Curved-End Leather Watch Strap for Cartier Ballon Bleu (28-44 mm)
Curved-End Leather Watch Strap for Cartier Ballon Bleu (28-44 mm)
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Description
Cut for the curve of the Ballon Bleu case — not straightened onto it.
Most replacement straps are cut square at the lugs. On a Ballon Bleu that leaves two thin slivers of bare case showing between strap and watch, and the whole thing looks borrowed. This strap is formed with a curved, notched end that follows the case profile, so the leather meets the case flush and the watch reads as one continuous object on the wrist.
Find your size in thirty seconds
Measure the gap between the two lugs — the spring-bar opening, in millimetres — not the case diameter. That number is the size you order.
| Ballon Bleu case | Lug width to order |
|---|---|
| 28 mm | 8 mm |
| 33 mm | 8.5 mm |
| 36 mm | 11 mm |
| 40 mm | 11 mm |
| 42 mm | 12 mm |
| 44 mm | 14 mm |
The 36 mm and 40 mm cases share the same 11 mm lug width, so one strap covers both.
Materials and build
- Genuine leather in a matte finish, medium temper. It holds its shape out of the box and softens to the wrist over the first weeks of wear instead of flopping or cracking.
- Embossed scale texture with tone-on-tone stitching and hand-finished painted edges — the look of a dress strap without the fragility of an exotic hide.
- Curved, notched ends matched to the Ballon Bleu lug profile.
- Medium thickness: enough body to stand upright on the wrist, slim enough to slide under a shirt cuff.
- Steel-tone hardware as standard. Gold-tone and rose-gold-tone clasps can be substituted on request.
Three ways to fasten it
No buckle. The strap arrives as a two-piece set only, so you keep the Cartier pin buckle or deployant already on your watch and just swap the leather. This is the choice for anyone who wants the original hardware to stay.
Pin buckle. A complete strap with a tang buckle fitted, ready to wear — useful if your original buckle is damaged or you are fitting the strap to a second watch.
Deployant clasp. A single-fold clasp that opens with a press instead of bending the leather at one hole every time. Over years of daily wear it is the option that ages best, because the strap flexes along its length rather than creasing at a single point.
Six colours, one silhouette
- Black — the safe pairing for a steel case; reads formal with a suit, invisible with everything else.
- Brown — warm, slightly vintage; the natural match for rose gold and two-tone cases.
- Navy blue — picks up the blue cabochon and the blued hands; the least obvious and most photogenic choice.
- Red — a deliberate accent, best on a 33 mm or 36 mm case.
- Pink — soft, low-contrast, reads almost neutral against pale skin.
- Purple — deep and muted rather than bright; the colour that looks most different in daylight and in indoor light.
What's in the box
One two-piece leather strap in the colour, size and buckle configuration you select. If you order a buckle option, the buckle is already fitted. Reuse the spring bars currently holding your watch head — they are standard and do not need replacing. A spring-bar tool makes the swap a two-minute job; fingers alone usually will not do it.
Care
Leather is a living material. Wipe it with a dry cloth, keep it away from direct heat and radiators, and condition it lightly once or twice a year. Water darkens and stiffens it, so take the watch off before swimming, showering or washing dishes. A strap worn daily typically lasts one to three years before the lining at the buckle end starts to soften — that is normal, and it is the point at which most people buy their second colour.
Fitment notes
Ends are shaped for the Ballon Bleu case only. They will not fit Tank, Santos, Ronde, Panthère or Drive, whose lug geometry is different. If your watch is a rose-gold or two-tone model and you want the clasp to match the case, message us before ordering so we can confirm the hardware finish. For any case size not listed, send us the lug measurement and we will tell you which option to take.
Questions people ask before buying
How do I know which size to order?
Measure the distance between the lugs where the spring bar sits. That is the number you order — 8, 8.5, 11, 12 or 14 mm. Case diameter alone is not enough, but the table above maps case size to lug width for the Ballon Bleu.
Can I keep my original Cartier buckle?
Yes. Choose the “No buckle” option and the strap arrives without hardware, ready for the buckle already on your watch.
Will it fit a 36 mm Ballon Bleu?
Yes — the 36 mm and 40 mm cases both take the 11 mm lug width.
Does it fit other Cartier models?
No. The curved end is cut specifically for the Ballon Bleu case profile. Straps for Tank, Santos and Ronde need a different end shape.
Is this a Cartier product?
No. YOSTRAP is an independent strap maker and this is a third-party accessory, not made, endorsed or sponsored by Cartier.
Will the colour match the photos?
Colours are photographed in natural light. Screens vary, and leather is a natural material, so expect small variation between dye lots — especially on red and purple, which shift most under warm indoor light.
YOSTRAP is an independent watch-strap maker and is not affiliated with Cartier. Cartier and Ballon Bleu are trademarks of their respective owner and are used here only to describe compatibility.