ELI5; Why can Vehicle tires last Tens of thousands of miles, While Shoes get destroyed after a couple hundred miles, Even though tires carry a much heavier weight than shoes and go much faster
In: Engineering
A funny thing happens with wheels, Imagine a wheel in motion, at bottom dead centre on the wheel where the rubber meets the road from the road’s perspective if we zoomed in a camera to the individual stitches of tread we would see that (unless the tire is skidding or under great acceleration) the tread is actually stationary from our road’s perspective.
This is all to say the tire’s contact with the road does not move relative to the road.
When we walk our feet slip, the act of separating your foot from the floor and putting it down again incurs a little slip, you may not even notice it but it does, your heel comes down the flat of your foot rolls kinda similar to the wheel then your foot departs exerting a lot of pressure on the ball of your foot that slips a little again and causes those two spots on your shoes to incur the most wear. And that’s not even taking into account all the times we pivot or slide on our feet.
A more apples to apples comparison of shoe to tire wear might be if I told you to press your hands against a wall, exert as much force as you possibly can while keeping your feet static to the floor…now how long do you have to press on the wall before your shoes wear out? The answer is a long time.
Vehicles are perfectly capable of killing a set of tires in a couple hundred miles just look at drift cars. The second the tire tread does start moving relative to the road you incur a lot of friction wear on the tire very quickly. And not just drift cars airplanes will only get about 500-1000 miles out of their tires, the act of touching down at 160mph and slamming on the brakes really has it in for them, and those tires are purpose built to do that job as many times as possible.
Now there are gonna be people out there saying it’s all about the rubber compounds of the tires vs the shoes and in some respects they’re correct, but even the most robust of work boot soles don’t live much past 4000miles. If it was just an issue of rubber compound someone would have just taken 6mm of tire rubber and added it to the bottom of a set of red wings to make a boot that lasts 25 times longer than anything in the current market. The real answer remains the differences in friction wear between walking and rolling.
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