One key factor that determines whether a dirt bike is appropriate for you is size. With many options available in the market today, making the right decision can be confusing. Confused about the right size?
Wondering which one to settle for between a 4-stroke and 2-stroke dirt bike? Doubting which seat height is apt for you? Well, all these are pertinent questions and issues that every dirt bike shopper grapples with.
In this article, we’ll delve comprehensively into the dirt bike size chart and what role it plays in the shopping or buying process of a dirt bike.
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What Is The Ideal Dirt Bike Size?
Whether you have plans of buying a dirt bike for yourself or your young one, it is imperative to consider a person’s height and size of the engine. Having a look at the seat height is paramount. The wise thing to do is to sit on the bike or have your child sit on it. Are you comfortable? Is the little one comfortable?
The golden rule is to ensure the feet can touch the ground. For purposes of future-proofing your bike, it is wise that the feet only touch the ground and aren’t flat. This is expressly the case with kids as they grow very fast. The last thing you want is to buy a bike only for your little one to overgrow it within months.
Your choice of a bike for the little one should be such that he or she can ride it comfortably in 2-3 years. For this reason, ensure their feet just touch the ground (at the tip of their feet is recommended).
Those purchasing for themselves as adults need to feel comfortable. Ensure the feet enjoy a tiptoe position while on the ground. While 50cc bikes are the ideal engine sizes for a child, adults have plenty of options in this regard.
Note: Before you move to other important factors when shopping for a dirt bike such as weight, experience, and age, it is prudent to primarily consider a bike’s engine size. As aforementioned, 50cc dirt bikes are appropriate for young kids.
Here’s a further breakdown of different age groups:
Bike Size Based on Engine
3 – 6 years
Some parents and guardians introduce their kids to dirt bike riding as early as 3 years. If your young one (s) are between the ages of 3 and 6, then they need to ride a 50cc bike. Settle for one with an incredible go throttle and twist. These types make it a breeze for the little ones to learn about dirt bike riding.
With such kinds of bikes, kids do not have to put up stuff such as gears and clutch which might be a little confusing and hard to work with at the initial stage of the experience. Once you notice that your child is getting comfortable, it’s time to shift him or her to the semi-auto dirt bikes.
7 – 8 years
After your son or daughter has become used to the go throttle and twist kind of dirt bike, you can transfer him or her to the semi-auto dirt bike. The Honda CRF50F is a great choice. Featuring a three-speed step-through type of gearbox, this bike will gradually and effortlessly introduce them to gears.
On top of such an easy to use the gearbox, the bike also brings with it a low-maintenance and durable engine to reduce any risk of hassles and any kind of frustration. Keyed type of ignition ensures that he or she can’t ride without your supervision. With an adjustable throttle meter, your young one won’t go too fast. Finally, the Honda CFR50F features an auto clutch meaning the young rider doesn’t have to worry about stalling.
9 – 11 years
Most kids in this age group have an easy time utilizing a standard gearbox. For this reason, you can move them to a 65cc bike from a 50cc one. What makes the former unique is the fact that most of them resemble adult bikes.
65cc bikes bring with them low speeds and just enough power for your little one to manage to handle. If you’re wondering which bike is appropriate for this category, consider the KTM SX65. With a seat height of 29.5 inches, you can rest assured that most kids of this age group will have an easy time feeling comfortable handling and riding the bike. The seat is adjustable.
12 – 14 years
As your child continues to grow and adapt to different dirt bikes, you can graduate him or her to a bike that’s tailored for kids aged 12 – 14 years. In this case, an electric dirt bike would suffice. You should settle for one whose weight limit is between 140 to 175 pounds.
On top of that, the bikes should boast speeds of around 14 – 17 miles per hour. A 150cc, 4-stroke dirt bike should work in this regard.
With dirt bikes of this age group, your child’s choice is between a motocross or trail types of dirt bikes. While no major differences exist between these two, noticeable ones are evident. Compared to the trail one, motocross bikes are lighter. These are mainly tailored for racing. Trail bikes are customized for a smooth-riding experience as the rider navigates technical trails.
15 – 17 years
With children in this age bracket, two key factors play a role – the weight and height of a rider. Kids of this age can ride bikes that are almost similar to those ridden by adults. 125cc, two-stroke, or 150cc, four-stroke dirt bike would suffice in this category.
Adults (18 years and above)
Adults, just like kids or teenagers, are also into bike riding. Adults who don’t have prior experience riding dirt bikes need to start it slow. An electric kind of dirt bike is the best one for such a situation. Bikes like the Razor MX 650 make the learning process of a dirt bike effortless.
The fact that it isn’t a pro dirt motorcycle means its highest speed is 17mph making it highly beginner-friendly. An alternative to this bike would be a 125cc or 250cc 4-stroke bike. Handling and controlling these types of bikes is a breeze.
More options exist for adults who have prior riding experience. A 125cc, two-stroke engine bike or 250cc, four-stroke engine, or even 450cc, four-stroke bikes are all available options. With the last option, it would be a great choice only if you boast a two to three dirt bike riding experience.
Bike Size Based on Seat Height
Another factor that can help you choose the right bike size is the seat height. Different age groups have specific requirements in terms of their seat height. Because people have different heights (including kids), one bike cannot be ideal or perfect for all.
Seat heights are also different further making it difficult and confusing to settle for a dirt bike. The good thing is that some dirt bikes bring with them adjustable seat heights which go miles to make it effortless for purposes of adjusting.
The ideal seat height is the one that allows you stable balance when riding, starting, or stopping your bike. Fortunately, manufacturers include all this important information to act as a guide to shoppers. Those buying their bikes from an auto dealership have an opportunity to test it personally.
Since some people’s legs are longer compared to others, the ideal thing to do is to ascertain your height from your crotch’s highest point to the floor. Once you get that height, match it with the seat height. The closet rough estimate should act as the best match.
The different ideal dirt bike seat heights for different individual heights are as follows:
- 5’10” – 6′ individual – 35″ – 39″ seat height
- 5’2″ – 5’8″ individual – 32″ to 38″ seat height
- 10 – 12 years – 26” – 32”
- 7 – 10 years – 21” – 28”
- 5 – 9 years – 17” – 21”
- 3 – 7 years – 50cc dirt bikes
Having looked at the different seat heights, next the million-dollar question would be, is it possible to adjust a dirt bike’s seat size? Yes, it is very much possible.
Perhaps you might be interested in a specific brand or you’ve landed an incredible deal with a second-hand bike but you’re having an issue with the seat size. In such a case, you can settle for the bike and then adjust the seat height to meet your specific height.
Different methods can adjust (lower or increase) the height. To reduce the height of a seat, here’s what you need to do:
- Cut the foam – Cutting the seat foam reduces its height. Nonetheless, avoid cutting it too much as you’ll make the seat hard and uncomfortable. Just stick to reductions of around 0.5 inches to 1.5 inches. Anything more than this will make the seat uncomfortable.
- Use softer foam – The use of softer foam is preferred by those who aren’t comfortable with slicing or cutting the foam. Choose the type of foam that compresses more as this ensures your riding experience is comfortable.
To increase the height of a seat, here’s what you need to do:
- Use harder seat foam – This is the opposite of using softer foam. A harder seat form, rather than reduce the seat height, increases it by roughly one to two inches.
- Consider sag setting – Sag setting simply entails adjusting the rear suspension’s sag setting to a higher level. Although it might have minimal effect on your bike’s steering, it is nothing serious.
Bike Size Based on Weight
Regardless of your height and weight, whether you’re a small or big boy/girl, you should have fun riding your dirt bike. What is for sure is that dirt bikes are powerful and can accommodate most heights. The different engine levels and/or sizes can accommodate less or more weight. However, there is more than meets the eye in terms of weight.
Do you know that these bikes can handle riders weighing as much as 320lbs? however, here’s the deal, if you exceed the aforementioned weight limit, customizing your bike’s suspension might be necessary.
Note: The amount of weight your bike can accommodate depends solely on its overall power and build.
The 3 major factors that inform the amount a bike can handle can be summarized into these three factors:
- A bikes engine cc
- Whether the engine is four or two-stroke
- The bike’s frame and weight
In terms of the cubic centimeters of a bike, every pound you weigh translates to you requiring one cc of power for the bike to move around if you’re considering a 2-stroke bike. What this means is that if you are let’s say 200lbs, you need to choose a 210cc – 250cc, 2-stroke bike.
The golden rule to always remember is that 4-strokes boast a little more power compared to 2-strokes. They are double the power of 2-strokes. Therefore, those around 200 pounds, will need a 400cc, 4-stroke bike. Get the drift?
The most important thing is to settle for a bike with adequate power to provide ample support over the hills and across trails without giving you a hard time controlling.
4 or 2-Stroke
Heavier riders should settle for 4-stroke bikes as they have more power to handle the weight. The only thing they’ll be sacrificing by settling for a 4-stroke instead of a 2-stroke is speed as the former is slower compared to the latter.
Frame and weight
When it comes to a bike’s frame weight and height, the more weight a bike has, the more it can support it. For instance, some motocross dirt bikes boast the ability to handle up to 240lbs in terms of weight.
There is more to a bike’s weight in terms of how strong or otherwise it is. Its frame is equally important. For this reason, heavier riders should purpose to settle for bikes with a strong frame such as those made of aluminum or steel. Heavier riders should opt for steel frames compared to aluminum ones.
Do you know that by altering the suspension of your bike you can make it support more weight? Just try altering the front fork and you’ll notice that your bike will support your weight in a better way. Most bikes have an ‘S’ and ‘H’ on their fork. They stand for soft and hard respectively.
When you adjust your bike’s fork towards the H side makes it efficient for bigger bumps on trails. On the other hand, adjusting it towards the soft side is better for the smaller rough bumps.
Another important thing or fact that you need to appreciate is that a rider’s weight affects their bike’s performance. Generally, lighter riders enjoy faster rides compared to their heavier counterparts. Nonetheless, this does not put into consideration experience and skill.
The overall observation is that heavier weight on a dirt bike results in more strain on a bike. Over time, replacing wheel shocks at the back or altering the bike’s suspension becomes the order of the day with heavier riders.