Adidas Adizero Evo SL

Does the Adidas Adizero Evo SL run true to size? Should you size up?

We checked, on 16,874 real feet. We worked out the inside measurements of the Adidas Adizero Evo SL Men's / Unisex in the standard width: the length, the width, and the forefoot volume (ball girth). Then we virtually fitted 16,874 real feet from our earlier in-store 3D foot scanners, the way a runner shopping online would, using the chart Adidas provides online for this shoe.

Does the Adidas Adizero Evo SL run true to size?

For fewer than 4 in 10 feet. If you follow Adidas's size guidance online, the Adizero Evo SL fits true to size for 37% of feet. Here, true to size means the size Adidas's online guidance gives you is less than a full size away from the size that fits best, with enough toe room and enough forefoot volume.

Adidas did a good job with the length. Adidas's size chart says clearly that the measurement to compare is your foot length from heel to toe, and the inside of the Adizero Evo SL is about 10 mm longer than the foot length the chart gives for each size, so the room in front of the toes is already built in. Most brands only list a measurement for each size, so shoppers don't know whether to add extra length to their foot measurement for toe room. The guidance falls short on forefoot volume, because the Adizero Evo SL comes in one width. If Adidas offered width options with width measurements in its guide, the Adizero Evo SL might have gotten a full score of 100!

Should you size up or down in the Adidas Adizero Evo SL?

Adidas's size chart is shared across its shoes, but how well the chart works depends on the model. Here is where every foot landed in the Adizero Evo SL, in the standard width, when we followed that chart and ordered the usual size, as Adidas recommends.

Share of 16,874 feet. Each foot is counted once.

• Right size from the size chart: 37% of feet got a size that fit both their foot length and their forefoot volume in the standard width. Adidas's online size guidance worked well for this group in the Adizero Evo SL.
• Sized up for more forefoot volume: For 25% of feet, the standard width had too little forefoot volume at the size the chart gave. The Adizero Evo SL has no wide version, so going up a size was the only way to get more forefoot volume, and the bigger size also adds length in front of the toes.
• Sized up for toe room only: No feet landed here: 0 of 16,874. Adidas's size chart leaves every foot enough room in front of the toes in the Adizero Evo SL.
• Sized down for less forefoot volume: For 38% of feet, the standard width had too much forefoot volume at the size the chart gave. The Adizero Evo SL has no narrow version, so a smaller size was the only way to get less forefoot volume. Most of these feet (5,895 of 6,427) still fit inside a size smaller than Adidas's guidance gave, but with less room in front of the toes. The other 532 feet are too long for the smaller size, so the Adizero Evo SL leaves them with too much forefoot volume at either size.

Does the Adidas Adizero Evo SL come in different widths?

No. The Adizero Evo SL comes in the standard width only. That leaves the size as the only choice a shopper can make: runners who need more forefoot volume can only size up, and runners who need less forefoot volume can only size down.

Will your heel slip in the Adidas Adizero Evo SL?

It depends on where your foot bends, more than on your size. A shoe bends at one spot called the flex point (usually at the widest part of the shoe), and your foot bends at its ball joint.

When there is room in front of the toes (and there should be), your foot slides forward a little until the ball joint settles at the flex point. When the ball of your foot sits closer to your heel than the shoe's flex point does, your foot keeps sliding forward until the ball joint and the flex point are aligned. That leaves a gap behind your heel, so your heel can lift out of the back of the shoe more easily. That is why a heel can slip even in a size that fits the length and the forefoot volume.

The heel counter of the Adizero Evo SL is shaped to hold the foot in well, so it can help reduce the risk of heel slip. But the foam padding around the top edge of the heel counter, which can help lock down the foot, is a bit thinner than in most running shoes. A heel lock lacing can also help.

(MatchUp's shoe fitting checks your arch length against the shoe's flex point, so you can be aware of potential heel slip before you choose a size.)

How will the Adidas Adizero Evo SL fit your feet?

Those were 16,874 other people's feet. Where do yours fall? Only a foot scan can tell. MatchUp's shoe fitting scans your feet with your phone and a sheet of paper. The fitting checks more than length: it looks at width, forefoot volume, and how your arch length lines up with each shoe's flex point. Then it ranks running shoes by how well each shoe fits your foot shape, and shows how each size of the Adidas Adizero Evo SL will fit, so you choose the size you want. Answer a few questions about how you run, and you also get a personalized fit guide with advice for your feet, including lacing techniques for your foot shape.

Get fitted

Free, nothing to install. You need a phone and a sheet of paper.

How we measured

We measured the standard width of the Adizero Evo SL and virtually fitted 16,874 real feet from our earlier in-store 3D foot scanners. Out of 17,311 foot scans, those 16,874 feet fall in the Adizero Evo SL's size range (US men's 4 to 15). For every foot, we followed Adidas's size guidance online: the length chart, ordering the usual size as Adidas recommends, in the standard width. A difference of a full size or more between Adidas's size and the size that fits best counts as a miss. These numbers show how the Adizero Evo SL fits a large group of feet, not how the shoe feels on a run.