Why are some toy cars faster than others?

[heisthegaffer]

Dear cleverer people than me on PH, my little lad has a 3m long hot wheels track where we let cars go to race.

One thing that puzzles me is some are quicker than others. Some start slow but ultimately are same speed and are slightly behind but parallel to the one in front.

Some have larger wheels than others. To get him interested we've weighed them and written the weights to compare. They range from between 33 and 36 gram with the odd one more or less.

Perhaps some of the wheels work a bit smoother?

Any other ideas?

Thanks

[rix]

Mass, friction/drag!

[heisthegaffer]

rix said:

Mass, friction/drag!

Does drag make a difference at the speed these cars go and on something so small?

[normalbloke]

Red ones are faster.

[Kent Border Kenny]

heisthegaffer said:

Does drag make a difference at the speed these cars go and on something so small?

Yes. It’s not only from the air, you get friction between the axles and the body too, which won’t be a constant between cars.

[Evangelion]

I always thought that the axles didn't rotate, just the wheels.

[Bill]

Get some silicone lube on the hubs* and see if you can make the slower ones faster.

*ie the wheel/axle interface...

[RBS Bob]

I've spent hours wayching these guys.

https://youtu.be/YlPKAgBLEO0

[heisthegaffer]

Thanks all. May see if I can oil.

[C n C]

RBS Bob said:

I've spent hours wayching these guys.

https://youtu.be/YlPKAgBLEO0

Thanks for that (he says as he loses a couple of hours down another youtube rabbit hole)!

[heisthegaffer]

C n C said:

RBS Bob said:

I've spent hours wayching these guys.

https://youtu.be/YlPKAgBLEO0

Thanks for that (he says as he loses a couple of hours down another youtube rabbit hole)!

Very enjoyable. Must take the geezer hours to film and edit etc

[thebraketester]

Low manufacturing tolerances probably means they vary quite a lot in "spec"

[normalbloke]

thebraketester said:

Low manufacturing tolerances probably means they vary quite a lot in "spec"

Blueprint?