The first disc brake?
When was the first disc brake fitted to a cycle? All the new motorbikes and even expensive bicycles have them of course, but it wasn’t always so. Just like so many other items, they were around 100 years ago. (Just for fun, here is a partial list of that 100+ year old tech: Transverse 4 cylinder motors, Water cooling, Telescoping forks, Monoshock rear suspensions, etc.)
Quickly defined, a disc brake has just two things: a disc and a caliper. The caliper has TWO or more pads that are actuated in the axial direction (along the axle direction). Drums have one or more pads or shoes that move radially away from the axle centerline. Exceptions occur of course.
The common answer the question is the Honda 750 or the Lambretta scooter. Those were relatively early examples of motorbikes with factory installed disc brakes. Going earlier, some folks claim the Douglas Reseach Association (RA) of circa 1922 as a disc brake.
But the Duggie was really just a dummy rim brake as was common in the 19teens. The dummy rim is spoked to the hub, with a shoe rubbing against it to decelerate the bike. Douglas’s invention was to cover the steel rotating rim with braking material instead of making the brake shoe from braking material. But otherwise, it looks very much like the rest of the brakes of the era. Dummy rim brakes had a V groove like the RA, sometimes the V was facing inward, sometimes outward. But the braking action was always from a shoe moving in, towards the axle. Just like the RA does. A good description is here, which is also were I found that photo. Click the link to read more about why it isn’t a disc brake.
For more pics of a typical V acting brake from 1913, with a V groove just like the RA, acting radially (this one acts outwards instead of inwards) onto a V rim that is spoked to the hub, click here to see how to make brake parts: https://occhiolungo.wordpress.com/2010/10/18/how-to-veteran-motorcycle-brake-blocks/
But if we go back further to the turn of the century, we see this Abingdon Axle. It has a caliper acting on a disc, although it uses cable operation not hydraulic fluid. Note that the caliper has two brake pads that moved axially towards each other. The V that is visible is the belt pulley, and is not part of the brake action. This terribly fuzzy image is from James Sheldon’s book, and I wish that I had more info than that. Has anybody ever seen a c1898-1905 De Dion fitted with a rear disc brake? Send your comments via the link.
This topic continues here: https://occhiolungo.wordpress.com/2013/11/10/first-disc-brake-continued-national-motorcycle-museum/
and continues further here: https://occhiolungo.wordpress.com/2013/11/18/the-first-disc-brake-part-3/
PS, Blaise D. sent in this from wikipedia for early autos:
Disc-style brakes development and use began in England in the 1890s. The first caliper-type automobile disc brake was patented by Frederick William Lanchester in his Birmingham factory in 1902 and used successfully on Lanchester cars. However, the limited choice of metals in this period meant that he had to use copper as the braking medium acting on the disc. The poor state of the roads at this time, no more than dusty, rough tracks, meant that the copper wore quickly, making the disc brake system non-viable (as recorded in The Lanchester Legacy). It took another half century for his innovation to be widely adopted.
Added Jan 17, 2014: This view from the VMCC brake supplies shows essentially the same brake as the Douglas, as fitted to many bikes in the 19teens. Note the inverted V cross section shape that was previously dictated by the V belt, and that the brake shoe has that negative V shape just like the duggie. And the trailing shoe action like the duggie. But the brake material is on the shoe, not on the rim. Moving the brake material to the wheel’s dummy rim was the novelty of the Douglas, but the braking action works the same as all the others. ;)