Thermals for winter - an opinionated view

Being winter, keeping warm is a priority for riders and the principle of layering helps maintain comfort.  Over the years as a cross country skier I've used base layers out of polypropylene (cheap and smelly), chlorofibre (a favourite with the yachties), polyester (widespread, comes under various brand names) and now fine merino (fibres of 20 microns or less).  This is what I've found.

Polyester gives the best balance of cost, stinkiness and warmth.  Fine merino gives the worst balance but if smell is key, then it's stellar.  I've worn an Icebreaker base layer for 4 days hard ski touring before it started to offend the olfactories.  That's twice the time of polyester.  But it's two to three times the price of polyester and not as easy to wash.  And there's another drawback: moths will eat it while they leave synthetics alone.  Too hard on their little molars.  I now have an Icebreaker polo top base layer with irregular holes.  So don't store wool in the dark or in plastic bags.

Next up from base is the mid layer.  Fleece is hard to beat.  Has a high insulation to weight ratio, better than a mid-weight fine merino but it's bulkier.  You shouldn't penny pinch here; go for a quality brand. Malden Mills in the US produce fabrics that perform well in a range of temperatures and the fibres don't pill and resist bunching.

Of course the wrinkle here is that your layers bulk up and a good fit in a leather jacket in summer feels like a throttling fit in the winter.  If there were a vest of Thinsulate on the market I'd get one.  There are down vests but a solid leather jacket would compress it too much.  Gore Windstopper fabrics are used for vests and they're not bad; they're wind resistant and breathable and come in versions with little or some fleece insulation.

The comeback of fine wool has been a testament to marketing skills.  Buy an Icebreaker and you get a baa-code (yes, really) that you can enter on their website to find out which sheep shagger in NZ shore the fleece for you. 

I loved my holey Icebreaker and have replaced it with one with three percent Lycra to show off my fantastic physique.  Growers have produced merino fibres down to five microns but they tend to break when spun.  12 microns seems about the minimum.  That's 12 millionths of a metre!

I used to ski tour with an old phart who reckoned that three layers of wool would see off any approach of hypothermia.  He wore a wool singlet, wool shirt and a wool jacket.  Once he got buried by a snow collapse off the quarry face near the Bogong High Plains road at Langfords Gap.  He was dug out and lived to tell the tale.

But for riders I'd say fine merino is a waste of money unless you have chronic BO problems or an aversion to washing.

Ern Reeders