Settle an argument

FZR400RRSP

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Speaking about power steering in the office.
A colleague is convinced there are cars out there where, at the push of a button, you can change the number of turns of the wheel required to go from lock-to-lock.
I say he's talking Horlicks, I say he's confused with buttons that alter the amount of power assistance, making the steering lighter or heavier.
Nope, he's adamant you can change the steering wheel movement need to go lock-to-lock.
Anyone know of a car where this can be done, I've never heard of it.
Doesn't make sense to me as changing the lock-to-lock wheel movement would mean changing the rack....?
 
Not found anything current but articles referring to Nissan Infinity drive by wire systems and this article about Ford adaptive steering suggest it's possible and coming...
Ford to lighten the steering load with Adaptive Steering system
While power steering has made it possible to drive around without giving yourself an exhausting upper body workout, the steering ratio of most vehicles – that is, the number of turns of the steering wheel required to turn the front wheels a certain amount – is fixed. Ford is shaking things up for non-luxury car buyers with its new Adaptive Steering system that will be available on select models from next year.

As the name suggests, adaptive steering system adjust the steering ratio of a vehicle to adapt to changing conditions – in this case, the speed of the vehicle. At low speeds, the system turns the front wheels a greater distance for the same amount of rotation of the steering wheel – or, if you like, less turning of the steering wheel is required for the same amount of turning of the front wheels. Ford says this makes the car more agile and easier to turn when, for example, maneuvering into a tight parking space.

....
Although similar systems are already available on some luxury models from other automakers, Ford looks set to be the first to bring the technology to the average consumer, with plans to make it available on select vehicles in 2015.

Ford's Bringing Adaptive Steering To the Masses - Slashdot
Adaptive steering builds on the existing speed-sensitive function of the electronic power steering system by altering the steering ratio and effort based on driver inputs and settings.
 
I found something suggesting BMW offer a variable ratio steering rack on the 5-series.
Definitely different ratios between parking and high speed, as opposed to same ratio but different amounts of assistance.
News to me, didn't think this was possible, I thought ratio was mechanical and 'set'.
Bummer, I may be owe him a Kit-Kat.:(
 
Variable speed ratio steering has been around for quite some time.

Honda has been offering it since 2000 Honda Worldwide | World News | News Releases | July 7, 2000
And BMW (as you say) and Lexus have offered it for a while too.

However, none of these systems can be adjusted from a button on the dash - that is reserved for the extra light steering you describe in your first post.

So you are both right and wrong! ;)

If you want to understand how it works, take a look at this: Honda Worldwide | World News | News Release | July 2, 1997
 
Ah well, I'll maybe avoid having to buy him a Kit-Kat on the 'button' technicality.
 
You could each buy a Kit-Kat, break it in half and give each other half, sounds fair to me :)
 
I'd keep the Kit-Kat.

The Honda link describes firstly speed-dependent power assistance, which is a common enough system which has been around for years.

The variable steering ratio, as Honda describe it, is achieved by the design and engineering of the pinion and the rack, the latter having a non-linear pitch on its teeth. Purely mechanical, and a fixed ratio for any given steering angle.

The engineering achievement is in moderating the amount of assistance according to the amount of steering wheel input and the speed of the vehicle.

A second possible factor, is the geometry of the track rods along with the attachment angle and the length and curvature of the steering arms, and possibly the king-pin inclination too - think of the bizarre angles Mercedes-Benz front wheels adopt on full lock.

My first car, a mid-50's Ford, had a Burman worm and nut steering box which, by its design caused the steering ratio to change towards full lock. This was because unlike a rack and pinion, where the rack moves left and right perpendicular to the pinion, the worm moves in a straight line but the nut moves in an arc.
 
Perhaps the second link does that, but read the first link about the S2000 V-Type which says:

"Tokyo, July 7, 2000 - Honda Motor Co., Ltd. announced today that it will launch the S2000 type V, a new version of the S2000, Honda's two-seater convertible sports car. The type V will be equipped with a variable gear ratio steering (VGS) system, the first in automotive history, and will go on sale throughout Japan through Honda's Verno dealership network from July 14, 2000. "
"The VGS system, which will debut in the S2000 type V, varies the steering gear ratio continuously according to vehicle speed and steering angle to provide a heightened "joy of maneuvering." The adoption of this variable ratio system ensures ideal handling performance through a broad range of driving conditions. Agile and exhilarating performance is especially noticeable on winding roads, since the front end of the vehicle turns sharply in precise response to driver steering input. While cruising at high speeds on expressways, the VGS offers a smooth and progressive ratio setup without excessive sensitivity, providing the driver with the relaxed and reliable driving feel of conventional steering systems. Astonishingly, the lock-to- lock ratio* is almost halved to 1.4 turns for better maneuverability in the low speed ranges. "


The bold and underlining is my own but shows that the gearing varies applies at both low and high speeds. It's a very clever system indeed.
 
I wonder what happened to VGS? do they still use it in modern vehicles or did it fall by the wayside?
 
See the link in my post to the Honda S2000 V-Type, which was equipped with VGS. AFAIK Honda don't equip any of their cars with it any more.
 
Honda also tried steering rear wheels for a while on the prelude

That must have felt weird

 
Assuming he's talking about virtual buttons then he's correct, the Infiniti Q50 has touchscreen adjustable steering response:


Honda also tried steering rear wheels for a while on the prelude

Several cars have had, Renault's Laguna was another:
 
BMW Integral Active Steering is available on the current 5 series.

4 wheel steering was an option on the gen5 Celica also.
 
Ford circa 1988:
Non-PAS cars (Escort, Orion) mechanical variable-rate to make parking lighter (more turns toward lock than at straight).
US PAS cars (Thunderbird) Variable (reduced) assiatance to make high-speed cruising steering heavier, except when a situation is detected..
Neither user-deselectable.
 
You've got me there IG, not a clue - enlighten me please...

There's lots of links on the web to the variable gear steering concept from Honda, but they all seem to refer to a car from 2000 ie 14 years ago.
 
BMW Integral Active Steering is available on the current 5 series.

4 wheel steering was an option on the gen5 Celica also.
I actually had it years ago on my '04 reg 645Ci. I really liked it. I'm sure it's still available as an option. It was introduced in 2003 on the 5-Series.

Active steering - Wikipedia, the free encyclopedia

It was not push-button, but automatic. The ratio changed with speed; it was less sensitive (needed more turns) at high speeds, to avoid over-correction. It felt a bit weird at first, as you tended to over-turn at a junction, but you soon got used to it.
 
Fiat used to have the 'city' button which made the steering very light to the point it almost had no resistance to the user.

It didn't alter any ratios but felt like it!
 
Golf GTi, GTD and R apprently have progressive steering that alters the ratio from 2.75 to 2.1 turns lock to lock.
 

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