The Nopinz Flow-socks have some lofty claims of speed, which are backed up by examples of pros opting to choose these particular socks over other options on the market. We don’t have the facility for verifying the aerodynamic efficiency, but in terms of the comfort, we can say that the lower portion did a good job of keeping cool while the upper was pleasantly compressive. The ankle seam did feel a little rough, but this didn’t result in any chafing.
Good breathability from the lower portion
Compressive feel from the upper
Chosen by pro cyclists
Ankle seam is a bit irritating
A little tough to pull on
If you generally average around 25mph (40kph) for a 10-mile TT (opens in new tab), switching to pair of aero socks isn’t going to have you suddenly going sub 20:00. But although the gains are squarely in the ‘marginal’ category, they do all add up.
It has been shown by wind tunnel testing that particular fabrics are more aerodynamic than just bare skin. (opens in new tab) Looking around at the full TT garb of the pros, such an abundance of long sleeves and socks certainly do serve to corroborate this.
Naturally, there is an arms race for who can provide the greatest gains. Designed in collaboration with Aerocoach, wind tunnel testing shows these socks providing a 5.3w saving over bare legs at 45kph – which would equate to being 9 seconds faster over a 10-mile TT. The testing also showed the Flow-socks as being 2.2w faster than generic aero socks with 1mm deep stripes running vertically.
Of course, I don’t have the facilities to verify these claims, and so won’t be able to comment on just how effective these socks really are. Differences of this level are essentially imperceptible in just general riding. So, the focus here is going to be on the comfort, breathability and how they feel in use.
But just before we leave the discussion of aerodynamics behind, it’s worth noting that Alex Dowsett was wearing a set of socks which look very similar to the Flow-socks when he won Stage 8 of the 2020 Giro d’Italia from the breakaway.
Nopinz isn’t an official sponsor of Israel Start-Up Nation, so naturally this isn’t something that can be confirmed. But as six-time national champ in the ITT, Dowsett does have a reputation for optimising his setup, and his choice of equipment does speak volumes.
The construction: Nopinz Flow-socks
The Flow-socks have a breathable lower portion, constructed from the same kind of lightweight fabrics as you get on a typical summer cycling sock. Around the ankle, there’s a seam where the lower portion of the sock meets the aerodynamically optimised fabrics – which go on to extend around 19cm up the leg.
There are two fabrics used on the upper portion, with Nopinz's Speedscalez fabric at the front being a bit thicker than the Pista fabric used on the sides/rear. The design is fully UCI compliant, so you shouldn’t have to worry about them being too long or having ribs greater than 1mm.
These Speedscalez and Pista fabrics are quite compressive, but to further ensure that the socks won’t slip down, there is a silicone gripper at the top to hold everything in place.
The lower portion of the Nopinz Flow-socks did prove to be highly breathable, as lightweight and quick wicking as you would expect from a summer sock. Both in the blazing sun and in the humidity of tree-lined lanes, my feet stayed at a manageable temperature within my shoes.
Moving up the socks, I found the seam around the ankle, connecting the breathable lower to the aero upper portion of the sock to feel a little rough against my skin. This isn’t a necessary evil of this style of sock, the Castelli Fast Feet aero socks manage the transition without a problem.
But that said, the sensation isn’t a deal breaker with these socks – although the join can be felt, it hasn’t caused any visible marks on my skin, even on rides nudging four hours in length. So no actual physical problems, even if it doesn’t feel quite as nice.
The Speedscalez front panel of the upper portion of the sock isn’t very permeable, you feel a little isolated from the wind by it – more so than other aero socks. But the thinner Pista rear/side panels did their job heat management-wise and I didn’t feel like I was overheating.
Together, the Speedscalez and Pista fabrics are quite tight; putting the socks on does take a bit of leverage. But once pulled up, they’re definitely not overly tight, the feeling is one of pleasant compression. I had zero issues with them slipping down – they could probably stand up even without the silicone gripper, but with that they stayed rock solidly in place.
Value and conclusion
At £28.99 the Nopinz Flow-socks are quite reasonably priced. They are significantly cheaper than Castelli’s Fast Feet aero socks (opens in new tab), which come in at £36, although more expensive than Condor’s Aero Socks at £24.99.
Price per watt saved over bare legs would be the best metric to measure value by, but unfortunately we don’t have back-to-back testing data to hand.
In all, Nopinz’ Flow-socks are a breathable and gently compressive set of socks which have aerodynamic credentials backed up by Aerocoach and some of those in the pro peloton. The ankle seam is a little rough against the skin, but doesn’t present an impediment when speed is the absolute focus.
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Starting off riding mountain bikes on the South Downs way, he soon made the switch the road cycling. Now, he’s come full circle and is back out on the trails, although the flat bars have been swapped for the curly ones of a gravel bike.
Always looking for the next challenge, he’s Everested in under 12 hours (opens in new tab) and ridden the South Downs Double in sub 20 (opens in new tab). Although dabbling in racing off-road, on-road and virtually (opens in new tab), to date his only significant achievement has been winning the National Single-Speed Cross-Country Mountain Bike Championships in 2019.
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