As one Subaru Crosstrek owner recently learned the hard way, it bears repeating that all-wheel drive is not the same as four-wheel drive. A Subie owner posted a warning letter they received a month after driving on Colorado River Overlook Road in Canyonlands National Park to the r/NationalPark subreddit. The letter notes that this particular road is restricted to 4WD vehicles only, and the Crosstrek is equipped with AWD, not 4WD. It also warns that they may face serious consequences if they’re caught taking an AWD car on a 4WD-only trail again.
I didn’t know the difference so I looked it up: https://www.spinny.com/blog/index.php/awd-vs-4wd-the-difference-explained/
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.
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.
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.
