Anyone know how makers measure the size of their rucksacks?

Tringa

Tringa

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One of my rucksack has, so the ad said, a capacity of 30 litres. It has one main compartment and a smaller pocket on the front, no extra top or side pockets.

If I really try I can get 4, 2 litre bottles into the main compartment. I haven't tried to see how many I can get into the smaller pocket but even if it was 3, 2 litre bottles, that is only a total of 14 litres. There is obviously some left over space between the bottles but if that doubled (which is very doubtful) the total capacity, it would still be less than 30 litres.

Does anyone know how the manufacturers come up with the quoted figures? Doesn't the Trade Description Act apply to them?

Dave

Yes, I know I should get out more.
 
Fill it up with polystyrene balls and try again.

Or

And I think this is the best way.

Fill up a load of buckets with water and pour them in........See if its full by the time youve done 30 litres worth:exit:


Maybe my first suggestion is closer
 
Put a poly bag/sack inside the rucksack then try and get 30 litres of water in.
 
Jannyfox said:
1 You really need to get out more
2 Rucksacks are like long lenses. However big they are, you always think they're too small................... ;)
Click to expand...

That's what my Mrs says!
 
mattyg said:
Fill it up with polystyrene balls and try again.
Click to expand...

This, or very similar.

Just use a measuring jug.

From Google :-


This is done as per the standards set up by authorities.
The standard entails using 20mm plastic balls as the filler. Packs are loaded up, then emptied and then contents are dumped into measuring devices. So this is like filling these devices which provide the readings either in cubic inches/centimeters or in liters. Liters are preferred as it’s more usable and easy to remember.
According to the standard, capacity measurements should not include any compartments that are not entirely sealed by zippers—such as shovel pockets, bottle holders, compression pockets, etc. But I suspect that some of the overstated daypack figures you mention erroneously include the capacity of these pockets
Backpacking sizes cubic inches to liters Conversions:
 
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Thanks, Wontolla. I still reckon in this sack is nowhere near 30 litres.

Dave
 
30 litres is not that big for a rucksack. A 'daypack' is usually around 25 litres.
I don't do that much 'hard' walking these days, but a 30 liter was my usual day out in the hills choice.
I always put a toploader on the hip belt for 40d + 70-300mm as the sack was usually full-ish. My avatar left shows the combo.
What make and model is the bag, there are lots of hiketographers on here with plenty of experience with rucksacks!
 
Thanks for the reply W. I'm not looking for a rucksack. For short/easy trips I use a cheapo photo one, for longer/more challenging trips I use my 55 litre (perhaps I should say "allegedly" 55 litre :)) walking rucksack. My query here was just how do makers come up with the capacities they quote? I can't see this little sack has got any chance of holding 30 litres.

Cheers

Dave
 
Tringa said:
Thanks for the reply W. I'm not looking for a rucksack. For short/easy trips I use a cheapo photo one, for longer/more challenging trips I use my 55 litre (perhaps I should say "allegedly" 55 litre :)) walking rucksack. My query here was just how do makers come up with the capacities they quote? I can't see this little sack has got any chance of holding 30 litres.

Cheers

Dave
Click to expand...

Yeh, that was why I thought that someone could confirm, or otherwise, the capacity, if they had the same bag. Not advice on buying! :)
 
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