The most popular dirt bike 20 years ago remains the most popular dirt bike today.
Regardless of brand, most adult riders prefer the 250cc dirt bike because of the balance between power and handling. A beginner can generally learn on this engine size far better than a 450 while the veteran enjoys a challenging thrill every ride day. Many believe, at least in Supercross, the 250cc dirt bike offers a better competitive balance with less injuries than the reigning 450 class. The 450 just too powerful for many thus the decision to stick with what worked for so long in Motocross and Supercross.
But how fast does it go? Too slow? I want a 450! Too fast? Give me a 125! Well, like all the rest in our series, let's investigate a bit before we tell you. Otherwise, scroll down and check out how fast a 250cc dirt bike goes.
What is a 250cc Dirt Bike?
The 250cc dirt bike, if you recall, used to compose the premier class in Indoor and Outdoor competition but now resides as the regional (or lites) class in Supercross and though a full series in Motocross functions as the stepping stone to the bigger bikes. Pros rode them, amateurs rode them and all of us at home wanted one. Then things changed. The 450cc dirt bike changed the racing landscape, and sometimes lives, forever.
Though the premier class pro and the emulating weekend warrior made the jump years ago, most stuck with the 250 bike because it was enough. And, various aftermarket modifications costing far less than a new 450 ride offered a significant bump in power and torque further challenging skills and requiring diligent practice to master the new speed and power.
Factors Influencing the Speed of a 250cc Dirt Bike
Like with any dirt bike, many factors influence the overall top speed of a 250cc version.
First, the 250cc engine refers to the engine's displacement, or the total volume of air-fuel mixture an engine draws in. A 250cc engine refers to the unit of volume to describe the size of the cylinder bore. A larger bore allows more fuel and air meaning more power. So, a 450cc engine produces more power than a 250 and a 250 more power than a 125, but that doesn't directly translate to speed. Just as you need to apply yourself in whatever endeavor you wish to succeed, the same applies to an engine.
Bottom line, most dirt bike brands pretty much look the same and feature the same mechanics. A novice or even an intermediate rider probably couldn't tell one 250 brand over another.
But, replace stock parts with aftermarket counterparts you then begin to realize the bike's full potential. A new exhaust, clutch and upgraded intake boost performance and power while handlebars and wheels, among other upgrades, drop the overall weight further contributing to the bike's speed potential. A rider's weight also factors into the top speed and so will an excessive amount of riding gear.
By the way, a 2-stroke 250cc dirt bike generally has more power-to-weight ratio (a measure comparing the performance of an engine to its weight, i.e. less weight more power) giving it an edge over the 4-stroke in terms of top speed.
Don't forget terrain. You ride dirt bikes on dirt, be it a Motocross track or trails, thus various obstacles get in your way and dampen speed so don't expect to get up to the bike's full potential because you simply can't on soft loamy dirt littered with rocks dips and sharp turns.
Finally, a seasoned rider well-acquainted with their dirt bike and plenty of confidence in their skills can roll the throttle further and longer, if needed, to reach top speeds.
250cc Dirt Bike Top Speed
Between torque and speed, you want more torque out of your 250cc to help with navigating through rough terrain. Unlike a street bike, aerodynamics play less a role in the top speed of a dirt bike, the knobby terrain-grabbing tires and suspension designed for off-roading further limits the true top speed potential.
All that to say, under normal operating conditions on hard pack (think dry desert trails) a 250cc dirt bike reaches a low high-speed of about 70 mph and with aftermarket performance parts a high speed of 85 mph. Pop some DOT-approved street tires on and hit the pavement, expect to further increase the speed. Outside a few straightaways on a Motocross track don't expect to speed along at 85 for very long because the joy of dirt bike riding comes from developing technical expertise and traversing challenging terrains and turning a track or trails into a personal rollercoaster.
