What Exactly is Body Roll in Cars?

[EnfieldRyder]

Hi guys, I have a query, I have seen lot of people mention a so & so car has body roll or some other car doesn't. I tried to look for info on google but couldn't find proper info or maybe I didn't search properly. Could anyone please explain what exactly is this & what are the positives & negatives of this if any?

Thanks in advance

 

[raj_5004]

ok, imagine this.

you are in a sedan like civic or fiesta. you are approaching a corner. you take the corner (right turn) at speed. you feel a slight push towards left. the entire car tilts towards left.

now you are doing the same thing in an SUV like scorpio or safari, the tilt would be more.

this is what is known as body roll. attached 2 images-

 

[Surfer]

Wiki
On wheeled or tracked vehicles, body roll is a reference to the load transfer of a vehicle towards the outside of a turn. When a vehicle is fitted with a suspension package, it works to keep the wheels or tracks in contact with the road, providing grip for the driver of vehicle to control its direction. This suspension is compliant to some degree, allowing the vehicle body, which sits upon the suspension, to lean in the direction of the perceived centrifugal force acting upon the car. Anti-roll bars are a part of the suspension specifically designed to address body roll.

When a vehicle is fitted with a suspension there is compliance between the mass of the vehicle and the vehicle's contact with the ground. Body roll is the noticeable (either perceived or measureable) deflection produced when load transfer acts on the compliant elements of the suspension. Anti-roll bars directly impact body roll but their design intent is actually as a tool to adjust roll couple percentage or roll moment distribution.

Ke70 Skid Pan - HMAS Body-Roll - YouTube

 

[EnfieldRyder]

Thanks for the info guys, I now understand what exactly body roll is :)

 

[TSIVipul]

@Enfieldryder:
Body roll is something that every car comes with,in fact you may call it a standard feature on every car from a Tata Nano to Bugatti Veyron,only difference is of its amount.

Actually center of gravity and suspension of the car,both plays a good role here in case of body role.Just see,if the suspension has long travel and the center of gravity is high,then on the turns that center of gravity will shift to outside(centrifugal force)and hence the suspension from inner side will open up and that on the outer will be pressed and hence tilting the body.
In case the travel of suspension is less than the shift of center of gravity then the car really rolls down and gets overturned..remember seeing overturned Omnis and Safaris too overturn a lot.Why?Both of them have a high center of gravity(Safari has massive weight too)and suspension travel isn't long enough to tackle hard steering inputs.
In case of sport cars,the center of gravity is low and suspension is tight and has quite good travel too and hence they never overturn...

I mean that the body roll is nothing but the tendency of a car to try to overturn on the turns,while suspension tries to prevent it by making the vehicle tilted.

 

[Tornado]

Spain Train Crash: CCTV Footage | Tren Descarrila en Santiago de Compostela: Camara de Seguridad - YouTube

Isn't this body roll ?

One question - Aren't these trains equipped with ESP ? I mean , whether ESP concept exists in trains ?

 

[Dr. AMITABH JAYASWAL]

So, what is good? I mean what prevents turning turtle? A vehicle with a larger value of BODY ROLL or vehicle with a lesser Body Roll?

 

[carcommentor]

So, what is good? I mean what prevents turning turtle? A vehicle with a larger value of BODY ROLL or vehicle with a lesser Body Roll?

Lower value of body roll is good. Larger value of body roll means the vehicle has greater probability of falling on to it's side. Turning turtle is rare with just body roll.

 

[Nanofreak]

So, what is good? I mean what prevents turning turtle? A vehicle with a larger value of BODY ROLL or vehicle with a lesser Body Roll?

Most cars with higher CG (center of gravity) meaning hatchback like Nano, Ritz, Santo, (mainly tall boys) and SUV's like Scorpio, Sumo etc are more prone to body roll, so to counter this effect, manufacturers attach Anti-roll bars between the front suspension, and high end cars have them in the back also.