Sinn 105 Design Analysis

Sinn 105 white dial

There are three reasons why Sinn’s carved out a special place in the traditional watch market. First, they’re German. The now-unified nation has a well-deserved reputation for precision instruments, from fine watches (A. Lange & Sohne) to luxury automobiles (Mercedes). Second, Sinn is a privately owned, independent watchmaker. They’re not chasing market share at the expense of quality. Third, Sinn has a distinct design philosophy. Their tool watches are easy to spot, easy to own. The Sinn 105 rests on this bedrock, but it’s not without its faults. But first, a little context . . .

Sinn 103

Sinn traces its history to its founder’s background in aviation: Helmut Sinn was a German WWII pilot and flight instructor. Frustrated with the design and reliability of post-War pilot watches, Herr Sinn set out to make his own. The original pilot chronograph, the 103, is iconic. It sports a classic three sub dial design, sleek syringe hands and day-date windows at three o’clock. The no-chrono 104 shares the same general design and the countdown bezel. Both watches are 41mm.

Sinn now sells several other types of “pilot” watches; the 556, 857 and most famously, the left-handed EZM-watches. When Sinn planned to release a new watch to complement to the 103/104-range, one could think of a great number of ways to develop this hugely successful design. While maintaining basic “Sinn-ness,” the Sinn 105 falls short in several respects.

Sinn 105 line-up

I don’t understand why Sinn didn’t upsize the third model in their 100-series range; they missed an opportunity to differentiate the 105 from its stablemates. Over the last few years, watchmakers have discovered that the market favors a one to two millimeter increase in case diameter above the “Goldilocks” 39mm standard – as the new 41mm Rolex Submariner indicates. Sinn should have released the 105 in either 42mm or 43mm diameter to diverge from the 103/104 range.

I’m also mystified by Sinn’s decision to equip the 105 with baton hands. The Sinn pilot’s syringe hands are a defining characteristic. Changing the style was a bold move – to a bland destination. If Sinn wanted the watch to appear more modern, they should have updated the syringe hands rather than ditching them entirely. Same goes for shovel seconds hand – replacing the sleek arrow – although it doesn’t have the same impact on the Sinn 105’s overall appearance.

black UTC

Creating a GMT version of the Sinn 104 was an excellent idea, oddly executed. The Diapal version of the Sinn 103 is also a GMT, elegantly adopting a hollowed-out syringe style hand.

For the Sinn 105 St Sa UTC, Sinn marks a second time zone with a large, orange, skeletonized arrow hand. Love it or hate it, you can’t ignore it. Ever. I say it detracts from the basic timekeeping function. Others will welcome it as a feature, not a bug. Speaking of distractions . . .

Sinn 103 two of em

The Sinn 105 St Sa’s vertically positioned day window is the watch’s most controversial design choice. While I’m not opposed to the idea, it would have been more successful if the Sinn 105’s case was larger with syringe style hands.

Given the Bauhaus feel to the watch, the window amplifies the appearance of the watch in the wrong way. The rest of the watch breathes unadulterated functionality. The vertical date window not so much.


Overall, the Sinn 105 is something of an odd duck: a brutally modern watch that fails to offer the reassuring symmetry and clarity of purpose of its 100-series brethren, but still possesses a style all its own. Maybe not exactly . . .

Sinn creates new models by combining and modifying established designs and features, sometimes in direct response to consumer feedback. Judging from the reception in Sinn forums and groups, the Sinn 105 hasn’t garnered the attention or kudos of its horological siblings. While I’m sure its owners are satisfied with both its looks and performance, I can’t help but wonder what a larger, more 100-series-like Sinn 105 could have been.


  1. It does appear that some intermediate evolutionary step was skipped. I’ve been unenthusiastic about Sinn in the past but I must admit to liking both the stacked day/date and the rounded hands that echo the indices.

    1. You are so right. Having lived in Germany myself, I do recognize some of the thinking behind the process that yielded the 105. I might well be wrong, but i dare to bet a case of beer on the 105 not becoming neither iconic nor a huge success. The stacked date is a fun thing.

  2. It’s interesting to see a design analysis of this watch that does not start by mentioning the Rolex Explorer II.

    1. My first impressions also led to the Explorer II. However, when looking past the dial and GMT-hand color, the similarities end quite fast.

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