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Are you in the market for a fast bike, but don’t really know where to start? We’re going to go over the top speeds for 21 different models of dirt bikes, so you’re in the right place!
The average top speed of the below-mentioned adult dirt bikes is 92.3 miles per hour. The average top speed of the below-mentioned children’s bikes is 37.3 miles per hour. Top speed will vary based on terrain and the weight of the rider.
With so many models of dirt bikes, the average speed will really depend on the specific model of bike you’ve got, along with a couple of other factors. Let’s talk about and compare some of the different models!
These examples were selected because they are regarded as being in the fastest range of bikes. These bikes are big, loud, and can get going pretty fast on an open course.
|DIRT BIKE||ENGINE (cc)||STROKE||TOP SPEED (MPH)|
Let’s talk briefly about the dirt bike model, engine size, engine stroke, and of course, top speed. If the main interest if just top speed, why include all the other extra information? While knowing the dirt bike model and top speed will help you find the bike itself, knowing how big the engine is and what KIND of engine the bike has will give you a much clearer idea of the capabilities of the bike, specifically where speed is concerned.
For example, more powerful engines generally aren’t made in a two-stroke option. In addition to knowing the cc of the bike, you’re interested in, knowing the stroke can give you a good idea of the type of speed you’re going to be able to coax out of your bike. Two strokes are more typically more quick at picking up initial speed, while four-strokes typically have a higher general top speed, while not being quick as quick to hit their top speed, generally speaking.
If you’re looking to buy a bike because you want something with a high-speed threshold, chances are you will probably be using your bike on the road, or for racing, since high speeds aren’t generally super useful or necessary for trail riding.
Adult Dirt Bike Size Breakdown
There are plenty of adult dirt bikes out there, but I have narrowed them down into a few different categories. Below are the sizes for each dirt bike class and their respective speeds and size.
250cc Dirt Bikes
In the chart of surveyed dirt bikes, the average top speed for 250cc dirt bikes is 78.45 miles per hour. The biggest gap in speed between the 250cc dirt bikes on the table is 17.8 miles per hour, with the lowest speed being 71 miles an hour from the KTM SX, and the highest speed being 88.8 miles an hour, presented by the Yamaha WR. If they’re both 250cc dirt bikes, why is there such a large discrepancy in speed?
Put simply, the KTM SX has a two-stroke engine, and the Yamaha WR has a four-stroke engine. Since two-stroke engines are lighter and built to complete their engine cycle in just two “strokes” of the engine, they generally do have a quicker “get up and go” than the four-stroke engine does. However, even though four-stroke engines are heavier, and built to complete an engine cycle in four strokes as opposed to the two, they do have a capacity for higher “top speed”.
This would make the KTM SX, or other two-stroke engine 250cc dirt bikes more ideal for trail riding, and areas where you’ll be needing more boosts of initial speed, and not worrying so much about maintaining a high top speed.
The Yamaha WR, on the other hand, along with other similar four-stroke 250cc dirt bikes, will be better if you’re not as worried about bursty speed, and more focused on hitting and maintaining a high speed for a more extended period of time. The Yamaha WR is ideal for racing on more open style tracks, riding on the road (as long as you’re street legal!), and is a great bike to choose great if you’re needing an option that can support a larger rider.
400cc-450cc Dirt Bikes
In the chart of surveyed dirt bikes, the average top speed for 400cc-450cc dirt bikes is 96.67 miles per hour. The largest gap in speed exists between the Honda CRF and the Suzuki DR-Z, at 17 miles an hour. The top reported speed of a Honda CRF is 87 miles an hour, while the top reported speed of the Suzuki DR-Z is 114 miles per hour.
Each of the 400cc – 450cc bikes in the chart have 4 stroke engine. Why aren’t there any 250cc engine dirt bikes included in the comparison? Once you start getting into the higher “ccs”, or larger engine sizes, bikes begin to be made more often in four stroke engines. Once two stroke engines get to a certain size, they reach a point where they become more dangerous and volatile, at which point the dirk bike becomes available almost exclusively with four stroke engines, which are able to handle the strain and work which comes from having a more powerful engine.
510-660cc Dirt Bikes
In the chart of surveyed dirt bikes, the average top speed for 510cc-660cc dirt bikes is 102.88 miles per hour. With a top speed gap of 12 miles an hour in the observed bikes, the Kawasaki KLR gives us our lowest top reported speed at 98 miles an hour, with the highest reported top speed being 110 miles per hour from the Honda XR.
Each of these bikes come exclusively with a four stroke engine. With engine sizes ranging from 510ccs to 660 ccs, these are some extremely powerful engines, which aren’t feasable to make in a two stroke model.
If dirt biking is something you’re wanting your kids to get into, or something they want to get into themselves, speed is probably something you’ll be thinking about as a concerned parent.
As a general rule of thumb, bikes that run on electric motors are going to be slower than combustion engines, so be aware of the differences in speed and maintenance that come with the different types of bikes, as well as any variations of inherent risks that come with having a child on a dirt bike.
|DIRT BIKE||ENGINE (cc)||STROKE||TOP |
|KTM 50 SX||50||2||45|
|KTM 65 SX||65||2||62|
|Coolster QG50 49cc||50||2||30|
|DR-X Holeshot 50cc||50||2||25|
|Kuberg 2016 Freerider||48 Volt |
|Razor SX500 McGrath||36 Volt |
When it comes to children’s bikes, the slowest bike is a Razor SX500 McGrath. Made with an electric motor, it hits a top speed of 15 miles an hour. The fastest children’s bike on the chart is a KTM 65 SX. With a 2 stroke 65cc engine, this bike gives us all the way up to 62 miles an hour, which should probably be reserved for the kids who have experience with dirt bikes, and know what they’re doing.
This gives us a difference of 47 miles an hour between the fastest and the slowest of the children’s bikes mentioned above, which will give you lots of leeway in finding a bike with a top speed that is just right for you and your family.
Kids Bike Breakdown
The term “Kids bikes” fits a really wide spectrum of bikes. There is so much room for choice when selecting a kids bike, but in terms of top speed, there is plenty of variety.
Below are several sizes and classes of dirt bikes that could be considered the right size for children. Their speeds are much lower than the adults obviously, but they are still pretty fast.
Electric Dirt Bikes
Electric dirt bikes are a bit of a joke when put next to the real thing. They can move, but you aren’t going to get going very fast.
When I was younger, I actually got one of these bikes as a gift. I attribute a lot of my initial intrigue with dirt biking to that little razor. It was just enough for me to get a taste, but not enough for me to have any real fun. Basically it was like having a bike that you didn’t have to pedal in flat areas but still needed help getting up steep hills. Honestly I think it is a better idea to just get an actual dirt bike, but these are generally pretty cheap so if you end up regretting the purchase you aren’t out too much.
These bikes rarely get over 35 miles per hour, and even that is quite the stretch. They only last for about an hour before they need to be recharged, meaning they have a range of 5-10 miles.
They are fun for riding around the culdesac, but they are terrible for off-road. I have seen little kids try to use their electric dirt bikes on all sorts of little dirt hills and tracks, but I have never seen any one of them successfully do anything on them. They always try to get their little bike to take them up the smallest of hills, only to be disappointed that they can’t get up to the top without getting off of their bike and pushing. These bikes seem great on paper, but in reality, they just don’t have the power to get going fast enough to do anything really fun.
50-70cc Dirt Bikes
These bikes are really small. This is what you get your 5-year-old kid that wants to have a real dirt bike over an electric one, this is a great option. Be sure to get them a great helmet though, because a little kid on a dirt bike this size can really get going.
You can expect these dirt bikes to get up to around 40 miles per hour, which is great considering how little they are.
If your child is new to dirt bikes, and I would assume they are, I suggest getting a dirt bike that has gears, and then just don’t teach them how to change gears until they are ready.
70-140cc Dirt Bikes
This size of dirt bike is where you are starting to get into the teenager range and even some very small adults. This size of dirt bike is designed to get going at much faster speeds, and you can expect them to hit anywhere between 40 and 60 miles per hour as a top speed.
These bikes are a transition bike, and I would recommend erring on the side of larger. Teenagers get bigger fast, and they will outgrow their dirt bike in a year if you are not careful.
If your child started out on a 50cc and is ready for a big upgrade, get them a 110 or 125cc instead of making the small jump to a 70. They will enjoy themselves much more, and they have the opportunity to grow into their bike. It may be a little too fast for them at first, but they will be fine and can adjust to the added speed.
These bikes are great for beginning teenagers as well, but if your teen has a decent amount of experience on a regular bike, then they might be happier on something a little bigger as well.
150-250cc Dirt Bikes
Although I didn’t list any examples of these dirt bikes, I think they are worth mentioning. This is the size of a dirt bike that you get if you are a beginner. They will get going around 70-80 miles per hour as a top speed, but since they are a beginner adult bike I didn’t think they should be in either category.
Great for beginners, but if you are looking to be the fastest guy out there then you need something a little bigger.
What’s the Big Deal With Speed?
Top speed is fun to know and can give you a good idea of your bike’s capabilities, but there are only a couple scenarios or places where you’ll actually approach or hit your bike’s top speed.
Races, open desert, and roads (if your bike is street legal), are the only places where you would reasonably come close to hitting your top speed.
Dirt bikes are designed to accelerate fast, and not have a really high maintained top speed. People that dirt bike normally are on trails or a track that has a lot of twists, turns, hills, and other obstacles. These obstacles require a lot of slowing down as well as speeding back up. Dirt bikes handle this by having great acceleration at the cost of not having a high maintainable top speed. The gear system is designed for a very fast recovery from a brief slow down instead of using the engines full power to get the bike at really high top speeds.
There is a huge difference between dirt bikes and street bikes, and this website is definitely an advocate for dirt bikes. I will say however that if you are looking to get going really fast, then a street bike might be a much better option for you. Their transmissions are generally built for higher speeds instead of acceleration in the short term. If all you are looking for is wind in your face, dirt bikes are not the only answer to your problem.
Let’s go over some ways you can cut down on the weight of your bike that doesn’t have the potential to compromise its structural integrity. Race day baby, let’s go!
What To Consider
When trying to decide which bike or bikes you should ride, or when picking a bike for someone else, you’re going to need to take into account the experience of the rider. With the variations in top speed, engine cc, and torque, the skill and technique the rider possesses should be taken into consideration.
Top speed is not the best indicator for dirt bikes. There are so many other factors that need to be considered about a dirt bike than just that.
Let’s Go FASTER
While your bike may have a base top speed, there are several ways you can increase the speed of your bike, to an extent. The most obvious of these ways is to either reduce the weight of your bike, or find a way to reduce your own weight.
Ways to reduce the weight:
- Hit the bathroom? – Yeah, this doesn’t really have anything to do with the weight of your bike, but it does have a lot to do with the weight on your bike. If you’re replacing nuts and bolts on your bike to save minuscule ounces, taking a trip to the bathroom before you race will make a much bigger difference than replacing those screws will. You can only take so much weight off your bike without compromising structural stability, so make sure you do your part!
- Nuts and Bolts – As I mentioned previously, you can replace nuts, bolts, screws, and the like, with titanium. The downside, as is so common with any kind of upgrade, is the price. Coming at (hopefully) no surprise to anyone, titanium parts are a tad bit spendy, so you’re going to have to weight the cost of…well… cost to benefit and decide if that’s an upgrade you’re willing to make.
- Gas tank! – If you’re racing, check to see if you actually need a full tank of gas to finish the race. Are you actually going to run out before the finish line if you don’t top off? Figure out how long the race is, figure out what kind of mileage you get on the track, and fill your bike up accordingly. Leaving out anywhere from a half gallon to a gallon of gas will take off a lot of weight from your dirt bike, so if you don’t need that full tank, don’t bring it to the track.
- Part Replacements – The most obvious and probably common replacement or alteration people make to their dirt bikes to make them lighter is to replace the exhaust. Generally made out of aluminum or stainless steel, they add quite a bit of weight to your bike that can be lessened by replacing it with, yep, you guessed it, titanium.
You might be thinking to yourself “isn’t titanium heavier than aluminum”? Yes, it is. If you have two exhausts built to the exact same measurements, one out of titanium, and one out of aluminum, the aluminum one will be lighter.
Titanium exhausts are lighter because they aren’t built exactly like aluminum exhausts. Titanium is stronger, which means titanium exhausts can be built to different, lighter and thinner specifications.
- Plastics – There’s a good chance that your bike either has the plastics that it came with still on it, or you have replaced them but for aesthetic purposes. There are specific racing plastics that you can buy that are lighter, minimalist so as not to add extra weight you don’t need, but also aerodynamically shaped. Not only do they look fantastic and weigh less, but they help the shape of your bike to reduce the air resistance that occurs when you hit high speeds. Are they kind of spendy? Yep. Unfortunately, there really is a “price” attached to success.
Gearing is a change that can be made to your bike that doesn’t really change the weight of the bike, but rather the acceleration and top speed of the bike. This is achieved by helping your bike maximize grip, and changing tire rotation ratios to achieve the best speed.
This is absolutely going to make a difference in how your bike shifts, so make sure and be careful. Do your research, or have someone help you who has previous experience changing out the gears on a dirt bike. You don’t want to do something wrong and burn out your engine, break a chain, or strip one of your parts.
If you’re changing out your gears, you’re going to be altering what’s called your “gearing ratio”. For example, if your rear sprocket has 300 “teeth”, and your front sprocket has 10 teeth, you’re going to have a gearing ratio of three. Three rotations in the front for every singular rotation in the back.