# By approximately what ratio does power steering (on a car) amplify the torque applied?

Power steering on a car is a form of torque amplifier: the driver applies X Nm (or ftLb) of torque, and the power steering adds Y torque - but maintaining the same angle of turn. But what's the approximate ratio of Y:X for the power steering on a typical domestic car? Is it e.g 10:1 ?

• Too broad, some add more, some less, depends on the tire sizes and ratios so many answers possible. I have driven vehicles where a finger is all that is necessary others where it has minimal effect. – Solar Mike Jan 23 '20 at 9:42
• I'm just looking for an example number, or even a range of numbers. For a domestic car that range can't be too broad. – Richard Pawson Jan 23 '20 at 10:36
• I am writing something about historical use of torque amplifiers (not in automotive use) that multiplied the torque by 10,000:1. I want to compare this to the power steering on a car, which I am guessing is maybe between 10:1 and 100:1? I am just seeking some confirmation that I'm in the right ballpark. – Richard Pawson Jan 23 '20 at 10:50
• You should just be able to measure this with your car and a protractor. Start with your tires straight, turn the steering wheel 180 or 360 degrees, see how much your tires have turned. Figure out how many turns of your steering wheel it would take to rotate your tires 360 degrees, this angular displacement reduction ratio is the same as your torque increase ratio (power in = power out = torque x displacement / time). – jko Jan 23 '20 at 13:16
• Older Chrysler products required about zero effort ; I believe they have changed as many did not like "no" road feel. – blacksmith37 Jan 23 '20 at 15:15