How light should a portable case be?

Answer: Work back from the loaded weight. For 200 m on one hand, keep it at 2.6 kg or less.

Can one case have both a handle and a trolley?

Answer: Yes, but each takes 20 mm of internal depth, so pick the dominant posture.

Why not quote the nominal dimensions?

Answer: Nominal covers the body only. Wheels and hinges add about 40 mm, exactly the clearance at a lift door.

What if the load sits off-centre?

Answer: Move the partitions so heavy items sit within 150 mm of the centre. Beyond 30 mm, changing hands will not fix it.

What should I ask about spares?

Answer: Unit price, lead time, and whether the spare comes from the same mould batch.

How to Choose a Portable Case: 5 Selection Criteria

Quick answer: Judge a portable case on five figures measurable on a sample: empty weight against loaded weight, the posture its handle and trolley allow, outside dimensions with protrusions counted, balance once packed, and whether wearing parts can be replaced singly.

Five criteria for a portable case
Criterion 1: empty weight and loaded weight
Criterion 2: handle, strap and telescopic trolley
Criterion 3: outside dimensions and clearance
Criteria 4 and 5: balance, fill rate and replaceable parts
FAQ

1. Five criteria for a portable case

Product pages lead with litres, material, colour and price. None answers whether one person can still carry the case when it is full.

The order matters: weight caps the load, the handle decides the posture, dimensions decide the door, balance decides whether it stays carryable. Two portable cases listed at 550 x 350 x 230 mm, one at 2.8 kg and one at 4.1 kg, are different jobs after 200 m on one hand.

Criterion	Measure	Acceptable line
Weight	Empty and loaded	Quarter of loaded
Posture	Handle and trolley	Wrist straight
Dimensions	Envelope plus protrusions	80 mm at the door
Balance	Offset, volume used	Offset within 30 mm
Spares	Handle, trolley, wheels	Sold separately

2. Criterion 1: empty weight and loaded weight

Empty weight is the first charge on the budget. Hold the load at 10 kg for 200 m on one hand, 12 kg for 50 m, 20 kg two-handed, and 8 kg where stairs are a daily route, which puts the empty weight ceiling at 2.6, 3.0 and 2.2 kg.

Portable case in olive green facing forward, folding handle at the lid centre, one twist latch each side, ribs across the lid

A 2.8 kg portable case with a 1.1 kg insert leaves a little over eight kilos for equipment. The shell is the smallest source: a moulded insert runs 0.6 to 0.9 kg heavier than a flat one, and metal latches add 0.2 kg.

3. Criterion 2: handle, strap and telescopic trolley

A portable case meets the person at three points only. Fix the posture first.

Grip diameter runs 25 to 30 mm, 35 mm with gloves. A mount passing through the wall with a 1.5 mm backing plate resists pull-out better than a screw into a plastic boss, and holds 500 N static for a minute.

Three trolley sections reach 1,050 mm with play under 8 mm; past 10 mm the case weaves as you walk. Wheels of 80 mm, rated 60 kg a pair; smaller ones leave the hand numb after 200 m of concrete.

4. Criterion 3: outside dimensions and clearance

A portable case passes three openings: office door at 800 mm clear, lift door at 900 mm, tailgate at 1,100 mm. Add handle and wheel protrusions, usually 30 to 50 mm.

Portable case in dark grey at a three-quarter angle, two wide latches on the front rim, vertical ribs down the wall, drain plug lower left

A case listed at 550 x 350 x 230 mm, with wheels standing out 20 mm, occupies 570 x 370 x 250; those 20 mm stop it at a lift door. Cabin limits are tighter: 550 x 400 x 200 mm with wheels counted.

Opening	Clear width	Usable envelope
Office door	800 mm	620 mm max
Lift door	900 mm	700 mm max
Overhead bin	550 x 400 x 200 mm	1,150 mm linear

5. Criteria 4 and 5: balance, fill rate and replaceable parts

Loaded, the centre of gravity should sit within 30 mm of the handle line. One kilo of offset at 300 mm adds 0.3 kg-m of torque on the wrist. A fill rate of 65 to 75 percent is sensible; below 55 percent the case is oversized.

The parts that fail first are the handle, wheels and latches, so those three should be replaceable singly. A bolt-on mount with four M5 screws is a ten-minute swap; a moulded-in one turns a cracked boss into a new lid.

Part	Failure	Spare
Handle	Elongated boss	One
Wheels	Tread worn to 70 mm	One pair
Latches	Spring fatigue	Two

Conclusion

Keep empty weight under a quarter of the loaded weight, fix the posture before the structure, count protrusions in every dimension, check balance with the case full, and insist that wearing parts can be swapped. Leave one out and the price stops telling you whether the saving sits in material or in parts. Chosen this way, a portable case survives a year of corridor work.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.