People across the globe have recently found themselves arguing over the same question - whether there are more doors or wheels in the world. The debate was sparked after Twitter user Ryan Nixon took to the social media platform to ask: “My mates and I are having the STUPIDEST debate...And I am here for it. Do you think there are more doors or wheels in the world?”
The tweet was accompanied by a poll, which closed with more than 220,000 votes and saw wheels win with a relatively slim margin of 53.6%. This question is impossible to answer, as no one can know exactly how many doors or wheels there are in the world.
Even arriving at a rough estimate of the respective numbers across Britain is extremely hard. For example, there were 24.7 million dwellings in England at the end of March 2020, according to data published by the Ministry of Housing, Communities and Local Government.
Equivalent figures for Scotland and Wales were 2.7 million and 1.4 million respectively – amounting to around 29 million residential units of housing. According to the 2011 Census, there was an average of 5.4 rooms per household in England and Wales. Assuming the average is the same including Scotland, and that each room has one door (and including a front door), that’s 6.4 doors per household.
That would mean around 184.2 million doors for houses across Britain, and if you assumed each one had a back door as well, 213.0 million. However, that only includes residential dwellings and not all the other buildings across Britain, before even considering sheds, fridges, freezers, cupboard doors, trap doors in theatre stages and many others.
Meanwhile, according to the latest Department for Transport figures, there are 39.2 million vehicles licensed in Britain. That breaks down to 32.0 million cars, 1.4 million motorcycles, 4.4 million light goods vehicles (LGVs), 505,223 heavy goods vehicles (HGVs), 141,772 buses and coaches, and 785,628 classed as “other”.
It’s probably safe to assume that cars, LGVs, buses and coaches have an average of four wheels, and motorcycles two. The number of wheels on HGVs (lorries) ranges from four to 12, so a safe assumption might be to take the average of eight. Vehicles classed as “other” include rear diggers, lift trucks, rollers, ambulances, Hackney Carriages, three wheelers, tricycles and agricultural vehicles.
At a rough estimate, that probably works out at an average of four wheels per vehicle. Taken together, that would equal 156.2 million wheels on licensed vehicles across Britain. If each one carried a spare, that would rise to 195.4 million, and if the steering wheel was counted as a wheel, the figure would stand at 234.6 million.
However, the picture is further complicated by the fact that vehicles also have doors, the average number of which is even more difficult to estimate than wheels. A very conservative guess might assume that cars, LGVs, HGVs and “other” vehicles have a minimum of two doors, buses and at least one and motorcycles none.
That would amount to at least 75.5 million doors on Britain’s licensed vehicles, and added to the estimated number of doors on residential dwellings, that amounts to 259.8 million (or 288.6 million including a back door for every home). So far, that’s between 156.2 and 234.6 million wheels and between 259.8 and 288.6 million doors.
But that excludes wheels on bicycles, unicycles and scooters, not to mention wheelbarrows, shopping trolleys, suitcases, roller skates, toy cars and many other possibilities. Indeed, the world's biggest producer of wheels (or at least tyres) is Lego. With no reliable data on these items, the question as to whether the world is home to more wheels or doors is likely to remain unanswered.