It all depends on the terrain that you are skating. For a beginner, a softer wheel is more forgiving. It will give you a smooth, grippy ride and will handle rougher terrain smoother. If you're planning to go to skate parks and skate a bit more aggressively a harder urethane wheel will roll faster across the smooth skate park terrain. Eventually, it all comes down to personal preferences and the style of skating you will be doing. For commuting and free riding a bigger softer will give you a smooth ride that will carry its speed. A smaller harder wheel for more technical park and street style skating. Or, scrap all that, you can ride any hardness of wheel, any size in any condition to your liking, have fun.
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