weight of steering when engine off

[macafee2]

When the engine is off the steering is very heavy, remember those times when cars did not have power steering?

How much of the resistance as a rough % is the weight of the car via the tyres onto the road and how much is it the power steering system?

macafee2

[oswestryalex]

As a 'feel' from a car on ramps and turning the wheel, I would say 50% - but that is no more than a gut level guess.

[rrobson]

Depends on which engine the cars got. The diesel and v6 will have a higher percentage on the front axle than the 1.8's but they definitely aren't a car that has a 50/50 weight distribution. Also depends on how much fuel you've got in it as well!!

Realistically though it's probably going to be 60-65% of the weight of the car on the front wheels

[macafee2]

not so much weight I'm after but the amount of resistance you feel when turning the steering wheel with the engine off. How much of that resistance is car to road and how much is it the power steering being forced?

macafee2

[klarzy]

Remember non power steering is geared differently as well so will take less muscle to turn....

[hogweed]

Possibly not a particularly useful observation, but way back in the days (25 years ago) when old Hogweed was an arrogant young(ish) salesman hurtling around the countryside in a bright red Astra GSI 16V, one day a power steering hose burst.

The car had very fat tyres, and a small steering wheel. It was virtually un-drivable – just about manageable if you kept the speed up, but impossible at very low speeds. You really felt like the steering wheel was going to break off trying to turn the car at walking pace :eek:

[macafee2]

Reason for my question, I was always taught not to turn the steering wheel when stationary as it puts a lot of strain on the steering components and can damage what is beneath the wheels.
I'm trying to gauge how much of the steering resistance of our cars with the engine off
is due to contact with road and steering components but not including power steering components.

I seem to recall our Ford Escort Hatchback and Orion were heavy as neither had power steering

macafee2

[wullie480]

You could maybe try and work it out but would depend on different factors.

You could jack car up so wheels are off the ground and with airbag removed use a torque gauge to turn wheels or maybe a force gauge on the wheel to see what force is required to move the wheel. This would give you the pressure required for steering alone. Repeat the same with wheels on ground and that would give you the force required to move the wheels deduct the force of the steering alone and you may have the answer your looking for.
It’ll differ from car to car depending on engine type,tyre make,tread depth road condition, even mileage on the components themselves etc.

[topman]

Seems to me if you wanted to know, you'd have to use a push-pull gauge. Attach the gauge to the steering wheel. Move the steering wheel x amount of degrees then do the same with the engine running. That would tell you the difference.

[HarryM1BYT]

not so much weight I'm after but the amount of resistance you feel when turning the steering wheel with the engine off. How much of that resistance is car to road and how much is it the power steering being forced?

macafee2

Easy....

Take the weight off the tyres by jacking it up it, you will then find it turns fairly easily. None power steering heavy cars, tended to have more turns lock to lock, to give more leverage. I still managed to nearly rip my shoulder out parking Granadas with no power steering.

[roverbarmy]

Reason for my question, I was always taught not to turn the steering wheel when stationary as it puts a lot of strain on the steering components and can damage what is beneath the wheels.
macafee2
Agreed. As an ex HGV man with years of driving with no power steering (big shoulders!) you get into a habit of only steering whilst moving, even rocking back and forth when manoeuvering in tight spaces!;) It makes me cringe when I see folks spinning the steering whilst stationary.:duh:

[macafee2]

Seems to me if you wanted to know, you'd have to use a push-pull gauge. Attach the gauge to the steering wheel. Move the steering wheel x amount of degrees then do the same with the engine running. That would tell you the difference.

I'm just looking for a rough idea and thought someone may know.
If I did not want to know I would not have asked.
I have no idea how much resistance power steering adds if any when the engine is not running
macafee2

[Al_B]

Jack the front up and pop the airbag out of the steering wheel. Then use a torque wrench to turn the wheel via the column nut. Starting off at the lowest setting and winding it up until it just doesn't click will give you the torque required. Then drop the car back on the ground and do it again to get the loaded reading. Simples.

Many modern cars use quite aggressive suspension and steering geometry which relies heavily on the power steering to control kick back and reduce the effort to manageable levels. Some years ago a customer had a power steering belt fail on a prestige car and was about to sue the manufacturer claiming the car was unsafe in the event of such a minor issue. The company responded by getting them to drive one of the development cars which had variable assistance and demonstrated that control was retained, albeit at increased effort. (as told to me by one fo the engineers)

[T-Cut]

Reason for my question, I was always taught not to turn the steering wheel when stationary as it puts a lot of strain on the steering components and can damage what is beneath the wheels. I'm trying to gauge how much of the steering resistance of our cars with the engine off is due to contact with road and steering components but not including power steering components.

Surely, the strain on the steering components as a whole is no different whether the engine's running or not? The effort needed to turn the tyres against the road surface is the same, so every component shares proportionately in that. The essential difference is in the effort you expend in turning the steering wheel. From that point down, the energy consumed is always the same. With the engine running, it provides most of the energy that you supply when it's off. The steering components are none the wiser - if you see what I mean. Watch the tyres when the steering's turned to full lock, when stationary/engine running. Lots of stressing and straining down there. I guess the rack/pinion gear is under a lower load, but that's all.

TC

[topman]

I'm just looking for a rough idea and thought someone may know.
If I did not want to know I would not have asked.
I have no idea how much resistance power steering adds if any when the engine is not running
macafee2

I'm just suggesting a way to find out for yourself if you are unable to find out the answer. Only reason I suggest a way to diy it is, it's not really something people would measure themselves. :}

[macafee2]

I'm just suggesting a way to find out for yourself if you are unable to find out the answer. Only reason I suggest a way to diy it is, it's not really something people would measure themselves. :}

not asking for an exact measurement but there are some very cleaver people here with much more knowledge them me and perhaps from their years of experience may have an idea.

I'd hazard a guess of not less then 80% but that's based on memory of cars from 145 plus years ago

macafee2

[macafee2]

Surely, the strain on the steering components as a whole is no different whether the engine's running or not? The effort needed to turn the tyres against the road surface is the same, so every component shares proportionately in that. The essential difference is in the effort you expend in turning the steering wheel. From that point down, the energy consumed is always the same. With the engine running, it provides most of the energy that you supply when it's off. The steering components are none the wiser - if you see what I mean. Watch the tyres when the steering's turned to full lock, when stationary/engine running. Lots of stressing and straining down there. I guess the rack/pinion gear is under a lower load, but that's all.

TC


I'd kind of go with rack and pinion too. The rest of what you say is over my head

macafee2

[HarryM1BYT]

I'd kind of go with rack and pinion too. The rest of what you say is over my head

macafee2

The power assistance occurs at the rack itself, so with engine off and no assistance its unlikely muscle power alone would be putting as much strain on the rack + ball joints etc. as would occur with power assistance working [1].

What would come under much greater strain is the steering wheel and the parts between it as far as the rack.

[1] My Granadas with no PAS - I was unable to turn the steering wheel unless the car was rolling.

Knowing how much strain is involved, even with PAS, I make a point of trying to ensure a vehicle is moving before turning the steering wheel.

[macafee2]

I don't think people realise how much strain the steering and tyres are under due to power steering.

macafee2

[slovcan]

I don't think people realise how much strain the steering and tyres are under due to power steering.

macafee2

I don't think the steering and tires are under any more strain whether standard steering, power steering engine on or engine off. The effort to turn the steering wheel of a power steering equipped car with the engine off is likely 3 or 4 times more than a standard steering car because of the resistance of the dead hydraulic system. Hydraulic fluid is non-compressible so in order for the wheels to turn the fluid must move in the system. Engine running the power steering pump does this job. With the engine off the driver must put in enough effort to push the hydraulic fluid through the little ports, passages & valves.

Cheers,
Glenn

[HarryM1BYT]

With the engine off the driver must put in enough effort to push the hydraulic fluid through the little ports, passages & valves.

Cheers,
Glenn

As already explained, the hydraulic load is minimal when compared to the massive effort needed to overcome the friction between road and tyre with the engine off.

If you doubt that, raise the front of the car off the ground, then notice how easily the steering wheel can be turned without the tyre friction.