Technical Archive

Montblanc
1858 117840— lug 20mm

Montblanc 1858 117840: 20mm strap. Alligator, box calf, shell cordovan and rubber, cut and stitched in Milano. Choose your leather.

1858 Geosphere Limited Edition 1858 Bronze / Black / Bund

Artisanal Note

"This model requires a precise 20mm lug width to preserve the original sartorial balance."

Technical Specifications

Montblanc 117840
Lug Width
20 mm

The essential strap measurement.

Browse 20mm straps →
Reference

117840

Movement

Montblanc caliber MB 29.25 Hours, Minutes, Additional 12 Hour Hand (adjustable), Day / Night Indication, World Time | Date

The Heritage

The Montblanc 1858 reference 117840 is powered by the MB 29.25 caliber with hour, minute, and adjustable hour hand seconds functions, and day/night indication. The watch offers world time function with date display. The movement features complications dedicated to the control of different time zones through the additional twelve-hour hand.

FAQ

What is the lug width of the Montblanc 1858 117840?

The lug width of the Montblanc 1858 117840 is 20mm. This dimension is specifically calibrated for the integrated lugs of the case, requiring precise aesthetic alignment. Measure the internal width between the two attachment poles where the strap sits to verify exact compatibility.

Which strap is most suitable for the Montblanc 1858 117840?

We recommend a strap in vegetable-tanned alligator leather, which enhances the patina of the bronze and delivers uncompromising elegance. Alternatively, premium calf leather or technical NATO webbing in military tones preserves the heritage identity. Your choice depends on intended use: leather for formal contexts, NATO for sporting versatility.

How do you change the strap on a Montblanc 1858 117840?

Changing the strap on the 117840 requires precise tools: a spring bar tool and a flat working surface. Insert the tool gently into the lateral slot of the lug, applying light inward pressure to release the spring bar. Alternate sides cautiously to avoid scratching the titanium case. Consult a specialist service if you prefer professional assistance.

Is an aftermarket strap for the Montblanc 1858 117840 truly compatible?

An aftermarket strap is compatible only if the lug width is precisely 20mm. However, construction quality and clasp type must be selected in relation to case architecture. Artisanal straps from Milano Straps guarantee geometric compatibility and craftsmanship aligned with the luxury standards of the 117840.

How long does a natural leather strap last on a watch like the Montblanc 1858 117840?

A premium strap with vegetable tanning and correct stitching has an average lifespan of 4–7 years under moderate daily use conditions. Longevity depends on exposure to moisture, direct sunlight, and mechanical stress. Vegetable-tanned leather breathes naturally, reducing premature degradation. Periodic treatments with natural wax extend service life to ten years or more.