After seeing a Reddit post asking this question, I got into a discussion with someone about this and we couldn't agree on which there were more of. It's actually a really interesting question, with no obvious answer. I'm convinced that it's wheels, although you can just as strongly argue that the correct answer is doors.

For transportation: Cars are obviously neutral, as they have four wheels and four doors. 2-doored trucks, uni/bi/tri/motor-cycles, 18-wheelers, and trains all have more wheels than doors.

Obviously, the majority of doors are in buildings, though - a skyscraper could have hundreds or even thousands of doors in it. But there are also tons of wheels indoors - there are office and gamer chairs, drawers can have between two and six wheels in them, and lots of furniture can be wheeled around. There are also lawnmowers, suitcases, vacuum cleaners, measuring devices, scroll wheels, dishwasher trays, and tons of different types of toys that all have wheels too.

You also have lots of doors that aren't part of buildings - all 17 million shipping containers have doors on them, and for every drawer in existence, there's at least one cabinet.

Like I said, I'm pretty strongly convinced that there are more wheels than doors, but leave a reply with your answer and reasoning.

Obviously there's more wheels. We never even got to Doors 9

I'm the someone with whom the discussion began, and I'd say I'm slightly in the doors crowd but have been mostly drawn more toward wheels than cemented in my favor of doors. The situation seems to highlight the fact that doors are usually very visible and well spread-out, while wheels are more hidden and concentrated; e.g., a house has lots of doors, but once you consider a kitchen or bedroom, the wheels contributed by a set of drawers alone could be enough to win out for the whole property.

Toy wheels are also deceptive in their power, given the oft-quoted statistic that the most popular brand of tire in the world is LEGO. But so are buildings in general, since the average building worldwide is probably net positive for doors (though in the West, the question is even more interesting). And as mentioned, cars should be mostly completely discounted, which is probably what prompted this question in the first place.

Do potentiometers and rotary encoders count as wheels? If so one could say a lot of electronic devices have wheels in them…

But I agree it’s totally wheels.

Then again, how does one define a door?

There's no way its doors if you are willing to count wheels on chairs/furniture, in toys, in drawers, etc.

Doors. that's all I have to say.

Edit: You know what i changed my mind.

Do spherical casters count as "wheels"? Because they're neither cylindrical nor disk-like... although they certainly roll like and function like a normal wheel.

Think about factories, though. They are big warehouses and have no doors, but millions of wheels each, and there are a lot of them.

I'm on team doors, because I think there are a lot more doors than people think. All the cabinets, plus little hatches on the back of electronic devices. If we're counting those, then I think cars are actually a win for team doors, because they have things like center consoles and a back door

If this entire thread is a setup for this jab/joke then I commend both of you .

If we're counting toys, it's obviously wheels. Think of LEGO wheels, RC Cars/Matchbox Cars!

Well, wouldn't the trunk door of a car be considered a door? If so, that would mean there are more doors on a traditional car than wheels.

Wheels seem like a pretty simple definition- a circular object that revolves on an axle.

Doors are a bit more complex- judging by your assumption of a car being neutral, you are defining doors only as the means that people typically get in and out of the vehicle. But there are a lot more types of doors. Sliding doors, revolving doors, garage doors, appliance doors (such as refrigerator doors, oven doors, and washer/dryer doors), doggy doors, even the gas tank door on your car.

A door is defined as "a movable structure used for opening and closing an entrance or for giving access to something."

So really, it depends what you consider a door.

Despite all of that, I am still convinced there are more wheels than doors, based on what I've read. If you consider that wheels are usually replaced much more often than doors, I'm fairly certain that wheels are the winner.

Therefore hinges are effectively wheels. #goteamwheels

Well, hinges aren't necessarily circular. The tuning dial on your clock-radio, though... That's a toughie.

I'd say this is akin to asking whether there's more water or sand. It's not so much that it's unknowable, it's that there's so much grey area and it's kind of pointless anyways. (Yay Fermi questions)

well yeah, but there's obviously more water

I think we're struggling with the definition of each before even getting to the count.

Yeah, plus there's stuff like, what about other planets and galaxies? Is there sand on other worlds? Water? Does a spiral galaxy count as a wheel? A black hole's event horizon a door?