Strap for 1858 Automatic 40 Stainless Steel / Bronze / Black / Calf

The lug width of the Montblanc 1858 Ref. 117833 is 20mm. This measurement represents the distance between the two metal spring bar attachment points on the case, and is the fundamental parameter for strap compatibility. In the 117833, the proportional relationship between the 40mm case diameter and the 20mm lug width reflects the classical golden ratio construction (1:2 ratio), ensuring visual and structural balance.

For the 117833 in bronze, the ideal strap is alligator with vegetable tanning in dark cognac tone, or deep brown shell cordovan. Both materials amplify the natural patina of bronze, creating a coherent aesthetic dialogue. Alligator offers granulated texture that emphasises the instrumental character, whilst cordovan develops over time a characteristic ring and visual depth. For a sportier approach, a military-style NATO strap in olive drab transforms the 117833 into a pure field watch.

To change the strap on the 117833, you must remove the two spring bars (small metal levers) from the case lugs. It is recommended to use a dedicated spring bar tool, available from specialist retailers, to avoid scratching the bronze case. Proceed by inserting the tool tip into the spring bar hole, gently push to release the spring, remove the old strap and insert the new one by aligning the two pins with the lugs. This intervention, whilst straightforward, requires caution on noble materials such as bronze.

Yes, the 117833 accepts quality aftermarket straps thanks to the standardised 20mm lug width. However, it is recommended to choose suppliers specialising in artisanal straps who understand the aesthetic profile of this collection. Straps in alligator, cordovan, vegetable-tanned calf leather and technical NATO guarantee perfect compatibility and longevity. Avoid generic synthetic leather straps, which would compromise the constructive identity of the watch.

The durability of a leather strap depends on the material, frequency of use and climatic conditions. A quality artisanal alligator strap with vegetable tanning typically lasts 4-6 years of daily wear, developing character and patina. Shell cordovan, being more robust, reaches 6-8 years. Smooth calf leather may last 2-3 years. Important: leather is not eternal—it is a noble material precisely because it is vulnerable. Protect the strap from prolonged exposure to water, perspiration and intense summer UV rays. It is advisable to have at least two straps in rotation to extend overall lifespan.