Deep Dive: The Rolex Bubblebacks

Did you know that Rolex had its own modding phase back in the 30’s to 50’s? Watch historians look back fondly in this period which can be described as Rolex’s “experimentation phase,” when they released plenty of different movements, cases, dials, and more. That’s right folks, before settling into the luxury sports / tool watches that we know and love today, we got egg-shaped divers, sector dials in barrel cases, and even California dials. And because of this abundance of choices coupled with relatively acceptable prices, people were keen to mix and match and even refinish their watches, much like how we do it with Seiko mods today.

And before the modern Oyster Perpetual became one of the most recognizable watches on the planet, there was a chunky little oddball with a domed caseback. The Bubbleback looks like a fun-loving vintage design, but it’s actually the watch that helped make the automatic wristwatch a commercial success. Rolex introduced its Perpetual self-winding movement in 1931, and the first Bubbleback followed in 1933.

Source: @joseph_c on IG

 

In this article, we look back at the vintage pieces with domed casebacks from this era, explore what makes them so collectible, and see if it’s possible for you to build an homage to these watches.

 

Why Bubbleback?

Source: Hodinkee

 

First, a quick clarification: “Bubbleback” is a collector nickname, not an official Rolex model name. It generally refers to the early Oyster Perpetual watches made from 1933 into the mid-1950s, recognized by their rounded, protruding casebacks. Later automatics with a less pronounced bulge are often called “semi-Bubblebacks,” so you’ll see both terms floating around. And by the way, these were the norm back then so much so that the “normal” casebacks that we have today were called by a specific term back then, which were “flatbacks”

The bubble was functional, not decorative. Rolex’s early automatic system used a rotor that swung a full 360 degrees around a central pivot, and it was mounted on top of an existing movement. Stacking the rotor assembly made the whole movement unusually thick for the era, so Rolex domed the caseback to give it room to spin. Think of it as an engineering compromise that happened to turn into an iconic silhouette. We can imagine how it must have dug into the wrist bone with that big of a bulge, but for many, it was a good price to pay for a fashionable look.

Pair that rotor with the Oyster case which handled water resistance, and you get automatic winding plus a sealed case - two ideas that are still the foundation of Rolex’s identity even today.

 

Becoming the Staple

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The Bubblebacks were not designed in one go, but were the result of years of research and development from Rolex. The Oyster case came out in 1926, and the first automatic Perpetual movement, the caliber 620, followed in 1931. Founder Hans Wilsdorf worked with the manufacturer Aegler to improve early self-winding movements, and Rolex ended up with patents covering a wristwatch wound by an oscillating rotor. That’s a big reason no one else made full-rotor automatics at scale until the 1950s. For nearly two decades, Rolex had the perpetual rotor mostly to itself.

The First Series Bubblebacks, starting with ref. 1858, ran on the caliber 620, Rolex’s first self-winding movement. That caliber stayed in use until around 1935. A year later, Rolex moved to a simpler two-piece case, which was cheaper and easier to build than the earlier three-piece design. By the 1940s, Rolex was making Bubblebacks in more dials, metals, and styles than at any other point. Most were small by today’s standards, around 30 to 32mm, though 34mm versions started showing up in the ’40s. 

Meanwhile, Rolex kept slimming down their calibres until they arrived at a thin enough design that needed less of that bulge to make room for the oscillating rotor. By the early 50’s, Rolex’s 1000 series were debuted and allowed for completely flat casebacks, effectively marking the end of the Bubbleback era.

 

Why Collectors Love Them

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The variety is a big part of the appeal for this unofficial series, with Bubblebacks coming in steel, gold, and two-tone, with Art Deco to Bauhaus-style dials, Arabic and Roman numerals, sector dials, enamel dials, and different bezels, lugs, and bracelets. In the 1980s and ’90s, the Bubbleback was the vintage Rolex to have, the way the vintage Daytona was all the rage in 2017. The more common designs fetched 3 to 5 grand, with rarer designs in better conditions getting bought for up to $30,000.

Watch dealers in the 80’s were very relaxed about swapping parts and regularly do what would be considered sacrilege in today’s horology scene. One prominent AD even planned a “Build a Bubbleback” catalog program where customers can pick and choose the parts they want to build a custom Rolex from scratch, which sounds a lot like modding, we know. Japanese collectors, though, always valued original dials, so many of the best vintage OEM Bubbleback units are still in Japan.

 

Can You Mod Your Own Bubbleback?

Source: @treasure_collection_hk on IG

 

There was a time when you could actually build your own Bubbleback, back when Rolex watches were only premium tool watches and not luxury pieces as they are perceived today.These days, very few, if there was anyone at all, would modify a surviving vintage BB and would probably prefer to keep it as a collector’s item.

But keep your patience, modfam: we’re already working on something that will allow you to build the ultimate throwback Bubbleback! It’s going to be a modern-sized case compatible with the NH platform, and in multiple finishes too. Stay tuned for more updates on this!

 

Wrap Up

These stout and likeable watches are small, awkward to service, and were out of fashion for decades, yet it’s still one of the most important Rolex watches ever made. The Bubbleback was the first watch to combine the two ideas Wilsdorf built Rolex around: “Oyster” for the waterproof case and “Perpetual” for the automatic movement. Nearly a hundred years later, those two words are still on almost every Rolex dial. 

And if all those mix-and-match dials and cases have you itching to build a vintage-inspired watch of your own, you know where to find us. We’ve got cases, dials, movements, modding tools, and everything else you will need to build your complete personalized watch from scratch. Check out our catalog today.

Happy modding!