Sinn 156 and Sinn 156b

ManufacturerSinn
Reference156b
MovementLemania 5100
Diameter43mm
Thickness15mm
Lug to lug51mm
Lug width20mm
MaterialStainless Steel
Water Resistance10bar
Service price600€-700€
Basic information

Sinn 156 is often referred as the successor of the Heuer bund, a watch used by German airforce pilots. Unlike the Heuer Bund, the Sinn 156 was never issued, as the era of pilot watches was already over by its release. Sinn 156b is a divisive pilot watch due to its size and movement. It is a large watch with 43mm diameter and 51mm lug to lug. Its movement, Lemania 5100 with central minutes, is considered a workhorse and provides an alternative for all the Valjoux 7750 powered chronographs.

Sinn 156 was in production for nearly two decades, and it came in two references 156 and 156b. Aside from the reference difference, there are a lot of variations, some which I will try to list in this post.

Dial, Bezel and the Movement

The dial layout of Sinn 156 is defined by the Lemania 5100 movement; three sub-dials and day/date. Chronograph hands are typically bright red. In contrast to Valjoux 7750, Lemania 5100 has central minutes, which leaves one of the sub-dials free from chronograph usage. The sub-dials are as follows:

  • (top) sub-dial 24h display,
  • (left) seconds dial,
  • (bottom) chronograph dial

All of the Lemania 5100s that I have owned have had distinct winding sensation and they are truly a pleasure to wind, serviced or not. The movement is considered a workhorse, but due to limited parts availability, I would not run unserviced Lemania 5100. The chronopushers of the Sinn 156 are similarly stiff to Valjoux 7750 and they make a satisfying crunch when triggered. The movement itself is not the prettiest.

The bezel of the Sinn 156 is anodized aluminium and it rotates smoothly both ways. The plastic crystal sits one to two millimeters above the bezel. The bezel develops wear just from rotation and winding the watch over time. The bezel is particularly vulnerable to contact with rocky surfaces. It is very typical to find watches where the paint has completely worn off from the sides of the bezel.

Worn paint at the side of the bezel.

Serviceability

Luckily, Sinn still has parts for the Lemania 5100 movement. The price of movement service of my Sinn 156 was 675 euros including shipping in December 2020. It is unknown whether Sinn has the capability to produce more parts for the Lemania 5100 and how long their parts supply will last. However, Sinn has produced watches with Lemania 5100 up until 2008, so it is possible that they have quite a bit of parts still left. Other manufacturers, such as Fortis and Tutima have had to stop servicing Lemania 5100, and Omega still has parts for their cal 1045, which was used at least in Speedmaster Mark 4.5.

The screw-down crown of the Sinn 156 is short, so one must take care not to break the threads. The crown of my Sinn 156b was replaced during service, and the replacement was identical. From parts scarcity angle, I’d say the overall serviceability of Sinn 156b is good.

Variations

The key difference between Sinn 156 and 156b seem to be the ‘Military’ print on the dial. Both Sinn 156 and 156b were produced with tritium dials, but Sinn 156b after 00s started to come with Luminova dials. The tritium compound on these watches seems to develop a very desirable orangish patina and it is rare to see watches with broken or tarnished tritium. To me this is a tell of good case construction.

The bracelet of the early 156s were the Sinn branded NSA bracelet. These bracelets are now very sought after and go on auction sites for over 600 euros. The later H-link bracelets are also rare to find loose, so it is best to buy a complete watch, if one intends to wear the Sinn 156 on a bracelet. I haven’t found a definite answer whether end-links from other watches will fit the Sinn 156 and it is best to assume they don’t. However, it looks like it is possible to file Sinn 103 end-links to fit the Sinn 156, but they won’t be a perfect match.

Most Sinn 156 and Sinn 156b came in a monocoque case, but some of the later Sinn 156b came in a screw-back case. The monocoque cases are interesting, since the case containing the movement is attached to the frame with screws that has the lugs. Some watches also have lug-holes, which in my opinion is a desirable feat in a watch.

FeatureReference
TritiumSinn 156/Sinn 156b
Lug-holesSinn 156/Sinn 156b
‘Military’ print on dialSinn 156b
Screw-back caseSinn 156b
NSA braceletSinn 156
H-link braceletSinn 156b

Sinn 156 was also produced for Bell & Ross and there is a Beams version as well. Other manufacturers such as Hamilton and Bulova have produced a very similar watch, but it is unclear whether the Hamilton / Bulova watches were made by Sinn.

Conclusion

Sinn 156 is a big watch with a fun movement and cool looks. Depending on the configuration, it can feel very vintage to very modern. Watches with NSA bracelet and full tritium are the most sought after, but watches with luminova dials can make excellent everyday wearers. With the Sinn serviceability, the watch is relatively care-free.

Sinn 158 on a bracelet

History

Sinn has made multiple successors to the 1550 sg produced by Heuer and Sinn. The Sinn 1550sg was directly succeeded by Sinn 156 and Sinn 156b and then followed by Sinn 155 and Sinn 158. Whereas the Sinn 155 is more true to the 1550 sg, the Sinn 158 sits somewhere between 1550 sg and 156b.

The elephant in the room is that neither Sinn 158 or Sinn 155 Darkstar was sold on steel bracelet whereas with Sinn 156 the bracelet was always an option. This leaves many Darkstar and Sinn 158 owners yearning for that cold hard steel on their wrists. The situation is bad, but it is not intolerable. Before the Darkstar and the Sinn 158, Sinn produced various watches with the reference Sinn 155. One of the came with steel bracelet.

First of the series is Sinn 155 ‘Manufactum’ with Valjoux 7750 movement. This was limited edition of 272 to the German market, sold via Manufactum. This watch features day/date chronograph seconds, minute register at top and hour register in bottom. I haven’t personally handled this watch, so I don’t know what the case is like. However, judging from pictures this is where the series begins.

The second entry to the series is Sinn 155 ‘Replica’, again a 300 piece limited edition made only for the Japanese market. The bracelet was optional for these watches. This watch features classic two register layout with minutes on the right and seconds on the left. Unlike the other versions, this watch uses manual wind movement. Judging from the packaging of the bracelet, the bracelet was supplied separately.

Middle Sinn 155 ‘Replica’, Right Sinn 155 ‘Manufactum’
(Photo used with permission of @milwatch_enthusiasts)

Finally, the third iteration before 158 is the Sinn 155 Darkstar collaboration with The Rake and Revolution magazine. Owners of these watches are in similar position as owners of Sinn 158. The Darkstar is very similar to the Sinn 155 ‘Replica’, but has automatic SW510 movement. Additionally, the Darkstar features a black star on the dial and faux lume, which makes it very attractive to those who want a modern equivalent to the Sinn 1550sg.

The Solution

The cases of Sinn 155/158 and Sinn 156b are not identical, so it is unlikely that the SEL bracelet of Sinn 156b will fit. The hollow end-link bracelet might, but until I have access to one, this remains to be a mystery. The solution for owners of the Sinn 155 Darkstar and the Sinn 158 is to acquire a bracelet for the Sinn 155 Replica. The cases of all these models seem to be identical.

In conclusion, the solution is not without problems. These bracelets are rarer than either Sinn 155 Darkstar or Sinn 158. However, they are a perfect fit. Those bothered by the Sinn 155 text on the bracelet can swap any bead-blasted Sinn clasp and have their nightly sleep. The end result is great and completes the watch.

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