# How Does a Wheel Mechanically Propel a Car's Chassis?

• Curiously interested
In summary: So, no matter how you turn the wheel, the axle will stay in the same place relative to the other components of the car.
Curiously interested
I understand the basis behind the idea that a rotating wheel driven by an engine will generate torque and the static friction of the ground will push opposite to its direction forcing the tire to go forward. However, I can't seem to understand how the wheel can drag the chassis with it. Does the middle of the tire, which will follow a linear path if the tire rotates and drives along, push the wishbone? Is it the cv axle that push anything?because on a bicycle, when the tire rolls in front, the center of it, which follows a linear path, pushes the bike chassis. How does it work for a FWD car with suspension then?

If the wheel did not drag the chassis behind it - what would happen?

You seem to be able to follow what happens with a bicycle - it is exactly the same with a car with suspension except that the suspension springs change length during acceleration and braking. The wheels are attached to the chassis - how they are attached changes the characteristic of the motion.

The wheel pushes the axle, the axle pushes the bearing, the bearing pushes the suspension (upright & wishbone), the suspension pushes the chassis.

If there are no suspension, then the bearing pushes the chassis directly.

On your (non-powered) bicycle front wheel example, it's the opposite:

The chassis pushes the bearing, the bearing pushes the axle and the axle pushes the wheel. The tire-road friction causes the front wheel to roll as it moves forward.

On some non-powered wheel designs, the axle is fixed and the bearing is inside the wheel, such that:

The chassis pushes the axle, the axle pushes the bearing and the bearing pushes the wheel.

Cars don't have solid straight axles but cv axles (they bend). So my take is, if we take them off and turn the wheels with our hands instead of the engine, the hub/bearing assembly will push the knuckles which will push the wishbones and then the chassis.
Logical?

Curiously interested said:
Cars don't have solid straight axles but cv axles (they bend). So my take is, if we take them off and turn the wheels with our hands instead of the engine, the hub/bearing assembly will push the knuckles which will push the wishbones and then the chassis.
Logical?
Not only logical, that is what happen and what I described. The part of the CV axle that goes within the hub/bearing assembly is what I refer as the "axle". No matter the design, there must be a part of the axle that is connected to the wheel (to allow rotation) and another part of the axle that is connected to a bearing (to support the lateral forces); CV joints or solid axle.

Here is a solid live axle:

The axle (23) pushes on the bearing (20), the bearing (20) pushes on the differential casing which is actually part of the suspension.

Here is one for an independent suspension:

The axle (green) pushes on the bearings (orange), the bearings (orange) push the upright (yellow) that is part of the suspension.

Here is a more complex one for a front live axle that incorporate steering and a locking/unlocking feature:

The "rotating" axle (21) goes through the "fixed" axle (60) and connects to the disc brake (67) via the locking/unlocking mechanism (70-76). The disc brake (67) pushes on the bearings (66 & 69) which in turn push on the "fixed" axle (60). The "fixed" axle is solidly linked to the differential casing and steering mechanism.

## 1. What is a chassis?

A chassis is the framework or structure of a vehicle that supports and holds all of the components together. It is typically made of metal and serves as the foundation of the vehicle.

## 2. How does a chassis move?

A chassis moves through the use of its suspension system, which includes springs, shocks, and other components that absorb shock and allow for movement. The engine also plays a role in moving the chassis by powering the wheels.

## 3. What factors affect the movement of a chassis?

The weight and distribution of weight on the chassis, the type of suspension system being used, and the power and torque of the engine are all factors that can affect the movement of a chassis.

## 4. What is the role of the suspension system in chassis movement?

The suspension system is responsible for absorbing shock and keeping the wheels in contact with the ground, allowing for a smooth and controlled movement of the chassis. It also helps to maintain balance and stability while the vehicle is in motion.

## 5. Can the design of a chassis affect its movement?

Yes, the design of a chassis can greatly impact its movement. A well-designed chassis will have a strong and rigid frame, as well as a well-placed suspension system and weight distribution, all of which can contribute to better movement and handling of the vehicle.

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