Sinn · Instrument Chronographs

Strap for Pilot Chronograph 103 Ti DIAPAL

Takes 20 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width20 mm
Case diameter41 mm
Reference103.078
FamilyInstrument Chronographs
MovementETA caliber 7754 Additional 24 Hour Hand (adjustable), Hours, Minutes, Small Seconds | Date | Chronograph

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

Straps for the Instrument Chronographs 103.078

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Instrument Chronographs 103.078, seen from the bench

The Sinn 103.078 belongs to the Instrument Chronographs line of the German manufacturer. It features the ETA 7754 caliber with chronograph, hour, minute, small seconds, date and adjustable 24-hour hand functions. The watch has 20mm lugs.

Frequently asked questions

What is the lug width of the Sinn Instrument Chronographs 103.078?

The lug width of the Sinn 103.078 is 20 millimetres. This is the distance between the two spring bar posts that protrude from the case lugs. It is critical to verify this measurement before purchasing an aftermarket strap, as 20 mm is a common standard but not universal. To measure accurately, remove the original strap and position a ruler perpendicular to the case lugs.

What is the best strap for the Sinn 103.078?

The choice depends on intended use. For professional environments and construction sites, an alligator or Nile crocodile leather strap offers the optimal balance of durability, usability and longevity. For maritime environments or high humidity, vulcanised rubber Tropic is the mandatory technical solution. Vegetable-tanned calf leather is ideal if you appreciate the aesthetic evolution of patina over time. NATO nylon is the versatile choice for frequent strap changes.

How do you change the strap on a Sinn 103.078?

The strap is changed using a spring bar tool (the specialised implement with a small hook). Position the watch face-down on a soft surface, insert the tool's hook under the spring bar post from one of the two sides, apply slight upward pressure to release the internal spring, remove the post, take off the old strap, insert the new strap into the post slot, reintroduce the post into the case and verify that it clicks securely on both sides. A non-invasive operation if executed with care.

What aftermarket strap is compatible with the 103.078?

Any strap with a 20 mm lug width is compatible with the 103.078. This includes the vast majority of quality leather straps, Tropic rubber straps for diving watches, standard military NATO straps, and technical fabric straps. The important thing is always to verify the lug width specification before purchase, regardless of the strap brand.

How long does a leather strap last on a Sinn 103.078?

The lifespan of a leather strap depends on material quality and frequency of use. A high-quality alligator or calf leather strap, with regular care (cleaning, drying after moisture, occasional light oil treatment), lasts 5-8 years of daily wear. Vulcanised rubber has a longer lifespan (10-15 years) as it does not become brittle. A NATO nylon strap is indefinitely durable, though seams may fray after 3-5 years of daily use. Environmental factors (extreme heat, salt moisture, solvent exposure) reduce these timeframes.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only