Castelli Nanoflex arm warmers

Starting with a standard pair of their Thermoflex armwarmers and coating it with millions of silicone 'nanofilaments', Castelli have created a water repellent fabric called Nanoflex that causes raindrops to bead off of the fabric as you are riding keeping you drier for longer. That's the theory; and the practice?

Well, in practice the Nanoflex arm warmers, like the Nanoflex knee warmers we tested recently, are pretty impressive too. Light rain and road spray are just blown off the material by the wind as you travel along. This process works in heavier downpours until the fabric gets overwhelmed and once wet the thermal fleece fabric keeps you warm so it's no real problem. In the dry they work exactly the same as the standard Thermoflex warmers they are based on. While warm they are not overly so and can be worn on spring/autumn mornings without the fear of overheating.

The Thermoflex material offers thermal protection using a fleece inside which also provides comfort as well. The fit is close with the size tested covering from wrist to armpit on me, there are no size guides on Castelli's website but to give a little idea of how they measure up my arm length is 46cm and a 18cm diameter bicep. They stayed put all ride thanks to silicone grippers either end and the fact they are so long stops that annoying gap between armwarmer and jersey sleeve happening.

Price wise we're looking mid to high end here at just over the thirty quid mark and being just a couple of pounds extra than the standard Thermoflex the Nanoflex coating is a worthwhile extra. The de rigueur colour choice of white, black or red is available in sizes from small to extra large.

All in all the water resistant coating makes good sense especially at this time of year when a full waterproof jacket is too warm in the rain but paired with a gilet these warmers keep the worst of the dampness at bay. Thin enough to be used as a layer in the minus temperatures winter throws at us under a softshell or jacket coupled with being able to use them in spring/autumn without overheating makes them versatile and probably one of the most used bits of kit in your wardrobe.

There is a downside though as ever, a large seam runs the full length which can get irritating after a while plus the graphics don't look like they will stay attached very long and look a bit rubbish once the material is stretched over your arm.

Verdict

A veratile product that should be of use for at least 75% of the year in the UK. The water repellent coating is impressive and works in all but the heaviest rainfall but by this stage you'll probably be thinking about a waterproof jacket anyway. A good fit though with a reasonable price tag which is only let down by that overly large seam.