2026-05-13
Best Watch Straps for the Seiko Prospex Speedtimer
The Seiko Prospex Speedtimer has one of the most specific origin stories in the current Seiko Prospex range. In 1964, Seiko was appointed official timekeeper of the Tokyo Summer Olympics — a moment that validated the Japanese watchmaker on the world stage for the first time. To meet the demands of Olympic precision timing, Seiko developed a new generation of high-precision chronograph instruments: a 1/5th-second wristwatch chronograph and a stopwatch designed for official athletic timing. These were not consumer products. They were precision instruments built to international sporting competition standards.
The Prospex Speedtimer launched in 2021 references both pieces directly. The SRQ035 mechanical chronograph's white dial reproduces the dial architecture of the 1964 pocket stopwatch — the same squared minute markers, 1/5th-second track, and pure legibility-focused layout. The SSC813 Solar Chronograph's panda dial with its tachymeter bezel references the 1969 Seiko 6139 Speedtimer — the world's first automatic chronograph and the direct descendant of those 1964 timing instruments.
The result is a collection with a cleaner, more specific heritage than most Seiko Prospex references — and straps that honour that heritage should reference the same 1964-1969 era directly.
Seiko Prospex Speedtimer Strap Size
Both the Solar and Mechanical Speedtimer families use 20mm lugs — confirmed by Strap Mill Canada, Strapsco, Delugs' own product page, and SJX Watches' hands-on review.
Speedtimer Solar Chronograph (SSC813, SSC815, SSC817, SSC819 and all Solar variants) — 20mm lugs. 39mm case, 13.3mm thick, 45.5mm lug-to-lug. Drilled lugs. Standard spring bars.
Speedtimer Mechanical Chronograph (SRQ035, SRQ037 and all Mechanical variants) — 20mm lugs. 42.5mm case, 15.1mm thick, 45.5mm lug-to-lug. Drilled lugs. Standard spring bars.
Quick reference:
| Reference | Case | Lug Width |
|---|---|---|
| SSC813, SSC815, SSC817, SSC819 | 39mm Solar | 20mm |
| SRQ035, SRQ037 | 42.5mm Mechanical | 20mm |
Important: Delugs' blog post lists the SSC813 at 18mm — this is wrong. Delugs' own product page for the same watch correctly states 20mm. Order 20mm for any Speedtimer reference.
Note on curved-end rubber straps: Some specialist rubber strap makers offer curved-end versions designed to sit flush against the SSC813's bracelet-adjacent lug geometry. Curved ends are not required — standard straight-end straps at 20mm fit correctly. Curved ends create a more seamless visual transition but are an aesthetic preference, not a fitting requirement.
The Speedtimer's Character — Two Different Strap Logics
The SSC813 Solar and SRQ035 Mechanical are closely related in appearance but have different characters that create different optimal strap priorities.
SSC813 Solar (39mm, 13.3mm) — slimmer, lighter, everyday-capable. Seiko ships it on a steel bracelet. The solar movement means it runs indefinitely in daily wear. The slim profile suits flat leather and perlon alongside rubber and nylon.
SRQ035 Mechanical (42.5mm, 15.1mm) — the collector's piece. Seiko includes a calfskin strap in the box alongside the bracelet — the brand's own validation that leather is the primary SRQ035 strap material. The 15.1mm thickness suits padded leather proportionally.
Best Rubber Straps for the Seiko Prospex Speedtimer
Tropical style FKM in black at 20mm — the most historically resonant Speedtimer combination. The vintage basket-weave and honeycomb surface patterns reference the 1969 Seiko 6139 Speedtimer's own era — the watch that the SSC813's design draws from was worn on similar vintage rubber in the late 1960s and early 1970s. The panda dial SSC813 on black tropical FKM is one of the most photographed Speedtimer combinations in the community.
Brown tropical FKM at 20mm — for the most warm and most specifically vintage character. The warm brown against the panda dial creates a temperature contrast that references aged 1960s timing equipment leather and rubber.
Classic FKM rubber in black at 20mm — the most practical active choice.
Dial-specific recommendations:
- SSC813 panda (white dial) — black tropical FKM for vintage coherence; brown tropical FKM for warm contrast
- SSC815 black dial — black FKM for unified dark palette; grey FKM for subtle contrast
- SSC817 gold — brown tropical FKM for warm coherence
- SSC819 black/gold — black tropical FKM
All at 20mm.
Best Leather Straps for the Seiko Prospex Speedtimer
Seiko includes a calfskin strap in the SRQ035 limited edition box — validating leather as the primary mechanical Speedtimer material. For the SSC813 Solar, leather creates the most rewarding transformation from bracelet to dress-sport piece.
Brown vintage two-stitch calfskin at 20mm — the most celebrated and most historically resonant Speedtimer leather combination. Seiko includes brown leather with the SRQ035, confirming warm brown as the factory-validated choice. The two-stitch construction references the 1964 and 1969 era of the Speedtimer's design origin. On the SSC813 panda dial, warm brown leather creates the most discussed Speedtimer leather pairing in the community — warm leather on a cool monochromatic dial.
Classic flat calfskin in dark brown at 20mm — the most versatile everyday leather, following Seiko's factory leather choice for the SRQ035 in full-grain calfskin.
Classic flat calfskin in black at 20mm — the most formally correct combination. The non-stitch variant is the most minimal.
Dark brown padded calfskin at 20mm — particularly appropriate for the SRQ035 Mechanical's 15.1mm case thickness.
Tan suede at 20mm — the most relaxed leather option. References the worn leather equipment of 1964 Olympic timing operations in a casual register.
Navy calfskin at 20mm — for a composed, formal alternative on the panda dial.
Best Nylon Straps for the Seiko Prospex Speedtimer
Single-pass nylon — Original at 20mm with the CNS solid buckle. Most appropriate Speedtimer colourways:
- Black — the most minimal. Suits all Speedtimer dial variants.
- Olive / khaki — for the most expedition and sports-timing world-adjacent character.
- Navy — clean and composed for daily wear.
- Black and grey — the most understated collector combination.
Marine Nationale elastic at 20mm — the most comfortable Speedtimer daily wear option.
RAF single-pass nylon at 20mm — for the most specifically heritage-operational combination.
Canvas at 20mm in olive or black — referencing the athletic and sporting equipment world of the 1964 Tokyo Olympics.
The Seiko Prospex Cluster
CNS covers the complete Seiko Prospex range:
Seiko SPB143 / 1959 Alpinist — 20mm.
Seiko Turtle — 22mm.
Seiko Prospex Monster — 20mm (42mm) and 22mm (Baby Monster).
Seiko Prospex Speedtimer — 20mm. The 1964 Olympics and 1969 automatic chronograph heritage.
Recommended Combinations
Most historically resonant — brown vintage two-stitch calfskin at 20mm — 1964 era leather, factory-validated by Seiko's own SRQ035 inclusion.
Most celebrated panda dial — black tropical FKM at 20mm — vintage rubber on the panda SSC813.
Most warm vintage — brown tropical FKM at 20mm — warm aged rubber against the cool panda dial.
SRQ035 Mechanical — brown vintage two-stitch leather following Seiko's included strap; dark brown padded calfskin for the most proportionally appropriate everyday leather.
Most comfortable daily — Marine Nationale elastic at 20mm.
Frequently Asked Questions
What size strap does the Seiko Prospex Speedtimer take? 20mm — confirmed by Strap Mill Canada, Strapsco, Delugs' product page, and SJX Watches. Both the Solar (SSC813-819) and Mechanical (SRQ035, SRQ037) use 20mm drilled lugs. Standard straight-end straps fit correctly — curved ends are an optional aesthetic preference only.
What is the best rubber strap for the Seiko Speedtimer SSC813? Black tropical style FKM at 20mm — the vintage basket-weave pattern references the 1969 Seiko 6139 Speedtimer era that the SSC813's design draws from. The panda dial on black tropical rubber is the most photographed and most discussed aftermarket SSC813 combination.
What is the best leather strap for the Seiko Speedtimer? Brown vintage two-stitch calfskin at 20mm — the most celebrated combination, referencing the 1964 Olympics and 1969 Speedtimer heritage. Seiko validates warm brown leather by including it with the SRQ035 limited edition.
What is the "Seitona" nickname for the SSC813? The SSC813 panda dial SSC813 has been nicknamed "Seitona" by some collectors — a portmanteau of Seiko and Daytona, referencing the visual resemblance between the SSC813's panda dial and the Rolex Daytona's white panda dial with contrasting subdials. The nickname reflects the SSC813's striking dial character but the Speedtimer has its own specific 1964 Olympic heritage that needs no borrowed references.
Do I need curved-end straps for the Seiko Speedtimer SSC813? No — standard straight-end 20mm straps fit the SSC813 correctly. Curved-end rubber straps create a more seamless visual transition at the lug, mimicking the integrated look of the factory bracelet. They are an aesthetic preference, not a fitting requirement. All CNS straps at 20mm fit the SSC813 without modification.
All CNS straps for the Seiko Prospex Speedtimer are available at 20mm. Standard delivery worldwide. 30-day returns.