In reply to sebflynn:
> ... if i havnt convinced you that a double boot with single boot warmth would be a pro rather than a con then i give up.
Ach, that's the problem with the youth of today. They give up so easily!
Seb, a "double boot with single boot warmth" is almost an impossibility, using current boot materials. I would almost entail deliberately backward-engineering. To make shell + liner both durable and functional they will be warmer than a single boot, as they are two substantial layers - as opposed to just a firm shell with somewhat insulating liner of a modern single boot. You seem to be wanting something more like a thin single boot with a removable 'sock' inner? This would ruin the improving fit that most climbers want now.
There are market forces. Most places people need to worry about liners freezing are overnight trips - i.e. winter alpine or Greater Ranges - and so modern doubles like Spantiks are needed for warmth anyway.
At home in the Alps in summer, or Scotland, or ice climbing in Canada/Norway/Cogne etc most people are just day climbing so can dry their boots at night, thus negating your concern. This is where the numbers are in the market nowadays, along with the fact that more people are climbing mixed and more people are wanting more technical boots (nimble, light, low volume, shaped), which again almost necessarily rules out doubles, which are inherently clunkier and less precise in fit - even if the two parts of the double are thinner than HA boots.
Where I think there is room for innovation - again something I discussed with Dane - and which Salewa have tried to address with their twist-adjustable-stiffness system, is a boot that is warm enough to use in the mountains, can take a decent crampon, but is more comfortable to walk in, probably via a more flexible or modular sole. Most mountaineering, in numerical terms, is on easy non-tech peaks (Mt Blanc, Rainier, Hood, Denali, Aconcagua, Island Pk, Mera Peak, Manaslu, Everest) and you really don't need boots you can front-point in, though you are doing a lot of 'walking' in crampons. More flexible boots would be less tiring, promote circulation and help prevent frostbite.
Post edited at 09:18