They have no engine. It’s just gravity.
Don’t forget the speed holes.
No heavier than 4 oz, iirc.
Heavier builds more momentum. Once off the slope, rolling friction provides a constant drag, fairly speed independent. With more momentum, the heavier vehicle will resist that drag longer,
You will not get anywhere near speeds where wind speed will be a major, and mass independent factor.
When I raced them, the heavier cars always won, barring cruddy bearings etc.
Time travel about 4 or 5 centuries into the future, and get a Romulan cloaking device.
Once you’ve got it scaled down, you’re golden.
:smack: Of course! That’s why Hot Wheels are faster than Matchbox. The name is IN a flame decal! 
The Mythbusters talked about and tested the physics of Hot Wheels…err Johnny Lightning cars on a Hot Wheels type track in Toy Car vs Real Car. https://is.nisd.us/apps/video/watch.jsp?v=72436
A lot to unpack, here. First, rolling resistance is proportional to speed. Second, it’s not a big factor here, because it’s based on the deformation of the wheels. What you’re probably thinking of is friction with the axle, which would behave as dry friction. Third, the relevant question is not whether it depends on speed, but whether it’s proportional to the mass, which both rolling resistance and dry friction are, so if that were all that were relevant, the heavier car would have more momentum but also more resistive force, and end up with the same acceleration and hence same speed at every moment. Fourth, such cars are absolutely at a speed where air resistance is relevant, for them. Air resistance at that speed would be negligible for a real car, but that’s because real cars have much more mass. The more mass you have, the less relevant the air resistance is, which is why we want more mass.
We tested all of my son’s cars down in the basement, using a table as a long ramp. Not idea and not identical to the final races, but enough to get a feel for which cars were fastest. We picked the top two fastest.
Then today, I took him to the store and said if we can find any FTE cars or anyting specific for racing, I’ll buy it for him and we can take those.
We picked two cars at the store that were, by complete coincidence, almost identical to the used ones we found to be fast yesterday. They are labeled “best for track racing” on the box and we’re hopeful they will work well since they are new in the box.
I can report back with how it goes after next weekend!
Some of it is not from wheel deformation, but simply from two surfaces, not perfectly smooth, moving past each each other. A hair on the track, or similar, or just track roughness, has its own speed dependent cost. Wood and rubber, or hard plastic, do not slide past each other with zero friction, even with no significant deformation. I may very well have wind resistance wrong, as I’m thinking of cars massing half a kilo. It will be an issue for say 100 gram cars,
Demonstrably, there are worse fates. :smack:
Sometimes the best answer to a bad whoosh is a deadpan correct answer.
Another factor for Hot Wheels is that the early production tires have a lip on the inner edge, reducing surface contact which may increase or reduce speed. https://onlineredlineguide.com/wheels/wheels.html
In the tweaks link I gave above, the first tip is sanding the tires, which I assume is to increase the tires grip, but also would reduce of remove the lip.
Anecdotelly, I disgree with the assertion that Hot Wheels are faster than MAtchbox cars. I had two cars in particular that the Hot wheels cars couldn’t even come close to beating during my racing days in the 70s. Meet Hairy Hustler and Blue Shark, which were virtually undefeated. Can’t speak to the Johnny Lightning cars as they weren’t available to me then.
In fact, the reason why rubber is the favored material for tires is that it slides past most other materials with a very great deal of friction. But we’re not talking about sliding, here: We’re talking about rolling.
Good info. I wonder if Matchbox designed/redesigned their cars after Hot Wheels were introduced in 1968, the selling point of course was the race track that hadn’t existed before. I had Matchbox and Corgi cars prior the Hot Wheels intro (I got my first set Christmas '68) and never bought any after that.
What brand was it that had a single sheet of die-stamped metal (no undercarriage, no plastic), in a uniform color? I had a lot of those.
They absolutely did. Look at a Matchbox car from the 1960s (Hot Wheels were introduced in '68) – Matchboxes weren’t built for racing, but for general play – the wheels were hard plastic, and the axles were essentially nails. Mattel’s designers specifically designed their cars (with low-friction wheels and axles) for speed.
When Hot Wheels were first introduced, they were wildly popular, and Matchbox responded by changing their wheel and axles to make them similarly fast to Hot Wheels. When Hot Wheels were first introduced, they absolutely were faster than the Matchbox cars that were available at that time (because Matchbox cars weren’t originally designed for racing).
Yup, I recognize all of those Tootsietoys, especially the one with the off-center cockpit with the single fin behind it. That’s definitely the brand.
I think that’s supposed to be a D-Type Jaguar. And the pink ones behind it are, I think, Cheetahs.