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Verdict: 
All the benefits of normal armwarmers with added rain resistance makes these ideal for changeable spring weather
Weight: 
76g
Contact: 
www.saddleback.co.uk
Castelli Nanoflex Armwarmer
8 10

These Castelli Nanoflex Armwarmer are no ordinary armwarmers. Castelli use a fabric that is treated with a with tiny silicone nanofilaments on the outside surface that means water beads off and rolls away, meaning they handle short showers and heavy downpours with aplomb, keeping arms dry in this unpredictable spring weather we're currently experiencing.

Inside is a Thermoflex fleece lining that makes them soft next to the skin but more importantly provides some thermal insulation. You can happily wear them when there's quite a chill in the air; for this reason they've been ideal for very early morning rides. Castelli quote an ideal working temperature range of 10 to 16 °C, but I've used them down to 5 or 6 °C quite comfortably. Any colder than that and I would be taking a different approach to my layering.

They're a very snug fit but not tight - typical Castelli and their racing roots - and this does mean they stay firmly in place. Some armwarmers can gradually slide down your arms during a ride, not cool, but not so with these. The tops are lined on both sides with sticky silicone gripper tape, which equally grips your skin and the jersey sleeve. They're simply constructed, with a single seam running the length of the arm, and it's hidden away on the underside of the arms.

While they're obviously very well suited to rides when you can expect the likelihood of rain, they're also very good when the forecast is a bit more positive. At this time of the year the weather can change suddenly and without much warning, and having the water resistance these provides is a real bonus over regular arm warmers. And on days when there was no chance of rain, they work just fine too, as they're very breathable so you won't overheat.

That alone makes them a very good armwarmer for this time of year and really, I can't see why you would use a regular arm warmer when you could use these. They're on the pricey side but they're a good investment in your cycling wardrobe. Put simply, they're better than all the other armwarmers out there.

Verdict

All the benefits of normal armwarmers with added rain resistance makes these ideal for changeable spring weather.

road.cc test report

Make and model: Castelli Nanoflex Armwarmer

Size tested: n/a

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

We always strive for total performance and total innovation, but sometimes we surprise ourselves. This Nano Flex fabric behaves just like our Thermoflex fabric in dry conditions, but then provides unbelievable water repellency when it starts raining. We don't claim that it's fully waterproof, but it's the most effective product we've ever made for keeping you comfort- able in all conditions. It's just short of a miracle.

Tell us some more about the technical aspects of the product?

Water -resistant Nanoflex fabric

Same breathability , stretch, and warmth as our standard Thermoflex warmers

Double-sided Silicone grippers keep the warmers in place

Great in every possible condition

Rate the product for quality of construction:
 
8/10

Tough and durable - they've stood up well to a lot of use in the time I've been testing them.

Rate the product for performance:
 
8/10

The water resistant treatment makes them a bonus when it rains, and they also work well when it's not raining, with good thermal insulation and breathability.

Rate the product for durability:
 
8/10

No frayed stitches or anything like that.

Rate the product for comfort, if applicable:
 
8/10

They're very comfortable once on, but they are on the snug side. That does mean they don't move about or slip down your arms during a ride though.

Rate the product for value:
 
7/10

As ever, there are more expensive and there are cheaper arm warmers available, but few offer the all-weather versatility these do.

Tell us how the product performed overall when used for its designed purpose

They work like regular arm warmers in the dry, but it's when it rains they pull ahead of all other arm warmers.

Tell us what you particularly liked about the product

The fit, comfort and water resistance.

Did you enjoy using the product? Yes.

Would you consider buying the product? Yes.

Would you recommend the product to a friend? Yes.

Overall rating: 8/10

About the tester

Age: 31  Height: 180  Weight: 67

I usually ride:   My best bike is:

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, touring, mtb,

 

David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.

11 comments

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Bez [602 posts] 3 years ago
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The million dollar question when it comes to rain-repellent clothing is: "How well does that rain repellency hold up over time if you bung it in the washing machine after every ride?"

So, how well does that rain repellency hold up over time if you bung it in the washing machine after every ride?  1

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GMC61_NewburyRC [10 posts] 3 years ago
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I've found no issues with repeated washings on a delicates setting.

Additionally, a very light iron with the lowest setting refreshes the water repellency.

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maldin [140 posts] 3 years ago
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Bez wrote:

The million dollar question when it comes to rain-repellent clothing is: "How well does that rain repellency hold up over time if you bung it in the washing machine after every ride?"

So, how well does that rain repellency hold up over time if you bung it in the washing machine after every ride?  1

For what it is worth, I have their full bib tights, same Nanoflex material (though there is also some wind resistant material too) and I have noticed that the knee area and top of thighs seem to be less water repellant now than when new. They have been washed but only weekly (they are padless  21 and only at 30C with delicate wash liquid. I still think they are wonderful tights, they got me through winter with snow and rain, but my awe is tinged with disappointment and suspicion that the effects are somewhat diminished with age and even careful regular washing.

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Colin Peyresourde [1773 posts] 3 years ago
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I have these and I can attest to their water resistance. I haven't had too many cases of late to wear these in the rain (it's been too cold, so I've been wearing my colder weather gear).

These make a short sleeve top (with a good base layer) like a long-sleeve top. Perfect for cold starts, moderate to warm weather and changeable weather conditions.

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russyparkin [570 posts] 3 years ago
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i have them and pair them with a gabba.

relentless rain will get in fairly fast but they dry really fast and still keep you warm but things like light rain low fog where as with other stuff you get wet these you dont. also short sharp showers are dealt with nicely. you know those 3-5 min dartmoor showers.

best kind of kit for engerland for sure

i have the sportful no rain leg warmers and they are arguably better as a bit thicker but a bit to thick when warm and less movement.

mine havebeen washed about 7000 times and are fine

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Bez [602 posts] 3 years ago
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GMC61_NewburyRC wrote:

I've found no issues with repeated washings on a delicates setting. Additionally, a very light iron with the lowest setting refreshes the water repellency.

Aren't those two statements somewhat contradictory?  1

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JonD [420 posts] 3 years ago
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I haven't had any comfort problem with the armwarmers, but the non-flatlock seam on the equivalent legwarmers tends to rub behind the knee and needs a bit of shuffling around to get comfortable. With the nanoflex shorts they're nice and warm in cold icy weather.

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Spooks [59 posts] 3 years ago
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Just got a set of these at the weekend AFTER getting soaked on a ride, tried em the following day and comfortable and dry. One thing I wasn't keen on was mine had an irritating label inside one of em..... I can see that getting removed.

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putmebackonmybike [19 posts] 3 years ago
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Yes those labels need careful cutting off. Typical snug tight castelli fit. Nice. It should be noted, showers aside, 10-15 mins of steady rain and they're wet through: they're not miraculous!

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chingwongfu [4 posts] 3 years ago
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I gently hand washed them in very diluted Assos detergent, air dried, and they basically turned them into normal warmers. Disappointing
I'll try to lightly iron them to "refresh" them

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smitty [3 posts] 3 years ago
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chingwongfu - ouch. The water repellency used here is a nanotechnology treatment that deposits millions of 25 micron "hairs" on the surface of the fabric. Kind of like the surface of a peach. But using that foo-foo detergent was like putting gel on those hairs causing them to all lay down flat. An iron will only refresh a chemical DWR finish, not this physical structure. Try repeated washings with a mild powdered detergent and they might snap back.