San MartinSN0109G-A
Homage to the Tudor Black Bay GMT
about$388
Regular price at the brand's own website, checked 31 Oct 2026. Marketplace prices change often.
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The San Martin SN0109G-A is a homage to the Tudor Black Bay GMT, with a 39 mm case, 2 mm smaller. It uses an automatic movement and is water resistant to 100 m. It costs about $388 at the official store.
Side by side with the original
Compared with reference M79830RB-0001. Values marked ≈ are estimates, such as a reviewer's measurement.
| Spec | SN0109G-A | Black Bay GMT (M79830RB-0001) | Difference |
|---|---|---|---|
| Case diameter | 39 mm | 41 mm | −2 mm |
| Lug-to-lug | 48.5 mm | Not published | Can't compare |
| Thickness | 12.25 mm | ≈ 14.5 mm | −2.25 mm |
| Lug width | Not published | Not published | Can't compare |
| Water resistance | 100 m | 200 m | |
| Movement | Automatic, HZ6460 | Automatic, MT5652 | |
| Power reserve | 40 h | 70 h | |
| Crystal | Sapphire, aR coating | Not published | |
| Bezel | 24-hour scale, Aluminum | Bidirectional rotating, 24-hour scale, Matte burgundy and blue aluminium | |
| Case material | 316L solid stainless steel | Steel | |
| Lume | BGW-X1 on hands and markers | Not published | |
| Bracelet | 316L solid stainless steel bracelet, 20 mm tapering to 16 mm | Riveted steel | |
| Weight | 146 g | Not published |
- ≈ Black Bay GMT, Thickness: median of 3 agreeing independent measurements (14.5–14.6 mm); the maker does not publish it.
The original
Tudor
Black Bay GMT
Reference M79830RB-0001, black dial, burgundy and blue bezel, steel bracelet
- Case
- 41 mm
- Lug-to-lug
- Not published
- Thickness
- ≈ 14.5 mm
- Water resistance
- 200 m
- Movement
- Automatic, MT5652
- List price
- $5,275
Why it scores as it does
Proportions and movement are computed from specs. Design details and functions are judged from the brand's official images. How we score
Lug-to-lug is neither published nor measured for one of the two watches, so there is not enough data to score.
Proportions— / 30
- Case diameter4 / 122 mm apart
- Lug-to-lug0 / 8Not published, left out
- Thickness1.5 / 62.3 mm apart
- Lug width0 / 4Not published, left out
Design signatures— / 40
- Burgundy and blue 24-hour bezel6 / 12Blue and red aluminum 24-hour bezel on three dial colours; the red is brighter than burgundy. The black-gold listing has a black and brown bezel.
- Snowflake hour and minute hands9 / 9Snowflake hour hand with a plain sword minute hand, as on the original.
- Red snowflake-tipped GMT hand2.5 / 5The GMT hand is yellow-orange with a square tip, not red with a snowflake tip.
- Riveted steel bracelet0 / 6Brushed three-link bracelet with no rivet heads in the official images.
- Matte black domed dial2 / 4One of four dials is matte black; doming cannot be judged from the images.
- Applied silver hour markers1 / 2Round lume plots in polished rims, a triangle at 12 and bars at 6 and 9; the original's markers are silver-toned.
- Large screw-down crown1 / 2Screw-down crown with the brand logo; it looks smaller than the original's large crown.
Functions and materials— / 20
- Complications4 / 8Date and a centre GMT hand as on the original. The brand does not say which type; the one review says the GMT hand sets independently (caller type).
- Bezel action4 / 4Rotating 24-hour bezel; the one review of this version found it bidirectional with 24 clicks.
- Case and bezel materials4 / 4Steel case and bracelet with an aluminum bezel insert, as on the original.
- Crystal shape and date window2 / 4Top-hat sapphire with AR coating; the original's crystal is not recorded in its specs.
Movement type— / 10
- Movement type10 / 10Same movement type.
What reviewers and owners say
We haven't read enough independent reviews of this model to summarise them yet.
Good
- Four dial colours
- Rotating 24-hour bezel with crisp clicks in the one review of this version
- On-the-fly adjustable clasp
- HZ6460 movement at 28,800 bph with a hacking seconds hand
- Top-hat sapphire crystal
Less good
- About 12.4 mm thick including the crystal in the one review
- Aluminum bezel insert rather than ceramic
- No lume on the bezel in the one review
- Only one review of this version so far
Versions and colours
- Matte black dialIts own colourway, not on the originalabout $388
- Matte dark blue dialIts own colourway, not on the originalabout $388
- Matte white dialIts own colourway, not on the originalabout $388
- Matte black gold dial, black and brown bezelIts own colourway, not on the originalabout $388
Earlier versions
- NH34 version: Earlier units were reviewed with a Seiko NH34 movement and measured about 13 mm thick, against the HZ6460 and the 12.25 mm the brand lists now.
Compare
Sources
Checked 31 Oct 2026. Every figure on this page comes from one of these pages.