What are the extra set of wheels for on the rear of cement trucks.?

Question

These wheels can be folded up. I've seen trucks drive on the road with the wheels folded up or down on the road. I also noticed they can steer a bit.

Answer 1

This set of wheels is called a tag axle and is used or loweredwhen the cement truck is carrying a heavy load. This type of axle is also used on dump trucks and milk trucks

Answer 2

They are called Dollies
They are used for heavier loads and are working by air bags for the suspension on the dollies

They are operated by an air valve inside the cab or back by the wheels,With a heavy load they let the dollies down to help support the extra weight,they have a pressure gauge to adjust how much weight they want to help support.

For instance,,100psi to the air bags on the dollies may support 1000 pounds which takes weight off the front drive tires

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Answer 3

This is a guess; I think they are for when the truck is loaded with concrete, it takes some of the weight off the other wheels and axles.

Answer 4

they are actually called tag axles. they are for supporting the extra weight of the load. When they are up the truck is unloaded and down it is loaded to max. capacity. Dump trucks, garbage trucks and some semis have them.

Answer 5

Consider the extra weight when the truck is full!
If you were 4 times your present weight, you'd like extra legs, eh?
They have the ability to raise when empty load as to save wear & tear on tyres.

Simple, eh?

Answer 6

it for the heavier weight that they haul.. They can only have so much weight per axle.. So it is all about the weight