eVENT vs Breeze Dry Tec (Mont Bell)

[Jon Solomon]

Mont Bell’s new Peak Shell must be attracting a lot of interest, and there has been a lot of well-documented discussion on this site about breathability. I don’t claim any expertise, just trying to make sense of the test result figures available to me the layman about moisture permeability of eVENT and Mont Bell’s new air permeable Breeze Dry Tec used in the Peak Shell.

Checking Mont Bell’s website, it’s very interesting to see that the moisture vapor test results they show indicate that the coating Mont Bell is using called Breeze Dry Tec is only about 15% higher than Gore Tex XCR (15,000 vs 13,000 g/24hr). The test used is JIS L 1099 B2. BPL cites figures for a variety of fabrics using a number of different testing methods, including JIS L 1099. Note the lack of a B2 at the end. I learned on a japanese site that there are two tests, B1 and B2, and that furthermore there is some conflicting report in the Mont Bell promo literature about which test they use, presumably the tests themselves are similar (desiccated inverted cup), but the values are different. The value in the test cited in BPL for Gore Tex XCR is much higher than the value given in the Mont Bell figures, so the two types of tests B1 and B2 must be indexed differently even though the relation between results in a single test are the same. It is interesting to see in the BPL test (where the new Mont Bell fabric isn’t listed as far as I know), nylon faced eVENT has a figure which about 30% higher than XCR (27, 800 vs 21,100. There was a recent posting that mentioned figures from Montane stating that the eVENT used in the Air Jacket is slightly less breathable than the eVENT fabric used in their Superfly and G Force smock. Anyway, going by the figure BPL cites, I suppose that still makes eVENT more breathable than Breeze Dry Tec–by a margin that is as great (or as small) as that between Breeze Dry Tec and XCR.

But as Alan Dixon has pointed out, it is very hard to tell from such figures how the thing actually works in the field.

Still, the combination of features, fabric, and price might make this the right choice for a lot of people. OutdoorsMagic says the Montane Air jacket will retail for GBP 175, which is the equivalent today of a whopping USD 337–a lot more than the $198 that Mont Bell asks for the Peak in the States. (Maybe Montane will adjust the price for the US market?). I think I know which one I would get…

The lack of pit zips for the Japanese market version is really interesting. I noticed it does put the jacket just under 10 ounces.

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