My teeth rattle every time I ride this thing

The wheels are wood with iron around them. I have gone thirty feet and it isn't just my ass that hurts. — Cyclist, 1869

The tire that fixed this was made by a veterinarian. John Boyd Dunlop's ten-year-old son complained about how rough the stone streets of Belfast were, so in 1888 Dunlop put rubber tubes full of air on the boy's tricycle, and the boy started beating his friends. Then the patent got thrown out. A fellow Scot had patented an air-filled tire about 40 years earlier, and everybody had forgotten. Good ideas get lost more often than you'd think.

What it broke: a tire full of air can go flat. The iron ones never did.

The full file

The fellow Scot was Robert William Thomson. He patented his "Aerial Wheel" on December 10, 1845, at 23.

His wasn't for bicycles. It was for horse-drawn carriages, to make them quieter and easier to pull. He showed them in London's Regent's Park in March 1847, and one set was said to have gone 1,200 miles without wearing out.

It never went into production. Rubber was expensive, and there were no bicycles or motor cars yet to want a soft ride. So it was forgotten until a veterinarian in Belfast heard his boy complain. Right idea. Forty years early.