Shimano S3100X NPU+ Shoe Cover review

Shimano S3100X NPU+ overshoes provide an impressive barrier against the cold, wet and mud, but the fit isn’t the most secure

Shimano S3100X NPU overshoes
(Image: © David Arthurs)

Cyclingnews Verdict

The level of insulation is superb and fitting them is easy, but they don’t stay securely on the shoes at all times, which is annoying


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    Easy to fit SPD shoes

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    The front has a tendency to pop up

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    Quite bulky

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When it comes to the best cycling overshoes, the Shimano S3100X NPU+ are an extreme cold and wet weather option designed for mountain bike and gravel shoes, which also makes them ideal for commuting. While the design is specific for off-road shoes with a large cleat opening, they also come in a road-specific version. They feature 3mm thick neoprene with fully waterproof seams, and are designed to offer a high level of waterproofing and insulation for extremely cold and wet riding. The wide opening makes them easy to fit over shoes and a zipper and Velcro combination fastens them in place. 

Design and aesthetics

The overshoes use a hook-and-loop sole that is easy to fit over mountain bike and gravel shoes while still keeping the tread available for walking. Despite the thickness of the neoprene they are smartly shaped around the shoe and fit flush, with a snug fit around the toe box where there’s a larger durable reinforcement material, which is replicated around the sides and at the heel. A wide Velcro strap secures the bottom of the overshoe opening across the sole of the shoe and a tall vertical zipper secures the overshoe around your ankle with a small Velcro tab for good measure. They’re also available in a road-specific version which uses a similar design. 


These are Shimano’s overshoes for the most extreme weather. They are rated down to -10ºC/14ºF and designed to keep feet dry in the most torrential rain. At the heart of these overshoes is a 3mm thick neoprene with a water-repellent coating, using an Anatomic Optimal Panel Construction to ensure a good fit around the shoe. A 3D-cut toe box is specifically designed to accommodate mountain bike and gravel shoes, which can be chunkier than road shoes, while the heel area is 3D cut, too, for a perfect fit around the ankle. All seams are waterproofed and there’s a large Velcro tab across the bottom to keep them in place especially when walking and an additional Velcro tab at the top of the zipper.


In bad weather they perform impressively well, keeping even my poorly circulated feet warm on the coldest and wettest rides. During the test period, I encountered ankle-deep flooded roads and sub-zero temperatures, yet they kept my feet warm and dry. They easily shake off puddle splashes and road spray, only submerging them on a flooded road got my socks wet, but the insulation of the neoprene quickly brought the temperature back to my soggy feet. 

While obviously good for off-road riding, they are also ideal for road riding and commuting if you prefer two-bolt SPD-style shoes for the ease of walking they offer. They do fit over road cycling shoes as well, but the underside doesn’t wrap around the cleat area as securely. However, there is a road-specific option available, which would be much more suitable anyway.

Fitting them is easy with the right technique. My pro tip is to pull the overshoes onto your ankles before your shoes, then pull the overshoe down onto the shoe. The Velcro tab pulls them taut across the bottom of the shoe, but the tall zipper can be a little tricky to do right up to the top. I also found after several muddy rides the zipper is less smooth in operation, so you’ll want to thoroughly clean them after very muddy rides. The size large fitted my size 45 shoes without the typical struggle that some overshoes can invoke. 

The only annoyance is the front of the overshoe can pop up off the shoe all too easily. In Shimano’s defence, they are ‘engineered’ for Shimano shoes though they stipulate they function with any footwear. 


For riding off-road or commuting, these are an easy-to-fit overshoe with adequate reinforcement and impressive warmth and ability to keep you dry in everything but flooded roads. The durability is good, though you need to keep the zipper clean from mud for best performance, pay particular attention to the fit around the toe box and ensure the bottom Velcro strap is sufficiently tight to prevent the tendency for the front of the overshoe to pop up. Naturally, for a thick neoprene, they are quite bulky bringing the risk of crank rub. While the fit isn’t as secure as it could be, the performance in challenging conditions is really very good and the price isn’t excessive. 

Tech Specs: Shimano S3100X NPU+ Shoe Cover

  • Price: £49.99 
  • Colours: Black
  • Material: Neoprene with waterproof seams

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