some unanwered queries ... - Team-BHP

narayan · 17th July 2007, 19:25

i guess some of u would have perceived these when ur driving/driven or watching other cars on road...ok heres wat i wanted to know...

why is it that the perception of acceleration is more when ur in the rear seat of a car than in the front seat ?

why does a car's rear sits down ( squats ) when u have a quick get away from a stationary position...? ( i can understand this phenomenon in a rear wheel driven car bcos the torque goes to rear axle and the tires bite onto the road and so the rear dips - but the same happens even in a front wheel drive )

am not sure , but i feel the above 2 phenomenon could be related also ?

experts - pls share ur theories....

Gordon · 17th July 2007, 19:29

Quote:

why does a car's rear sits down ( squats ) when u have a quick get away from a stationary position...? ( i can understand this phenomenon in a rear wheel driven car bcos the torque goes to rear axle and the tires bite onto the road and so the rear dips - but the same happens even in a front wheel drive )

IMO,
The axle/engine/tyres are all attached to the chassis. The body is connected to the chassis via a suspension. So obviously when you floor the accelerator, because of simple physics, the rear should dip.

n_aditya · 17th July 2007, 19:35

In a front wheel drive when you suddenly accelerate, weight is transferred from the front to the rear. The power on the front wheels is high (or torque) that the front "lifts" slightly and shifts the weight to the car's rear.

Someone could explain this better i feel.

gr8guzzler · 17th July 2007, 19:38

Quote:

Originally Posted by narayan

why is it that the perception of acceleration is more when ur in the rear seat of a car than in the front seat ?

I think this is more psychological as when you drive you are in control and it does not seem that you are going fast as compared to sitting in the rear and watching at the same speeds. There might be a bit of physics too involved as I definitely feel more comfortable in the front passenger seat than in the rear.

narayan · 17th July 2007, 23:10

Quote:

Originally Posted by n_aditya

In a front wheel drive when you suddenly accelerate, weight is transferred from the front to the rear. The power on the front wheels is high (or torque) that the front "lifts" slightly and shifts the weight to the car's rear.

Someone could explain this better i feel.

ya - so the opposite shud happen in a rear wheel car ...but rear wheel cars wil have much more front lift and back squatting...
in fact some of the americal muscle cars use this principle to do wheelies...

CrAzY dRiVeR · 17th July 2007, 23:42

Guys,

Isn't there a simple answer to this- INERTIA?

In RWD cars, the front end is raised more because the lever arm is more (Distance from the fulcrum- In this case, where wheels are connected to chasis).

DieselFan · 18th July 2007, 09:47

Crazydriver is correct. It is inertia that impacts the back squatting when the car accelerates from stop suddenly or Front Dipping when we brake hard.

Gordon · 18th July 2007, 12:50

Quote:

Originally Posted by Gordon

IMO,
The axle/engine/tyres are all attached to the chassis. The body is connected to the chassis via a suspension. So obviously when you floor the accelerator, because of simple physics, the rear should dip.

Yes Inertia along with the above information is the reason.

17th July 2007, 19:25	#1 (permalink)
narayan BHPian Join Date: Aug 2006 Location: gurgaon Posts: 628 View My Garage	some unanwered queries ... i guess some of u would have perceived these when ur driving/driven or watching other cars on road...ok heres wat i wanted to know... why is it that the perception of acceleration is more when ur in the rear seat of a car than in the front seat ? why does a car's rear sits down ( squats ) when u have a quick get away from a stationary position...? ( i can understand this phenomenon in a rear wheel driven car bcos the torque goes to rear axle and the tires bite onto the road and so the rear dips - but the same happens even in a front wheel drive ) am not sure , but i feel the above 2 phenomenon could be related also ? experts - pls share ur theories....

17th July 2007, 23:42	#6 (permalink)
CrAzY dRiVeR Senior - BHPian Join Date: Jun 2006 Location: Temporarily out of coverage area... Posts: 3,031 View My Garage	Guys, Isn't there a simple answer to this- INERTIA? In RWD cars, the front end is raised more because the lever arm is more (Distance from the fulcrum- In this case, where wheels are connected to chasis). __________________ I'm far from perfect. I hope i can improve. Thats why i'm here! Last edited by CrAzY dRiVeR : 17th July 2007 at 23:49.

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17th July 2007, 19:35	#3 (permalink)
n_aditya Senior - BHPian Join Date: Oct 2005 Location: Currently at Chennai. Originally from Blore. Posts: 1,682	In a front wheel drive when you suddenly accelerate, weight is transferred from the front to the rear. The power on the front wheels is high (or torque) that the front "lifts" slightly and shifts the weight to the car's rear. Someone could explain this better i feel.

18th July 2007, 09:47	#7 (permalink)
DieselFan BHPian Join Date: Mar 2007 Location: Bangalore Posts: 457	Crazydriver is correct. It is inertia that impacts the back squatting when the car accelerates from stop suddenly or Front Dipping when we brake hard.