Marathon band size chart by family

Marathon sorts its watches into military size classes, and the class sets the strap: the 34mm and 36mm General Purpose watches take 16mm [1] [2], the 36mm Medium Divers take 18mm [3], the whole 41mm Large class (GSAR, TSAR, 41mm OSAR-D, the Steel Navigators) takes 20mm [5] [8], and the 46mm Jumbo class (JSAR, JDD, CSAR, 46mm OSAR-D) takes 22mm [9] [10]. Every width below is printed in the specifications block of Marathon's own product pages or carried in the store's own lug-width filter tags, cross-checked against dealers and owners. The trap is real: the SAR name spans three widths depending on case size, and at least one strap retailer lists the GSAR at 18mm, which is wrong [16].

Quick answers: GSAR and TSAR 41mm take 20mm. JSAR, JDD and CSAR 46mm take 22mm. OSAR-D splits by case: 36mm takes 18mm, 41mm takes 20mm, 46mm takes 22mm. MSAR 36mm (quartz and automatic) takes 18mm. GPM 34mm and Officer's GPM 36mm take 16mm. Steel Navigator SSNAV/SSNAV-D and CeraShell NAV 41mm take 20mm. Marathon's one-piece nylon straps follow MIL-S-46383B and come in 16mm, 20mm and 22mm only.

The size class is the answer

Marathon is a spec-sheet brand: the same family name appears at two or three case sizes with different lugs, so the diameter, not the dial name, picks the strap. The GSAR name alone is ambiguous until you see the case: 41mm means 20mm lugs [5], while the Jumbo 46mm watches that look like its big brothers run 22mm [9]. The OSAR-D is the worst offender because it exists at 36mm, 41mm and 46mm, spanning all three strap widths, 18, 20 and 22mm [4] [7] [8]. Marathon's own store makes the mapping navigable with a lug-width filter that tags every watch, and the filter's values match the spec blocks printed on the product pages, which is what the table below is built from. Type a model name to filter.

The chart: 11 verified rows

The Lug width column is the figure printed in the specifications block of Marathon's own US product pages, or the store's own straplug filter tag where the block omits it; the case and lug-to-lug figures come from the same blocks. Independent legs are Marathon dealers, the strap trade, and owner threads, and where a third party contradicts Marathon, the first-party figure wins and the conflict is named. The spring bar sizes guide covers the pin side of the swap, and the measuring guide is the 30-second check that beats any chart, including this one.

Marathon band width by family
FamilyCaseLug widthLug-to-lugStrap notes
General Purpose Mechanical 34mm (GPM, GPQ, GPQ-D)34 mm16 mm41 mm16mm lug width in the GPM spec block; every 34mm GPM and GPQ variant carries the store's 16mm lug tag; Marathon's 16mm nylon is sold as the general purpose strap [1] [14] [2]
Officer's Mechanical 36mm (GPM, steel SSGPM)36 mm16 mm44 mmMarathon's own GPM page prints 36mm case, 11mm thick, 16mm lug width; the steel Officer's variants share the 16mm tag [2] [15]
Medium Diver's 36mm (MSAR Quartz and MSAR Auto)36 mm18 mm43.5 mm18mm lug width in the MSAR spec block; Marathon's 18mm rubber kit and 18mm steel bracelet are the Medium Dive replacements [3] [17]
Original SAR w/ Date 36mm (OSAR-D)36 mm18 mm43.5 mm18mm lug width in the 36mm OSAR-D spec block; same case class as the MSAR, same 18mm strap rail [4] [17]
Large Diver's 41mm (GSAR automatic, TSAR quartz)41 mm20 mm48 mm20mm lug width in both spec blocks; Marathon's 20mm rubber, nylon and bracelet are the Large Dive replacements; the Delugs 18mm listing for the GSAR is wrong [5] [6] [16]
Original SAR w/ Date 41mm (OSAR-D)41 mm20 mm48 mm20mm lug width in the 41mm OSAR-D spec block; shares the Large Dive 20mm strap program [7] [18]
Steel Navigator 41mm (SSNAV, SSNAV-D, SSNAV Auto) and CeraShell NAV41 mm20 mm48 mm20mm lug width in the SSNAV spec block; the CeraShell NAV carries the same 20mm tag; the Navigator is the pilot watch Marathon's 20mm nylon has been fitted to since the mil-spec era [8] [14]
Original SAR w/ Date 46mm (OSAR-D)46 mm22 mm55 mm22mm lug width in the 46mm OSAR-D spec block; despite the SAR name it is Jumbo-class at the lugs [9] [19]
Jumbo Diver's Quartz 46mm (JSAR)46 mm22 mm55 mm22mm lug width in the JSAR spec block; dealer spec sheets print the same 22mm lugs on the older 46.6mm generation [10] [20] [13]
Jumbo Day/Date Automatic 46mm (JDD)46 mm22 mm55 mm22mm lug width in the JDD spec block and body copy; owners confirm 22mm against the GSAR's 20mm [11] [13]
Jumbo Diver/Pilot's Chronograph 46mm (CSAR)46 mm22 mm55 mm22mm lug width in the CSAR spec block; same Jumbo 22mm rail as JSAR and JDD [12] [19]

The 18mm trap, and who falls into it

The most expensive Marathon mistake is buying an 18mm strap for a 41mm watch, and it is an easy mistake because a real strap retailer makes it. Delugs lists the GSAR at 18mm, and the strap trade has called this out directly: the GSAR takes 20mm lugs, confirmed by Marathon's own specifications, and an 18mm strap leaves a visible gap on both sides [16]. The confusion has a rational root: 18mm is a real Marathon width, but it belongs to the 36mm Medium Divers [3]. Marathon's own store removes the guesswork with a lug-width filter that tags every product, and the GSAR sits in the 20mm bucket next to the TSAR and the Navigators [5]. The reverse trap exists at 46mm: owners upgrading from a GSAR to a JDD report the lug width is different, 20mm on the GSAR and 22mm on the JDD and JSAR [13], so the strap collection does not carry over. And the OSAR-D buyer must check the caseback first, because that one reference name spans 18, 20 and 22mm across its three sizes [4] [9].

MIL-S-46383B: why Marathon nylon comes in three widths

Marathon's one-piece ballistic nylon straps are built to the US military watch strap specification, and Marathon's own strap pages say it verbatim: manufactured in accordance with watch strap specification MIL-S-46383B [14]. The spec shaped the product line: the nylon comes in exactly 16mm, 20mm and 22mm, the widths of the general purpose, large and jumbo classes, and the same page describes it as the replacement strap for navigator, general purpose wrist watches, and wrist compass [14]. Lengths are fixed per width and printed on Marathon's strap listings: the 16mm ballistic nylon runs 254mm (10 inches) with a 292mm (11.5 inch) long option, the 20mm runs 254mm or 305mm (12 inches), and the 22mm runs 280mm (11 inches) or 305mm [21] [22]. The DEFSTAN nylon (12 inches, 305mm) and leather lines run the same width ladder. One caution for wrist sizes: the mil-spec 12-inch strap is cut for an 8.5-inch wrist over a sleeve; on a 7-inch wrist the tail is long, and Marathon's 10-inch options exist for exactly that reason. The NATO strap length guide covers the length question in depth, and the Zulu size guide covers the five-ring hardware.

What Marathon itself sells, by width

Marathon's own replacement rail is the cleanest compatibility statement any brand in this class makes, because the store tags every strap with the same lug-width field the watches carry. 16mm: ballistic nylon and DEFSTAN nylon, the GPM and wrist compass widths. 18mm: the rubber kits and steel bracelet marked For Medium Dive, the MSAR and 36mm OSAR-D rail [17]. 20mm: the deepest pool, rubber kits, ballistic nylon, DEFSTAN nylon, leather and the bracelet marked For Large Dive, covering GSAR, TSAR, 41mm OSAR-D and the Navigators [18]. 22mm: the Jumbo rail, including the rubber straps Marathon lists by NSN (6645-21-886-8975, 6645-01-544-0408) for government-contract watches [19], the 22mm bracelet, and the 22mm DEFSTAN at 318mm. If your Marathon is not in the table, read the case diameter off the caseback before anything else: 34 or 36mm General Purpose means 16mm, 36mm Diver means 18mm, 41mm means 20mm, 46mm means 22mm, and the band size chart plus a quick measure between the lugs finishes the job.

Related guides

Once the width is settled: the NATO strap length guide handles the other Marathon question, how long, and the Zulu size guide covers the heavier hardware. The lug width chart is the brand-by-brand index, the band size chart puts Marathon's 16/18/20/22 ladder in context, and spring bar sizes plus the spring bar tool guide cover the swap itself. For sibling brand charts: Luminox (the other military-adjacent brand with a width trap), Victorinox, Seiko, Citizen, Casio, Bulova, Timex and Vostok.

Sources

  1. Marathon Watch, 34mm General Purpose Mechanical (GPM) product page, spec block: 34mm case, 12.5mm thick, 41mm lug-to-lug, 16mm lug width: marathonwatch.com
  2. Marathon Watch, 36mm Officer's Mechanical (GPM) product page: "a case diameter of 36mm, a thickness of 11mm, and 16mm lug width"; spec block 44mm lug-to-lug: marathonwatch.com
  3. Marathon Watch, 36mm Medium Diver's Quartz (MSAR) product page, spec block: 36mm case, 13mm thick, 43.5mm lug-to-lug, 18mm lug width (MSAR Auto identical): marathonwatch.com
  4. Marathon Watch, 36mm Original SAR w/ Date (OSAR-D) product page, spec block: 36mm case, 13mm thick, 43.5mm lug-to-lug, 18mm lug width: marathonwatch.com
  5. Marathon Watch, 41mm Large Diver's Automatic (GSAR) product page, spec block: 41mm case, 14mm thick, 48mm lug-to-lug, 20mm lug width; store lug-width filter tag 20mm: marathonwatch.com
  6. Marathon Watch, 41mm Large Diver's Quartz (TSAR) product page, spec block: 41mm case, 14mm thick, 48mm lug-to-lug, 20mm lug width: marathonwatch.com
  7. Marathon Watch, 41mm Original SAR w/ Date (OSAR-D) product page, spec block: 41mm case, 14mm thick, 48mm lug-to-lug, 20mm lug width: marathonwatch.com
  8. Marathon Watch, 41mm Steel Navigator (SSNAV) product page, spec block: 41mm case, 11mm thick, 48mm lug-to-lug, 20mm lug width (CeraShell NAV 41mm carries the store's 20mm lug tag): marathonwatch.com
  9. Marathon Watch, 46mm Original SAR w/ Date (OSAR-D) product page, spec block: 46mm case, 17mm thick, 55mm lug-to-lug, 22mm lug width: marathonwatch.com
  10. Marathon Watch, 46mm Jumbo Diver's Quartz (JSAR) product page, spec block: 46mm case, 17.5mm thick, 55mm lug-to-lug, 22mm lug width: marathonwatch.com
  11. Marathon Watch, 46mm Jumbo Day/Date Automatic (JDD) product page: "With a lug width of 22mm and a case thickness of 18mm"; spec block 55mm lug-to-lug: marathonwatch.com
  12. Marathon Watch, 46mm Jumbo Diver/Pilot's Automatic Chronograph (CSAR) product page, spec block: 46mm case, 17.5mm thick, 55mm lug-to-lug, 22mm lug width: marathonwatch.com
  13. Reddit r/MarathonWatch, bracelet thread: "The lug width is different. 20mm on the GSAR and 22mm on the JDD/JSAR": reddit.com
  14. Marathon Watch UK, Ballistic Nylon Strap 20mm product page: "Manufactured in accordance with watch strap specification MIL-S-46383B"; "Original replacement strap for instruments using nylon straps from 16mm, 20mm, and 22mm wide. Used for navigator, general purpose wrist watches, and wrist compass": uk.marathonwatch.com
  15. Sekvens (authorized Marathon dealer, Sweden), Marathon watches page, Officer's Watch: "a case diameter of 36mm, a thickness of 11mm, and 16mm lug width": sekvens.com
  16. CNS Watchbands, Best Watch Straps for the Marathon GSAR: "The Marathon GSAR uses 20mm lugs, confirmed by Marathon's own official specifications... Important: Delugs incorrectly lists the GSAR at 18mm, this is wrong. An 18mm strap will leave a visible gap on both sides": cnswatchbands.com
  17. Marathon Watch, 3-Piece Rubber Strap Kit 18mm and 18mm Stainless Steel Bracelet (For Medium Dive) product pages, WATCH LUG WIDTH: 18mm: marathonwatch.com
  18. Marathon Watch, 20mm Stainless Steel Bracelet (For Large Dive) product page, WATCH LUG WIDTH: 20mm (bracelet tag For Large Dive = the 41mm class): marathonwatch.com
  19. Marathon Watch, BRACELET Rubber 22mm for NSN 6645-21-886-8975 product page, WATCH LUG WIDTH: 22mm, OVERALL LENGTH 124mm and 89mm pieces, fits 6 to 9 inch wrists: marathonwatch.com
  20. Broadarrow, Marathon JSAR listing: "Diameter 46.6mm, 17mm high, 22mm lug width. Supplied with 22mm natural rubber strap": broadarrow.net
  21. Marathon Watch, Ballistic Nylon Strap 20mm product page: OVERALL LENGTH 254mm (10 inches) and 305mm (12 inches), WATCH LUG WIDTH: 20mm: marathonwatch.com
  22. Marathon Watch, Ballistic Nylon Strap 22mm product page: OVERALL LENGTH 280mm (11 inches) and 305mm (12 inches), WATCH LUG WIDTH: 22mm (16mm page: 254mm and 292mm): marathonwatch.com