Let's think about the purpose of the ski boot. Besides keeping the foot warm and dry, what is it designed to do? To transmit your energy to the ski. So what is the best way to accomplish this? With a snug, uniform fit that allows the foot and boot to work as one, ideally with little or no discomfort. Therefore, listen to your gut (or in this case, your feet) and determine how a boot fits your foot, and forget what people say about the boots that fit them or what you read in the magazines.

In the last issue, we talked about how numbers can be misconstrued when we talk about skis. What about boots? Well, boots use numbers that are even more inconsistent. For instance, it seems like it should be pretty easy for an expert skier with a pretty average size 9 foot to find a boot. Just walk into a ski shop or go online, pick any 27.0 (because 2+7=9, a trick taught to beginning bootfitters many years ago),100 mm (because the internet says 100 mm is medium), and 130 flex (because, again, the internet says an expert needs a stiffer boot). Put the boot in your actual or virtual cart, pay for it, and you are ready to go. What could possibly go wrong?

Well ... everything. I am going to skip “Bootfitting for Dummies” and assume you recognized that my tongue was planted firmly in my cheek. (If you do have basic questions, please ask them on the forum in our Boots section; you will get honest, straightforward, non-snarky answers and not just replies like “Have you seen a bootfitter?”) The reason I used the numbers in my example is that none of them are standardized.

Let's start with that size 9 street shoe and its correlation to a 27 Mondopoint. Mondopoint is an actual ISO measurement that basically corresponds with centimeters; the Wikipedia definition is here. Again, as when talking about skis, Mondopoint does not always translate to your eventual boot size. A term that has been thrown around a lot lately is “downsizing.” That word mostly sounds like "pain," as if you will be put into a boot that is too small. I prefer “rightsizing": the key is to put you in the right size boot for the shape of your foot, which does not always correlate to the initial measurement, especially with a performance fit.

Width? Again, more numbers, and these are the second least consistent numbers in bootfitting. You hear numbers like 104, 100, 98, and even 92 mm. (The uber-narrow numbers are usually in a plug boots, generally for racers or skiers with pencil-thin feet, and found only at the highest-end specialty or race-oriented ski shops.)

Okay, you want to be an an educated buyer, so you measure the width of your foot and get 100 mm. A 100mm boot is based on a 25 or 26 Mondo, depending on brand, and the shells are scaled from there, so a size 23 might be 95 mm and a 29 might be 103 mm. With this scaling, if you have a 28cm foot but measure 104 mm across the metatarsals, you should start with a 100mm shell because a size 28 will be 104-ish, not 100 mm; a 104mm shell will actually be more like 107 or 108 mm.

I do find it interesting that the standard for measuring shell width is the forefoot across the widest part of the foot. This is the easiest part of the shell to work on when making accommodations. I think the consumer would be much better off if the measurement were based on the ankle, where the shell is thicker and, depending on the boot, much more difficult to modify. If you recall Salomon’s original sizing process, it measured the volume of the ankle and instep to ensure a proper fit; length was secondary. Salomon figured if you controlled the ankle, the rest of the fit would be easy. Ahead of its time, for sure.