A breathable cycling jacket
Fed up with the poor breathability of my breathable Montane cycling jacket, I set about finding a waterproof cycling jacket made from a material that really is both waterproof and fully breathable. After some investigation, I opted for the Quito jacket from Páramo Directional Clothing Systems. It's fashioned by former street ladies in South America, from a material called Nikwax Analogy Light fabric.
The classic waterproof breathable fabric is of course Gore-Tex. Analogy fabric is not like Gore-Tex. As I understand it, Gore-Tex is made with 'high tech fabrics' bonded either side of a microporous Teflon membrane with holes so small that rain can't leak through, but the pores are large enough to allow moisture vapour from sweat to escape. It relies on the fact that molecules in water vapour are much smaller than those in drops of rain. Or something like that.
My personal experience of Gore-Tex is that the breathability works to a degree. It's better than a simple nylon waterproof fabric that is not breathable at all. But after a while it stops working and becomes neither waterproof nor breathable. At that stage there is little to be done, other than to buy a new garment.
Páramo Quito jacket
Fully breathable fabric
The Nikwax Analogy waterproof fabric on the Páramo has a pump liner layer that mimics the way in which furry mammals stay dry and comfortable, pumping water away from the body. At least that is what the makers say. They also say you can fill it with pin holes and it stays just as waterproof. The material feels completely different to Gore-Tex, or my current Montane jacket, which is, I think, made from a fabric called eVent. The Quito jacket is soft and silent, compared to the crinkly feel of the others.
I can't say I really understand the technical differences between Gore-Tex type fabrics and Nikwax Analogy, but I can actually blow through Analogy from the inside to the outside. I can't do that with my Gore-Tex and Montane jackets. And the Páramo Quito jacket is much more comfortable to cycle in. I leave it on when cycling up hills where I would normally take off the Montane, even when it's cold, to prevent overheating. It stays very comfortable all the way up, and at the end of wet weather rides the inside of the jacket is still bone dry.
Impression so far: the Páramo Quito jacket really is waterproof and breathable, perfect for cycling. Another plus, according to the Guardian newspaper, is that Páramo products are manufactured in an ethical factory run by nuns in Bogotá, supporting the local community.