The Sinclair C5 - the "green" vehicle that was way ahead of its time

The Sinclair C5 - shown here superinposed with a "Mini" for size comparison.
Picture from the official press release that accompanied the launch of the C5 on 10th January 1985
(and, therefore, as it was part of a press release,
my use of it in this article would appear to be both legal and ethical)

Read my C5 review here.

The Sinclair C5 was released in Britain on the 10th of January 1985, and initailly priced at about 400 pounds (640 dollars, 480 euros, at current exchange rates, but not allowing for inflation!).

Although it was a commercial failure, it is a very good case study of a "green" vehicle.

I remember the original release (I'm nearly 50 years old!), and later, the C5s being sold at half-price to get rid of the stock.

I didn't buy one, as back in January 2005, I was a clerk at the Ministry of Defence (if you're an American, think Department of Defense, and you're pretty close!), and iirc, my MONTHLY wage was about 400 pounds before taxes etc. and about 300 pounds by the time it actually reached my bank account, so being priced at five-and-a-half weeks pay, the Sinclair C5 (at the original price) wasn't exactly cheap!

Iirc, about 10 or 15 years, some C5s were uprated to have solar panels on them and were sold in iirc California.

I am posting this article because it might inspire someone to design a practical, modern, "green" vehicle, but do read my review first, for my comments on actually driving (riding?) the Sinclair C5!
Anyway, onto the dimensions.
There are a few link at the end of this piece where you can go to download manuals etc. for the Sinclair C5.


Size

• Overall length: 1.744m (5' 9")
• Overall width: 0.744m (2' 5")
• Overall height: 0.795m (2' 7")
• Wheelbase: 1.304m (4' 3")
• Rear track: 0.630m (2' 1")

Weight

• Empty weight (without battery): 30kg (66lbs)
• Battery weight (each - one or two could be fitted): 15kg (33lbs)
• Maximum recommended gross weight (including rider): 150kg (330lbs)

Powerchain

• Chainwheel: 42 tooth
• Rear chain sprocket: 20 tooth
• Cranks: 130mm
• Chain: 1/8", 181 links
• 250W motor driving a 13:1 gearbox
• Max motor revs: 4100 rpm, giving 315 rpm at the rear wheels
• Battery rating: 36 Ah, @ 5 hour rate
• Battery rating (in operation): 15 to 28 Ah, depending on motor load
• Front wheel size: 12 1/2 inch (203mm), with a 2 1/4 inch tyre fitted NB: caution - please read notes and comments below
• Rear wheel size: 305mm, with a 2 inch tyre fitted NB: caution - please read notes and comments below

Carrying capacity

• Rear boot(trunk): 28 litres (1 cu. ft.)
• Maximum recommend cargo weight: 10kg (22lbs)

Performance

• Maximum speed:
  motor only: 15 mph (24 km/h)
  pedal gearing is too low to allow pedal assistance to get much above the speed quoted above
  maximum speed (motor only) can fall to 12.5 mph (20 km/h) in cold weather
• Acceleration (motor only - "average" weight driver):
  0 - 5 mph (8 km/h): 1.8s
  0 - 10 mph (16 km/h): 6.9s
• Range:
  1 battery, motor only: c. 13 miles (c. 21 km)
  2 batteries, used sequentially (that is to say, using one battery only first, then using just the second battery), motor only: c. 25 miles (c. 40 km)
  2 batteries, wired in parallel, motor only: c. 33 miles (c. 52 km)
  range can be doubled in all three cases by using the pedals to move away from stationary, and by using the "burn and coast" technique
  range could fall by up to 50% from the above values in cold weather.

Notes:

• Information is taken from several sources:

1. the "Sinclair C5 Owners Handbook" by Sinclair Vehicles, 1985, the handbook supplied with all new C5s, particularly page 32
2. the Sinclair C5 original marketing brochure "Sinclair C5. A new power in personal transport."
3. information about performance and battery characteristics is primarily drawn from the work of P. Milner and P. Newman, who both worked for various Sinclair companies, and were both heavily involved in the development of the C5. Their data has been published in "The Unofficial C5 Service Manual", to which they both contributed, and elsewhere.
4. additional information about cold weather performance is drawn from an Automobile Association report from 1985, quoted in "Sinclair and the Sunrise Technology" by Ian Adamson and Richard Kennedy, Penguin Books, London, 1986.

• The wheel sizes can be confusing as they are listed by Sinclair as different sizes in different places!
  NB: caution - please read comments below:

1. The front wheel is listed in the Owners Handbook as being 12 1/2 inch diameter, while the rear wheels are listed as being 16 inch diameter, while they are listed in the brochure as being 317mm and 12 1/2 inch diameter for the front, with 406mm and 16 inch diameter being quoted for the rear pair, despite their actual diameters being 203mm and 305mm !!!
2. The "normal" "modern" bicycle convention is to list a 317mm diameter wheel as a 16 x 1 3/4 inch wheel (a size apparently popular on older Schwinn children's bikes), while a 406mm diameter wheel is a "decimal" 20 inch wheel size, and is the same as the wheel size on my folding bike! Such 20 inch wheels are fitted to BMX bikes, children's bikes, folding bikes, trailers and some recumbent cycles
3. The brochure (presumably prepared by an external advertising agency) seems to have assumed that Sinclair followed a different sizing convention for stating wheel size than was the case. Sinclair list the wheel sizes as 12 1/2 inch and 16 inch, but the brochure has assumed that they would be more generally known as 16 inch and 20 inch wheels in the bicycle world - indeed a 16 inch (actual) diameter wheel with a two inch tyre on it would be 2+16+2 = 20 inches in total diameter! AND 16 inches in metric is 406.4mm, so the brochures conclusion is not irrational.
   However, the TRUE rear wheel size is a 12 inch (actual diameter) wheel with two inches of tyre at the top and bottom, giving 2+12+2 = 16 inches!
4. Buy tyre sizes by the ISO size, not the "inch" size" - tyre sizes (according to the brochure) are 203mm x 57mm (front), and 305mm x 51mm (rear) NB: caution - please read comments section below
5. The late, great, bicycle mechanic Sheldon Brown has a feature article on wheel sizes on his website - worth a look to give you an idea about how different measurement systems can be confusing (and confused!), and reminds us all why the "modern" ISO (previously known as ETRTO) measurement system is so popular!
6. The conflict between the C5 having 2 inch tyres on 16 inch (actual diameter - i.e. 406mm) wheels, as suggested by the brochure, or having 2 inch tires on 12 inch (actual diameter - i.e. 305mm) wheels can be resolved by dicussion with an owner, visiting a C5 in a museum (I believe there is one in Manchester), or careful comparitive measurement of available photos.

Links:
The Sinclair C5 brochure
C5 Alive user group
SinclairC5.com user site

If you wish to thank me for this article, then please comment or click on one of the advertisers' links - you might like some of the "green" related stuff (I know I do!)