Just a random thought as I sweated my way to work in the cold this morning.

Do the site experts think that trying to vent a shell jacket in very cold conditions is a good idea?

Surely this would cause any water vapour to condense on the inside of the jacket rather than passing through it??

Just a thought, I'll go back to worrying about more important things.....

Personally I reckon venting's more about cooling than aiding breathing - less sweat means less moisture. Just rolling up your sleeves, opening the main zip and keeping your head uncovered makes a big difference. Pit zips? Personal taste, but I don't use them that often in the UK.

Agreed. I have vents on the sleeve of a Windproof soft shell, and to be honest they do tend to funnel the cold air down into the chest.

I sweat so body much nothings breathable enough for me anyway!

I vent my Montane Epic to cool down - it is very breathable, so don't know if it helps with sweat.
Incidently, when I used to do mega-cycling commutes (Homfirth - Leeds or Holmfirth - Greenhead via Saddleworth Moor), I used a thick woolly jumper + light Goretex - the goretex went on if wind was bad or it was raining. Otherwise, I just sweated through the jumper. This worked in some really awful weather atop Saddleworth in winter.

MMmmm.. good points. I used my Montane over a Helly Base Layer in Snowdonia in January and found with fair winds the combination was great when using the vents, and as Jon says, more about cooling. I've used vents on Buffalo's and Vaude shells and am now thinking that, with the flexibility of venting, a long or short sleeve base under the Buffalo, topped with a lightweight shell with vents, would work well most of the year except high summer. Personal choice of course. Incidentally, the windproof outer of the Buffalo or Montane means the waterproof shell would only go on in downpour, so a lighter one packed suffices.

Side pockets with vents are a good idea.

I've got some on a Karrimor cycling waterproof I've got. I find them very useful, certainly more handy than pit zips and a better alternative to opening the main zip on a bike.

Having problems finding a decent replacement, the goretex patches on elbow the result of fall on the bike are just beginning to peel off.

Lloyd I have the Karrimor o2 jacket with pocket vents. They do work on the bike but i am not keen on them for walking as they can let water in too easily, and when on foot I usually want things in my pockets to stay there not back along the way.

it's still sold if that's what you are after, not Goretex but KS135.

Mark, Yep, it's the Karrimor O2 extreme jacket I've got. It's well designed cycling jacket with a drop tail and a map pocket and a removable hood.

So few cycling jackets bother with pockets but I find them useful, especially as it as doubled as my summer waterproof for walking.

I'll keep a look out might be able to replace it with the same.

Lloyd, Wiggle do em for £99.99

Don't have time to read the thread, but in answer to your original post Mark, I reckon you have a point there. Just as when the outside of the jacket saturates and breathability is greatly impaired, the effect of cold air cooling the jacket's inner surface leading to internal condensation could saturate the inside, leading to a similar blocking effect. Possibly.

In fact, I once read in the only science journal article I've ever found on the topic (not that I've looked much) that it's best to leave vents closed. This is because breathability depends on it being wamer and more humid inside than out, to 'drive' the water vapour out through the material. That makes sense to me, though I guess if you can rid of *all* the dampness and excess heat through the decent vents you get on today's jackets (the study is 1995ish), then you may as well do that.

Personally though, I'd say just play around and see what's most comfortable for you.

But if you're cooler, through venting, then you are going to produce less moisture.

Well I will hold my hand up and confess to being a venter.

In fact while skiing last week, the only time I fastened up my pitzips was when it reached minus 22 on the glacier. (I kept them open at minus 17.) Even with face, neck, hands, head etc covered against the searingly cold wind, my core was hot and the last thing one needs in extreme conditions is cold perspiration hanging round. That way madness lies.

Mike - definitely, no doubt on that one.

I reckon it's just a case of finding some compromise, the happy medium..

Which sort of leads me back to the traditional layering system as opposed to the Buffalo approach.

Jeannie, those are exactly the conditions I would be tempted NOT to vent, the differential between extreme cold and your body 'should' lead to decent breathability surely?! (not a cue for loads of 'yes, but don't call me Shirly' jokes)

As long as the moisture passes through your first couple of layers you should be fine, venting would allow the cold air to permeate into your insulating layers causing the moisture vapour to condense before it hit the shell....

Hey, but wasn't the football good last night.....

Well, it works for me! I wasn't sweaty, I was wearing wicking / breatheables, I just don't like being hot. No wind got in as the vents are under my pits. The wind-chill was on the face/front as I was skiing downwards. Soon as I was off the top I stopped and took off the hat and unzipped the neck as I was heating up so rapidly.

hmmmmmm hot & sweaty


sorry

Better get rid of that Legolas face, Jeannie, it's getting Dan all worked up, like.

I to am a venter. On the jackets that dont have vents i always seem to end up with sleeves rolled up (even in middle of winter) On the jackets with pitzips i tend to open them depending on conditions. My board jacket doesnt have mesh over the vents so in big stacks loads of snow gets in! having said that i rarely closed the vents on my trousers when boarding and i dnt wear anything under those! (even in -22 temps!)

I dont think pit-zips are essential but can be dam useful when you know your for-arms are going to go numb the minute you roll sleeves up and the rains going to get in the main zip!

Plus i like cooler temps and the feeling of fresh air flow rather than stuffy feelings!

Wot?!?! dan fancys legolas.....i always knew there was something he wasnt telling us!

DANS COMMING OUT!!!!!!

Trouser vents all open, hey Ben? Toooooooooooo much detail, man!

hey youve seen my board pants and the vents are around the knees! and when i say nowt under them i do of course mean no thermal leggins underneith! you have to wear quiksilver boxxers under them to get the stylish band showing above ya trousers when u jump n stuff!!!