000. The what happened page charts them all. The fairest summary we can give is that most of the C5s built were sold in the end, but many of them only after the company had failed, at a fraction of the price.