FlyerTalk Forums - View Single Post - Volume/Weight Ratio as a Luggage Criterion
Old Aug 20, 2009, 2:57 am
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tfar
 
Join Date: Jan 2009
Location: Berlin and Buggenhagen, Germany
Posts: 3,509
Arrow Volume/Weight Ratio as a Luggage Criterion

With rolling bags we had almost forgotten about the burdens of heavy luggage. That lasted just about until the weigh restrictions hit us. Why carry a heavy bag if all that tare weight is just subtracted from your actual packing capacity?

What one would want is a bag that is light but still packs a lot of stuff. Therefore I advocate the introduction of an important criterion in luggage selection: the volume to weight ratio. How much volume does the bag pack per pound or kg of bag weight. The higher the number, the better.

No wheels usually are better than wheels. The more wheels the worse.

Duffels usually fare better than suitcases because they have less framing material.

In the same sense soft materials are better than hard materials.

Nylon is better than leather.

Basically, this puts a soft, unstructured nylon duffel without wheels at the top of the list and a four-wheeler (spinner) hardcase on the bottom.

Here are some numbers as a reference:

http://www.flyertalk.com/forum/12253102-post26.html

NB: You have to keep in mind the use of the particular bag. Some bags get so big that you cannot fill them with an ordinary mix of stuff (mostly clothes). The weight will have reached 50lbs before the bag is even full. This means that you are carrying literally "empty weight" around. My experience indicates that the balance point for the standard 50lb load can be reached best with a 24-26" suitcase. If you get much bigger e.g. 28-31 inch suitcase the bag will not be full when 50lb are reached. If you go below 24" you cannot fill it to 50lb unless you pack books or heavy things in it.

For duffels this has to be calibrated accordingly.

This means that you can play with the v/w ratio. In principle a high number is better because it allows you to pack more weight and it means that even if you don't pack it fully, you carry less dead weight. So ideally you'd have to determine what your typical load looks like and then find the smallest and lightest case where it will fit well.

As another reference point let's look at a fairly standard 22" rollerboard with the standard 22x14x9 measures adding up to 45 linear inches. The packing volume of such a bag is around 2700 cubic inches or 45 liters. This is unfortunately not a linear relation. A 62 linear inch bag will have a volume of more than 100 liters. Said rollerboard usually weighs between 9 and 10lb.

Let's say 10lb for the sake of simplicity. 2700:10=270 or in metric 45:4.5=10. Somehow, once again, metric turns out to be the easier system.

The very lightest rollerboard (Travelite) has a volume of around 42 liters and a weight of 1.9kg for a v/w factor of about 22.

Something on the really heavy side like the Valoroso 22SAX model has a v/w of 7.6.

Now, if we use the famous A. Saks 21" expandable carry-on, it has a volume of 43l in normal mode and about 62l expanded. It weighs 545 gram. This gives us a v/w of 78.8 in normal mode and 113 expanded. That's what I call light weight luggage.

Check for list of lightest luggage here:
http://www.flyertalk.com/forum/12177519-post48.html

EDIT: In general, as brunotattaglia says below, you can figure that if you want to fully load a bag with a standard assortment of items that you can fill a 25-26" bag with the check-in limit of 50lbs (23kg). If the bag is bigger there will be empty space. Your belongings will shift, unless you use some voluminous but lightweight "stuffing". If the bag is smaller, you won't be able to put 50lbs worth of stuff in there, unless you transport bricks or books.

Till

Last edited by tfar; Apr 6, 2012 at 4:41 am Reason: added lightest luggage link
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