Independent watchmaker Armin Strom has released the brand-new Gravity Equal Force P.03, which has been crafted in collaboration with California-based Collective Horology — founded by Asher Rapkin and Gabe Reilly in 2018, the group has done projects with mainstream brands like IWC and Zenith as part of their “Collective Series” and independent names like J.N. Shapiro and Urwerk for their “Portfolio Series.” The Armin Strom Gravity Equal Force P.03 joins the latter group and, as the P.03 designation indicates, is the third in the Portfolio Series.

This isn’t a mere “colourway collaboration” as there are some significant changes and flourishes made to the base watch. Notably, this is the first Armin Strom Gravity Equal Force watch to be done in a titanium case. Additionally, there are milled-out pockets on the two top and bottom dial-side bridges while the shorter centre bridge has a step. Below you can see a photo of the standard issue steel model that I photographed some time back side-by-side with the P.03 for comparison.

The case of the new Armin Strom watch measures 41mm wide and 12.65mm thick with 30m of water resistance. For the P.03, the offset dial is done in a matte khaki fumé with lumed coating on the hands and numerals as well as mirror-polished indices. You’ll also notice the “tech-style” guilloché pattern done on the movement plate in the background. The colour scheme of the Armin Strom Gravity Equal Force P.03 is really quite attractive, especially coupled with the khaki rubber/leather strap that is excellently finished and very comfortable.

The openworked Manufacture ASB19 automatic movement of the new Armin Strom watch features a micro-rotor which you can see on the dial side at 1 o’clock and equal force barrel beneath it at 6 o’clock. If you’re unaware of the impressive developments Armin Strom has made to core watchmaking as part of their “System 78” collection, here is a brief primer on the salient mechanism. The Gravity Equal Force mechanism is a rather ingenious way of negating the adverse effects of poor isochronism on accuracy. The extremes of inconsistency in torque come when a movement is fully wound (high torque) and when it’s nearly unwound (low torque). This mechanism doesn’t use the first few turns of the barrel at all and, in fact, limits the mainspring barrel to nine full turns out of a possible twelve-and-a-half. By sacrificing a longer power reserve, Armin Strom Gravity Equal Force P.03 delivers a 72-hours that are remarkably accurate. As this is an automatic movement the issue of overwinding is addressed by the novel “stop-work declutch” which is used on a self-winding calibre for the first time ever here.