iPhone Duo fold tests: the hinge holds, the crease does not

The iPhone Duo's hinge survived the folding machines. The groove in the inner screen did not stay as quiet as it looked on day one.

That split matters in the first retail week of a phone that launched at $1,999. Android Authority's Aamir Siddiqui and Dexerto's write-up of YouTuber Tim Pan's machine test agree on what held, and they agree the center crease got easier to see. Joanna Stern's separate run, as Siddiqui reports it, is a hinge result. It is not a second measurement of the crease.

Pan's test, as Dexerto describes it, started with a new Duo beside one folded 500 times by hand. The crease was already easier to notice, though he found the difference hard to see in ordinary use with the display on. A machine then ran 10,000 folds at room temperature and another 1,000 at minus 4 Fahrenheit. Dexerto says Pan told viewers the hinge was still smooth after that sequence and still assisted the opening the way it had on day one. He also called the phone structurally strong after trying to bend it the wrong way. Dexerto adds that hair and sand could enter the hinge at some angles.

Siddiqui puts the room-temperature count at 10,500 folds before those freezer cycles, and he describes the hinge as 3D-printed titanium. The two counts are close enough to be one test told two ways. Neither outlet published a depth or width for the groove. Deeper, here, means it looks deeper and feels deeper.

Stern's rig, which Siddiqui says she calls Hingy, logged more than 32,000 partial folds across four days. He reports that the hinge stayed as stiff and sturdy as on day one. He does not say she measured the crease. Counting her run as a second vote for a deeper groove over-reads his account.

Siddiqui's account of Pan's video adds four quirks the fold total skips. The NFC antenna sits on one side, so tap-to-pay is awkward with the phone open. The inner display has no earpiece, and opening the phone mid-call moves the audio to speakerphone. Heavy use while unfolded raised the surface by about 3.6 degrees Fahrenheit, with the A20 Pro side warmer. Opening or closing the hinge too slowly could flip the interface or black it out briefly.

Those details come from one writer's viewing of one video. They are still the kind of thing a buyer hits in a shop, which a fold counter will not show. Siddiqui describes the inner display's nano-texture finish as a way to diffuse reflections and soften the look of that center groove. Pan's 500-fold comparison says the groove is already easier to see with the screen off, finish or not.

A machine is not a year in a pocket. Pan's cold cycles and Stern's partial folds are not the same stress, and the room-temperature totals in the two write-ups do not even match exactly. Nobody in these reports has a number for how much the crease grew.

The agreement worth keeping is narrow. The hinge assist did not go slack in either reported test, including Pan's freezer run. The crease became easier to see early, then more pronounced after the long machine run. Someone who opens the phone dozens of times a day, and who cares most that the hinge still helps, has encouraging short-term evidence. Someone who wanted the inner screen to stay nearly flat should look at the after pictures before the return window closes, and should not treat a stiff hinge as proof the groove stopped changing.