Saucony’s Endorphin Speed lineup has become synonymous with lightweight propulsion, blending nylon plate efficiency with daily trainer comfort. With the arrival of the Endorphin Speed 4, Saucony refines this popular formula with upgraded foam, redesigned geometry, and dialled-in upper fit — delivering a more aggressive, stable ride for tempo efforts, long runs, and interval training alike.
Positioned between race-day carbon models and soft everyday trainers, the Speed 4 caters to runners chasing performance without sacrificing comfort.
Key Specifications
| Feature | Detail |
|---|---|
| Weight | ~227g (Men’s UK 9), ~190g (Women’s UK 6.5) |
| Drop | 8 mm |
| Stack Height | 38 mm heel / 30 mm forefoot |
| Midsole | PWRRUN PB (PEBA-based), full-length nylon plate |
| Upper | Engineered mesh with internal midfoot cage |
| Outsole | Reinforced rubber zones with tread refinement |
| Fit | True to size; athletic profile |
| Price (RRP) | £170 (often £150–£160 discounted) |
Midsole and Ride Feel
The Endorphin Speed 4 retains the PWRRUN PB midsole found in previous versions, offering elite-level energy return thanks to its PEBA base. What’s changed is the geometry and plate placement:
- New forked nylon plate improves stability and forefoot engagement without stiffening the ride
- More pronounced rocker encourages turnover and quicker transitions
- Foam feels firmer than Speed 3, offering more control at pace
- Still responsive and snappy, but with a slightly more grounded feel for longer runs
The result is a ride that’s still energetic — but more confident at tempo pace and more adaptable across training blocks. The Speed 4 no longer feels like a “race trainer in disguise” — it now balances pace and practicality.
Upper Fit and Design
The engineered mesh upper improves over previous models in comfort and lockdown:
- Refined mesh structure offers breathability and contouring without excess overlays
- Internal midfoot cage adds hold without pressure
- Tongue is gusseted and moderately padded, helping with midfoot lockdown
- Heel collar feels stable and slipper-like, reducing pressure on Achilles
Fit is true to size, with a performance-oriented silhouette — not narrow, but streamlined. Wide models are available in select colourways. Over 20K runs, testers experienced no hot spots or irritation.
Outsole and Grip
Saucony subtly improves the outsole:
- Rubber compound is slightly firmer, aiding durability across high-mileage users
- Zoned rubber placement targets heel and lateral forefoot
- Flex grooves and transition line complement the rocker geometry
- Improved traction on wet pavement and smooth gym surfaces
Durability after 200km showed minimal rubber wear, especially at the toe-off point. Grip is suitable for all-season road training and treadmill use, though not designed for off-road or trail surfaces.
Tempo and Race Testing
The Speed 4 really shines in fast-paced environments:
Tempo Runs (10–15K)
- Highly responsive; transitions feel natural
- Foam remains springy across longer efforts
- Forked plate adds control during fatigue
Intervals and Repeats
- Snappy toe-off encourages speed pickup
- Stable forefoot landing zone helps midfoot strikers
- No lag or mushiness in foam rebound
Long Runs
- Softer than pure race-day shoes
- Capable of handling 25K+ with reduced fatigue
- Breathability and upper fit hold up well over distance
The Speed 4 isn’t a replacement for carbon racers like the Endorphin Pro 4, but it can handle half marathon race pace with ease — and doubles as a race backup or long-run option for runners wary of carbon stiffness.
Durability and Longevity
After 200km across mixed surfaces:
- Midsole foam retained bounce, with no visible creasing
- Rubber outsole remained intact, even on coarse pavement
- Upper mesh held shape, with no stretch or seam wear
- Tongue and eyelets showed no signs of fatigue or distortion
With careful rotation, the Speed 4 should offer 500–700km lifespan, outperforming many plated trainers in longevity due to its nylon-based structure rather than carbon.
Comparison Table: Endorphin Speed 4 vs Key Competitors
| Shoe | Plate Type | Foam | Weight | Best For | Price |
|---|---|---|---|---|---|
| Saucony Endorphin Speed 4 | Nylon | PWRRUN PB | ~227g | Tempo + Long Runs | £170 |
| Nike Zoom Fly 5 | Carbon | ReactX | ~290g | Race training | £160 |
| ASICS Magic Speed 3 | Carbon | FF Blast+ | ~230g | Intervals + races | £155 |
| Hoka Mach X | Pebax Plate | PEBA foam | ~240g | All-round speed | £170 |
The Speed 4 strikes a near-perfect balance of tempo durability and race-day snap, without the aggressive rigidity of full carbon options.
Pros
- Snappy, energetic ride with improved stability
- Lightweight feel with high-cushion comfort
- Nylon plate adds control without harshness
- Upper redesign improves lockdown and breathability
- Durable outsole performs well across seasons
- Ideal for tempo work, longer efforts, and mild racing
Cons
- Slightly firmer than Speed 3 — not ideal for soft-ride purists
- Limited grip for wet off-road or trail segments
- Premium pricing may deter casual users
- Less explosive than full carbon racers
- Some heel-heavy runners may prefer softer crash pad
Final Verdict
The Saucony Endorphin Speed 4 marks a mature, refined evolution of one of the most successful tempo trainers on the market. With smarter plate geometry, responsive foam, and a precision-focused upper, it delivers confidence at pace and comfort at volume.
Whether you’re training for a half marathon, sharpening intervals, or logging midweek long runs, this shoe hits the sweet spot between speed and reliability — now with better lockdown and a more stable ride feel.
Rating: 9.4/10
Best For: Tempo runs, intervals, race pace long efforts
Avoid If: You prefer ultra-plush cushioning or off-road versatility
