Spring is getting closer, and many have to buy a new dirt bike. Either the old has had its day or you just want a new bike. There are many things to consider when buying. You worry about the color, features, price, but the most important thing is to buy the right size. Here is a dirt bike size chart!
Table of Contents
Dirt Bike Size Chart
|Height (cm)||Frame height (inches)||Frame height (cm)|
|155 to 165||14 to 15||35 to 38|
|165 to 170||15 to 16||38 to 41|
|170 to 175||16 to 17||41 to 43|
|175 to 180||17 to 18||43 to 46|
|180 to 185||18 to 19||46 to 48|
|185 to 190||19 to 21||48 to 53|
|190 to 195||21 to 22||53 to 56|
|195 to 200||22 to 23||56 to 58|
Many dirt bicycle manufacturers offer a calculation of the frame size on their website. But not that simple. We will go into that in more detail later. Now, as recommended by the manufacturers, we introduce the main table for the frame height in inches and centimeters.
How to Make a Correct Measurement?
Measuring the stride length
The stride length is the length of the inside of the leg. It is best to measure the stride length with the help of a spirit level and a measuring tape, yardstick, and folding rule. But you better not use a ruler because we think it is too short.
If you do not have a spirit level on hand, a book or notebook can be still suitable. Now simply place these items on a surface as stable as possible. Then clamp the spirit level or the book horizontally between your legs. The best thing to do is to pull it until it stands. Now, just measure the distance from the upper edge of the spirit level or book to the floor. The value then corresponds to your stride length.
Determine the correct frame height
Multiply your stride length by the factor of 0.226. The value you then get is your theoretical frame height in inches. Multiply by 2.54 and you will get the frame height in cm. Denote that road bikes, trekking, or cross bikes have different factors for calculating the stride length.
Frame height about the height
You can also determine your frame height using your body size, but the method is not that precise. Every bike manufacturer suggests the table above on the internet.
Types of Dirt Bike
The dirt bikes come in the off-road or dirt bike segment, where there are bikes such as motocross, Enduro, trial, and track-racing. Compared to the lines on-road and off-road, the dirt bikes have simpler and lighter engines, longer-travel dampers, large ground clearance, simple bodywork, no crank or plastic details.
Once known as a scrambler, motocross is short, off-road racers. These vehicles often have small fuel tanks to reduce weight. The large shock absorbers allow the steering wheel to make jumps at high speeds. Motocross engines are usually single cylinder 2 or 4 strokes, usually with a capacity of between 50 and 650 ccs.
It is a revamped motocross and can be used properly on the street, plus handy details like horns, lights, muffled exhaust, and license plate holders. Enduro is also ideal for racing with the shorter track of a motocross.
Rally Raid (Rally)
It is a special form of the Enduro with a larger fuel tank and a long track through the deserts. Engine capacity is also larger, about 450 to 750 cc.
A trial is a special form in on-road vehicles, used to challenge balance and more accurately than speed. For a trial, low weight and throttle response sensitivity were the two factors of preference. The trial usually uses two-stroke engines, with a capacity of 125 to 300 cubic centimeters.
They are perfect for racing oval-shaped roads at high speeds, especially without brakes and rear shock. It burns the engine with methanol, a single-cylinder four-stroke engine with a long piston stroke. Most gearboxes only have two levels. To sell their products to the market, carmakers often refine each line of vehicles to meet the public road traffic law.
This car is now most known for its custom-built models, quite a few cars come from the factories of the manufacturers. The exterior design of a cafe racer has all the elements, including clip-on handlebars, tailpipes extending backward, one-seat saddle, large carburetor, and fiberglass fuel tank or aluminum. The origin of the cafe racer came from England during the 1960s.
Tracker or Street Tracker is the combination of track-racing and street. Starting with the 1960s races, many fans wanted track-racing cars to run on public roads. That meant adding safety components to the law such as lights, brakes, and mirrors. Since then, the tracker was born. Overall, the tracker is like a mantis with high handlebars, saddle stretched back but limited to a cafe racer-style seat, no front fenders, multi-track tires.
Dirt Bike vs Enduro
Dirt bikes come with the lightest weight and fastest acceleration possible. They do not have a great top speed, but they get it quickly. Top speed is not a factor of much interest in dirt bikes, nor are they designed for speed. Normally, a dirt bike with a 450cc 4-stroke engine will reach about 120km/h.
To achieve the fastest acceleration, manufacturers have reduced weight in any part possible, such as a small capacity fuel tank, the most restrictive electrical switch system, and no starter switch. And to speed up as quickly as possible off the start line, exit curves, and fly over dirt, the dirt bike will have a short gear ratio between gears.
You can tweak it by changing the number of teeth on the gear and sprocket. But the dirt bike has a gearbox and disc-slug gears that are not suitable for cruising at high speeds. Short gear ratios and large revs also cause the rider to pull the gearbox harshly. It means a lot of noise, especially when the dirt bike has a minimal exhaust system with less noise filtering. If you want to ride a dirt bike, the standard exhaust will need to be replaced to meet noise regulations.
Dirt bikes are not available to feel comfortable or to travel long distances. They have stiffer suspension, a stiffer saddle, and a lighter steering wheel. Tires are spikes designed only for off-road riding and not for asphalt roads. Although the tires are clinging to the dirt road, they provide a small contact surface on the asphalt.
Other things that add to the weight of the vehicle include the kickstands, thicker seat sockets, steering guards, and a larger capacity fuel tank. Some older bikes also use heavier metal fuel tanks. Previously, the plastic fuel tank did not meet the regulations on evaporative emissions because the low density of plastic particles still had certain gaps, making the gas vapor evaporate easily. Currently, alternative models use new plastic, so the problem is only with old cars.
Enduro vehicles require mixed tires, used on both asphalt and good off-road performance. The tires of these cars cannot be compared to the tires of a bike on the dirt road. But they still have a good grip under these conditions. The standard exhaust system on the Enduro can reduce noise and exhaust levels, meaning they will be heavier than the dirt bike exhaust.
The Enduro bike’s fork system will also have a shorter journey, and both the forks and saddle are softer than the dirt bike. It makes driving the Enduro more comfortable over long distances. To make the bike suitable for use on the street, manufacturers also mount a heavier electric steering wheel for the engine. It makes the engine softer without reducing the capacity or torque of the car.
- Strength: Dirt bike and Enduro will usually have the same power specifications. For example, the Enduro KTM 450 EXC and Motocross KTM 450 SX-F both produce 62 horsepower.
- Traveling on the road: Enduro will be more friendly to use on the road. Although dirt bikes have kits available to validate them on the road, the noise part of the engine is not resolved.
- Use in the track: You can run the Enduro on the track, but it is not suitable when the dirt bike was born for just doing this.
- Use in the dark: If you want the dirt bike to run at night, install additional lights. And the Enduro comes with headlights, meaning you can ride comfortably in the dark.
- Comfort: The dirt bikes are made to race in 45-minute intervals, so comfort for long trips is not taken into account. Enduro vehicles will be smoother and more comfortable for long trips.
- Weight: The Enduro is heavier. If we compare the KTM 450EXC and the KTM 450SX-F, the Enduro weighs more than 9kg.
- Acceleration: If you want to speed up fast, then the dirt bike will win all the time.
- Top Speed: Since the gear ratios between gears are getting longer, the Enduro will have better top speeds. The KTM 450 EXC reaches about 153km/h.
- Maintenance: With the stiffer suspension and the more extreme the engine, dirt bikes will need more frequent maintenance.
So now, you have calculated your perfect frame size. As we said, it is simple but unfortunately only theoretically. In practical terms, there are many other aspects to consider. We will face many types of bicycles of the individual brands and the resulting frame geometry. Then, there are people with long upper bodies but short legs or the other way around.
Many people like their dirt bike to be big, the others prefer small. The right frame size also depends on the seating position that you ultimately feel most comfortable. Saddle and handlebar position or stem length impact your dirt bike. No matter who you talk to about the topic, everyone knows better, has a different point of view. We have already seen discussions after discussions on this subject.
Ultimately, everyone has to know for themselves how best to get down from the mountain. Our advice for all mountain bikes, free rides, downhill, or fully riders that go to the bike shop is to get advice and test the bike. You can try different sizes.
Yes, we know that is not always easy because bike shops have all sizes on-site, especially free-riders or downhillers. But at least you should try it. If you buy the wrong size, it means that you have spent a lot of money on a bike that is not fun in the long run. We are thinking of constant pain, long-term orthopedic damage because of incorrect stress on your back and leg muscles. Also, we are talking about the stress you have because you have to get yourself a new one next year, and then the whole thing starts all over again.