ASICS Mega Blast vs Saucony Endorphin Speed 5: Two Versatile Trainers, Two Very Different Rides

Introduction

The ASICS Mega Blast and the Saucony Endorphin Speed 5 sit in a similar space: both are premium, versatile trainers that can handle easy mileage, tempo runs, and even some faster work. But they go about it in very different ways. The Mega Blast is a big, bouncy, high-stack shoe built on cushion and energy return. The Endorphin Speed 5 is a lighter, plated shoe with a firmer, more direct feel. Choosing between them comes down to which ride style suits your running.

Specs at a Glance

The ASICS Mega Blast costs £210 or $225, weighs 225 g (7.9 oz) for men in a size 8, and has an 8 mm drop. It uses an FF Turbo squared midsole designed to balance a cushioned, smooth ride with a high level of energy return, paired with an ASICS Grip outsole for traction and control, and a lightweight, breathable engineered woven upper.

The Saucony Endorphin Speed 5 costs £180 or $175, weighs 242 g (8.5 oz) for men in a size 8, and also has an 8 mm drop. It keeps the same Poweron PB foam as its predecessor, tweaked to feel softer, alongside updated geometry and plate design for a smoother ride with added stability. The outsole gets expanded heel coverage for durability, and a new lightweight single-layer engineered mesh upper improves breathability.

Fit and Sizing

Both shoes fit true to size in normal running shoe sizing, with good toe room, solid heel and midfoot hold, and comfortable padding around the collar without being overbearing.

The Endorphin Speed 5 fits like a glove, with good clearance at the end of the toe box, a reasonable amount of flex, and spot-on lace lockdown. The narrower heel collar style caused no slipping at all. There is a bit more forefoot space than in the Speed 4, making it a roomier fit that still locks down well. For anything longer than marathon territory, going half a size up could add a little extra toe room, but staying true to size works fine for most.

The Mega Blast is generally sound on fit, with one caveat: the toe box tapers quite dramatically, leaving less clearance on the outside edge of the toes. That caused noticeable rubbing on the little toes on runs over an hour, which could be a concern for efforts beyond two or three hours. Going half a size up might help, though everything else in the fit feels right, so trying them on first is the smart move. The Mega Blast also runs slightly long, with generous forefoot and midfoot space for a performance shoe.

Ride Feel and Performance

The Mega Blast delivers big cushion and bouncy energy. At easier paces the stack feels incredibly soft, even a bit mushy, with plenty of movement underfoot that created some instability for one tester. It really comes alive at marathon or half marathon pace, unlocking a light, lively, bouncy energy with a smooth rocker feel. It is lighter and sprightlier than the Super Blast, but feels bulky above half marathon pace.

The Endorphin Speed 5 is a shoe with balance and poise. It feels fast and light but comfortable, snappier with a more direct feel and a stiffer edge. It performs better for faster intervals and on the track, because there is less shoe on the foot, more ground feel, and a snappier, more immediate response. It is notably lower than the Mega Blast, especially under the forefoot, with a Speedroll rocker that moves you through foot strike quickly, plus generous foam at the heel for comfortable easy-pace landings.

Both shoes are genuinely versatile and handle easy runs, tempo sessions, and interval work. The Mega Blast has the edge over longer distances, offering more comfort and protection under the forefoot, and it makes a solid marathon shoe for cruising at a consistent pace. The Speed 5 feels nimbler and faster, easier to take corners at speed, and is the better pick for short reps and 5K racing. Stability is close between the two; the Mega Blast is tall but wide and stable, while the Speed 5 is reliably stable with a more agile feel at speed.

Durability and Outsole

The Mega Blast outsole is fine rather than exceptional. The rubber sections are fairly thick, but there is a very large area of exposed midsole foam, and that foam does not look especially durable. No issues have appeared so far, but it is worth watching.

The Endorphin Speed 5 has updated outsole coverage, similar in style to previous versions, with good coverage front and back and also a sizeable exposed midsole section. It is roughly on par with the Mega Blast. Both outsoles are solid, but both carry that exposed-foam caveat.

Which One Should You Buy?

The Mega Blast is arguably the best value of the two in pure performance terms, because it does so much: comfortable at easy paces, bouncy and lively at marathon pace, protective on long runs. If you love big stack, soft and bouncy rides, this is your shoe, and some runners may even race a marathon in it as a non-plated option.

The Speed 5 is the more conventional feeling shoe: firmer midsole, snappier response, better ground feel. It is better at the very top end, more stable and reliable at slower paces, and around £30 cheaper in the UK. The Endorphin Speed line also tends to get reduced in sales, and the similar Speed 4 is often discounted, which is worth considering ahead of both.

Conclusion

These are two excellent daily mileage shoes that cover similar ground in very different ways. The Mega Blast is the pick if you want maximum cushion and bounce, especially for marathon training and long runs. The Speed 5 is the pick if you prefer a more direct, agile, controlled ride and better value, particularly as a speed trainer for intervals and shorter races. Pick based on whether you want big and bouncy, or nimble and responsive.