Earlier this year Grönefeld launched their amazing new Parallax Tourbillon. You can still find our report HERE, but the gentlemen had something else coming up, where they were pretty suspicious about earlier this year.

This week Tim & Bart Grönefeld presented their new One Hertz!


The new One Hertz is part of series of timepieces with independent dead seconds. The One Hertz 1912, One Hertz Dune, One Hertz Ruthenium, One Hertz Titanium, One Hertz Platinum, One Hertz Fire, One Hertz Ice and in 2013, the open-dial One Hertz Techniek was launched.

While the new member of the collection is technical identical from the ones from previous collections, the look is very different. Presented in a 43mm red gold case, with slightly domed sapphire crystal and solid silver dial, that is blasted with brass particles to get that frosty sparkling finish, the watch gives a very clean impression. To prevent the dial from tarnishing, an ultra thin layer of lacquer is applied


The flames blued hands, stand out and guarantee excellent readability. All applied elements are rhodium plated with circular graining and beveled edges. The polishing of the bevels is done with a diamond paste, to create scintillating reflections of light.

When the watch is turned around the high end finishing of the steel movement bridges, is visible through the flat sapphire crystal, display back.

– The reverse side of the One Hertz looks as good as the front –

A Grönefeld One Hertz is a unique watch, since its dead seconds are powered by a secondary gear train, which is completely independent of the gear train for the hour and minute indications. Before Grönefeld presented their first One Hertz in 2010, dead seconds was usually derived from mechanisms requiring considerable force from the going train, witch created more wear.

– The 43mm case has a great fit on my 18cm wrist –

The release of the new One Herz and the launch of the new Parallax Tourbillon earlier this year, turns 2014 into an important year for the Grönefeld brothers. While the Parallax Tourbillon is substantial and more expensive than the One Hertz, both watches share  an amazing level of finishing, which makes them both look very good.

——— Specs ———-

Calibre G-02: Mechanical hand-woundmovement; independent dead seconds
Movement dimensions: Diameter 151/4’’’ 34 mm; thickness: 9.5 mm
Number of components: 285 in the whole movement
Number of jewels: 39 jewelsin gold chatons
Power reserve: 72 hours
Barrels: 2 barrels, one for the going geartrain and one for the independent dead seconds mechanism; both barrels are wound at the same speed and in the same direction
Balance wheel: Free sprung variable inertia balance wheel (9.12 mm diameter)
Frequency: 21’600 vph
Balancespring: Phillips terminal overcoil curve; triangle-style stud
Escapement: Swiss lever escapement
Mainplate: Spotted and snarled rhodium plated nickel silver
Bridges: Hand bevelled; stainless steel X46Cr13 Micro-blasted centre; circular grain on the top; relief engraved in the micro blasted surface
Gearing: Two gear trains with their own energy sources (2 barrels)
Dead seconds: Independent mechanism; cam with 30 teeth on the fourth wheel of the going geartrain; special escape wheel on the fourth wheel of the independent geartrain; double lever with four jewelled pallets
Winding-setting: Crown with push function to choose between winding or setting; hacking seconds
Power reserve: Classic Breguet mechanism by means of a cone moving up and down on the threaded barrel arbour