Saucony Endorphin Speed 4: First Run Impressions of a Refined Super Trainer

Introduction

The Endorphin Speed 3 set the benchmark for super trainers, so expectations for the Speed 4 were always going to be high. Saucony has kept much of the DNA that made the previous version such a hit, retaining the power run PB midsole foam and the Speedroll rocker geometry, while tweaking the nylon plate and the upper. This is a shoe built for racing and speedy runs, and the early signs suggest the formula has been refined rather than reinvented.

Specs and Details

The stack height stays the same at 36mm in the heel and 28mm in the forefoot, for an 8mm drop. Weight comes in at 8.6oz (245g) in a UK 8.5 test shoe, ever so slightly heavier than the Speed 3, but still among the lightest daily trainers available. It’s lighter than the Triumph 21 and slightly heavier than the Hoka Mach 5.

On price, the Speed 4 lands at £180 in the UK, which is £5 more than the Speed 3, while the US price stays the same at $170.

Fit and Sizing

Fit impressions across our testers were mostly positive, with one recurring theme: the shoe runs roomier than earlier versions. One tester with narrow feet found the shoe slightly wider than the Speed 3 and needed to cinch the laces tighter, though the heel rub felt less severe than before. Others found the fit bang on in their regular Saucony running size, with secure heel and midfoot lockdown and a roomy, flexible toe box.

The recommendation across the board is to go true to size. Wider-footed runners should find the fit comfortable, while narrow-footed runners may want to use a heel lock lacing technique to take up the slack.

Midsole, Plate and Ride

Underfoot, the Speed 4 keeps a decent stack of PWRRUN PB super foam with a re-engineered winged nylon plate adding stability, rigidity and forefoot flexibility. The Speedroll geometry and rocker shaping carry over from the Speed 3, and there’s a responsive sockliner inside for extra bounce and step-in comfort.

On the run, the midsole delivers plenty of energy and bucket loads of protection. The foam cushions the road without sinking too far and returns right when you need it, giving a lively, punchy feel at faster paces. Drop down to an easy cruise and there’s enough softness to handle heavier miles too. One caution: runners who need maximum stability may notice a bit of wobble in the platform.

It’s worth noting that one tester felt the shoe rode slightly bulkier than the Speed 3, with measured weights of 204g versus 221g in a UK size 7. The heel also felt wider underfoot at first, though that extra width added a sense of stability once settled in.

Upper and Comfort

The upper uses zonal mesh with a similar structure and density to the Speed 3: light, airy and perforated, with slightly more padding in the heel collar. The thin, racy tongue of the Speed 3 has been swapped for a thicker padded tongue, though some testers found the new knitted tongue a bit flimsy and worried about the stitched-in lace tabs holding up over time.

Step-in comfort is a genuine highlight. The shoe disappears on the foot quickly and feels natural from the first strides, with excellent instant comfort the moment you lace up.

Outsole and Durability

The outsole has been redesigned with one large lattice section covering the whole forefoot for more protection and grip, plus two heel sections that cover more of the key impact zones than before. The Speed 3 had a habit of scuffing on the outer edges, and the added rubber there should help address that.

In wet conditions, the updated grip performed well, with solid traction in general and confident cornering. Wet manhole covers remained slippery, but that’s a common weakness across most shoes.

Early Verdict

After steady runs, a half marathon pace session and an easy hour near 10 miles, the Speed 4 feels very much like the Speed of old: smooth, comfortable, easy to turn the legs over and relaxing at slower paces while still responding well when the pace picks up. The slight weight gain didn’t make itself felt on the run, and the plate provides a subtle benefit on sustained efforts.

The consensus is that Saucony has tweaked a winning shoe and not broken anything. It may not deliver quite the same poppy, race-day sparkle as the Speed 3, and one tester felt it leans more fast workout shoe than substitute race shoe, but it hits the same great high notes: propulsive, versatile and reliably comfortable. For runners choosing between the two, the Speed 3 remains the cheaper pick in the UK, while the Speed 4 looks like a safe, excellent all-rounder with all the hallmarks of one of the best super trainers available.

Conclusion

The Saucony Endorphin Speed 4 takes a beloved super trainer and refines it with a re-engineered plate, more durable outsole and plusher upper. Early impressions are overwhelmingly positive: instant comfort, a lively cushioned ride and genuine versatility from easy cruises to tempo work. If you loved the Speed 3, this should feel like coming home; if you’re new to the line, it’s a compelling place to start.