When it comes to picking the perfect sized dirt bike, there are a lot of different factors you have to put into the equation. Your main goal is to be able to stay comfortable and secure on the bike, so going too large or too small can have serious repercussions on your decision.
However, to make the decision much easier here are a few things you need to consider before choosing a dirt bike:
Your Experience Level
Whether you're just getting your first dirt bike at 30 years old, or if you're planning on getting your child his or her first bike, experience is a critical factor to your decision. First off, if you're buying a bike for a new rider less than 5 feet tall and 10 years of age, you're going to want a dirt bike under the 110cc range. There are plenty of options that come with three-speed transmissions and automatic clutches to help a young first-timer get used to riding on two wheels before learning the clutch system.
However, if you're an adult and a first time rider, you want to get with something more appropriately sized, but likely keep the cc's under 250 to get used to the feel of a dirt bike. Additionally, if you're 15 or older, you want to get used to the clutch system if it's your first bike, but if you're already used to it, then size should be your next priority. Size plays an important role, but first you have to know your experience level before you purchase your first bike.
When deciding on a new bike, your size truly matters to your overall safety and comfort on a dirt bike. One of the best ways to know a dirt bike fits you is to get on the bike, sit forward and see if your feet touch the ground.
If you are flat footed on the ground while sitting up on the bike, the ride is likely too small for you. This will put more weight on the suspension, which you'll really feel when you hit a bump or a rock in the trail. However, if you're barely able to stand up straight on the bike and find yourself using the very tips of your toes to find balance, the bike is probably too large.
You want to be able to put one-third of your foot on the ground, so you're not flat footed or unbalanced on your tip-toes. If any big bump were to come your way, you want to be able to control the bike if you have to put your feet down.
For beginner riders who weigh less than 100 pounds versus a tenured rider who weighs 200 pounds, the amount of suspension you need will change dramatically. Beginner riders shouldn't start with a bike that is too small because their weight could affect the suspension, but people often learn how to ride much faster on smaller bikes instead of taller rides.
For those who weigh 150 pounds or less, it might be smart to work with something under 250cc to get accustomed to the bike's height and weight. However, for bigger riders, you want a ride that has enough suspension to take you down any dirt path comfortably. Choosing something between 250cc and 450cc might be a better choice. However, again, experience plays an important role - even if you're heavier or taller. Choosing a 450cc might be too powerful for the extremely novice rider, but going above 250cc's is smart for those who have grown accustomed to riding dirt bikes.