May 19, 2022
By Ross Purnell
Sometimes there are huge leaps forward in our fly fishing, like moving from neoprene to breathable waders, or from fiberglass to graphite rods. Tungsten beads, fluorocarbon tippet, and wading boots with “sticky rubber” compounds all made us more effective. The industry standard for these types of rubber outsoles for a decade has been a compound called Vibram IdroGrip. It was created, tested, and produced specifically to stick on wet rock. It’s used on many brands of premium wading boots, as well as on footwear for kayaking, canyoneering, rafting, hiking, and cycling (BMX, downhill, dual, or fourcross) and of course technical approach shoes. I used La Sportiva shoes with Vibram IdroGrip soles this past summer to summit Pingora Peak—a situation where if you slip on wet rock, death is a potential outcome.
It seems as though the chemists and engineers at Vibram have been busy, because they now have an improved rubber compound called IdroGrip Flex, and it’s exclusive to the outsole of the new Simms Flyweight Access Boot ($250, simmsfishing.com). According to SATRA—an independent testing lab based out of the UK—IdroGrip Flex provides more slip resistance on wet surfaces than any other competitive products or previous Vibram products. Vibram’s own internal testing makes IdroGrip Flex Vibram’s new gold standard for traction in water footwear.
It’s not just the outsole that’s new. The Flyweight Access Boot has a lightweight non-absorbent mesh upper, and a supportive and comfortable web lacing system that combine to make the boot feel like a comfortable lightweight hiker you’d want for long-range adventures. It has welded TPU overlays in high-abrasion zones, closed-cell neoprene foam lining, and pull-on loops for easy on/off.
I wore them on three different rivers in Chile, ranging from weedy spring creeks to tailwaters and massive freestoners, and also in lake fishing, jumping in and out of aluminum and fiberglass boats, wading rocky shorelines, and navigating muddy cutbanks. I’m no lab rat, but the soles seemed grippier to me than any previous rubber I’ve worn. To the touch, the rubber is more malleable and compressible to conform to the contours of the rock and provide more surface area and greater contact. With rock climbing rubber compounds, softer rubber provides better friction, but also wears out faster than harder rubber, so it’s possible these soles will wear down a little faster than previous Vibram soles. I’d still guess they’ll outlast the rest of the boot, and will have 20 times the lifespan of any felt sole.