Light duty Wheel, 50mm Dia. Grey Rubber tyre with black plastic centre and Plain bearing. Axle set and threadguards are included. Using the Axle set reduces the bore to 6mm. Load capacity 35kg. Despite being invented by Scottish vet John Dunlop in 1888, who initially developed the idea for bicycles, it was fellow Scot Robert Thomson who actually patented his idea for 'aerial wheels' back in 1845. Dunlop's air-filled rubber tyres proved their worth in cycle races, but it was the Michelin brothers who were first to fit them on a car, the 1895 Peugeot-L'Eclair that took part in the Paris-Bordeaux-Paris road race. Not only did these air-filled devices – made possible by Charles Goodyear's invention of strengthened vulcanised rubber – make the ride more comfortable than that given by a solid carriage-style wheel, they also allowed for greater speed. Tubeless tyres didn't come until 1903, however.