Stomp Lox’s Slack cycling shoes have a unique approach, with a distinctive appearance and an uncommonly wide toebox. They can be worn with or without SPD cleats.

In testing, I’ve found these to be a genuinely innovative pair of shoes that have performed excellently for both gravel riding and mountain biking. I really appreciate the wide toebox and the fact they can double up as a casual shoe off the bike.

However, the central seam rubbed on the widest part of my midfoot on both feet, indicating these might not be the best shoes for long-distance riding.

Stomp Lox Slack shoe construction

The Slack shoes are certainly distinctive, with their bowling-shoe like appearance. They’re quite unlike anything else on the market and have certainly started conversations on my group rides.

The shoes are designed to be comfortable to walk in and Stomp Lox claims they offer the perfect balance of stability and flexibility.

This is largely thanks to the use of a replaceable Vibram sole, which Stomp Lox refers to as its ‘Power Ride Core System’.

The upper is made from a cow-suede leather, while there’s a pig-skin inner, which is claimed to be breathable and water-resistant. The pig-skin material is also used on the inside of the shoe’s tongue.

Because suede leather is not waterproof, Stomp Lox recommends applying a waterproofing spray to the shoe every two months. The brand specifically recommends using Collonil Carbon Pro Waterproofing Spray.

The shoes use laces to close, which attach onto Viking-like metal loops. I asked Stomp Lox if it considered incorporating a lace keeper and the brand confirmed it’s considering adding one to a future version of the shoe. For now, you’ll have to make do without.

There isn’t any grippy cat’s tongue material on the inside of the heel, which can be effective in preventing heel lift.

The Slacks come with plates if you want to run cleats, or you can use them as flats.

They’re available in two colours: ‘Olive Suede’ or black.

I weighed my size-45 sample in at 435g each.

Stomp Lox Slack shoe sizing and fit

Stomp Lox’s first run of shoes was originally designed around a wider ‘Asian’ fit, but has since developed a ‘US/EU’ fit for those with narrower feet.

As such, the brand offers the Slack in US sizes 8 to 13; UK 7 to 11.5; EU sizes 40.5 to 46.5 and the wider Japanese sizes, 26 to 31.

My feet are reasonably wide, but with a narrow heel. I tend to take a size EU 45 in most brands.

After following Stomp Lox’s fitting guide, I opted for an EU 44.5.

Out of the box, the shoes fitted me perfectly, with the toebox especially roomy. The heel cup was also nice and tight, although I found I needed to de-tension the laces fully from the first loop to then be able to slot my foot in.

Like all of the best cycling shoes, sizing and fit will, to a certain extent, come down to the shape of your feet and personal preference. We’d highly recommend trying shoes on for size before purchasing.

Stomp Lox Slack testing conditions

I’ve tested the Stomp Lox Slack shoes in a variety of weather conditions and cycling genres for the best part of 1,000 miles. Temperatures ranged from 7°C to 26°C and I used Shimano XT M8000 pedals.

The shoes were tested predominantly on gravel rides, which included a mix of shorter evening group rides through to all-day escapades.

They were also tested on some trail-centre based mountain bike rides.

I regularly used the shoes on commutes into Open VTT HQ and wore them throughout the day in the office.

Testing culminated in a one-week 850km bikepacking epic on The Pictish Trail through Scotland. I didn’t have space in my bikepacking bags to store a pair of casual shoes for the evenings, so the Slacks were put to constant use.

Stomp Lox Slack shoe performance

The Slacks proved excellent performers and the full-leather upper and pig-skin inner were both very comfortable straight out of the box, conforming well to my foot shape.

I replicated my cleat position from my other off-road shoes and got both sides spot-on straightaway, setting them reasonably rearward. I didn’t have any issues with hotspots during any of my initial rides.

In fact, the first ride the Slacks were subjected to was a seven-hour gravel epic and the shoes were comfortable from the off.

An aspect worth pointing out is the thread in the included cleat plate is very shallow.

I found I could never quite get the cleat bolts as tight as I would like them (I typically like to torque the bolt up to 5Nm) before they would start to protrude through the internal side of the plate.

I’d say the Slacks achieve their claim of finding the sweet spot between stability and flexibility. While I could detect some flex from the Vibram sole, it’s reasonably rigid and it wasn’t a problem on more powerful efforts.

On trail-centre mountain bike descents, I appreciated the flex because it took the sting out of the bone-shaking trail features.

The shoes are easy to walk around in and I didn’t experience any heel slippage despite the lack of cat’s tongue material.

There’s not much in the way of toe protection, so you may want to avoid using these for bigger days in the mountains. I managed to cause some minor damage to the front of the top lip of the Vibram sole on the right shoe in testing.

Ventilation is fine but could be improved. My feet felt the heat on warmer rides, which was likely down to the properties of the suede leather.

The need to re-waterproof the shoes every two months means these shoes require slightly more cost and labour to maintain. The finish coped very well over the week-long bikepacking trip, despite lashings of Scottish rain every day.

I liked the black colourway and the waterproofing did a good job, although they’re not the easiest to keep clean.

There were four nights when I wild-camped overnight and the morning dew didn’t soak the suede material through. At no point in the trip did I have wet socks from the shoes becoming saturated.

I’d like to see a lace keeper introduced because there were a couple of occasions on my bikepacking trip when the laces came undone. A lace keeper would neaten everything up.

At $250, the Stomp Lox shoes are quite a pricey proposition, but there’s nothing quite like them on the market and the attention to detail is very good.

However, my main criticism of the shoe is that on very long rides, it rubbed on the widest part of my midfoot on both feet.

On a 100-mile gravel ride, they were certainly a little red, and on the second day of my bikepacking trip, I had to pull over and dig out some plasters from the first aid kit to avoid them blistering.

On every subsequent morning, I replastered the area on both of my feet so it didn’t cause me any irritation.

Looking closely at the shoe, the seam that connects the two parts of the suede overlaps at the metatarsals and I suspect this is why it rubs.

When I put my findings forward to Stomp Lox, the brand said I was the first user to raise this issue, but claimed it will try to find a way to cover the seams on the inside.

However, it’s important to recognise that sizing and fit will differ among users and you may not experience the same problems I did.

Stomp Lox Slack bottom line

The Stomp Lox Slack shoes are excellent for multi-purpose use and particularly comfortable over long distances. They offer something genuinely different from everything else on the market.

With a different central seam design, these could be near-perfect.

If I hadn’t experienced any rubbing, the Slacks would undoubtedly be my new benchmark shoes. However, such an issue can’t be ignored.