The Black Bay GMT gave Tudor a genuine travel watch with an in-house movement, and it sells steadily on the UK market. Identifying the exact reference keeps the valuation accurate.
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The short answer
The Tudor Black Bay GMT is reference 79830RB: a 41mm steel case, in-house GMT calibre MT5652, and a burgundy-and-blue anodised aluminium bezel — not ceramic. It's most familiar with a black dial, with a later opaline (silver-white) version. It is not the steel-and-gold "Root Beer" and not the 39mm BB58 GMT. Fair Vintage confirms the reference from the watch, grades the condition, values the box and papers, and gives a free, no-obligation valuation — all by post from Bedfordshire, with insured postage and payment by bank transfer within 72 hours of you accepting.
The Black Bay GMT is reference 79830RB: a 41mm steel case, 200m water resistance, and Tudor's in-house GMT calibre MT5652 (COSC, roughly 70-hour power reserve). Its bezel is a burgundy-and-blue anodised aluminium insert in the classic "Pepsi" colour scheme — an aluminium bezel, not ceramic. It's most familiar with a black dial, and Tudor later offered an opaline (silver-white) dial version.
The most familiar Black Bay GMT: 41mm steel, MT5652, burgundy-and-blue anodised aluminium bezel, black dial. The core reference this page covers.
Tudor later offered an opaline (silver-white) dial version of the same reference. It appeals to a different audience, so we value each dial variant on its own condition and demand.
The collector nickname "Root Beer" does not refer to this steel 79830RB. It relates to a separate steel-and-gold Black Bay GMT reference (79833MN) with a brown-and-black bezel — a different, two-tone watch.
Tudor's 39mm Black Bay 58 GMT is a different, smaller watch and isn't valued on this page. Keep it distinct from the 41mm 79830RB.
Condition, whether the watch has been polished, bracelet vs strap and any stretch, dial variant (black vs opaline), and completeness of the set. The opaline version has its own audience.
Clear up the "Root Beer" mix-up before you sell. If someone has described your steel Pepsi-style GMT as a "Root Beer," that's a mistake — the Root Beer is a separate steel-and-gold reference (79833MN). Correctly separating the two means your watch is valued as exactly what it is.
Buyers like the warranty card, box and booklets, the original bracelet or strap, and any spare links so it can be sized. If yours came with both a bracelet and a fabric strap, include both.
We buy the Black Bay GMT without box or papers, confirming the 79830RB from the watch and reflecting any missing items in the offer.
Send the reference and photos for a free, no-obligation valuation. If it suits you, we arrange a free, fully insured Royal Mail Special Delivery label, check the watch, and pay by bank transfer within 72 hours of acceptance. It's a postal service from Bedfordshire.
Correctly separating the steel 79830RB from the steel-and-gold Root Beer, and from the 39mm BB58 GMT, means your watch is valued as exactly what it is. For more on how model detail shapes an offer, see our guide to luxury watch resale value in the UK.
Exact reference identified. Condition graded honestly. Box and papers valued. Free insured postage both ways. No obligation — we return your watch free if you decline the offer.
Request a free valuation →Is the Black Bay GMT bezel ceramic?
No — the 79830RB uses a burgundy-and-blue anodised aluminium bezel insert.
Is my steel Black Bay GMT a "Root Beer"?
No — Root Beer refers to a separate steel-and-gold reference (79833MN) with a brown/black bezel, not the steel 79830RB.
What movement does it use?
Tudor's in-house GMT calibre MT5652, COSC-certified, with roughly a 70-hour power reserve.
Is the opaline-dial version worth more?
It appeals to a different audience; we value each dial variant on its own condition and demand.
Is this the same as the Black Bay 58 GMT?
No — the BB58 GMT is a separate 39mm model; this page covers the 41mm 79830RB.
Can I sell without box and papers?
Yes — we confirm the reference from the watch and reflect any missing items in the valuation.
Also see: Sell Tudor watches · Sell Tudor Black Bay 58 & 54 · Sell Rolex GMT-Master II
Also buying: Luxury watch buyers · Sell your watch · Watch valuation