1950s Zenith Automatic Cal. 133.8 “Bumper Movement”

Without a doubt, the El Primero is Zenith’s most famous watch of all time, and ever since it first appeared in 1969 and forever set the standard for self-winding chronographs, virtually all other Zenith watches were destined to exist within the El Primero’s colossal shadow. However, Zenith’s history dates all the way back to 1865 in Le Locle, Switzerland and long before the concept of an automatic-winding chronograph had captured the imaginations of the watch industry, Zenith was producing refined and reliable three-handed timepieces that were designed for everyday wear and use.

Due to the giant shadow cast by the El Primero, other models created by the legendary Swiss manufacturer are frequently overlooked by today’s collectors, and can often be picked up for surprisingly affordable sums – especially when you consider what comparable offerings will cost you from similarly prestigious Swiss brands. This makes watches like the incredibly well-preserved 1950s Zenith Automatic that is featured in this week’s episode of Under the Radar the perfect vintage timepieces for collectors who want a beautiful watch from a blue chip manufacturer, all for an attractive price that won’t break the bank. 

Unlike the modern approach to creating a self-winding watch movement, which features a free-spinning rotor that is able to rotate a full 360 degrees, bumper movements like the Caliber 133.8 inside this Zenith Automatic feature winding weights that function like tiny pendulums, moving back and forth and winding the watches in the process. While they are mechanically inferior to the modern style of automatic movement that is used throughout the vast majority of the watch industry, bumper movements are emblematic of an important era in mechanical watchmaking, and timepieces like this 1950s Zenith Automatic can be seen as tiny, wearable pieces of history.