Grand Seiko · Mechanical

Strap for Automatic Hi Beat 36000 GMT Stainless Steel / Mount Iwate / Bracelet

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

Lug width20 mm
Case diameter40 mm
ReferenceSBGJ201 (aka: Mount Iwate)
FamilyMechanical
MovementGrand Seiko caliber 9S86 Hours, Minutes, Additional 24 Hour Hand (adjustable), Seconds | Date
CaseStainless Steel

Spring bar

Swiss Standard universal spring bars

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

Straps for the Mechanical SBGJ201 (aka: Mount Iwate)

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Mechanical SBGJ201 (aka: Mount Iwate), seen from the bench

The Grand Seiko Mechanical SBGJ201 "Mount Iwate" is a stainless steel watch featuring the caliber 9S86 automatic movement. The case measures 40.00 mm in diameter with a 20 mm lug width, combining brushed and polished surfaces using the Zaratsu polishing technique. The dial includes hours, minutes, an independent 24-hour hand, seconds, and a date window at 3 o'clock, reflecting the precision standards of Grand Seiko's Shizukuishi workshop.

Frequently asked questions

What is the lug width of the Grand Seiko Mechanical SBGJ201?

The lug width of the SBGJ201 is 20 mm. This is the distance between the two horizontal pins that attach the strap to the watch lugs. Any aftermarket strap must be drilled precisely at 20 mm to ensure proper fitment and correct functionality of the deployant clasp or buckle.

What is the best strap for the Grand Seiko SBGJ201?

There is no universal "best" strap, only informed choices based on usage. For formal elegance: brown alligator or black shell cordovan. For sophisticated daily wear: vegetable-tanned calf leather. For practicality and sports: high-density rubber. The SBGJ201 supports all these interpretations thanks to its harmonious proportion and case geometry.

How do I change the strap on my Grand Seiko SBGJ201?

Remove the pins from the lugs using a spring bar tool or equivalent. Push gently inward to release the spring mechanism, slide out the old strap, and thread the new one through the lugs. Reinsert the pins ensuring they click into position. Verify the deployant clasp or buckle closes correctly before wearing the watch.

Can I use an aftermarket strap on a 20 mm Grand Seiko SBGJ201?

Yes, any strap with a 20 mm lug width is compatible. Ensure the strap is drilled correctly and that the deployant clasp (if present) does not create friction on the case. We recommend straps from specialised suppliers that guarantee precise tolerances and materials consistent with the watch's value and aesthetics.

How long does a leather strap last on a Grand Seiko SBGJ201?

A quality leather strap, treated with vegetable tanning, lasts 3–5 years with moderate daily wear. Factors such as sun exposure, humidity, and frequency of wear influence longevity. Alligator and shell cordovan offer greater resistance (5–8 years). Technical rubber guarantees 7–10 years. Regular maintenance (cleaning, occasional conditioning) extends useful life.

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