In this video, I compare the Razor electric dirt bikes in two different sizes: the 24-volt MX350 and MX400 vs the 36-volt SX500, MX650, and MX500. The MX350/MX400 features 8-inch tires, a maximum rider weight of 130 lbs, a top speed of 12-14 mph, and is perfect for kids aged 4-7. On the other hand, the SX500, MX650, and MX500 come with 10-inch tires (MX models have a 14-inch front tire), top speeds of 15-17 mph, support a maximum weight of 200-250 lbs, and are ideal for riders aged 7 and up, including adults.