Blue one is £137 classed as weather resistant not waterproof?
Technically its not ‘waterproof’ because even though the fabric, basically Gore Windstopper is functionally waterproof, Gore doesn’t class Windstopper as such. Two reasons: one is that Windstopper garments are rarely taped – I don’t know if this is the case with the Rapha jacket, can’t tell from pics on the site – and they will eventually leak from the seams. You can get round this a bit by using as few seams as possible and locating them so they’re less exposed, eg: on the inside of the sleeves, not on the top of the shoulders etc.
The second reason is a little more arcane, and is that Windstopper, while it uses the same EPTFE membrane as waterproof Gore-Tex, doesn’t have a PU element to protect it from contamination. This means it’s more breathable, but early Gore-Tex garments using similar fabrics, were vulnerable to a process called reverse osmosis, where water could be pulled inwards through the fabric due to contamination from sweat or sun cream, bodily oils etc. I don’t know for certain, but I suspect in the longer term, this will still happen with Windstopper, because it is very similar to first generation Gore-Tex from the 1970s.
My guess is that Rapha chose this fabric because they reckon – correctly – that Gore’s waterproof fabrics simply won’t be breathable enough for mountain bike use with its high peak efforts, but still wanted lots of weather protection. Haven’t used one, but I suspect it’d be pretty good.
Sorry for the geekery…