If you’re buying larger luggage to check, the most common options are 24 to 30 inches (measured on the longest dimension of the case). You can find suitcases as large as 36 inches; check with the carrier for size limits.•Two-wheelers. Suitcases with two wheels, also called rollers, use the same type of wheels found on in-line skates. They only roll forward and backward. The wheels are slightly recessed into the case, which confers two advantages: protection from snapping off (beneficial for checked luggage) and economy of space. If you need a suitcase that can easily clear curbs or roll on uneven surfaces such as sidewalks or cobblestones, a two-wheeler will work better than a four.
This style has some shortcomings, though. Since you have to pull the wheeled case, some travelers complain that this position causes shoulder, wrist and back pain. Also, it can be cumbersome to drag a two-wheeler in a crowded space because you need some clearance between yourself and the bag.
• Four-wheelers. Suitcases with four wheels are also known as spinners because each wheel swivels 360 degrees, like on a shopping cart. You can push them, pull them, wheel them alongside you and turn them in any direction. They are also easier to navigate in tight spaces, such as the aisles of planes, trains, subways and buses. A heavy or large suitcase may be easier to manage with four wheels. If you are concerned about ergonomics, the spinner is a better choice than the roller because it does not put stress on your shoulder.
There are some downsides to the four-wheelers. Since the wheels are externally mounted instead of recessed, they are more prone to snapping off. Spinner wheels also occupy valuable real estate within fixed allowable dimensions, reducing the amount of internal packing space. It’s wise to check if the published size of the bag includes the wheels – they will be included in the allowable dimensions for a carry-on. Another drawback: If your suitcase is on an incline, it could roll away.Soft-sided luggage is made of fabrics that move and yield. Its two biggest advantages are that it is usually lighter in weight and that it can flex and compress to conform to tight spaces.
Hard-sided luggage, also known as hard-shell luggage, has come a long way. It used to be, you went with hard for maximum protection and soft for minimum weight. Today, hard-sided luggage is made with such high-tech plastics as ABS (acrylonitrile butadiene styrene), polycarbonate and others that are lightweight and durable.
Hard-sides are best for protecting the contents of your luggage from breakage. They also provide better security because they have integrated locks and can’t quickly be ripped open with a blade. That said, most composite plastic hard-sides close with a zipper, which can be vulnerable. Hard-sided luggage stacks easily, making it ideal for cruise ships, which stack baggage in the belly of the boat before departure.