The Big Car Database

The Mighty Atom

The Mighty Atom, Circa 1921, From Little Things...Another great example of New Zealand motorcycle creation, the aptly named 'Mighty Atom' was hand built by Mr J S Gibbons (his name being punched into the brass petrol tank cap).

  • ½ x 3/16 all-chain-drive
  • Gear ratios are top 3.5 to 1, low 7.2 to 1
  • Weight: 65 pounds
  • Wheelbase measures: 31in
  • Height to top of bars: 26in
  • Saddle: 18in.

Many components were entirely handcrafted, such was the number-eight-wire mentality that was applied. Putting aside the very unusual scale of the machine, much of the bike, on first impressions, reflects all the things you would want in a motorcycle. The following extract is quoted from N Z Motor Cycle, 1 August 1933:'The small motorcycle illustrated was designed and built by Mr Gibbons of Onehunga, New Zealand. Considerable ingenuity has been shown in its design and construction; notwithstanding its size, it is thoroughly roadworthy and is in daily use by Mr Gibbons.'For the benefit of readers, Gibbons has been good enough to supply us with details which will prove to be of interest. The frame and fork are made of 1/6 sheet steel, pressed to channel section with solid lugs and corner pieces welded in.

A single central spring is employed on forks, employing the Webb principle. It has aeroplane section tyres are 12 1/2 x 12 3/4 on 8', wheel base rims provide comfortable riding and the rear wheel is fitted with an external contracting brake, entirely home-made.'Perhaps the most interesting part of it is the engine: Ohv 2 port, which is a mixture of various parts. The crankcase is Akd to which is attached a cylinder of unknown origin fitted with a liner and alloy piston. Bore and stroke are 2 x 2 giving a capacity of 100cc and a compressed ratio of 7 to 1. With the Amac carburetor, Mr Gibbons reckons on getting 400 miles per gallon. The gearbox is a Douglas shell cut down, and new gears cut to fit a cork clutch made specially thin to fit inside the frame complete this unit. 1/2 x 3/16 all chain drive is employed. Gear ratios are top 3.5 to 1, low 7.2 to 1. Sixty-five pounds is all this wonder motor cycle weighs; wheelbase measures 31', height to top of bars 26', saddle 18'.'Mr Gibbons, who is 5' 6' in height and weighs 11 stone, has already ridden it 600 miles, and says it is capable of 50mph. Tested against a car, 38mph has repeatedly been attained. Tested on a skating rink, Mr Gibbons was able to tow 16 men!'The present owner bought The Mighty Atom roughly 35 years ago from Charlie Emmerton who lived in Ellerslie and was a bus inspector for the Otahuhu Passenger Transport Co.

This is a rare and wonderful machine that captures the essence of New Zealand's early custom-build culture.