Double Tourbillon 30°

The 2004 original and the Technique that followed

The brand's history page dates the Double Tourbillon 30° to 2004. The original case measures 43.5 mm across and the movement has a 72-hour power reserve. The inner cage turns once every 60 seconds and the outer cage once every four minutes. The brand records 144 examples made between 2004 and 2010, so the original is rare as well as technically significant.

Later versions followed, including the Double Tourbillon 30° Technique. Its standard case measures 47.5 mm across and 16.84 mm thick, with a 120-hour power reserve and a 30-meter water resistance rating. The Technique is a larger watch with a longer reserve, so the case size and the reserve tell you which version you're dealing with before anyone looks at the movement.

The Edition Historique won the Aiguille d'Or at the Geneva Grand Prix in 2010, which is one reason the design is still discussed in watchmaking circles. When you describe a fault to a watchmaker or the concierge, name the version first, since the reference decides the case size, the reserve and the scope of the job.

How the nested cages affect the rate

A tourbillon carries the escapement and balance around so that position errors average out over time. Here the inner cage is inclined at 30 degrees relative to the first cage, so the two rotations act on the regulating assembly at different angles. That's why a rate can look fine in one position and drift in another, and why positional testing is part of any proper service. Ask the watchmaker how the inner cage is timed relative to the outer cage, since that relationship is what the design depends on.

The pivots and bearings in a double tourbillon are small, and a cage out of balance will show up in the rate. Ask the watchmaker to check the cage rotation and the balance in several positions, and to report the rate for each position, not a single figure for the whole watch.

A service that changes the rate in one position and leaves another untested is incomplete. Ask for the positional results, and compare them with the manufacture's own figures if the brand provides them.

Servicing: the factory route and the limits of independents

Greubel Forsey directs factory service and warranty questions to its concierge in La Chaux-de-Fonds. The brand doesn't publish repair charges, turnaround times or warranty exclusions, so the first step is a conversation followed by a written plan.

An independent can be a sensible second opinion, particularly once the warranty has expired. For a full overhaul, the manufacture knows the design best. If you go outside the brand, ask in writing what will be opened, which parts will be replaced and whether the brand will still stand behind the watch afterward.

Ask whether polishing or refinishing of visible parts is proposed. On a watch with this finishing, that decision changes the watch. Get any diagnostic fee and the estimate in writing before work starts, and ask for any original parts that come out to be returned to you.

Buying pre-owned: what to verify in a double tourbillon

Check which version you're buying, whether the original, a Technique or a limited edition. The case size, the power reserve and the dial details all depend on that. Ask for the reference and serial, and check them against the box, the papers and the caseback.

A pre-purchase inspection should open the movement and check the cages, the balance and the adjustments, with a written report. A visual check of the case tells you little about a movement this complicated. Ask for photographs of the movement taken during the inspection, so you have a record that travels with the watch. If the watch has been through an auction house, ask for the condition report and any service documentation the house holds.

Auction lots sometimes include a complimentary service or a warranty term. Read those terms closely, because they belong to that sale and don't pass automatically to every later buyer. Confirm them in writing before you bid.

Care, storage and positional checks at home

A double tourbillon is sensitive to position and knocks, so keep it in a stable place, preferably in a case that holds it still. Wind it by hand at a steady pace, and avoid leaving it on a surface where it can be bumped. A few minutes of care each day protects the cages and the balance more than any service can repair.

Some owners like to check the rate in a few positions at home. A simple timing record taken after a full wind, with the watch lying in the same position each time, will show a drift, but it can't replace a proper positional test on the bench. Use home readings as a warning and bring the record to the watchmaker rather than trying to adjust anything yourself.

Storage matters for a watch this rare. Keep the box, papers and any original accessories together, and check the seals whenever the watch comes back from a service. Ask for a written note of any parts replaced, and keep the originals if they were removed, since a future service may need to match them.

What to check on a Double Tourbillon 30°

• Experience with nested tourbillon cages, not only general high-end work
• Positional rate testing before and after any service
• Written confirmation of warranty status and the concierge route
• Clear agreement on polishing and visible parts before work begins

Common questions