RIDING AN EARLY BIKE #4: Stopping
Eventually, you must stop the bus. This can be much more exciting than the process of getting it going in the first place!
Pre WWI postcard, UK
Early brakes are nothing like the things that modern riders are accustomed to. They were marginal even new, by design! Back then, roads were mostly just dirt trails, with horses leaving fresh, slippery roadapples behind them as they travelled. I’ve also read a lot of reports of “grease” on the early unpaved roads in England and the Isle of Man, but I am unsure what material they are referring to. It seems to be something slimy that came up out of the dirt and rocks, leading to the oft-mentioned Dreaded Sideslip. Early motors sat high up in frames adapted from pedal bicycles, and beaded edge tires were very skinny and ran at ~40 psi to keep them on the rim. With that backdrop, and with every customer being a new rider, it is easy to understand why makers shied away from adding powerful front brakes onto their bikes. It took decades until really powerful front brakes came into fashion (c1928), right about the time that tarmac (macadam) was being widely used to pave the roads in the towns and countryside.
1919 Excelsior Advertisement
What did the early rider encounter then? American motorbikes typically had no front brakes fitted until the late 1920’s models, but often had two independent rear brakes after the 1914 models; One internal expanding drum brake, one external contracting drum brake, both operating on the same drum. Pre 1915, the rear brake was a coaster style brake like a pedal bicycle often had. (you pedal backwards to apply brakes). These brakes can fade considerably when hot…
1916 Excelsior dual rear brakes
X Internal brake. Note how small it is in diameter, as well as in width. It is similar to the expanding single leading shoe brakes used on bikes and cars for most of the 20th century, except that there is only one continuous shoe. Unfortunately, it is a ‘trailing’ shoe, not a leading shoe, so it has poor braking efficiency. It is operated by the rider’s right foot.
The external band can be see in the background of the photo It constricts onto the outside of the brake drum, and is operated by the rider’s left foot. The old brake material for the band is on the floor, note the big hole! A future How-To article will discuss how to reline antique brakes…
1913 Premier front brakes
1913 Premier rear brake
1914 Rudge rear brake
British motorbikes had front brakes that were rim brakes, simply scaled up slightly from the pedal cycles of the era. These were almost useless for the weight and speed of a motorbike. (Momentum and Newton’s law again). The design has poor leverage, coupled with very thin and weak metal parts. They did a great job of removing the paint from the rim though! Rear brakes were wedges of wood that were forced by a foot pedal into the drive pulley. The first such brakes acted on the lower portion of the rim, but designers discovered around 1911 that if the brake shoe acted on the top half of the rim that there was a self-servo effect. The rim pulled the brake shoe tighter, like the way a twin leading shoe drum brake operates, or a Vincent clutch.
The Premier rear brakes shown in the photos act on the inside of the dummy rim while the Rudge brakes act on the outside of the belt drive pulley. Both are terrible in performance compared to later bikes, but the Premier is less terrible.
So our rider is now chuffing along at a good clip, say 35-45 mph. Carb and magneto and belt are all working in harmony. And then a soccer mom in a Volvo SUV pulls out of her driveway! Forget the front brakes. Close the throttle, and immediately retard the timing. Down shift if you have time: single and two cylinder motors with small amounts of valve overlap work well for engine braking. Try the rear brake, it might work. If you have a boot that isn’t being used on a control pedal, drag it on the ground. As a last resort, lifting the exhaust valve will curb some speed from the bus, hopefully helping to avoid the oblivious soccer mom.
Time for a bottle of ale!