Dirt Bike Gearing: (Explained For Beginners)

If you have any issues with the gearing on your dirt bike, then having an understanding of how it works is going to aid you and make it easier for you to fix the issue.

The single most essential thing to grasp is what differentiates a dirt bike from other types of bikes, specifically normal bikes. Now that we have that out of the way, let’s speak about the inner workings of a dirt bike gearbox, shall we?

It would be a great pain if something were to break inside the bike while you were using it because it would disrupt your ride.

If you have a solid understanding of how each tool operates, it will be much simpler for you to determine what the issue is with the dirt bike. My point of view is that it is not enough to be able to ride a dirt bike; you also need to have a solid understanding of how to keep it in good condition and make repairs to it.

When you get out of a situation where no one else can help you, you may feel relieved. You need to have an understanding of how a gearbox functions on the inside and how it functions in order to have an understanding of how it functions on the outside.

Gearing plays an important role while doing different stunts on dirt bikes. One of the most popular stunts is the whip, and I have written a separate article on this, which you can read how to whip a dirt bike by clicking here.

What is a Gearbox in a dirt bike?

When we talk about the Gearbox, it cannot be evident for a beginner because engineers and designers use many synonyms.

The Gearbox is also named a gear reducer and gear head.

So now, here we will talk about the basic definition of a gearbox, and that is “Gearbox is a component that consists of a series of integrated gears. It is inside a housing.”

Mainly Gearbox works like a system of gears that functions to alter the torque between a driving component and a load. Here we suppose a motor as the driving component.

The gears used inside a gearbox can be of different types, such as bevel gears, spiral gears, planetary gears, and worm gears. The gear is mounted on a shaft.

A rotating bearing rotates this shaft.

It is a mechanical method used to transfer the energy from one component to another component, resulting in an increase in torque and a decrease in speed, and vice versa.

Types of gearbox:

  • Constant-mesh gearbox
  • Sliding mesh gearbox
  • Synchromesh gearbox

Structure of a Gearbox

A gearbox consists of a driving gear with a particular diameter connected to the driving mechanism linked to another gear of larger and smaller diameter coupled to a driven mechanical load.

If the driving gear is linked with the smaller gear of size, then the driving mechanism will have a higher speed than the driving one.

And if the diameter will be more significant of the gear, then the rate of the driving mechanism will be lower than the driven one.

The Gearbox system and mechanism are used for achieving speed and torque.

If the dirt bike is going to move on an upward path, it will require higher torque, which can be achieved by lowering the speed at the same power. When the bike requires less torque, then the rate can be increased with the same power.

How Does Dirt Bike Gearing Work

how does dirt bike gearing work

In a gearbox, there are different sizes of gears assembled. For getting different speeds, it needs to have gears of many sizes.

While running a bike, sometimes it requires high torque, and in that situation, getting high torque speed is decreased, and torque is increased.

And when a rider wants to increase speed, then torque is decreased, and hence speed increases.

For example, when the slop is high while riding, then the bike requires high torque for this, and then you need to shift to first or 2nd gear, then your speed is low, and now torque increases.

Inside a gearbox, the enormous size of the gear produces maximum torque, and it is the first gear.

And then, as you go up like 2,3,4 in sequence, the gear sizes will decrease in a row.

In simple words, when the engine starts, it transmits the power to driving gear which is mounted on a shaft, and then according to your choice of gear, driving gear engages with driven gear, and then this rotates, and hence connected wheels also rotate.

Dirt Bike Gearing Working Principle:

If we talk about the Gearbox, you need to know that there are two gears in a conventional gearbox. One of them is input, and another one is output.

Then output gears are mounted on the counter-shaft and creating a single unit. This counter-shaft drives the individual gears on the main shaft. Hence shaft here rotates on the bearings.

The gearbox arrangement passes the power to drive the wheels. The speed depends upon the gear which is selected and engages in the main shaft.

When you push the lever of gear, then according to your selection, that gear locks to the main shaft and rotates it by giving its power. Hence the main shaft rotates at the speed of the engaged gear you have selected, and this provides the output power according to the engaged gear ratio.

We are here giving the information about the gear ratio in a gearbox. So first of all, you need to understand what is the gear ratio.

We are here giving the information about the gear ratio in a gearbox. So first of all, you need to understand what is the gear ratio.

What is Overdrive?

In short, the top gear or the final gear is the smallest in size. This gear provides the minimum traction and maximum speed. When we say overdrive for a gearbox means.

In simple words, the gear rotates faster than the speed of the engine, which provides a better efficiency to run the vehicle quickly.

In the advanced technology dirt bikes, more than one Overdrive gears used to and it’s normal.

Hence the dual overdrive provides better efficiency and higher speed in a dirt bike.

Overdrive means the output will be higher than its input.

As we will talk about gear ratio, then you can clearly understand it. More giant gears provide less speed but a higher traction power ride

What is the Gear Ratio?

Gear Ratio is the ratio between the input and output gears. As we have already discussed, two types of gears work in a gearbox that is driving gear and driven gear, which defines the ratio.

The input gears get the engine’s rotation and rotate the output gears when they turn and the wheels spin.

The ratio of the number of rotations of earth put gear with the number of course of input gear is called the gear ratio.

Formula to understand gear ratio in terms of the number of teeth in gear.

Gear Ratio = Number of teeth of output gear/Number of teeth of the input gear

Assume there are two gears, input and output. No of teeth in input gear=40, No of teeth in output gear=120

Let’s say there are two gears, one for input and one for output. There are 40 teeth in the input gear, and there are 120 teeth in the output gear.

Therefore, the gear ratio is 120 / 40, which equals 3:1. This indicates that the output gear will complete one rotation while the input gear, which is driving, spins three times.

How Many Gears Are There Inside A Dirt Bike Gearbox

When we talk about the gears that can be found on dirt bikes, there are a lot of different kinds of dirt bikes that come with them. Having said that, the overwhelming majority of dirt bikes are outfitted with five different gears. These days, the most contemporary vehicles almost always come standard with a six-speed transmission.

When shifting gears on a dirt bike, almost all of them have the same layout of gears, which consists of first gear at the bottom, followed by neutral, then second gear, and so on. If you have a dirt bike and don’t know how to locate the neutral gear, then this article will help you rapidly fix that problem.

  • Sixth Gear
  • Fifth gear
  • Fourth gear
  • Third gear
  • Second Gear
  • Neutral
  • First gear

Gearbox: Speed vs Torque

If you are a dirt bike rider, you can understand the importance of speed and traction both because both are essential for driving. The gear inside a gearbox provides you the power to decide on what rate you want to go.

According to the condition of the track, you choose the gear. There are many times you need to climb a higher way and have a slope, and then you need to shift into the first or second gear to provide maximum torque that will pull your bike upward.

But in a flat track, you can increase your speed by shifting into the fifth or sixth gear.

The number of gears inside a gearbox gives you a collective combination of torque and acceleration. Dirt bike helps you drive by your decision to get 100% of output according to the situation.

You can ride your bike on a sloppy surface taking throttle using first or second gear.

For bikes which gears are used?

  • Sliding mesh
  • Sliding Mesh is Generally used in two-wheeler/bikes.

Final words

Just riding is not enough for a beginner but understanding all the systems of a two-wheeler is very important. It can be an extra advantage if you know all the systems and their processes.

So here in this article, we have discussed how dirt bike gear works.

I hope that this article has given you enough information to help you fully understand how a gearbox works and how it does its job.

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