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Castelli's Nano Flex Pro 2 W Omloop bib shorts are a winter-worthy gravel short, and a great under layer for mountain biking. Warm, slightly windproof and with a comfortable chamois pad, these are ideal – if expensive – shorts for cold weather.

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The Castelli Nano Flex Pro 2 W Omloop bib shorts might have a long and complicated name, but the design principle is rather simple; produce a warm winter bib that works well with knee warmers and stays comfortable for long periods. Castelli has nailed the concept, although – with regards to styling – you may, like me, rather keep them tucked away under baggies.

Castelli's Nano Flex Xtra Dry Fabric is supremely comfy, with a warm fleece backing. Supposedly it's water-resistant, but while it might fend off some light rain, that's about it. Don't expect these to keep your bum dry. The thick-ish material does keep the worst of the wind off though, and retains body heat very well indeed. 

On the noticeably long legs you find a 'raw cut edge,' and it obviously works well as it hasn't frayed or rolled up during six months of use. It also means there's no chance of 'sausage-leg,' which is pretty appealing...

Those long, reflective-trimmed legs work well to seal over knee warmers (or knee pads) trapping warmth with a large overlap. Seams are kept to a minimum – one on each leg – lessening the potential for rubbing and chafing. They're very comfy.

The stretchy bib straps lie flat and never produce any chafing or pressure points, though they do wrinkle up in the wash – you need to re-stretch and flatten them before wearing. 

Lastly, the chamois pad is a real pleasure to wear. The Women's Progetto X2 Air Donna has got it all: 4-way stretch, seamless joins, good airflow and perfectly-judged variable thicknesses defined by the areas they're protecting. I'll be sad when the weather is too warm for these shorts, as the chamois is one of my favourites. 

The Castelli Nano Flex Pro 2 W Omloops are expensive, but definitely worth their £140 price tag if you do a lot of winter cycling, and especially if you don't mind the rather serious looks. They're well-made, work well with kneepads, have a fantastic pad of their own and stay toasty warm – and comfy – in foul conditions. 

• www.saddleback.co.uk

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