As with any discovery of a new way to enhance your child's motor skills and enjoyment, it's easy to be carried away with excitement and make a snap decision to buy the product that looks cool, the one that costs the least, or the one that "everyone is buying". There are more details than meet the eye, so it's good to be equipped with some knowledge that will help avoid the dreaded "buyer's remorse".
Decals versus stickers: Ever notice that the logos and markings on high quality bikes have decals that are covered with a clear topcoat? When you run your hand over the decal, it's like it's not even there. Cleaning the bike is easier and it just plain looks good and those looks last a lot longer. Stickers?.. They're applied over the final coat of finish, leaving them vulnerable to getting dog eared, collecting grime at the edges and eventually peeling off. Decals are preferred, and found on better balance bikes. When the finish of a child's bike matches the quality of a good adult bike, you know it's something special. An excellent example of good decals, below.
Headsets versus bushings/clamps: What is a "headset"? It's a system of ball bearings and races that are designed to fit together and rotate smoothly and endure the trauma that's transmitted through the front wheel and into the frame and fork. They are locked in place with a pair of large nuts that are tightened in opposing directions. Almost every bike on the planet has a headset connecting the frame and fork. The only ones that do not, have some plastic bushings used to connect the frame, fork and handlebars with either a bolt or a quick release clamp. Headsets are the way to go, but only the more expensive balance bikes will have them. Here's a good example of a real bike's headset below (the black parts). The bearings are concealed, but you can be sure that this bike will endure the harshest of terrain without failure.
Rubber air tires versus foam (EVA) tires: This is an easy one! Rubber is the material of choice when only 1 square centimeter of material is keeping a bike from sliding out in a corner. Foam is a maintenance free option, but certain elements are compromised: 1. the harshness of the ride (more trauma transmitted from the wheels to your rider's spine), 2. the inability to control the tire's pressure for various surfaces (an air tire can be pumped hard for pavement or pressure removed for softness when off-road) and 3. Rubber grips all surfaces much more successfully than foam (sliding out in a corner uses a lot of band-aids, lets avoid this by choosing air tires)
Good geometry versus bad geometry: This is a little bit more difficult to detect, but we will help you visualize the issue. Whenever considering a balance bike (especially online) look for the profile view of the bike, from the side. Pay close attention to the horizontal distance from the seat to the handlebars. Some bikes use a T-shaped handlebar, configuring them such that the rider's cockpit is very small. The result is that the rider's elbows are bent to nearly 90 degrees, which is a very bad way to steer a bike. Bikes with proper geometry will have a bigger distance from the seat to the handlebars, so that the rider's arms are comfortably extended fully, and steering is managed by the shoulders and shifting body weight, rather than relying on the biceps to do the steering. For a good example, observe the arms of any adult riding a racing style bicycle or a motorcycle. Arms will always be extended 90-100%, not bent at a 90 degree angle. Below find examples of good geometry and bad geometry. Can you tell which is which?
Fork rake versus no fork rake: This one is a little more difficult to describe, but it refers to the front fork of the bike. On most real bicycles, the fork will either have a slight taper forwards at the fork tips, or the fork will be angled to achieve the same wheel position. In other words, fork rake is when the front wheel is offset forward from a line drawn through the center of the frame's head tube (see illustration below) This makes the bike handle with more stability both while riding in a straight line, and while cornering. This issue is explained in great detail courtesy of Dave Moulton's Blog, which is worth checking out. If you observe a balance bike's fork is perfectly straight, without any "rake", it's going to be a bit squirrelly and more difficult to control, especially for the youngest riders aged 2 and 3, for whom stability is important!
Brakes or no brakes: Some careful research will reveal something about the many brands of balance bikes out there: they are produced with only toy industry safety standards. No air tires? No headset? No fork rake? It's a toy. What we've observed over 12 years of selling [nothing but] balance bikes is that only the real balance bikes (with actual bike industry safety testing) have these features, and that they almost always includes brakes as a means of slowing down and stopping. What is often omitted from marketing (despite the usual "fear sells" protocol) is that dragging the feet to stop only works well at slow speeds and only on textured pavement. It's not very effective on slick surfaces, at high speed, and especially off-road, where feet tend to just slide along in the dirt with little or no stopping power. When kids get good at riding their balance bikes, they will go faster than you expect, and they will want to explore dirt trails where there is more freedom to roam. A hand brake is recommended, and gives the rider a new dimension of control.
Keep these things in mind during your search and you will much more easily drill down to the best balance bikes, without wasting time considering those that seem to be merely imitating real bikes with lots of shortcuts and cost-cutting to keep the price low. You get what you pay for: a better first cycling experience, an enhanced level of safety, and of course great durability that is easily serviced with industry standard bike components.