In Reply To:
I don't think breathable on a bike in the rain is possible. I go with the cheap waterproof.
We rode 100+K yesterday in a Biblical down-pour. Half of our group of 6 had cheap water-proof plastic cycling rain jackets, the others did not. I was in the latter group, but I was fine for most of the ride. I was wet right through, but I had enough on( base layer, jersey, wind vest, arm-warmers, knee warmers, rain booties, full finger gloves) that I was fine until the final 15 minutes when my feet started to get a bit cold. It was about 15C. The trick was to keep the foot on the gas( intensity up) and keep working hard and stay well hydrated and eat well.
The people wearing thew plastic rain jackets said they were getting just as wet with sweat from the inside!!
I agree. I tested all kinds of different so-called water-proof breathable miracle fabrics when I was working at Sugoi a number of years ago and they all disapointed.
+1. We've studied a lot of waterproof/breathable (wp/b) fabrics at Backpackinglight. At high exertion, even the most breathable can't keep up with your sweat production. It's definitely better to run "wet" with just a windshirt rather than a wp/b jacket. Cycling is tougher as you have substantial windchill to deal with.
FWIW, the most breathable wp/b fabric we've seen is eVent. It's also expensive and doesn't pack down as small as thinner polyurethane-based wp/b fabrics.
Interestingly enough, second place in breathability goes to a very inexpensive fabric called Propore made by 3M. It's a non-woven polypropylene fabric. Rainshield makes an inexpensive cycling-specific jacket out of the stuff. But, it doesn't pack down very small either.
Stay Warm. :)
-Mike
"100% of the people who confuse correlation and causation end up dying."