Why do tractors have rear wheels big and front are small?

Question

Why do tractors have rear wheels big and front are small?

Answer 1

the above answers are good, however, none of them answer why are the front tires smaller.  The front wheels are smaller because they are cheaper. much in the same way as a lot of older tractors had only 3 wheels. Also, the smaller wheels can make a tighter turn, because they a big tire would hit the engine at full lock. If you look at some of the big 4wd tractors you will notice that they have the same size wheels in the front and back, but they are articulated (meaning that the wheels don't pivot for steering, but the tractor is hinged in the middle like a skidder or large wheel loader)

Answer 2

Thats because the rear wheels are the ones with power going to them. They have to have big tread to dig into the ground and also be pretty big because the wheels aren't made to spin fast....if they were the same size as the front wheels it would take a lot more to get them to spin fast enough to get the tractor up to speed... watch the tires, the small front ones spin a lot faster than the back ones because the back ones are bigger.

The front tires have no power to them. They are basically along for the ride... just something to hold up the front of the tractor lol.

Answer 3

Big tires to reduce the ground pressure.

If you have a lot of rubber they don't sink into the ground and get stuck. You don't pack the ground down as much either.

A large diameter wheel also rolls over small obstacles and holes like plough furrows easily.

When a tractor is working properly all of the weight is on the rear wheels. Sometimes when a tractor is being worked too hard you will see the front wheels actually lifting off the ground

Answer 4

1.  power and traction

2.  more surface area means less soil compaction

most new tractors are either 4 wheel drive or front wheel assist

also more models have a choice between wheels or tracks

Answer 5

The front wheels only need to bear the weight of the machine, and provide steering. The rear wheels have to provide pulling power, and Theyy have to be big enough to do so im heavy soils and mud, and to deliver the torqued power of a relatively small engine.

Answer 6

probably cuz it rear wheel drive!