In an unexpected departure from their its horological extravaganza, Richard Mille has just unveiled the time-only RM 55-01. With a focus on simplified movement architecture and lightness, the RM 55-01’s movement is a hand-wound exercise in restraint and weighs under 5 g – equivalent to one sheet of A4 paper.

Initial thoughts

At its debut in the early 2000s, Richard Mille basically introduced and then perfected the niche offering of ultra-expensive, “hyper” sports watches, juggling complications, materials and bold aesthetics to create an outrageously expensive cocktail of lightness and ergonomics.

With the RM55-01 the same brand returns to the basics, with a caliber developed for extreme lightness, doing away with automatic winding or any complications. The watch only tells the hours, minutes and seconds — which is not really something one expects from Richard Mille these days. 

This RM 55-01 feels like a spiritual descendant of the discontinued RM 55 “Bubba Watson”. The case lines and the movement itself are very reminiscent of that model, although the RM 055 was mostly marketed as a light but sturdy golfer’s watch. The new RM55-01 is presented as a pure exercise in weight reduction.

Though the price of the RM 55-01 is unavailable, it is probably unjustifiable in any tangible or intrinsic sense. But is a mechanical watch that weighs as much as a few sheets of paper extremely cool? Yes – if you can afford it.

Airy construction

The RM 55-01 is built with openness in mind. The hefty case is reminiscent of an aquarium, with the movement floating inside. The colourful bezel and case back frame the watch and each colour scheme has its own distinct personality. 

The RM 55-01 debuts in three colourways: White Quartz TPT, Grey Quartz TPT and Carbon TPT. “Grey” is a misleading naming choice, since the model in question has a pastel blue colour, which can’t possibly be qualified as grey. While all the three models look rather clean, the Grey(-ish) Quartz TPT is a personal favourite.

The TPT composite for the bezel and caseback are come from a Swiss producer called North Thin Ply; TPT is short for Thin Ply Technology. Unlike more common composites used in watchmaking, this specific composite has a rough, layered texture which is suggestive of the more esoteric material science practices by Richard Mille. The aerospace-like cleanses of the titanium middle case balances out the composite components. 

The movement powering the RM 55-01 is the RMUL4, with “UL” short for “Ultra Light”. Apart from some nuance in surface finishing and some slight cosmetic changes done to the active portion of the movement itself, the RMUL4 is basically structurally the same as the RMUL2 found in the “Bubba Watson” RM 055. 

In terms of finishing, the RMUL4 follows the industrial high-tech style championed by Richard Mille. The grade 5 titanium bridges underwent Titalyt treatment and then some PVD coating. The spline screws are proprietary to Richard Mille and are designed to work with a wide range of torques. The screws go mostly unaffected by physical manipulation and thus will age well over more service cycles. 

The movement architecture is stripped bare to the essentials — barrels, going train and oscillator. The construction is tidy and qualitative, with a free-sprung 4 Hz balance and two series-linked barrels.

The RMUL4 only achieves a 55 hour reserve, suggesting fast-turning barrels. This construction is used for achieving more consistent torque transfer across the power reserve while not inputing too much torque into the going train. The same trick was used in the legendary Longines L.990 series and many modern Omega Co-axial movements. 

Key Facts and Price

Richard Mille RM 55-01

Case diameter: 37.95 mm by 47.33 mm
Height: 10.75 mm
Material: Quartz TPT or Carbon TPT
Crystal: Sapphire
Water resistance: 50 m

Movement: RMUL4
Functions: Hours, minutes and seconds
Winding: Manual
Frequency: 28,800 beats per hour (4 Hz)
Power reserve: 55 hours

Strap: Textile with folding clasp

Limited edition: No
Availability: Only at Richard Mille boutiques
Price: On request

For more, visit Richardmille.com.