Parents often ask this question before buying a 50cc dirt bike for their kids or teenagers.
Here comes an ultimate answer after we have checked the top speed of around 20+ models on the market.
Table of Contents
How Fast Are 50cc Dirt Bikes?
Most 50cc dirt bikes can go as fast as 10 mph to 45 mph, mostly catering to kids.
Such dirt bike top speeds are the average from the following dirt bike specifications:
| No. | Dirt Bike/Pit Bike | Engine | Maximum speed |
| 1 | MotoTec 50cc Demon Kids Gas Dirt Bike | 2-stroke | 25mph |
| 2 | SYX Gas-powered 50cc Dirt Off Road Motorcycle | 2-stroke | 30mph |
| 3 | Xbox Mini Dirt Bike | 2-stroke | 31mph |
| 4 | 2023 KTM 50 SX Kid Racing Bike | 2-stroke | 45 mph |
| 5 | Honda CRF50F | 4-stroke | 40mph |
| 6 | The Yamaha TTR50 | 4-stroke | 32mph |
| 7 | 2023 Yamaha PW50 | 2-stroke | 28mph |
| 8 | The SSR 50cc Motorsports Bike | 2-stroke | 25mph |
| 9 | The Suzuki DRZ50 | 4-stroke | 33mph |
| 10 | KTM 50 SX MINI | 2-stroke | 45 mph |
| 11 | Husqvarna TC 50 | 2-stroke | 45 mph |
| 12 | 2022 Suzuki DR-Z50 | 4-stroke | 30mph |
| 13 | 2023 GasGas MC 50cc Motocross Dirt Bike | 2-stroke | 10 mph |
| 14 | 2023 CX50SRX KING | 2-stroke | 45 mph |
| 15 | 2023 Cobra CX 50 JR | 2-stroke | 45 mph |
| 16 | 2023 Cobra CX50SRX FWE | 2-stroke | 45 mph |
| 17 | Crossfire CF50 Blue | 4-stroke | 30mph |
| 18 | GMX MOTO50 Trail Dirt Bike | 4-stroke | 20mph |
| 19 | Razor Dirt Rocket SX500 | 2-stroke | 15mph |
| 20 | MBOX49 Pro Version Mini Trail Motorcycle 2022 | 2-stroke | 20mph |
| 21 | 10Ten 50R 50cc MX Kids Safe Motocross Bike | 4-stroke | 20mph |
Factors Affecting 50cc Dirt Bike Top Speed
Remember that the specified top speed of motocross bikes is just for reference. Instead of being constant, it is affected by numerous factors.
Engine size
A 50cc dirt bike’s engine is either a 2-stroke or 4-stroke engine. The earlier engine type is usually lighter and with higher horsepower. Thus, it assists the bike to go more quickly.
You can assume how faster a 50cc 2-stroke engine is by scanning the list above – the fastest bike also has this engine and is up to 45 mph, compared to 20-40 mph of the four-stroke dirt bikes.
However, being quicker does not always mean being better. 4-stroke dirt bikes are preferred for children and trail riding due to their effective traction on both tires and quick engine braking.
Gear Ratio
This specification refers to the teeth ratio on the rear and the countershaft front sprocket. The two gears have the chain directly fitting on their edges.
When the gear ratio is lower, sprocket gearing is higher, and there is less rear wheel rotation at each speed. At that time, you can expect lower engine RPMs, less fuel consumption, and higher potential top speed. Nonetheless, the throttle acceleration and response are slower.
Thus, you can adjust the sprockets’ teeth to improve or decrease the overall speed.
Wheel Size
Answered by knowledgeable readers on The Guardian UK, larger wheels require more effort to turn around, yet they can go faster at the same RPM by reducing energy waste through tire resistance and friction.
The Carrying Weight
It is a rule of thumb that the more weight you add to the dirt bicycle, the more inertia the wheels and components will increase. This will slow down the acceleration rate.
In other words, kids having lighter weights can go faster than others on the same 50cc bikes.
However, to prevent flipping over, you should still maintain a safe weight on the bikes, from 90 to 110 lbs.
Resistance Due to Terrain, Topography, and Weather
Resistance is a penalizing factor that affects how fast a 50cc motorcycle is.
For example, terrains with hard-pack dirt, sand, gravel, etc., create more friction under the wheels and slower the overall speed. It is also difficult if you ride uphill or against strong winds.
How To Measure Your Dirt Bike Speed?
Suppose you have a dirt bike and want to check its top speed for your kids’ sake, then check the measurement guide here.
What you need:
- Speedometer to measure the speed directly (in miles per hour.)
- GPS Unit to measure the distance and time traveled.
- Clock to determine how long your ride lasts from the start.
- Tape to calculate the distance the dirt bike travels.
- Calculator to calculate average speed from a distance by time.
Measurement to consider:
- Time, using the clock or GPS Unit (an hour.)
- Distance traveled, with the GPS Unit or tape (in miles.)
- Miles per hour, using the speedometer or calculating the result of dividing distance by time.
Measure the speed with a speedometer:
- Have a mechanical speedometer on your bike to measure your kid’s speed while dirt bike riding.
- Check the front wheel’s size and adjust the wheel-drive adapter on the tool. Then, the speedometer sensors will automatically count the rotations of the revolution, measure your distance, and calculate the speed.
- Take notes of the ten measurements on the screen and calculate the average speed accordingly.
Measure the speed with a GPS Unit:
You can install a GPS app on the mobile phone and place it into the kid’s bag. When your kid starts riding, the GPS app saves their positions and maps them into a route.
Later, some apps calculate the average speed based on the distance and time to complete the route. Otherwise, you can use the calculator.
Measure the speed with a clock and an odometer:
Back to the manual, you can measure the distance and time length yourself with an odometer and a clock.
- Mark the start and finish lines on different terrains and ask your kid to ride along.
- Start the countdown clock when your kid kicks off the dirt bike and stop it at the finish lines.
- Use a tape in miles to measure the distance traveled and also take note of the timebox per hour.
- Divide the distance by the time using the calculator or an online tool. At least ten records should be calculated to give out a reliable average speed.
How to Fasten a 50cc Dirt Bike?
A 50cc trail bike can be with your kids from four to 14 years old. As they grow as experienced riders, they want the vehicle to go faster. Interestingly, you can adjust some parts to increase the current top speed:
- Maintain the motor to enhance its activity. You should clean the exhaust pipe and muffler from dirt and carbon byproducts.
- Remove the vehicle’s adjustable speed restriction (known as RPM limiter.) You should consult the manufacturer or have professionals help with this task.
- Lubricate the chain, sprockets, and joints with synthetic motor oil.
- Also, use higher-octane gasoline recommended by the sellers.
- Replace the original spark plugs with V-notch ones because the latter ignites the fire quickly and effectively.
- Improve the sprocket gearing by increasing the number of teeth on the front while decreasing the teeth on the rear sprockets.
How to Limit The Speed of a 50cc Dirt Bike?
In contrast, you should slow down the kid-size dirt bike when your kids are beginner riders.
We have revealed some tips for the sake of those novice riders.
- Choose a dirt bike having a modest top speed of under 20mph, such as the 2023 GasGas MC 50 or Razor Dirt Rocket SX500.
- Also, go for 4-stroke bikes for lower top speed.
- Reduce the gearing by leveraging the gear ratio between the rear and front sprockets.
- Attach a throttle limiter to minimize the turning radius of the throttle and keep the dirt bike within a certain max speed. If your motorcycle supports the limiter, you can secure the throttle grip at the last hole to choose the minimal speed.
- Also, install a kill switch where your kid can easily access and shut down the engine in emergent cases.
FAQs
What Is An Acceptable Speed For Kids To Ride?
Safety first, always!
According to the National Library of Medicine, one report once revealed that kids 13 years old or younger should maintain an average speed of 8.9mph, and those from 14 and older ages can travel at 9.7mph.
Although there are no updated reports on this topic, a widely accepted speed is now between 12 to 14 mph and up to 20mph.
Is A 50cc Dirt Bike Safe For Kids?
Yes, it is.
Since the top speed of 50cc dirt bikes is from 10 to 45 mph, some models are within the acceptable speed range for kids. Some quicker than 20mph can travel more slowly using our tips above.
In addition, your kids must always wear protective gear such as a dirt bike helmet, riding goggles, chest protectors, elbow pads, knee pads, etc.
What 50cc Dirt Bike To Buy For Kids?
Placing your trust in brands like Honda, Yamaha, Suzuki, or KTM will not let you down.
If top speed is your priority for kids’ safety, you can buy the following models:
- Kawasaki KX65
- Honda CRF50
- Yamaha TT-R110E
- Suzuki DRZ125
- KTM SX E5
- GMX MOTO50
- Razor Dirt Rocket SX500
- MBOX49 Pro Version Mini 2022
- 10Ten 50R 50cc MX Kids
Bottom Lines
With our effort to gather all information about the 50cc dirt bikes’ top speeds in one place, we hope you have already been clear about the topic and can choose a suitable bike for your kids.
Do you have any other questions? Our comment box is always open for your queries.
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