Rolex · Day-Date 36

Strap for Day-Date 6511

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

Lug width20 mm
Case diameter36 mm
Reference6511
FamilyDay-Date 36
MovementRolex caliber 1055 hours, minutes, seconds | date, day | chronometer
Year1956/1 - 1957
CaseYellow Gold

Recommended spring bar

Spring bars Rolex Daytona 16528 yellow gold — 20mm

Technical match for lug width and diameter · lug 20 mm · Ø 1.8 mm · drilled lugs

All Rolex spring barsOpen →

Straps for the Day-Date 36 6511

Selected for the 20 mm lug width · workshop selection

All 20 mm straps →

The Day-Date 36 6511, seen from the bench

The Day-Date 36 reference 6511 is powered by the Rolex caliber 1055 with chronometer certification, displaying hours, minutes, seconds, date, and day of the week. The model features 20mm lugs and represents one of the historical configurations of the Day-Date collection. The movement offers the essential timekeeping functions with the distinctive dual time indication characteristic of the line.

Frequently asked questions

What is the exact lug width of the Rolex Day-Date 36 6511?

The lug width of the Rolex Day-Date 36 reference 6511 is 20 millimetres. This dimension is determined by the geometry of the integrated lugs characteristic of this model. To measure accurately, position a calliper perpendicularly between the centre of the two attachment pins, from their inner extremity to the opposite inner extremity. Any strap with a wider or narrower lug width will not fit correctly in the case.

Which strap material is most suitable for the Rolex Day-Date 36 6511?

Alligator is the natural pairing for the 6511, thanks to its fine grain texture and regular scales that evoke haute couture accessories. Shell cordovan is an excellent alternative for those seeking longevity and evolving patina. Vegetable-tanned calf offers a more understated, tactile profile ideal for formal business contexts. Vulcanised rubber straps are an intelligent choice for rotational use, offering conformability and simplified maintenance.

How do you change the strap on a Rolex Day-Date 36 6511?

The procedure requires specific tools: a pin extractor or dedicated Rolex tool, precision screwdrivers, and a protected work surface. Position the watch on a soft cushion, gently extract the two pins from the old strap using uniform pressure, then insert the pins into the new strap ensuring they are fully seated. If you lack experience, entrust the operation to a certified watchmaker to avoid damage to the pins or case.

Is a 20mm aftermarket strap compatible with the Rolex Day-Date 36 6511?

Yes, any aftermarket strap with an actual lug width of 20 millimetres is mechanically compatible with the 6511. However, construction quality varies considerably: vegetable-tanned or alligator leather straps from specialist ateliers guarantee longevity, aesthetic coherence, and durability comparable to Rolex OEM straps. Avoid synthetic or inferior-quality leather straps, which deteriorate rapidly under the weight and heat of the yellow gold case.

How long does a leather strap last on a Rolex Day-Date 36 6511?

Longevity depends on material and usage. Alligator or shell cordovan from specialist ateliers last 3–5 years with moderate daily use, thanks to fibre density and abrasion resistance. Vegetable-tanned calf has slightly shorter longevity, approximately 2–4 years. The screw-down crown on the case does not cause premature leather wear. Minimal maintenance—occasional cleaning with a damp cloth, conditioning with products formulated for fine leather—significantly extends the strap's operational 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.

Request an appointment →

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