Wheels, tires, tubes, and rim strips.
How much can there be to understanding bicycle wheels? A lot actually! We're just going to cover the basics here.
Wheels: Obviously a critical component of any ebike, there's often more than meets the eye with bicycle wheels. Here are a few helpful tips and bits of information.
Wheel bearings: These should be a smooth rolling component with long life. When you receive your bike, make sure everything is rolling smoothly. If things feel sloppy (any wiggle side to side) or rough, check the bearings. A cone wrench may be required to adjust any play in the wheel that doesn't belong. DON'T overtighten, the wheel should spin freely. If the wheel has a grinding feeling, make sure there is adequate grease on the bearings. A lack of grease will wear out the hub prematurely.
Spokes: ALWAYS - always check spoke tension on any new bicycle. Grab two adjacent spokes and squeeze them together. They will flex, but shouldn't move. If they are properly snug, check them again after the first 100 miles or so of riding. They will settle in and loosen up. All you really need to tighten spokes is some know how and a spoke wrench. If you want some detailed information on how to do this, I recommend following Sheldon Brown's tutorials. If you're not comfortable learning this very useful skill, most bike shops will tighten spokes or true a wheel for $20 - $30.
Tires: Thousands of pages have been written on bicycle tires alone. We'll start with the stock Sondors ebike tires. The Chaoyang "Big Daddy" as its known in other parts of the world is a 26" x 4.9" tire. What does this mean? It gives us an idea of the wheel size the tires is intended for. The outer diameter of the tire is actually closer to 29.5". These particular tires are thin, relatively light, and designed for travel on sand or snow. If you ride primarily on street, the first thing you'll notice is the noise - no sneaking up on anyone with these tires! You'll get used to a moderate hum from the tires as you ride along.
Multiple other options are available, but be careful to hang onto your wallet. Fat tires are not particularly cheap. Anything from low profile street tires to studded winter tires are available. Here's why you might want them:
Low profile tires: The Sondors bike is only available in a "one size fits all" frame. The main intent of offering these tires was to lower the bike for shorter riders. Some just like the low profile look.
26" x 3.5" street tires: If you don't need the knobby tires (or the noise) multiple options are available. The Vee speedster tires are a good option if you want to maintain the original size and style of the bike. They're specifically made as a street tire for fat bikes and work well. The Maxxis Hookworm is another popular option for maximum traction on the street.
26" x 4" Off road tires: Many off road options are available. The Mission Command by Vee tires is a good upgrade to the stock tires. It has a very low rolling resistance for a fat tire and should have better longevity. If you want to add a unique flair to your ride, they are sometimes available in different colors as well. The tires will allow fast efficient travel just about anywhere, without losing the ability to travel on snow or sand.
Tubes: The stock tubes for the Sondors ebike are 26" x 4.0/4.9". (Direct replacements available here.) They will work with any tire rated as 26" x 4" to 26" x 4.9" there is some flexibility with tubes, so you may be able to squeeze them into smaller or larger tires. If putting them into a 3.5" tire, the main concern would be the increased possibility of pinch flats. You can always swap the tubes for 26" x 3.5" to be sure. Valves: There are two main valves for bicycle tubes, Schrader and Presta. The Sondors comes with Schrader valves, so it's best to buy tubes that way as well. Presta valves will work, but the valve itself has a smaller diameter and can make for a sloppy fit into the wheel, especially if running a low psi setting.
Rim Strips: The primary job of the rim strip on any bicycle wheel is to protect against unwanted punctures in your tube. The rim strip protects the tube against any sharp edges on the wheel or spoke nipples. Most fat bike rims also have holes to reduce weight, making the rim strips visible from the outside. For this reason rim strips are now available in many different colors.
Tire Liners: Tire liners are an extra form of protection against flats. They go inside the tire and create a barrier between thorns, nails, and whatever else tries to poke a hole through your tube. They do add a little weight, but if flat protection is your main concern they are highly recommended.