On a suitcase the wheels and the handle are the product

The points below about suitcase construction are ordered by how much difference they make, not by how often they get repeated.

What actually breaks

Wheels take every kerb, kerbstone edge and escalator lip, and the bearing or the axle mounting is where the impact ends up. Telescopic handles fail through bent tubes, worn locking mechanisms and broken plastic guides, usually after the case has been dragged sideways. Zips fail when the slider wears and no longer closes the teeth, which is a symptom of an overpacked case rather than a bad zip.

Shells crack occasionally, and the crack is usually at a corner or at a screw boss rather than in the middle of a panel. Because the failures cluster in three components, the useful question is whether those three are replaceable rather than how strong the shell is.

Shell materials and what each trades

Polycarbonate flexes under impact and returns to shape, which makes it resistant to cracking and prone to visible scuffing. Polypropylene is lighter and cheaper and generally less impact resistant, with more permanent deformation after a hard knock. Aluminium is rigid, heavy and dents rather than cracks, and it can often be worked back into shape by a repairer.

Compared like for like, fabric cases are lighter for the same volume, expand more usefully and offer no impact protection to what is inside. Shell thickness and rib design matter as much as material, and neither is published, so weight per litre is the accessible proxy.

Wheels in detail

Two-wheel cases use larger wheels running in a fixed direction and roll better over rough surfaces at the cost of needing to be tilted. Four-wheel spinner cases roll upright on smooth floors and their smaller wheels stall on cobbles, grass and broken pavement.

Sealed bearings last far longer than plain bushings, and the difference is not visible without turning the wheel and feeling for drag. Wheels mounted in a recess are protected from side impact, while proud-mounted wheels roll better and take more punishment. Whether the wheels unscrew for replacement is the single most useful fact about a suitcase and is almost never stated in a listing.

Handles, zips and locks

A telescopic handle with two tubes is stiffer than one with a single tube, and the number of stop positions is a comfort matter rather than a strength one. Handle rattle when new tends to worsen, since the play that causes it is what wears the guides.

Compared like for like, zip quality is visible in the size and finish of the teeth, and coil zips self-heal after a jam more readily than chain zips. A zip is not a security feature, since coil zips can be opened with a blunt point and reclosed by running the slider. Locks approved by transport security agencies in some countries can be opened by staff with a master key, which is a deliberate trade rather than a weakness.

Capacity claims and airline limits

Quoted litres are internal volume measured in ways that vary between makers, and packed capacity depends heavily on lining and pocket design. External dimensions usually exclude wheels and handles, while airline cabin gauges do not, which is where cabin cases fail at the gate.

Expansion zips add several centimetres of depth and take many cases outside cabin dimensions when used. Empty weight matters directly, because every kilogram of case is a kilogram removed from an allowance you paid for. Checking the maximum dimension including wheels against the airlines you actually use is a two-minute task that prevents an expensive surprise.

Judging repairability before buying

Look for a manufacturer that publishes a spare parts page listing wheels, handles and feet with prices. A long warranty that covers only manufacturing defects excludes airline damage, which is how most suitcases are actually broken. Some makers operate repair networks and will fit parts for a fee after the warranty, which is a different and more valuable proposition.

Screwed-in wheels and riveted wheels tell you immediately whether a replacement is a workshop job or a five-minute one. This site does not put luggage through baggage systems, so long-term owner reports and airline handling damage discussions are the practical evidence.

Everything above, in order of what to do first

1. What actually breaks. Wheels take every kerb, kerbstone edge and escalator lip, and the bearing or the axle mounting is where the impact ends up.
2. Shell materials and what each trades. Polycarbonate flexes under impact and returns to shape, which makes it resistant to cracking and prone to visible scuffing.
3. Wheels in detail. Two-wheel cases use larger wheels running in a fixed direction and roll better over rough surfaces at the cost of needing to be tilted.
4. Handles, zips and locks. A telescopic handle with two tubes is stiffer than one with a single tube, and the number of stop positions is a comfort matter rather than a strength one.
5. Capacity claims and airline limits. Quoted litres are internal volume measured in ways that vary between makers, and packed capacity depends heavily on lining and pocket design.
6. Judging repairability before buying. Look for a manufacturer that publishes a spare parts page listing wheels, handles and feet with prices.

The takeaway

Ask whether the wheels and the handle can be replaced, because that is where the suitcase will actually end.

The question is rarely which is best. It is which is enough.