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Marc Clarke
(marcclarke) - F

Locale: Front Range of the Rocky Mountains
Re: pack weight? on 07/12/2010 02:04:08 MDT Print View

Montbell Ultra Light Spiral #3 Long in factory stuff sack
Ultra Light Spiral #3 Long in factory stuff sack (using the smaller of the two draw cords) and Montbell inflatable pillow in its sack.

Edited by marcclarke on 07/12/2010 02:05:56 MDT.

Marc Clarke
(marcclarke) - F

Locale: Front Range of the Rocky Mountains
Re: pack weight? on 07/12/2010 02:12:05 MDT Print View

The stuffed size is given in the review. Please RTFM. :-(

Stuffed Size
5.3 x 10 in (13.5 x 25 cm)

jimmy benson
(biggyshorty) - F
dimensions to liters on 07/12/2010 08:10:38 MDT Print View

Hi Marc,
I did RTFM but what i'm curious about is a conversion of dimensions to liters - i've always been confused about that. i am debating between getting the super stretch #3 and the UL super stretch; i guess the only difference is a few oz of weight and maybe the packing size, that's why I was asking. thanks for your help.

Marc Clarke
(marcclarke) - F

Locale: Front Range of the Rocky Mountains
Volume of a Cylinder on 07/12/2010 11:41:50 MDT Print View

Google is your friend, as always. (Who knew?)

First, you Google "volume of a cylinder" to learn what the formula for a cylinder is, where the first page I see is:

http://www.mathsteacher.com.au/year9/ch14_measurement/18_cylinder/cylinder.htm

and the formula for a cylinder is
Volume = pi * radius * radius * height

Since we may have all slept through high school geometry, we'll Google "radius", and Wikipedia helpfully reminds us that the radius is one half of the diameter (and gives us pictures, even).

http://en.wikipedia.org/wiki/Radius

radius = 13.5cm / 2

And, since we are assuming we all slept through high school geometry, we'll Google "pi" to find out what the value of pi is. We find:

http://math2.org/math/geometry/circles.htm

which tells us that pi is 3.141592

but we'll just use 3.14 to save ourselves some typing. Besides, the measurements in the review aren't all that precise. (For a calculation this crude, we could just use 3 as the value of pi and be plenty close.)


Then you plug in the numbers from the review, using
radius = 13.5cm / 2
height = 25 cm

and

Volume = 3.14 * 13.5cm/2 * 13.5cm/2 * 25cm

We'll use Google to do the calculation for us (no scientific calculator needed), typing in

3.14 * 13.5cm/2 * 13.5cm/2 * 25cm =

and sure enough, Google does the math, figures out that you are using cm for dimensions, and gives you the answer in liters (kinda cool, huh?). Google says:


((((3.14 * (13.5 cm)) / 2) * (13.5 cm)) / 2) * (25 cm) = 3.57665625 liters


No text books, no calculator, no nothing. Just Google all the way.

If you have had your coffee today, you could do the same calculation in inches:

3.14 * 5.3in/2 * 5.3in/2 * 10in

which Google calculates and returns as liters:

((((3.14 * (5.3 in)) / 2) * (5.3 in)) / 2) * (10 in) = 3.61345413 liters

Presto! (Again.)

Since the stuff sack is not a perfect cylinder, but has rounded ends, you can assume that the actual volume of the stuffed MB Spiral is a little less than the full 3.6 liters, probably 3.5 or 3.4 liters.

Edited by marcclarke on 07/12/2010 12:23:47 MDT.

Marc Clarke
(marcclarke) - F

Locale: Front Range of the Rocky Mountains
Re: dimensions to liters on 07/12/2010 11:45:27 MDT Print View

Now that we have had our daily lesson Google-Fu, it is left to the reader to plug in the approximate dimensions from the picture I posted of my UL Spiral #3 long earlier in this thread to calculate the approximate volume of the long version of the sleeping bag in its stuff sack. :-)

Marc Clarke
(marcclarke) - F

Locale: Front Range of the Rocky Mountains
Montbell U.L. Spiral #3 Long and Compression on 07/12/2010 11:59:22 MDT Print View

For what it is worth, I think the Montbell-supplied stuff sack is WAY TOO SMALL (as does the original reviewer). I carry my #3 Long in a 20 liter dry bag loosely fit into the bottom of my pack rather than in the tiny factory-supplied stuff sack.

Similarly, the Montbell factory-supplied cotton storage bag that came with my U.L. Spiral #3 Long is also WAY TOO SMALL, as I literally have to stuff the sleeping bag into the cotton storage bag. I'm out shopping for a MUCH larger non-Montbell cotton storage bag.

Edited by marcclarke on 07/13/2010 00:26:08 MDT.

jimmy benson
(biggyshorty) - F
lessons learn-ed on 07/12/2010 23:39:37 MDT Print View

marc,
great breakdown. thanks again. for what its worth to you, rei has great large "natural cotton" non-stuff storage sacks for sleeping bags. i've gotten 2 in past sales for $1 each...

Marc Clarke
(marcclarke) - F

Locale: Front Range of the Rocky Mountains
Re: lessons learn-ed on 07/13/2010 00:19:10 MDT Print View

I picked up an aftermarket "natural cotton" non-stuff storage bag today. Thanks for your tip. :-)

M Stein
(a.k.a.) - F

Locale: Northern California
Inferring an EN Rating for the MontBell UL SS bag from the WM Summerlite rating on 07/15/2010 17:09:22 MDT Print View

Hello, all,

I myself recently asked MontBell customer service to provide EN ratings, and in my case, they wouldn't give it out.

But by poking around the sites linked to on Western Mountaineering's "international dealers" page, I was able to turn up the super-secret EN Rating for the WM Summerlite.

The Summerlite is +6 C/+2 C/-14 C, or for us retrogrades who use the Neandertal scale...

WM Summerlite
COMFORT: 43 F
LOWER LIMIT: 36 F
EXTREME: 7 F

Treating James' experience as a baseline (where the WM bag proved warmer than the MB), we might consider the MontBell bag to be a 40 F bag, rather than a 30 F.

For what it's worth....

Hike Ultralight
(HikeUltralight) - M

Locale: Southeast
Re: Inferring an EN Rating for the MontBell UL SS bag from the WM Summerlite rating on 11/30/2010 14:17:53 MST Print View

"The Summerlite is +6 C/+2 C/-14 C, or for us retrogrades who use the Neandertal scale...

WM Summerlite
COMFORT: 43 F
LOWER LIMIT: 36 F
EXTREME: 7 F
"


Thanks for this info. However, based on everything I have read here on the Summerlite (which is quite a few threads) most people say the summerlite has a pretty conservative rating. Why would WM put out a 32 degree bag that has a lower limit of 36? Or are you saying these tests were done independently of WM?

Either way, most here agree the Summerlite is true to rating, or maybe even conservative. I agree that the UL Super Spiral wouldnt be quite as warm, but 40 seems too high for the bag.

Dave U
(FamilyGuy) - F

Locale: Rockies
MontBell UL Spiral Down Hugger Sleeping Bag Review on 11/30/2010 14:23:31 MST Print View

"Why would WM put out a 32 degree bag that has a lower limit of 36? Or are you saying these tests were done independently of WM?"

Yes - EN testing is done by an Independent body. For all intents and purposes, this WM is a 36 degree bag.

Hike Ultralight
(HikeUltralight) - M

Locale: Southeast
Stand Corrected on 11/30/2010 15:31:42 MST Print View

I stand corrected then. So 40 degrees for the UL Super Spiral, I was about to puchase but that makes me hesitate.

I find the Summerlite too confining.

Jerry Getz
(jerzyshore) - F

Locale: Southeastern, PA
The BAG of my dreams on 06/01/2011 18:08:45 MDT Print View

I am a very fidgety side sleeper, and the room afforded by this bag is truly second to none. In my opinion the best thing is the way the bag sort of sucks itself down close regardless of position, minimizing open airspace between the bag and your body. For me, that is what makes all the difference.

JSG