I didn't know the difference so I looked it up: https://www.spinny.com/blog/index.php/awd-vs-4wd-the-difference-explained/
this post was submitted on 10 Aug 2024
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AWD has the ability to drive all four wheels, but not necessarily all of them at the same time. 4WD has the ability to drive all four at the same time.
The main difference is the additional physical gearing for 4 high and 4 low gears, both of which have different gearing than "regular" drive.
I have an older Audi with a Torsen Quattro AWD system, and an ancient Toyota 4Runner with 4WD. The 4Runner can be switched into either 4 wheel high or 4 wheel low gears to deal with different conditions. The Audi always has the same gearing, it cannot be switched.
It's like the gears on a bicycle - 4 low is the one where you barely move while standing on the pedals - maximum torque per revolution.
You can go rock crawling in a 4Runner in 4 low. You really should not go rock crawling in an Audi or Subaru without 4 low, no matter how much ground clearance the vehicle has.
The National Park Service has this rule because it doesn't want to spent time and taxpayer money rescuing people who think AWD is the same as 4WD with a low range gearbox.
Subaru has x-mode for difficult terrain, which is different gearing. They also have hill descent. https://www.sportsubaru.com/subaru-x-mode.htm
Why would you want 4wd with wasted energy when you could have symmetrical awd and get all the power to wheels that have traction, skipping those that don't have traction?
I only see awd outperform 4wd when it comes to a subie, but other awd systems from other manufacturers are probably not up to snuff.
Edit: meant to say symmetrical awd instead of slip differential.
What color is your Subaru?
Was metallic gray, can't see the paint any longer. Dented, scratched, and brown. You okay?
What color is your jeep commander that sits in a driveway 99% of the year?
Kinda greenish blue
I didn't down vote you, but you've got some misconceptions.
X-mode isn't actually different gearing in the mechanical sense. It's an electronic system that optimizes the existing drivetrain components.
It doesn't provide additional gear reduction like a low-range gearbox, it adjusts the CVT's (continuously variable transmission, which doesn't even have "gears" in the traditional sense, but is a set of chains and pulleys) behavior, traction control, and power distribution, but doesn't change the fundamental gear ratios. Hill descent control is a braking function, not a gearing one.
True 4WD systems have a physically separate low range gearbox that allows the driver to physically engage different gears to vastly reduce the gear ratio to allow the vehicle to make much more efficient use of the available engine power.
You would waste far more energy trying to get an AWD Crosstrek over a boulder with X-mode than an actual 4WD vehicle with a lever to put the vehicle into 4 Wheel Low gear.
While excellent for many things, Subaru's AWD system is essentially a fancy electronic traction control system. It cannot reduce gearing to the level of a 4WD low range gear box. And that's fine! But the incorrect assumptions of people who overestimate the capabilities of their vehicles is the precise reason for the rules the NPS has in place; Subaru Crosstreks with X-Mode are gonna need to be rescued by NPS staff far more often than 4Runners with a low range gearbox.
Subaru marketing is great, but NPS roads with AWD restrictions are not rally stages in a Finland forest, they are roads with boulders or mud or deep water or sand or many other things that a 4WD vehicle will probably be able to handle, but an AWD vehicle will probably not be able to handle. And on these roads, if you get stuck, a park ranger is going to have to rescue you, at tax payer expense, because you thought your vehicle could do something that it could not.
How expensive would it be to rebuild 4x4 trails into ones compatible with AWD though?
I imagine a lot less than rescuing a few dozen AWD vehicles that get stuck
My AWD Subaru Solterra EV has better 4wd than most 4wd vehicles. Dual motor AWD for the win.
Honest question from someone who has never owned either, but who once went camping with someone with an AWD Subaru and who, in turn, managed to get us stuck as fuck. Isn't the difference not so much the drive as it is the clearance of the vehicle? The Subaru was a glorified station wagon and just wasn't built to go through rugged terrain, regardless of how the wheels worked.
Clearance, tires, and open diffs are the big 3.
Most awd vehicles use torque sensors to brake the wheel that has no traction to push power to wheels that do. It doesn’t always work and most awd systems are clutch based so there’s slippage.
More of the basic 4wd vehicles these days come with electric lockers, more power, and better clearance. They still have road tires though so there’s room for improvement there.
I will say, most people that don’t do this stuff on a semi decent basis have ZERO idea on how to actually wheel. You can get pretty far in a base model but even the cheapest new bronco or wrangler are better equipped to deal with actual wheeling than a Subaru.
Driving Sports TV on YouTube shows how most of the vehicles work in light off-roading, and spoiler, most are terrible.
Much obliged!
Tires are well and truly goofy. Black magic engineering. The things you could do in an astrovan with the right tires VS a wrangler with the wrong tires just doesn't seem right.
Tires are just incredibly use specific, Usain Bolt would do terribly in a sprint with bowling shoes, and would hurt himself bowling in running shoes. It doesn't matter what you drive if you've got the wrong shoes for the drive.
A truly skilled driver/rider might be able to pick a good line, but most of that skill will show when they go "nah. Ain't doing it".
Signed - an ADV rider who's tires are and will forever be a compromise between dirt and tarmac performance.
I strongly doubt this.
How does it lock front and rear?
It only needs to lock left and right as the front and rear are separate drivetrains. They (electric AWD vehicles) usually provide locking of a wheel with no traction by using the brakes on that corner
That’s not 4WD, then. That’s AWD.
This guy is who the sign is for lol
Indeed. I'm just pointing out that electric AWDs often do have effective locking on both axles.
I wouldn't take a Tesla X on a trail as it doesn't have the clearance, though it can ensure drive goes to wheels with traction almost as well as 4WD
Soltera is a shit car, but I absolutely agree that dual or quad motor awd is better than 4wd. All other things being equal I'd even argue that basic awd with electronically locking diff is better than 4wd in most cases.
I think this rule should be changed to high penalties for pulling out stuck cars. Period. Take whatever you want, but if your Civic gets stuck, make the cost of pulling it out 50% of car's value.
Lol good thing my civic is only worth $300 😹
I agree, most of the problem is people putting rental civics where they shouldnt be. A subie with a lift is enough to get u through mosy of national park 4w only roads. It's usually driver error that gets u stuck. Garuntee most people they pull out never had any kind of gear to get themselves out.
That said, it Def helps to roll with some one who does have 4w incase u get a little head strong.
Tell me more about a car you've never even driven.
Unfortunately I did drive it. Easily one of the worst Subarus ever made. Pretty much every review and user rating online confirms this.
No you didn't, you read some review.
Doesn’t have gear reduction.
If you have 4 wheels, logically 4WD is AWD. Why not just say you need to have a locking diff?
It's honestly more of a clearence issue, but either way it is most definitely a driver issue. If u aren't skilled it doesn't matter what ur driving, I've seen idiots in rental Jeeps with foot plus clearence high center on obstacles that aren't really that challenging
The rule defined the requirements and explicitly called out the difference between 4WD and AWD.
Isn't that the technical distinction between awd and 4wd? Why create a new definition when one already exists?
They do say that.
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That's splitting hairs, tbh. Especially in the case of a Subaru. Though I guess it scares off anyone with a shitty AWD system from going on the trails.
Imagine a Cybertruck there. It's "4WD".
And as a longtime owner of both 4WD and AWD vehicles, it's not splitting hairs
Now that the locking differential was released, is it not 4wd now?
Just because you don't know the difference doesn't make it splitting hairs.
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Not to mention clearance of cars doesn't match that of trucks.
If there's only a cluch pack between the secondary axle and the prime mover, it's AWD and will overheat when you need it most. 4WD has dogs in the transfer case and the front and rear driveshaft are locked at the same speed.
I say a dual motor EV counts as 4x4
"But officer, I pushed the X-Mode button!"
"But officer, they went camping with their dog in the commercial!"
I rode a one wheel drive motorcycle on that road. I wonder if there's an exception for motorcycles.
If a motorcycle gets stuck you (by yourself or with a buddy) could reasonably get it unstuck in short order without a tow.
Yes
The worst consequence is that you get stuck with 4 days of food and water and no one comes through that can help for a week. Cell phones don't work everywhere, maybe a satcom subscription and equipment could help, but a rescue is going to be way more expensive than whatever fines they are issuing.
I feel like there had to be a personality issue with this one
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