Adidas AdiZero Boston 12 Introduction

I have fond memories of my very first Adidas Boston (which was the 5th version). At the time, it had all I wanted in a running shoe: it was light, it was lean and it had enough cushioning for the short to medium distance runs I was doing.

The Boston 5 was a very different beast to today’s Boston as we know it. Those were the days when lean and minimal were still characteristics that people wanted in a running shoe. The Boston 9 and earlier versions were designed to be versatile, lightweight trainers for uptempo runs, daily runs or even racing.

The Boston of today fills a completely different role in the Adidas lineup. It’s designed to be a speed trainer: a more durable, cheaper version of their flagship marathon racer, the Adios Pro 3.

The last Boston version that I tested was the 10th version. I enjoyed testing it but I felt like it was more of an easy day/long run shoe than a speed trainer. I liked how stiff its midsole was but I found it a bit too firm for long distances.

The Boston 11 was only an upper update but the new Boston 12 has been entirely refreshed. It now weighs 9.4 oz (267 g) which is 0.2 oz (6 g) lighter than the previous version but much heavier than competitors like the Magic Speed 3 and Razor 4. It also has a thinner midsole than the Boston 11 and its price remains $160 which is the average price for a plated, speed trainer.

Adidas AdiZero Boston 12 First Impressions

My first run was an easy 41 kilometres right out of the box. At first, it felt a bit stiff and blocky but after 20 kilometres, the shoe broke in and it felt much better.

The most noticeable changes were the forefoot stiffness and the ride softness. The forefoot felt much more flexible so there was less of a rockered ride. The midsole felt a little bit softer than the Boston 10’s midsole and it had enough cushioning for the full distance.

On that first run, it didn’t strike me as a speed trainer. It felt like a daily trainer with relaxed transitions. It also didn’t feel as energy-saving as the Boston 10 because the forefoot rocker wasn’t as aggressive.

I also noticed some slight discomfort at the narrow midfoot where it poked into my arch but it didn’t cause any blisters. This is something that I never experienced with the Boston 10.

Adidas AdiZero Boston 12 Upper

The Boston 12’s upper is lighter and more flexible than the previous version but I don’t find it very comfortable. The most annoying thing is the thin, ungusseted tongue which slides downwards during runs and bunches up at the bottom of the lacing area.

The lacing system doesn’t work very well and I have to stop to adjust the lacing several times during long runs because it creates pressure spots on the top of my foot.

I find the heel fit loose. The problem is that I can’t tie the laces too tight or I feel the lacing pressure. I used a runner’s knot but I still experience a loose heel fit which makes the upper feel sloppy.

The forefoot and toe box are fine but the midfoot is narrow which causes some arch pressure. This might be an issue for wide-footed runners or runners with flat fleet. The fit is true to size and works best for me with medium or thick socks.

Adidas AdiZero Boston 12 Sole Unit

The feedback from the Boston 10 and 11 was that they were too firm and too heavy so Adidas has addressed this by adding more Lightstrike Pro foam into the midsole and reducing the amount of Lightstrike. They have also changed to Lightstrike 2.0 as the firmer bottom layer of the midsole which provides extra stability and durability.

I don’t notice a big difference between Lightstrike 2.0 and the original version of it because it’s EVA- it still feels like a midsole foam from 4 years ago. The Boston 12’s new midsole doesn’t deliver a lot more energy return but it does feel more forgiving than the Boston 10 and after my long run, my legs felt great. It definitely has enough cushioning for a full marathon.

The glass-fibre energy rods in the midsole have also been tweaked. They are more flexible than in the Boston 10 so the 12 has a more flexible forefoot with a less prominent forefoot rocker. This was a mistake in my opinion. The stiff forefoot of version 10 gave it a more similar ride to the Adios Pro 3. It used to feel more efficient over long distances.

There’s no more plate under the heel like in the last 2 versions so the ride feels smoother and more consistent now. Under the heel is a pretzel shape which is connected to the Energyrods.

I find that the Boston 12 is best for easy runs. It’s not particularly light and it’s not very energetic so it doesn’t really encourage me to pick up the pace. Its weight and its ride make it feel a bit clunky to me so it leans more towards a daily trainer than a workout shoe.

The Boston 12’s durable outsole is its best feature. It has thick, grippy Continental rubber which will last a very, very long time. There is very little wear showing on my pair after the testing period. I also find that the exposed Lightstrike midsole is durable so it won’t wear down prematurely.

Adidas AdiZero Boston 12 Conclusions

I don’t think the Boston 12 is a great update.

The changes have moved it more towards a daily trainer than a speed trainer or workout shoe. They already have the Solar Boost, Solar Glide and Supernova for daily training. I would have been happy with a Boston update with a softer ride, a more aggressive rocker and a wider midfoot.

The majority of runners will be happy with it because it’s lighter and has a softer ride but for me, it feels nothing like the Adios Pro 3 which is stiff, energetic and has a prominent forward-tipping sensation.

I don’t love running in the Boston 12 and I find it to be a very average trainer which does nothing to stand out. It doesn’t feel like a $160 shoe.

There are other speed trainers which are the same price or cheaper that feel faster than the Boston 12, like the Skechers Razor 4, ASICS Magic Speed 3 and Puma Deviate Nitro 2. They’re also lighter and more fun to use.