Sinn · Instrument Chronographs

Strap for Pilot Chronograph 103 Ti Ar

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
Reference103TiAr
FamilyInstrument Chronographs
MovementETA caliber 7750 hours, minutes, small seconds | date, day | 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 103TiAr

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Instrument Chronographs 103TiAr, seen from the bench

The Sinn 103TiAr is a column-wheel chronograph built for professional pilots and demanding users. The 41 mm grade 5 titanium case houses the ETA 7750 movement, featuring three independent counters (hours at 6 o'clock, minutes at 3 o'clock, small seconds at 9 o'clock) with date at 3 and day at 12. The 20 mm lug width is proportioned to the case diameter, maintaining classic aviation watch aesthetics. This is a mechanical chronograph without compromise: pure timekeeping through human energy and Swiss geometry. The 20 mm strap width accommodates leather, rubber, or fabric options suitable for instrument-grade chronographs.

Frequently asked questions

What lug width does the Sinn Instrument Chronographs 103TiAr feature?

The Sinn 103TiAr features a 20mm lug width. This lug width specification is particular to the model and permits compatibility with straps manufactured to this exact measurement. To verify your strap is compatible, measure the linear distance between the two lugs (the lateral extensions of the case): it must correspond to 20mm.

What is the best strap for a Sinn 103TiAr?

There is no universally 'best' strap—rather, the choice depends on intended use. For flying and uniform wear, brown or black alligator leather offers institutional elegance. For sport and outdoor activity, nitrile rubber ensures grip stability and moisture resistance. Military-grade canvas NATO is ideal if you desire aesthetic versatility with historical robustness. Vegetable-tanned calf leather with titanium deployante minimises wrist weight.

How do I change the strap on my Sinn 103TiAr?

The Sinn 103TiAr employs standard spring bars. For strap change: 1) Obtain a spring bar remover or a flattened tool (pen, watch tool). 2) Insert the tool into the groove of one spring bar, applying pressure to extract the spring. 3) Gently extend the old strap and release the bar. 4) Repeat on the opposite side. 5) Insert the new strap, aligning the ends to the lugs, and compress until the spring clicks home. Do not force: spring bars must yield under controlled pressure.

Can I use an aftermarket strap on a Sinn 103TiAr?

Yes, provided the lug width is precisely 20mm. Quality aftermarket straps—in alligator leather, calf, rubber, or canvas NATO—are fully compatible with the Sinn 103TiAr. Verify that the strap is engineered for 20mm lugs and that spring bars are standard (not proprietary). Specialised manufacturers such as Casati Milano create bespoke straps for chronographs in this category.

How long does a leather strap last on a chronograph like the Sinn 103TiAr?

Durability depends on material and usage patterns. An alligatore strap with vegetable tanning lasts 3–5 years in daily wear; industrially-tanned alligator can exceed 7 years. Soft calf leather ages more rapidly (2–3 years) but develops desirable patina. Nitrile rubber lasts 4–6 years. Canvas NATO easily surpasses a decade. Critical factors: perspiration exposure (accelerates wear), ambient dryness (brittles leather), periodic maintenance (dust removal, neutral protective cream every 6 months).

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