Gear ration confirmation..........
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
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From: SANTA CRUZ CA
Gear ratio confirmation..........
I read the following link regarding how gear ratio relates to speed and torque. Based on the explanations, I'm of the understanding that a vette with a 3:31 rear gear ratio will have less torque than a vette with a 2:59 ratio.... all other factors (HP, weight, etc.) being equal. Am I correct, or do I have it backwards?
http://wiki.answers.com/Q/How_does_g...eed_and_torque
http://wiki.answers.com/Q/How_does_g...eed_and_torque
Last edited by don hall; Apr 24, 2013 at 04:24 PM.
Drifting
Joined: Oct 2004
Posts: 1,477
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From: Hawaii
Thread Starter
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Racer
Joined: Aug 2009
Posts: 337
Likes: 6
From: Kanata ON
Just think about the math 
These are important relationships:
power = torque x speed
acceleration = force / mass
In the case of an ideal car the force is (or more correctly is proportional to) torque and thus acceleration is also proportional to torque.
So if power is constant then when speed goes down (that's what the x:1 ratio means -- x turns of the input shaft per turn of the output shaft) torque goes up. So assuming a 1:1 transmission ratio an engine putting out 330 ft. lb at the crank going through a 3.31:1 ratio differential is going to be putting down 1,091 ft. lb. at the wheels (ideally half to each). That same engine torque with the 2.59:1 diff would work out to only 855 ft. lb at the wheels.
That's probably more than you wanted to know but helps explain, amongst other things, why torque is important.
These are important relationships:
power = torque x speed
acceleration = force / mass
In the case of an ideal car the force is (or more correctly is proportional to) torque and thus acceleration is also proportional to torque.
So if power is constant then when speed goes down (that's what the x:1 ratio means -- x turns of the input shaft per turn of the output shaft) torque goes up. So assuming a 1:1 transmission ratio an engine putting out 330 ft. lb at the crank going through a 3.31:1 ratio differential is going to be putting down 1,091 ft. lb. at the wheels (ideally half to each). That same engine torque with the 2.59:1 diff would work out to only 855 ft. lb at the wheels.
That's probably more than you wanted to know but helps explain, amongst other things, why torque is important.
