How do you decide the density of the sole?

We did this through multi-phase, extensive wear-testing, along with pressure data capture and analysis of flat-pedal riding.

We started this entire process by consulting with our tire team, footwear engineers, and rubber chemists to tune our SlipNot compound. We reviewed and set objectives for the rubber (What does the rubber need to do? What is the purpose of the rubber?) and from there developed 8 different rubber compounds to take into testing, each with specific durometers, tensile strengths, tear elongation percentages, tackiness, and abrasion resistance properties.

From there, we also knew we needed to tune the material that supports the rubber – the EVA. Soft rubber doesn’t guarantee great ride quality if it’s support structure is too firm. The rubber needs to be soft for pin penetration, and the EVA behind it needs to be soft to subsequently accept the rubber deformation due to the pins. It’s important that these two materials work together for the best pedal connection. This was tuned by first, analysing rider pressure data to see what types of forces to expect, rate of force increase, rate of force decrease, and impact frequency (think of this like your suspension, EVA durometer is like setting the amount of pressure in the air chamber, rate of return and frequency is like your rebound control). From this analysis, we developed 3 EVA compounds to take into testing.

Once we felt comfortable with these variables, we started with a qualitative test with a few of our most sensitive riders (notably Dylan Dunkerton and Curtis Robinson of the Coastal Crew). We spent a few days doing the same run over and over, swapping out shoes for different constructions on each lap, and gathering feedback for how each rode. The shoes were scored against rubber hardness, pedal feel, pedalling stiffness, pin engagement, and pedal connection over varying terrain (big jumps, small jump, brake bumps, rock garden/root section).

From the qualitative testing, we found there were 3 clear front runners that were very close in performance. These are what we took into quantitative testing and had around 20 different riders start logging hours on the shoes. From this testing, we got to our 1 best construction.

What impact does this have on ride quality and damping?

It has a major impact! Our testing (both through data collection and by gathering rider feedback) showed to us that the properties of the EVA (density, thickness, rebound) is the single most-important component to good flat-pedal ride quality. This totally debunks the industry myth that it is all about the rubber.

Is there a difference in sole density between flats and clips and why?

Yes. With the flat shoe, we need to go ultra-soft with the sole for pin engagement. This comes at a cost – increased wear rate. With clip shoes, the cleat is what’s holding you to the pedal, so we can go firmer with the midsole and rubber to increase the durability.

What is the profile between heel and toe and how does this affect rider position and fatigue?

Not sure I fully follow the question, but I think you’re asking about heel drop? We’ve been referring to this as “degrees of hangulation” and an extreme amount of hangulation helps in a few ways specifically with flat pedals

1. It helps keep you on the pedals – there’s a lot of lateral rearward force being applied to the rider over bumpy terrain. More hangulation means the shoes are oriented more-perpendicularly to this force and are less-likely to skip forward on the pedals.
2. More hangulation also stretches the gastrocnemius muscles towards their limit of extension. This means the rider can rely on the resting tension of the gastrocnemius and Achilles tendon, as well as the range of motion in the skeletal system, to stabilize their foot, and the muscles won’t need to fire constantly to sustain a specific amount of flexion. The result – less muscle fatigue.

Is it a dry weather or wet weather shoe?

Riders have asked for an all-conditions shoe, that’s what we’ve built. Rubber blends can vary if you’re targeting a purely wet or dry environment, but we’ve asked for the help from our tyre team to build a mixed blend that works well in both. Grip and durability being the focus, we feel we’ve made a compound that will impress in both conditions.

How have you decided on compound and depth of tread pattern?

I wrote a little about compound earlier so won’t double up here. For the tread depth and spacing we started by looking at the pedal. One of our designers (Jon Takao) created an awesome template which overlaid data gathered from these pedals (pin location on the pedal, pin width, pin height). From this, he designed the tread pattern so that there would be a large enough gutter between each of the lugs, enough girth to the lugs so they aren’t fragile and prone to tearing, the right height of the lugs to allow for pin-penetration into the net rubber before contacting the pedal body, and enough variability to the way that he overlay the pedal template to ensure that the rider would have a lot of foot placement options and the lug pattern wouldn’t be overly specific for foot rotation (0d, 3d, 5d, 7d, 9d, etc) and fore-aft placement (mid-foot vs fore-foot)

What part do socks play?

We were not able to measure any variance due to sock choice. But I could certainly see a loose-fitting sock resulting in poor control of the shoe.

How important was durability?

Durability is paramount. We have added a few features to the shoes to add protection in high-wear areas (particularly in the toe and heel), placed high-abrasion materials where damage from rock strikes or crank rub is most likely, and validated with hundreds of hours of wear-testing that the shoes were holding up to the expectations of riders. We’re confident that the shoes will hold up through the harshest conditions and their integrity and grip.

Are there different insoles available?

There are. These shoes will work with all our aftermarket Body Geometry SL footbeds with varying amounts of arch support, and with a custom molded footbed like our Retül ones.

 What is meant by body geometry in a shoe?

There are 3 “Body Geometry” features in all our shoes (including the 2FO). These features represent a small amount of biomechanical correction that we’ve found is beneficial for most riders. For best results, we recommend riders consult with a Body Geometry Fitter for a prefit assessment, Body Geometry fit, and personalized amount of support.

1. Forefoot Varus Angulation – the medial side of the forefoot is 1.5mm thicker than the lateral. This angulation helps correct for Valgus forefoot collapse, which eventually works up the chain and results in the knee falling into valgus, which often results in knee pain.
2. Longitudinal Arch Support – Arch collapse has similar results to forefoot collapse. The collapse works its way up the chain and causes the knee to fall medially. Our shoes ship with our “red” insole which is our lowest amount of arch correction. While many riders will need more arch support, this ensures that all riders can use the shoes out of the box.
3. Metatarsal Button – This is the little bump in the middle of our insoles. This works to help spread the metatarsals apart and prevent toe numbness that may happen when the shoes are tied too tightly.

What is faster down a hill, flats or clips? Do you have hard facts?

Oh man! That’s the age-old questions! I think you’ll be as hard-pressed to get a definitive answer on this as you would be to get one on wheel and tire size. I think my answer would be: do what you like and what you’re comfortable with and you’ll be plenty fast.

My personal preference: flats