The Ultimate Fly Fishing Boot | Simms G4 Powerlock

The most advanced and innovative wading boot Simms has ever released, the all-new award-winning G4 Pro Powerlock boot offers supreme durability and superior grip thanks to state-of-the-art materials working in tandem with the new Powerlock cleat system for on-the-fly traction customization.

Simms G4 Pro Powerlock Tech Review

At Simms, the G4 Badge isn’t slapped on just any wader, piece of outerwear, or boot. Instead, it’s reserved for the most technologically advanced, performance driven pieces in the entire collection. So when Simms began tinkering with a new cutting-edge cleat retention system, it only made sense to start formulating the blueprints for an all-new member of the G4 family. Enter the G4 Pro Powerlock Boot — the most rugged, most advanced wading boot Simms has ever released.

Simms G4 Powerlock

In the early days, cleats and studs would go directly into the rubber or felt outsole. It was somewhat of a cumbersome process and the reality was, the cleat retention wasn’t great. Eventually, ESS plates were utilized so that the cleats and studs would have a harder material for the cleats/studs to bite into. This system undoubtedly helps limit cleat loss and is widely used across the fly fishing industry — but, it’s not something you can do on-the-fly.

Simms G4 Powerlock fly fishing boot

The product development team at Simms began looking at golf shoes and rugby boots and noticed a very unique, and widely used cleat retention system and started thinking about the possibilities. The initial goal was to utilize the same idea they found in the golf and rugby industry and adapt it to work in the same manner in a wading boot. The idea was to offer anglers a boot with a simple system that allowed cleat installation and removal on-the-fly.

Simms G4 Powerlock

All G4 Pro Powerlock Boots ship with a set of TPR cleats (ideal for use in drift boats) and a set of aluminum cleats for better traction on slippery river bottoms and terrain. The boots also come with the Simms Ripper tool, the tool that allows installation and removal. Unlike a threaded T-Nut system which utilize threaded receptacles and threaded screws, the Powerlock system does not — which means there aren’t any threads to compromise or damage.

Simms G4 Powerlock Fly Fishing Boot

Truth be told, the Powerlock system is very simple, but it does come with a slight learning curve to be able to install the cleats properly. Simply get the cleat started with your fingers and place the ripper tool in the grooves of the cleat. Apply healthy pressure with your thumb half on the biting part of the wrench and half on the cleat itself. This is an important to note — if you omit this tip, the wrench could slip off. Once the wrench is secure, turn counter clockwise or counterclockwise depending on whether you’re installing or removing. For both TPR and aluminum cleat installation, once again, simply insert the cleat with your fingers and place the wrench around the cleat — rotate the wrench just under 180-degrees. At this point, the cleat should feel secure. As with all pieces in the G4 collection, the G4 Pro Powerlock went through thousands of hours of testing around the world in a variety of environments and terrain. The boot’s approval rating was extremely high. Testers reported extremely minimal cleat loss but also noted that the boot was very comfortable and supportive — especially for such a heavy-duty boot.


No doubt, the Powerlock system is the most noticeable innovation but, there’s a lot going on with the rest of the boot that offers next-level durability, support, and stability. To explain these aspects, we’ll do a quick run through of the G4 Pro Powerlock’s Tech Review.


Simms G4 Powerlock Fly Fishing Boot

G4 Pro Powerlock Tech Review (from the ground up)

  • Powerlock Cleat Retention System (explained above)
  • Outsole: Vibram Idrogrip — When it comes to rubber outsoles, soft outsoles offer the best slip-resistance but durability is sacrificed, and vice versa. Idrogrip is an advanced compound the provides a happy medium between the two. Rugged and durable, but still very grippy.
  • Tread Pattern: The G4 Pro Powerlock Boot utilizes a traditional Simms multi-directional lug pattern. This type of pattern offers grip in all directions whereas say a hiking boot tread pattern generally offers a forward directional pattern.
  • Rocker Profile: A forefoot rocker has been applied to the G4 Powerlock Boot. It allows for ease of step when walking on the trail or in the water. This type of rocker is common in the latest running and active footwear.
  • EVA Midsole: Simms utilizes extremely high end EVA compounds comparable to any high end hiking boot. EVA is the most widely used midsole compound, primarily due cushioning capabilities combined with its durable nature. This midsole offers comfort, support, and impact cushioning.
  • Heel Clip: A TPU heal clip is a technology developed initially for athletic shoes. It allows stability and support in the boot.
  • Molded Rubber Heel Cap: This has been added for increased durability.
  • Drain Holes: The G4 Powerlock comes equipped with drain holes for drainage when out of the water.
  • Ankle Lock: High on the ankle of the boot, the G4’s ankle lock system provides additional ankle support when the laces are tightened.
  • Leather and Fabric: The G4 Pro Powerlock is built with incredibly durable, waterproof synthetic leather, natural leather for comfort, and a highly abrasion resistant synthetic mesh upper to decrease weight and offer flex in the working area of the upper.

Simms Fly Fishing Powerlock Boot g4

From the ground up, the G4 Pro Powerlock provides outstanding cleat retention, rugged durability, comfort and support for anglers that demand a heavy-duty boot that’s easy to wear, easy to use, and will last for seasons on end.



Article first appeared and reproduced courtesy of Simms Fishing -