4-Wheel steering

[parapyropig]

4WS would allow the TCT to make hairpin turns, and even allow “crabbing“ like a tiller on a ladder fire truck.

This feature would be especially useful off road, such as with negotiating tight switchbacks on mountain roads, as well as maneuvering through older (read: European) streets.

Would the juice be worth the squeeze?

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[Keeney]

Would the juice be worth the squeeze?

The cargo bed would need to be narrower or much higher (above the wheels like a flatbed) to make clearance for the rear wheels to steer. I would vote no.

 

[ajdelange]

I'm sure the Tesla engineers have concluded that they advantages of rear wheel steering are not appreciable relative to what is available from torque vectoring and, as the latter is easier and less expensive to implement, have chosen to go that route. Independent steering may offer some advantages relative to torque vectoring but I am guessing they would not be nearly enough to justify the cost.

 

[Cody the cat]

4WS would allow the TCT to make hairpin turns, and even allow “crabbing“ like a tiller on a ladder fire truck.

This feature would be especially useful off road, such as with negotiating tight switchbacks on mountain roads, as well as maneuvering through older (read: European) streets.

Would the juice be worth the squeeze?

For urban cowboys street rolling, don’t think so. However, off road warriors would benefit I would think. Could this be an option or upgrade, I think so. Question of the bed width is valid. But would off roading 4ws only engage when full lift is engaged.
I don’t know but worthy of debate.

 

[drcarric2650]

This is a 1 % use case for 1% of customers. So no.

 

[Mike Hickey]

3 point tractor turn will dramatically reduce the turning radius. It can be accomplished with software only. I.e. hard left, lock pivot wheel, power other wheel(s) to advantage. Switch to hard right... to complete 1 cycle. 3-5 cycles depending on model = 180°.

 

[Sirfun]

3 point tractor turn will dramatically reduce the turning radius. It can be accomplished with software only. I.e. hard left, lock pivot wheel, power other wheel(s) to advantage. Switch to hard right... to complete 1 cycle. 3-5 cycles depending on model = 180°.

I would think this would really make sense in reverse. Like in autopilot, the driver requests a 3 point left or right turn in reverse. The vehicle looks with cameras, making sure there's room, then turns front wheels full lock and locks brake on the appropriate rear wheel, applies the proper amount of throttle and the vehicle does a reverse 180, in a super tight radius.

 

[ldjessee]

I tried to find a video of this, but failed. Maybe the 3 point tractor turn has another name?

I kept getting videos about 3 point hitches on tractors...

 

[Mike Hickey]

I tried to find a video of this, but failed. Maybe the 3 point tractor turn has another name?

I kept getting videos about 3 point hitches on tractors...

3 point - tractor turn is My term. It combines the 2 concepts. Here's a video that is close to what I'm talking about:


We've all done 3 point turns. Up right, back left , up right, back left, up right, back left... until we get turned around. It's exhausting. A tractor turn, best with a vintage tractor, is lock 1 drive wheel and pivot around it 180° with the other power wheel.

Autopilot can do all of the work in a tighter radius than either concept done separately.

 

[HaulingAss]

4WS would allow the TCT to make hairpin turns, and even allow “crabbing“ like a tiller on a ladder fire truck.

This feature would be especially useful off road, such as with negotiating tight switchbacks on mountain roads, as well as maneuvering through older (read: European) streets.

Would the juice be worth the squeeze?

I say KISS (keep it simple, stupid).

One of the big benefits of an EV is the simplicity. I want my Cybertruck to be simple, reliable and easy to maintain. No RWS for me, not enough benefit for the disadvantages and extra complexity.

 

[firsttruck]

I would be interested in it if Tesla made a robust system. Why should it be that different from front wheels. Most trucks to not have independent rear but the Cybertruck will have independent rear.
Might be much easier and less costly to do with Cybertruck compared to most other trucks.
What if Tesla could use the exact same parts in front & rear suspension but limit angle range of rear to +/- 10 degrees.

GM had quadra-steer for several years and I could not find any complaints in forums. I found several owners of GM "quadrasteer" that 10 years later still wanted it on their next new truck.
GM owners reported the quad-steer really helped with turns when pulling a trailer.
The reason quad-steer was not generally popular was because as usual, GM mishandling of marketing & availability at dealers for demo (sounds familiar, EV1,Chevy Volt, Chevy Bolt). Most GM/Chevy truck buyers never even knew about quadrasteer and its advantages when towing.

 

[jcryer3]

I think a tight turning radius is extremely important. Trucks generally have a poor turning radius because of a long wheelbase. My wife hates driving my truck. I think the Cybertruck will have a lot more support if at least there is an option. I will definitely add. I just hope it is not offered after I get my truck.

 

[HaulingAss]

I would be interested in it if Tesla made a robust system. Why should it be that different from front wheels. Most trucks to not have independent rear but the Cybertruck will have independent rear.
Might be much easier and less costly to do with Cybertruck compared to most other trucks.
What if Tesla could use the exact same parts in front & rear suspension but limit angle range of rear to +/- 10 degrees.

GM had quadra-steer for several years and I could not find any complaints in forums. I found several owners of GM "quadrasteer" that 10 years later still wanted it on their next new truck.
GM owners reported the quad-steer really helped with turns when pulling a trailer.
The reason quad-steer was not generally popular was because as usual, GM mishandling of marketing & availability at dealers for demo (sounds familiar, EV1,Chevy Volt, Chevy Bolt). Most GM/Chevy truck buyers never even knew about quadrasteer and its advantages when towing.

From a maintenance and reliability perspective I don't think it is that different from having the front wheels steerable. But that is not entirely non-problematic as the vehicle ages because there are twice as many steering systems. But that's only 10-20% percent of the issue as I see it.

The real issue: Fixed rear wheels have less play as the vehicle ages. This means the driver can tolerate a certain amount of play in the front wheels before needing to take action. But having the same amount of play in the rear wheel steering system multiplies the effects of the play in the front and makes it less tolerable to have wear in the steering system. Alignments become problematic much sooner in the vehicles life along with tire wear issues, etc. Basically, the point at which the vehicle becomes not worth keeping on the road happens sooner.

Sometimes simpler really is better.

 

[firsttruck]

General Motors Quadrasteer Technology is 17 years old and owners still using it.

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4 wheel steering on trucks helps with
1. turning into parking slot in parking lots with narrow lanes
2. turning right on intersections with tight corners and narrow lanes
3. towing at high-speed and lane change
4. low speed towing forward and turns
5. low speed towing backing up and turning
6. higher payload & towing GCWR (gross combined weight rating)

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*** great article with diagrams of how it worked

General Motors Quadrasteer Technology
https://gmauthority.com/blog/gm/gen...chassis-suspension-technology/gm-quadrasteer/

Benefits
Quadrasteer benefits can be realized while parking and towing.
Turning Circle with Quadrasteer
Compared to vehicles without Quadrasteer, vehicles with the feature have a smaller turning radius. This can be very handy for big vehicles such as pickup trucks and SUVs when parking in small spaces. In addition, a smaller turning circle is particularly useful for those who tow boats, fifth wheels, or other large equipment, as it enables easier maneuverability when towing and parking.

The Quadrasteer system adds about 285 pounds of additional weight to the truck but gives back this amount and more in additional towing and hauling capabilities over the C3. The rear axle’s weight rating increases by 250 pounds to 4,000 pounds and maximum GCWR (gross combined weight rating) climbs from 14,000 to 16,000 pounds. Trailering capacity has increased from 8,700 pounds to 10,000 pounds. The wider rear axle also provides more stability when towing.

** this same range as Cybertruck & many Ford Superduty 2500 pickup trucks.

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Chevy's Quadrasteer: Four-wheel steering makes this rig ideal for tugging trailers.
By Drew Hardin
September 18, 2007
https://www.outdoorlife.com/articles/gear/2007/09/chevys-quadrasteer/

.....
new Quadrasteer option available on some 2003 Chevrolet Silverado pickups. A steering rack on the rear axle controls the direction of the back wheels, steering them in a direction opposite the front wheels at low speeds, and in the same direction at highway speeds. The low-speed operation cuts the Silverado's turning circle to a compact-sedan-like 37 feet, while the high-speed function increases stability during lane changes and other maneuvers.

.....
A Trailer Puller's Dream
We found the low-speed mode particularly helpful, as the smaller turning circle made this long-wheelbase truck more nimble than it used to be. If you pull a trailer, you'll like how the rear-steer feels on the highway, but be prepared to practice backing up to get the hang of how the rear-steer moves the trailer tongue around.

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Denali Swoops Into Tight Spaces Thanks to Quadrasteer System
By Jonathan WelshStaff Reporter of The Wall Street Journal
March 1, 2002
https://www.wsj.com/articles/SB1014926541434987080

.....
Being able to handle a full-size pickup truck used to be a point of pride: Parking took the strength of a weightlifter. Backing a trailer down a boat ramp took the timing of a shortstop.

Now, General Motors says, it has the truck for everyone else -- the GMC Sierra Denali, with a new steering system called Quadrasteer. Its gimmick: All four wheels -- not just the front two -- turn when you crank the wheel, allowing the big rig to maneuver more like a smaller car. Yes, it's handy for off-roading and towing big trailers. But what seems to matter most is that it lets the new Denali swoop into tight parking spots without those old-style 20-point turns.

.....
At high speeds, Quadrasteer turns the rear wheels in the same direction as the front wheels, although at a lesser angle, which makes changing lanes on the highway surprisingly smooth. At low speeds, the rear wheels go in the opposite direction, giving the truck a 37-foot turning circle -- about 10 feet less than a standard-steering Sierra.

.....
Behind the WheelFour-wheel steering makes this big pickup handle like a small car in parking lots, and makes towing easier.

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steveMCHS
2020
Got a 2003 denali quadrasteer. Old man bought it new and then i bought it. Truck has been going strong its hole life and always been in 4ws. Honestly best truck ive ever driven and worth every penny especially when towing and city driving. So far never had a issue with the quadrasteer.
One thing though is when new it was 7000 option but in 03 it dropped to 5000 and it dropped every year. In 05 it was somewhere around 800 for the option.
Problem was gm failed at marketing it as well as the fighting with the partner company. There was alot of fighing. They actually were going to come out with a 3/4 ton and 1 ton with it.
Lucky there are still parts to find if you know where to look (quadrasteer fb groups) as well as people who rebuild them as well as some who are in the works of reverse engineering them.

All in all i will have this truck and keep this truck working for as long as i live. Oh and key advice if you have one.
1. Keep out of deep water
2. Use the 4ws! Dont just use it on the odd day. Thats another reason why they brake is because people dont use them for a long time and thing go without lube and rust up. If you can just leave it in 4 wheel steering.
3. Look into some water protection. Thats what my mechanic did for me making it water tight. As i said still working great for 17 years.

steveMCHS
2020
Depends on the condition, they can be cleaned but carefully. I suggest joining the three big quadrasteer groups on fb. They will give loads of help
Chuck Taylor
2020
Many thanks for the Quadrasteer Facebook groups. Great people including an former GM engineer designing a new sensor/control to overcome the discontinued sensor issue! Could be a new part/product coming down the line.

Just A Truck driver
2020
A company name Goood Systems is makingh new sensors that are completely sealed

 

[FutureBoy]

From a maintenance and reliability perspective I don't think it is that different from having the front wheels steerable. But that is not entirely non-problematic as the vehicle ages because there are twice as many steering systems.

Redundancy increases reliability silly!!

LOL

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