GORUCK I/O Cross Trainers – Training Shoe Review

Disclosure: Links to other sites may be affiliate links that generate us a small commission at no extra cost to you.

GORUCK’s Black Friday sale is live! Check out their deals on rucksacks, apparel, boots, and more!

GORUCK, the rucking company, recently entered the cross training shoe game.

And their MACV-1 rucking boot blazed a trail of innovation – they created a light-weight but tough boot that has minimal break-in time.

But now they’ve released a cross training shoe – the GORUCK I/O Cross Trainer.

I/O Cross Trainers from GORUCK
The I/O (Indoor/Outdoor) Cross Trainer from GORUCK is a shoe like no other – it’s made for high mileage walking/hiking/rucking and for use in the gym. Read on to find out more…

Our review pair is on order, and we’ll have our first thoughts soon.

But, in the meantime, we’d like to tell you all about this super versatile shoe.

Here’s what we’ll be looking at in this review:

I/O Cross Trainers from GORUCK (Black) I/O stands for Indoor/Outdoor - and of course you can use these shoes for rucking, but they are also versatile training shoes for the gym. Shown here in Black.

I/O Cross Trainers from GORUCK (Black + Gum) The I/O Cross Trainers are also available in Black + Gum. In either case, they have the same great features.

Let’s take a close look at the I/O Cross Trainers from GORUCK.

Hands On First Look

Don’t like to read? Watch our hands on first look video from YouTube instead:

GORUCK I/O Cross Trainers – Sizing

WARNING: These shoes run BIG, real BIG.

I ordered my normal size (11) and they are simply far too long, and wide.

I/O Cross Trainers from GORUCK
Sizing? They run BIG, real BIG. So make sure you read GORUCK’s sizing advice before you order. These ARE NOT true-to-size shoes.

I’ve returned them, and requested size 10s instead (based on how huge the 11s were.)

To be fair, GORUCK says the shoes run large right on their web page about the shoe – but I failed to notice that before I ordered.

I highly recommend you follow their sizing advice. DO NOT order your normal shoe size…

With that out of the way, let’s focus on these cross trainers and what makes them special.

Are these Rucking Shoes or Cross Trainers?

Let’s get this out of the way first – are these rucking shoes or cross trainers?

The answer is YES.

They are both.

They have features to ensure versatility – but unlike your average cross trainers these should be more than capable of racking up the miles on a ruck march (in relative comfort).

I/O Cross Trainers from GORUCK
GORUCK I/O Cross Trainer is for Indoor or Outdoor use (hence the I/O). That outsole has an aggressive lug pattern for all terrain traction, but the heel is solid enough for lifting weights in the gym.

Most cross training shoes on the market have minimal cushion – and aren’t good for a 10 mile ruck march with a 30 lb ruck plate, for example.

With that out of the way, let’s look at the features.

I/O Cross Trainers – Fit & Feel

Sizing snafu aside, these are shaping up to be very comfortable shoes.

These cross trainers have a few unusual (in a good way) features.

For one, the heel counter is wrapped in premium suede.

I/O Cross Trainers from GORUCK
See that? That’s suede. The premium suede heel counter wraps inside, around a supportive, injection molded plastic heel counter. This combo stabilizes your heel as the suede leather prevents the kind of friction that causes hotspots and blisters.

This results in outstanding comfort – and little to no break-in time.

I/O Cross Trainers from GORUCK
Another shot of that glorious suede lined heel counter.

This is a trick that GORUCK carried over from their also excellent MACV-1 lightweight rucking boot.

You have to feel it to believe it, but trust me, it works.

Secondly, GORUCK has opted to use a very wide toe box on these shoes.

That’s good because many cross trainers are simply too narrow for the average foot (Nike – we’re looking in your direction…)

I/O Cross Trainers from GORUCK
The I/O Trainers have a wide toe box.. This generous forefoot area lets your toes breathe. Over time and distance during any activity including rucking or traveling, your feet will swell. This extra space reduces the friction that can occur if your feet rub against the insides of your shoe.

This won’t be a problem in the I/O trainers. Take a look at your feet. They are widest in the toe area, are they not?

And being able to splay your toes out in that generous toe box gives you better stability – and this is much better for a high mileage shoe.

Remember, GORUCK is the rucking company – and that means miles and miles on the road, trail, or elsewhere.

For additional stability, the I/O Trainer has midfoot webbing.

I/O Cross Trainers from GORUCK
The 2″ knit webbing provides stability even during quick movements on uneven terrain.

Let’s take a look at the laces.

The I/O Cross Trainers use 3 mm diameter speed laces.

These are much smaller than normal boot laces (which are 5mm – or nearly twice as big) and we like these smaller laces much better.

For one, it’s less bulk slopping around.

I/O Cross Trainers from GORUCK

I/O Trainers use 3mm Speed Laces. Speed laces are 3mm as opposed to standard 5mm. Debris and mud doesn’t collect on the 3mm laces like it does on the 5mm, the 3mm rinse off and dry faster, and they’re faster to tie because there’s less bulk.

But GORUCK also says that 3mm speed laces are quicker to tie, and won’t attract as much debris and mud.

They will rinse off and dry faster too – there’s simply so much less material to absorb water.

Are these smaller diameter laces tough enough? On the MACV-1 boots, this seems to be the weak point – the laces can be prone to breaking.

We don’t know for sure yet, but we expect the laces on this shoe will experience the same.

Here’s another important stat on these shoes – the so-called “heel to toe drop”.

The GORUCK I/O Cross Trainers have a 10mm heel-to-toe-drop (also sometimes called the “offset” or just plain “drop”.)

This means your heels are 10mm higher than your toes.

I/O Cross Trainers from GORUCK
Heel to toe drop is 10mm. This is good for long range endurance on the ruck march.

Having this slight heel raise means less stress on your Achilles – which means better endurance for distance.

At the same time, it’s not a ridiculous amount of heel raise like you might find on a weightlifting shoe.

Inside the shoe there is a compression molded EVA midsole.

The midsole is the cushioning part of the shoe between the outsole (the part that touches the ground) and the insole.

So you can’t really see it, but trust us – it’s there and doing it’s job.

I/O Cross Trainers from GORUCK
Inside, there’s an EVA midsole and custom compression insert with great cushion and excellent arch support.

What you an see is the custom compression insert that GORUCK also provides.

This insert uses a dense foam compression system to support your entire foot – from the heel to the toe.

It’s also got excellent arch support.

How’s the cushion in these? It’s definitely not over-cushioned – and that’s a good thing.

I’ve put some time in on the ruck march with highly cushioned trail running shoes (like the Pegasus Trail 2 – which uses a lot of Nike’s React foam).

Shoes with that amount of cushioning are not good for rucking with weight – it’s simply too squishy and not stable enough in the heel.

Let’s look at the outsole – or more simply the sole.

This is where the “rubber meets the road” – literally.

GORUCK learned from their first foray into an all-terrain shoe (the MACV-1 boot) and made an updated, aggressive outsole for this shoe.

I/O Cross Trainers from GORUCK
The dual compound rubber outsole has an aggressive outdoor tread pattern – but it’s firm enough to work indoors too.

Check out the lugs on that tread.

It’s made from a dual compound rubber – it’s sticky and grippy up front for traction, and firmer and more supportive in the heel for stability.

I/O Cross Trainers from GORUCK
Another view of the outsole.

That’s just what you need in a cross training shoe.

There’s one more special trick that the I/O trainer has up it’s sleeve.

I/O Cross Trainers – Water Draining Ports

This is a rucking shoe. And it’s meant for heavy duty use, like at a GORUCK Challenge event.

And that means water immersion.

Not a light dewy mist of water – but rather fall on water immersion.

And therefore this shoe isn’t waterproof – in fact it is the opposite – it’s made to drain water as quickly as possible.

I/O Cross Trainers from GORUCK
Drain port – Keep sand and debris out and expel water with old fashioned technology that just works – with every step, you push the water out the side of the shoe.

There is one mesh covered drain hole on each shoe.

The mesh keeps sand and debris out – but let’s water flow freely with every step you take.

I/O Cross Trainers from GORUCK
Another view of the mesh covered drain port.

I/O Cross Trainers – Materials

What are these shoes made of?

GORUCK’s favorite materials – 1000D Cordura (which is what they make their super-tough backpacks from) and their new innovation: Challenge Leather.

1000D Cordura is not historically known to be a breathable material – nor is it very flexible.

I/O Cross Trainers from GORUCK
The vast majority of the upper is 1000D Cordura, but made with polyester for a more flexible fit. Normal 1000D Cordura is made with Nylon.

(That’s because it is so dense and tough.)

But the 1000D Cordura on this shoe uses polyester instead of the regular nylon material.

GORUCK claims this results in better flex and fit – and we’ll have to see where it ends up as far as breathability.

I/O Cross Trainers from GORUCK
Here’s a close up look at the Challenge Leather on the toe cap. It looks to be high quality. Notice as well that the outsole wraps up slightly to provide a toe guard.

The toe cap, eyestay, and heel tab are all made from GORUCK’s new Challenge Leather.

Spoiler alert: it’s leather but GORUCK says it’s tougher than the previous leather used in shoes and it should improve with time and use.

And by the way, for a limited time you can get an American flag on the heel.

I/O Cross Trainers from GORUCK
American flag on the heel – this is a limited time option.


There’s a thickly padded tongue to protect against lace bite also.

I/O Cross Trainers from GORUCK
Here’s the thickly padded tongue that protects against lace bit. It’s also got the GORUCK spearhead logo – it looks nice.

I/O Cross Trainers from GORUCK – In Summary

That’s the new cross trainer from GORUCK.

We look forward to our longer term test results.

Check back and we’ll have more details soon.

You may also be interested in the GORUCK MACV-1 Jungle Rucking boot – we’ve reviewed that shoe extensively.

I/O Cross Trainers from GORUCK
Spearhead logo on the heel.

Why GORUCK Products?
We’re a GORUCK affiliate – so if you order equipment after clicking the links in this article we receive monetary compensation. But that’s not why we recommend GORUCK. It’s because their equipment is innovative, built to last, and made with high quality features.. They are the driving force behind rucking not just as exercise, but as a way to make people better. And that’s why we love them.

Photo Credits

  • Some product photos on this page are provided by, and property of GORUCK.

I/O Cross Trainers from GORUCK
One more look at the I/O Cross Trainer. This is the Black + Gum color option.