Steering Wheel Going 'Round and 'Round

I regularly drive a race car that has a 'quick rack' on. (I'm talking an old Ford Capri, not a lightweight single seater) The 'lock to lock' movement on the steering wheel is 1 ¼ turns – standard is 2 ½. (I think!) I don't run power steering (uses valuable engine power) so at low speeds it's quite heavy – you wouldn't want to parallel park on a Saturday in town!

Advantages; - good 'feel' at speed, steering reacts quickly and positively to inputs when cornering, if the car gets out of shape at the back – over steer (yumyumyumyumhehehehehe….ahem…sorry), less input is needed to correct, with a standard rack, it's flailing arms and bruised thumbs time.

Disadvantages; - As I said, very heavy steering at low speeds, this can cause heavy wear on steering joints, pinions, racks etc. Always check these on an older car with power steering. (Not a worry on the track as minimum mileage is covered and constant maintenance is essential), and quite twitchy on the straights, if you sneeze you can swap lanes!

Bear in mind this a rear wheel drive car, and so has no torque steer or other driving forces through the steering.

Just a few points to consider.

Okay, that should have been obvious . I'm not a motorhead but if I were to design the things, I'd make them so that the initial steering ratio (is that the correct term?) is less when its near the center. That way, if I turn the wheel from center (straight driving), the car won't turn so quickly. As I turn the wheel more, the ratio gets higher.

I've heard about drive-by-wire where the steering wheel is not directly connected to the steering mechanism. It's driven by a servo motor or something. The steering wheel just tells the servo what position it should be in. Honda is one that makes these but they too, have the steering wheel going round several times. I thought it was an industry standard or something.

Ahhhh! I getcha!

Right, I'm not going into to much detail, but if you work out you're castor, camber and toe out/in angles for straight ahead, full lock right and full lock left, you will see that as a function of turning the wheel, the inside wheel, that is the wheel that has to travel less distance, turns more of an angle than the outer. This has the same effect, to a lesser degree. But to turn the wheels through more of an arc towards the end of the travel, for the same amount of steering movement, sounds a bit dodgy. I can imagine some interesting effects, especially in tight corners!

My road car is a Honda, and the power steering applies more force the greater the turning angle, is the effect you mentioned?

No, not power, ratio. I admit that, discussing this rather than just thinking about it, it now sounds a little impractical. However, if you drive with this steering system, you'll eventually get the hang of it. Might be a couple of fender benders along the way though.

Highway driving doesn't involve much turning of the steering wheel. It's low speed driving, like parking, swerving around obstacles, turning tight corners that requires large steering movements. At these low speeds, the change in ratio shouldn't be much of a problem since you should be able to make corrections before you hit anything (!).

I don't know about Formula 1 though. Their steering seems to be what I described (doesn't turn a full circle). Am I wrong or what? Can't find a technical description in their website.

Hi Vulcan,

Sounds to me like you want an analogue type of steering like you can set on PC Sims instead of linear. You could also set the sensitivity and vagueness of the whole thing. You could also put all those programmable buttons that sim wheels have and the buttons for gears up/down and the like. I don't know if you have ever tried to drive a serious sim with the steering set to analogue, but it gives an un-natural feel to the steering. A good linear setup with true feeling is what you need. Take a real Porsche for a drive. I'll think you'll find what reel steering should feel like.

But I do get your point. 270 degrees of rotation so your hands don't need to come off the wheel. See a power steering specialist, if you pay them enough money, they'll do whatever you like.

The concept of having a variable ratio steering rack was patented about 30 years ago by a fellow called Arthur Bishop. His company in Australia sells the technology world wide and specialises in car steering and manufacturing. His steering rack design increases the steering ratio by up to 40% between straight ahead and full lock. If you Google his name you should come up with a few references including his company aebishop.

For a few reasons not including steering pump or electronics failure the authorities prefer to have a mechanical link between the wheels and the steering wheels of vehicles. Vehicles that don't, such as articulated cranes and forklifts are speed limited to 60-75km/h depending on the transport authority involved.

F1 steering uses a very 'quick' rack. They can change the ratio's to suit the track. The 'longest' ratio they use is at Monaco because of the hairpin, there the whell turns nearly 360 lock to lock.

Hi: drive-by-wire is a good point. I know that NSK (bearing frictionless manufacturer) has this system available for cars. I don´t know if there some brand using the system.

I didn't know about the Arthur Bishop but have played with the idea on a small scale. I have a high performance 4WD R/C model car that can do a scaled speed of something like 300Km/Hr. Originally it had a linear steering ratio and was almost impossible to control at speed so I modified the steering so when it was near center it produced a smaller front wheel deflection that when it was a lock. The result was amazing and made the model considerably easier to control. I havn't however tried this on a full scale car but would expect that it wouldn't be that hard to get used to, after all the controls on a aircraft work pretty much like that.

I have always wondered why we stick to a steering wheel. Why not use a joystick like they do in aircraft?. You could link it to the accelerator and brakes so that forward meant faster, backwards was breaking and right and left to steer.

There are vehicles that have calibrated steering technologies that give more acute steering at low speed as in a parking situation but they have to increase the ratio drastically to avoid over-sensitive steering at highway speeds. Many racing cars have a lower steering ratio but they are very "twitchy" and require expert driving skills. Think about the minute steering corrections you make at 65 or 75 mph--imagine making them 14 times (3.5/.25) more sensitive. That's why things are as they are.

BMW has a power steering system with something like a gear box between the stering wheel and the wheels so that the ratio can be changed at all times. You have to research this subject for more info as I can't find a link right now.

There are quite a few cars out there that have some sort of variable assist steering. GM has Magnasteer and there are other that change the amount of power steering assist based on speed. Slower speeds get more assist, faster speeds less assist to help with road feel. While this is different then variable ratio I thought I would throw it out there.

Shawn

I recently saw an ad for a Mercedes which has no steering wheel, or for that matter, no pedals. The whole thing is run from a center console joy stick. Of course the thing probably costs an arm, a leg, and your first born male child... but so what? You don't need those things to drive the car anyhow, and I had all girls.

Early cars (stanley steamers I think) had tillers instead of steering wheels. Seems quite sensible as long as you don't plan to go more than 20 KPH.

I've only been up close and personal with one Stanley Steamer and it had a steering wheel. It could also break 100mph.You're right, there were other early cars with tillers.

A tiller is somewhat different to a joystick. The primary difference is they work backwards ie. when you move a tiller to the left you go to the right and they are generally located at your side where a joystick on an aircraft is usually positioned in front of the pilot or between the pilots legs and when it is moved to the right the aircraft banks to the right. As for the problem with trying to control things at speed some fighter aircraft travel at 2 ½ times the speed of sound and all use a joystick as the primary control input. When an aircraft turns you use the rudder pedals to overcome the secondary effect of the ailerons which tries to yaw the aircraft in the opposite direction to the bank.

Well, I've learned a couple of things. This idea is not new so there might be someone I could see about changing my steering. Of course, if it costs me an arm, a leg, and my first born male child (I'm exempted, my 1st is a girl) then I'd have to live with it awhile.

That article about Bishop was interesting but he only licenses his ideas. As far as I've read, he doesn't have a company that makes the things. Other car manufacturers make them based on his designs and pays him royalties (that's something I'd like to do too!).

I saw that Mercedes on tv. It had a small lever a little to the right of the driver though still on the instrument panel. I think it only moved about 45 degrees or so to the left or right. Interesting but the range of movement seems too small. Just think, 45 degrees and your wheels are locked already! As you say, just sneeze and you'll find yourself changing lanes, if not having a rollercoaster ride! Bad for your wrist too. The small corrections you have to make will give you whatever-you-call-that-injury with your wrist.

I don't think the fighter plane is a good comparison, sorry to say. Not much traffic up there but we'd probably see it being tried, if it hasn't already.

What about the Blue Angels that fly FA-18 hornets at Mach 0.95 with wing tip to canopy separations of less than a meter.

If you can find a dirt track racer that runs modified or outlaw cars ask them who built their rack. Most of them have very fast turning ratios. Usually a 90 degree turn to the left or right will run the wheels to full lock.

Your description and question confuses this poor fellow. First, was your "car" ever a jeepney? Second, at one time American cars were ubiquitous in P.I. Can you say the year and model of your car? At one time all American cars had steering that turned numerous times--people even installed knobs for turning the wheel with one hand-- so you didn't have that bump, bump, bump as you hands slapped the wheel trying to turn--turning with one hand was actually easier than with two. It wasn't until long after they were common with European marques that rack and pinion and shorter turning steering gears were introduced in USA--during the '70's and beyond for the most part. This was about the time that radial tires began to replace bias belteds in the US. So it is possible, if you car is old enough, that it runs on bias belteds--and it might be questionable whether to change the steering. Power steering was introduced mostly in the early 50's and had become commonplace by the 70's. So from your description (and some of the replies), it's hard to know whether either you haven't driven very long, or you're so young that recent things seem like old stuff to you? Just wondering so Please clarify.

Was my car ever a jeepney? No, it's a '95 Nissan LEC with what we call here "pawis-steering", a play on words because "pawis" means sweat in English. It's good for my chest muscles.

You're right, I haven't driven very long, just a little over five years. This is my first car and, from the looks of things, it's going to stay with me awhile longer. Instead of buying a new one (which I can't afford anyway) I'm thinking of having it fixed up a bit. I was also thinking of putting in a few modifications along the way. I made a post on HUD (heads-up-displays) somewhere. I was thinking of putting that one in too.

Depends on what age is considered young . I'm 45 years old though people think I'm much younger. As I mentioned earlier, I'm not a motorhead (not sure now if that's the correct term). I had absolutely no interest in cars until I got the chance to buy this old thing five years ago.