Adidas Boston 12 vs Saucony Endorphin Speed 3: Which Super Trainer Deserves Your Money?

Introduction

Super trainers have become the sweet spot of modern running footwear: they borrow the best foam and propulsion tech from top-end racing shoes but are built to handle the bulk of everyday training. The Adidas Boston 12 and the Saucony Endorphin Speed 3 are two of the most complete examples of the category, and choosing between them is genuinely difficult.

Both are versatile shoes that can absorb easy miles and still deliver when you pick up the pace. The differences come down to ride character, upper comfort, and outsole grip. Here is how they stack up.

Meet the Contenders

The Boston 12 is the newer and cheaper of the two, priced at £140 in the UK and $160 in the US. The Endorphin Speed 3 costs £165 and $170. The Speed 3 is also the lighter shoe, at 240g (8.5oz) in a UK 9, versus 259g (9.1oz) for the Boston 12.

On paper, the geometry differs subtly. The Speed 3 runs an 8mm drop with a 36mm heel and 28mm forefoot stack, while the Boston 12 uses a 7mm drop with a taller 38mm heel and 31mm forefoot.

Under the hood, the Speed 3 pairs Saucony’s PWRRUN PB foam with a flexible nylon plate that includes small winglets for added stability, plus the brand’s Speedroll rocker geometry. The Boston 12 goes dual-density: a bouncy Lightstrike Pro top layer over Lightstrike 2.0 EVA, with glass-fibre infused Energy Rods 2.0 running under the forefoot to add spring at toe-off. Its outsole is Continental rubber, a long-standing Adidas strength for grip and durability.

Fit and Sizing

Both shoes fit true to normal running shoe length, though note the sizing quirk: a UK 9 equates to a US 10 in Saucony and a US 9.5 in Adidas.

Width is where they diverge. The Boston 12 is the narrower shoe, and runners with narrow feet will likely find a more secure hold there, though the minimal, racy upper can create some lace pressure on the top of the foot. The Speed 3 was widened for its third version, which makes it friendlier for wider feet but trickier for narrow-footed runners who have to cinch the laces down hard, and some heel rubbing has been reported despite the heel counter.

Ride Feel: Rocker Smoothness vs Snappy Pop

This is the heart of the comparison. The Endorphin Speed 3 is the smoother, more rockered shoe: there is less snap, and the speed comes from an efficient rolling motion created by the Speedroll geometry, plate, and foam working together. It feels relaxed and approachable at every pace, from recovery runs to track reps.

The Boston 12 has a snappier character. At faster efforts you feel a distinct kick from the Energy Rods and the Lightstrike Pro layer, with a poppy toe-off and a more grounded, direct feel. Interestingly, at easy paces the two foams blend into a surprisingly smooth, cushioned ride, so the Boston softens its personality when you slow down.

Which Shoe for Which Training?

For short, sharp reps like 400s, the Boston 12 has the more direct feel: it is easier to kick into gear and accelerate hard. If short intervals are your priority, it edges ahead.

The Speed 3 shines on longer, harder sessions. In long tempo runs or hour-long steady efforts, its smooth, efficient ride helps you hold pace with less effort and less fatigue. It is also the better pick as a marathon racer, thanks to that more comfortable overall ride, and the lighter weight makes it the slightly more accomplished all-rounder for many runners.

The Boston 12 does have one compelling practical advantage: the Continental rubber outsole grips and wears better, especially on greasy pavements and wet tracks where the Speed 3 can feel a little slippery. If you train regularly in very wet conditions, that alone is a good reason to lean towards the Adidas. It is also worth noting that Adidas shoes tend to appear in sales and discount codes shortly after release, so real-world savings are often possible on the Boston.

Conclusion

There is no bad pick here. Both are excellent all-round super trainers that handle a wide variety of training with real flair. The Endorphin Speed 3 gets the narrow win for its smoother, more relaxed ride, lighter weight, and superiority over longer sessions, while the Boston 12 fights back with a snappier ride, better outsole grip, and a lower price. Let your ride preference, foot shape, and local weather make the final call.