More Adventures in Solo Loop Sizing

Wednesday, 23 September 2020

Impeccable timing on my part last night:

This makes me suspect that many are using Apple’s measuring tool inaccurately, or printing it out at the wrong scale, or both, and perhaps Apple should clarify the printed instructions. The current instructions simply read:

Cut and wrap the tool around your wrist, snug but not too tight.

What those instructions don’t make clear, but perhaps should, is that I think you’re supposed to use the tool to precisely measure the circumference of your wrist, not to simulate the circumference of what you think would be a comfortable watch band. Think about how a tailor measures your chest or waist — you’re not cinching a tourniquet, but you don’t want any slack at all.

Apple today updated its Solo Loop PDF sizing tool. The sizes remain exactly the same, but the instructions have been clarified, much as I suggested, and are now accompanied by a helpful illustration. They now read:

Cut the tool. Then wrap it tightly around your wrist where you typically wear your watch. You can use tape to hold the wider part in place. Make sure the tool feels snug and doesn’t slide up or down.

No more ambiguous “snug but not too tight”. Now they’ve made clear that it should wrap tight enough not to slide around. Apple also clarified what to do if your wrist seems to fall between sizes:

Note the number the arrows point to — that’s your band size. If the arrows point to a line, choose the smaller of the two numbers closest to the line.

A few people have wondered why Apple doesn’t just map fluoroelastomer Sport Band sizes to Solo Loop sizes. I can see why Apple doesn’t do that — they can’t assume everyone already has access to an Apple Watch with a Sport Band, and even for people who do have access to one, Apple can’t assume it’s the right size watch (38/40mm vs. 42/44mm). And to further complicate matters, each Sport Band comes with two sizes for the side with the holes: “S/M” and “M/L”. So that’s four separate mappings from Sport Band holes to the new Solo Loop sizes. That’s complicated. But it’s no longer a safe assumption that everyone has access to a printer, either, so let’s figure out the mappings here.

It turns out Sport Band holes do map exactly to the new Solo Loop sizes. That makes sense, when you think about it, but it hadn’t occurred to me until today to just lay Sport Bands next to the measuring tool. The distance between the holes in every Apple Sport Band is exactly the same as the distance between the 12 sizes of Solo Loops on Apple’s measuring tool.

[Update: My measurements for the smaller 38/40mm Sport Bands had an off-by-one bug1 when I originally published the photo and table below. Sorry about that. I believe they are correct now.]

[Update 2: Don’t overthink these photos. The top of the bands aren’t supposed to line up. My methodology was simple. I tried all four Sport Band combinations on my own wrist: 40 and 44mm watches, with both the S/M and M/L bands. Then I lined up the Sport Band hole that fit my wrist best with the Solo Loop size that I know fits me best (size 7). That’s it. You line up the Sport Band hole that fits you best with the Solo Loop size that fits you best and the other hole-to-Solo-Loop-size mappings just fall into place. The fact that the tops of the bands don’t line up when you do this is irrelevant.]

Here are two photographs to illustrate the mappings. First, these black Sport Bands are for smaller Apple Watches (38/40mm):

Two black 40mm Apple Watch Sport Bands, one S/M and one M/L, laid next to a printout of Apple’s PDF sizing tool for Solo Loop bands.

These gray Sport Bands are for larger Apple Watches (42/44mm):

Two gray 44mm Apple Watch Sport Bands, one S/M and one M/L, laid next to a printout of Apple’s PDF sizing tool for Solo Loop bands.

No matter which width and length, all Sport Bands have 7 holes. The following table shows how those holes correspond to Apple’s new Solo Loop sizes:

38/40mm 42/44mm
S/M 1–7 3–9
M/L 4–10 6–12

To me, the photographs above make the mappings much more obvious than the table. It practically demands an illustration, lest you get lost between counting Sport Band holes and counting Solo Loop sizes.

The range of wrist sizes for the Sport Bands corresponds exactly to the new Solo Loops — the first hole on the 38/40mm S/M Sport Band is a size 1, and the last hole on the 42/44mm M/L Sport Band is a size 12.

  1. Here’s my mistake. It was really dumb, like any good off-by-one bug. I have a slew of old Sport Bands from various Apple Watches over the years, but not as many actual spare watches. And the spare watches I do have are mine, and thus are 42/44mm models. When I tried the smaller 38/40mm Sport Bands on my wrist, I snapped those bands onto my 44mm Apple Watch, rather than bother my wife or son to borrow one of their smaller 40mm watches, thinking it wouldn’t matter, because I happen to know the watch connectors will properly snap into place for all straps on all watches. It doesn’t look right, width-wise, but functionally you can securely connect a small Apple Watch band to a large Apple Watch, and vice versa.

    The obvious problem: trying small Apple Watch bands on a large Apple Watch body didn’t account for the fact that the larger watch body spreads the watch connectors a few extra millimeters apart. Hence the off-by-one bug. Duh. ↩︎