Many motorcycles have their front wheels, be it an alloy wheel or spoke wheel, are bigger and larger in diameter, whereas the rear wheels are smaller in diameter. In addition, the front tyre will be skinnier and rear one wider in these motorcycles.
So, why do there is a difference in the motorcycle wheel sizes? Front wheels are bigger and have skinnier tyres to provide easier steering and maneuverability. Rear wheels are smaller and have wide tyres since they have better traction, stability, heat dissipation, and load carrying capacity.
Let us look into the reasons why motorcycles have bigger and skinnier front wheels, and the rear wheels smaller and wide tyres.
Why Front Wheels Are Bigger In Motorcycles
While the front wheel is mainly used for handling and steering, the rear wheel’s main functionality includes power transfer, traction and stability.
The power generated in the engine is transferred to the rear wheel through chain drive. The motorcycle moves mainly becomes the rear wheel pushes the motorcycle. The front wheel, on the hand, steers the motorcycle towards which direction to move.
No matter the model or the cc of the motorcycle, the rider always handles and steers the bike through the handlebar and the front wheel. The steering of the front wheel guides the motorcycle to move in the direction intended by the rider.
Now, since front wheel is responsible for handling and steering the motorcycle, it should be easier for the bike rider to handle the front wheel easily and in smooth manner.
And that’s why large wheels and skinnier tyres in the front of motorcycle comes in handy. When front wheels have large diameter and the tyres are skinnier, the steering becomes easier for the rider and the motorcycle can easily be guided towers the intended direction.
In addition, skinnier and larger wheels are less sensitive to rough roads and terrain. Even in such harsh road conditions, front wheels will provide better stability because they have larger diameter and skinnier tyres.
On the other hand, if the front wheels were smaller and are fitted with wide tyres, then on the rough roads and terrain, the rider will face difficulties in the handling and steering of the motorcycle. Also, the stability will be decreased since the impact of the rough road is heavily felt on the handlebar for the rider through the wide front wheel.
Why Rear Wheels Are Smaller In Diameter
Now, we understood why front wheels need to be larger and have skinnier tyres in the previous section. But, what’s the need for the rear wheels to be smaller in diameter and their tyre being wider?
As discussed earlier, while front wheel in a motorcycle is used for handling and steering the motorcycle, rear wheel’s main function is to sustain the load from the engine and move the motorcycle forward. The power gets transmitted from the engine to the rear wheel through the chain drive.
Since, rear wheel is the one that drives the motorcycle forward, the wheel should possess good stability and must have solid traction with the road surface. In addition, the tyre should also dissipate heat fast.
For these reasons, to provide better stability, traction, and heat dissipation, the rear wheel of a motorcycle will usually be smaller with wide tyre.
Front Tyres Are Skinnier And Rear Tyres Are Wider
Whenever you accelerate your motorcycle, the load will be transferred to the rear wheel first. The engine power is transferred to the rear wheel which gets the rear tyre moving and only after the rear wheel starts moving do the load gets transferred to the front wheel.
The rear wheel will always be under more stress and overloaded when compared to the front wheel. As a result, the rear tyre would need better and more traction from the surface.
Since rear tyres need more traction and larger contact surface area with the road, the rear tyres are usually wider than the front tyres. That’s why rear tyres are typically wider and since front tyres do not require that much traction, they will be skinnier.
Another important aspect is the optimum operating temperature. Tyres have an optimum operating temperature beyond which the tyre will not be functioning properly.
Since rear tyres are subjected more loads and are under more stress, the heat generated in the tyre will be much higher. In order to not exceed the optimum operating temperature of the tyre, the heat generated should be dissipated from the tyre easily.
And for the heat dissipation to take place faster, the rear tyre should have larger contact surface area. Hence, the need for a wider tyre in the rear end of the motorcycle.
Advantages Of Different Sized Wheels In A Motorcycle
Now that we know why the front wheel of a motorcycle is bigger and has skinnier tyre and why the rear wheel is smaller with wider tyre, let us look into the advantages these different sized wheels provide to a motorcycle.
#1. Better Acceleration
Rear wheel is the one that carries load and power from the engine through the chain drive. It powers the motorcycle to move forward.
Whenever, you accelerate the motorcycle, the rear wheel increases its speed and pushed the motorcycle at a higher velocity owing to the additional power obtained from the engine.
If the rear wheel is smaller with wide tyre, the stability, the traction and the load carrying will be much better and as a result, the motorcycle will be able to accelerate in a much more efficient manner.
#2. Easier Turning and Cornering
If you are turning or cornering at a high speed in your bike, the turning radius and the area over which the motorcycle is using for the turn will reduce when you have this combination of different sized wheels in your motorcycle.
This lower turn radius results smoother turning and cornering with decreased chances of falling down from the bike.
#3. Better Load Carrying Capacity
Most of the load applied on the motorcycle will be carried by the rear wheel. The motorcycles are designed that way since front wheel is necessary to have a free play for smooth handling and steering for the rider.
And when the rear wheel has a wide tyre, the traction and stability is substantially improved, thus, improving the load carrying capacity of the rear wheel.
Do All Motorcycles Have Different Sized Wheels?
Not all motorcycles have different sized wheels. Lower cc motorcycles, which does not reach high speeds, have their rear wheels almost same in size as the front wheel and their tyre not much wider.
While the different sized wheels do provide some advantages with a skinny front tyre and wide rear tyre, it not a mandatory design specification and is not seen in all the motorcycle models.
Different manufacturers have different wheel size specifications according to what’s best for that specific model. That’s why, while changing the tyre it is advised to not change the tyre width and stick to the manufacturer’s recommendation.
Skinny Tyres Vs Wide Tyres – Which Tyres Are Best?
Both tyres provide distinct set of advantages. However, wide tires are typically considered better since they provide better traction, road grip, speed handling, stability, off road driving, and braking effectiveness.
Skinny tires do have their advantages like low cost, high mileage, and easier maneuverability.
Since wide tyres offer better traction, stability and speed handling, rear wheels typically have wide tyres. And since skinny tyres provide easier steering and maneuverability, front wheels usually have skinny tyres.