Wheels of the longboards are produced from melted polyurethane. The wheel firmness is marked by A letter. The softest wheels will mark 72A and the most firm 97A. As in the car, the more firm is the wheel the easier the coasting but the lesser the traction. And vice versa if you choose soft wheels you’ll have a soft and comfortable ride and good road traction. They are easy to stop, but the coasting would be weaker.
Well, now let’s talk about the sizing. They could be in a range from 60 mm. to 107 mm. The larger the wheels - the faster you are. Large wheels offer better coasting and you’ll feel comfortable even on paving stones. The possibility of wheelbite is a shortcoming of the big wheels that could lead to a sudden fall.