On 23/06/2018 06:26, The Natural Philosopher wrote:
On 22/06/18 22:01, Vir Campestris wrote:
On 22/06/2018 20:40, Chris Green wrote:
Does it*really*Â* work like that?Â* Tyres have steel or nylon bracing in
them to*stop*Â* them stretching much.Â* If you run on a flat tyre it
squishes somewhat but, unless it's actually skidding on the road
surface, the same circumferance will roll along the road surface for
each rotation.

Some of that circumference must rotate while it's off the ground.

The _radius_ at the bit on the ground is reduced, so it must spin the
tyre faster.


It would if a flat tyre was circular.

Since it isn't, you are talking relative ********

What is the radius of a tank track?


I'll take this slowly, but only once.

Imagine a wheel that was flat at the bottom so that it had half its
original radius. The rolling radius of the wheel is the radius where it
touches the ground - half the normal radius.

This bit at the bottom is the only bit that counts. The rest is not on
the road.

A tank track doesn't have a radius. It isn't a circle. The effective
rolling radius of tank wheels is exactly the same as it would be if the
track wasn't there - it's just they are rolling along a track, not the
road. This is why it is called a track laying vehicle.

Andy