Saucony Zealot ISO 3 Review


The Zealot ISO 3 is a 4mm offset, sub-9oz, full stack shoe. It offers plenty of cushioning and flexibility and has more toebox volume than recent Saucony models. With an exceptional cushion-to-weight ratio, it is an ideal high-mileage option for Kinvara runners looking for more cushioning on longer runs. Those looking for a firmer ride should also consider the Saucony Freedom.


The Saucony Zealot ISO was released three years ago as the final shoe in the initial triumvirate of the ISO series. While the Triumph and Hurricane fit clearly into the high-cushion neutral and stability categories, the Zealot was a bit of an odd duck. With a 4mm offset and ample cushioning, it wasn’t as easily slotted into the typical shoe types. I tend to think of it as a “Kinvara-Plus”, for Kinvara users that want some more cushion and protection for higher mileage days. It became my go-to high mileage shoe and I’ve run many 30k’s, marathons and an ultra in version 1. Version 2 was released last year, but I stayed away because of the tighter toebox and increased weight. Version 3 (v3) marks a return on the many of the traits of the original that made it so appealing.



The upper has received a complete overhaul from the last two versions. While the original had a bootie construction with a soft plastic cage that forms the ISOfit system, v3 effectively reverses the construction. The upper is made of engineered mesh with integrated reinforcements and welded Flexfilm overlays. The ISOfit bands now threads under the mesh, similar to the Pro-Lock system seen in the Kinvara. The ISOfit bands seem to be reinforced for additional stiffness. The lacing starts on the mesh, flowing entirely through the ISOfit bands, before the final eyelet at the throat of the shoe. This effectively decouples the middle of the shoe from the lacing, allowing for more freedom of movement. The large radius loops also allow the lacing to flow back and forth.

The toebox has more length, width and volume than recent Saucony models – specifically the Freedom and Kinvara 8. My US men’s 9.0 fit true to size. My example weighed 250g or 8.9oz for one shoe. This is a welcome decrease from v2, which gained a full ounce from v1. For a sub-9oz shoe, it has an exceptional amount of cushion and is 0.5oz less than the Freedom.

The tongue is gusseted, which prevent slipping to the slide. It is moderately stuffed with foam. On the other hand, the heel collar is heavily stuffed and poofy. Personally, I don’t like overstuffed collars, as I find it hard to cinch the laces down agains the top eyelet.

Midsole / Outsole

The midsole is surprisingly voluminous. Similar to other Saucony models, comprised of EVA foam with an TPU Everun topsole. it is in between the Triumph and Kinvara in cushioning level, which stillmakes it quite squishy, in the grand scheme of things. I found it more suitable for longer distance and recovery runs, and less ideal for fast paced intervals. The flexibility is quite good, allowing for a smooth, bump free transition. The outsole is full contact, with the now-standard Saucony Tri-Flex chevron pattern. The high wear areas are covered with blown rubber and the amount of coverage is less than the Triumph and more than the Kinvara. In my grey-green colourway, Saucony has coloured the blown rubber the same green colour as the EVA foam, so it can be hard to tell at a glance which is which, without feeling the material.

Running Experience

I found the Zealot 3 to offer plenty of soft cushion for those high mileage training runs. The roomy toebox and ISOfit system provides an unobtrusive, no-nonsense upper fit. The overstuffed heel felt plush, but didn’t impact the fit of the heel, which was good on my foot. Picking up the pace, I felt the amount of cushion to start to absorb more energy than I would like. The Freedom or Kinvara would be a better option for tempo runs and intervals. The midsole was decently flexible and moved with my foot without restricting it through the gait cycle.

As its construction would suggest, the Zealot ISO 3 bridges the difference between the Triumph and Kinvara. It’s a fine high-mileage shoe for runners that prefer a lower offset platform. The upper has ample volume and addresses the sizing issues in other Saucony models. A 4mm offset, full stack midsole shoe is a niche category and one might consider it to be a more releaxed counterpart of the Freedom.


The Zealot ISO 3 returns with many of the attributes that made v1 such a favourite of mine. 4mm offset, high cushion to weight and a unobtrusive upper means I will probably run many long run miles in version 3.



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