Why in cars or motorcycles front brakes are big as compared to rear & fat rear tyre as compared to front?

Question

I have seen in most vehicles Big brakes at the front and big tyres at the rear.

Answer 1

Ok.
For you to be able to immagine the situation,I give an example.
Immagine you are driving 60 mph and suddenly there is a Rhino in the middle of the road.
You hit the brakes right,and your nose almost touches the windsheild.
Why that happenned?
It's the act of Inertia.
Inertia is something that like its current condition.
When the object is moving, its inertia resists any stoping force( that's why when you suddenly hit the brakes your body tends to move forward.your body's inertia still wants to keep you moving forward).When the object is not moving, its inertia resists any driving force(That's why if you sit in a supersport car, you feel you are being pushed into your seat when the car accelerates. that's your inertia pushing you back and resisting the driving force of the car)

Now The car also have the same inertia, When you hit the brakes, a large inertia is still pushing the car forward, so the car is said to nose dive, this exerts a higher force on the front axis compared to the rear axis.So the front brakes need to be stronger to be able to fight the huge force in the front so that you won't be fined for hitting and ijuring a rear type of rhino.
Likewise, when the cars accelerate, a huge force is on the rear asis and thus on the rear tires.
Have you seen "The Fast and The Furious 1".In the last scene, Van Diesel steps on the Black Camaro and the car nose flys up.
Now you can immagine what a huge force is exertec on the rear tires when accelerating..The bigger the tires, the bigger the friction surface between the tire and asphalt would be and consequently the friction force will be bigger. Bigger friction force means faster acceleration and less traction.
But this case is only true when the car is rear wheel drive. Front wheel drive cars don't need such huge tires. What you have seen is most probably in supersports such as McL F1, Ferrari Enzo and Lambo Murcielego. That is correct, Super cars are either RWD or AWD.(Alfa is an exception)
Now you may ask why not put same size of rear tires in front to increase the stability of the car in cornering?
While huge tires are good in terms of stability and transferring the engin force to the asphalt surface, they are really bad if used in the front.
They decrease the aerodynamic of the car and exert an extra resisting focr on the steering wheel.

Answer 2

Traction is from the rear tires, thus the bigger the more traction. Brakes need bigger at the front because when stopping, the vehicle dips at the front. Big brakes at the rear will just skid, as there is less weight on the rear tires. 70% of braking is done from the front, on cars. On bikes the rear brake is the main, and the front applied carefully, or you run the risk of skidding the front tire. Bad idea.

Answer 3

As with any vehicle the bigger brakes in the front is because the front brakes provide over 70% of the stopping force (changing kenetic energy to heat energy).
Depending on the application, larger tires on the rear give more contact area on the pavement providing better "grip" or traction when accelerating (rear wheel drive vehicles).

Answer 4

When you stop the weight of the car shifts forward, so the front brakes carry the majority of the breaking load, conversely under acceleration the weight shifts to the back, so the back tires carry the weight and plant the power. The big back tires only help on a rear wheel drive car.

Answer 5

type, frequently. Rear tires are generally a splash wider, because of the different techniques expressed right here.....yet.... the largest clarification for those quite fat rear tires is only ordinary seems. an exceedingly fat tire only does no longer turn contained in an analogous way a slender one does. It makes the rear sluggish. potential? no longer the real reason in any respect. maximum of your braking potential is......the front wheel. as a replace of putting down the potential, this is doing the opposite - on an analogous fee or extra powerful. lots of the older cycles (and the somewhat some extra moderen) run an analogous length on the two ends. HD traveling motorcycles are a solid occasion. there is others.

Answer 6

Big tires on rear for traction from the rear wheel drive and weight shifting back on acceleration while weight shifts forward on braking so bigger brake on front is needed (in extreme cases the rear wheel(s) have no braking effect.

Answer 7

when you brake, the vehicle will nose dive putting weight onto the front. hence larger braking swept areas are required.

rear wheel drive generaly have wider tyres on the driven axel.