4WD Questions!

Hi All, new here!

We purchased a 2020 SR5P, in October, it’s my wife’s vehicle and she absolutely loves it. Last year we did have a few heavy snow days, the first time she drove it in the snow she had put it in 4HI to drive around for extra safety even though she knows even 4HI doesn’t mean she still can’t slip, it performed flawlessly with the Falken Wildpeaks we put on but she called me nervous because of how the truck binded up when pulling into a parking space.

The 4Runner is our first real part time 4WD vehicle and still learning, how do we handle heavy snow days? Does she put keep it in 4HI and then if she has to pull into a space, put it in 2WD? What’s the best way to go about it?

Thanks for any help you could provide!

 

Correct. You shouldn’t be doing sharp turns in 4wd

 

If you didn’t already know, a typical 4WD system is RWD until its mechanically locked into 4WD. When it's in 4WD the front and rear are locked together and forced to spin at the same speed, but that's not physically possible unless you’re driving straight or a tire is slipping. When you’re turning the path of the front wheels is longer than that of the rear wheels - an easy visual to picture in your head is a semi making a right hand corner at an intersection. They pull very very wide into the intersection almost crossing into the oncoming side of the road with the cab yet the back wheels of the trailer barely make it around the corner without hopping up on the curb. The front wheels traveled a further distance than the rear wheels did. All vehicles do the same thing just on a more compact scale. With a vehicle locked in 4WD the drivetrain WILL start to bind up while driving anything but straight ahead, the result is that something has to release the tension - either a front tire drags or a rear tire spins to make front axle speed match the rear axle speed, or the inner workings of the transfer case blow out the side of the housing and dump onto the road. The latter being the least likely but it does happen, especially over time with repeated binding. Try pulling into a parking space with a vehicle locked in 4WD, it'll get stuck from binding up so bad while trying to turn. When you drive in the snow in 4WD you’re forcing tires to break traction and slip which obviously isn’t doing you any favors.

AWD allows all 4 wheels to be driven while letting the move at different speeds as needed.

Now let’s look at the advantages of 4WD and AWD. It will help you accelerate. The end. It will not help you stop, it will not help you turn, it will not help you hold the road around a bend, it will not help you switch lanes over the slush channels, it will not help you with anything except applying power to accelerate. The rest is all up to the one thing on the vehicle that actually contacts the ground, the tires. Winter tires are the only thing that is going to improve safety, braking, handling, and grip of your vehicle in winter driving conditions, getting up to speed is irrelevant if you can’t control it once your there.

The single thing that determines traction is the tires ability to maintain grip with the road.

 

For city winter driving, my wife's Mazda CX-5 with AWD is better than my traditional 4x4s. That is one smart system.

But tires still trump everything because they help you stop and turn. Back when we lived in Chicago, we ran dedicated snow tires on our Corolla. Unless the snow was so deep you started plowing, that thing was unstoppable.

Note that backcountry snow driving is almost nothing like city snow driving. In the backcountry, snow behaves a lot like mud, and something like the 4Runner is better. But in town, packed snow behaves nothing like mud and more like ice.

 

Ok this makes sense. I currently have a 2020 Grand Cherokee Trailhawk and I know it has a VERY different AWD system set up. I had never experienced the binding before so it definitely through me for a loop. I know tires mean more than 4WD generally do for snow driving. We have a set of Falken Wildpeaks on her 4Runner and they have been great. I tested it out both in 4WD and 2HI and only slipped a little bit. I think we just have to get used to how the 4Runner system works and it being a traditional 4WD system.

So in reality, unless its very deep snow, 2HI should be ok?

Got it! I know what you mean, the AWD system in my trailhawk is great and I dont have to think about it. I had just assumed a traditional 4WD system would perform better in the snow but I'm forgetting how "smart" newer AWD systems have become.

 

Spoken with the succinct conviction of someone who has driven in snow, Agent_Outside. Great explanation.

 

4 WD, I call it “real” 4 WD, lol, does help your vehicle track through snow ridges, left by snow plows and other drivers, and does give some small measure of security. A vehicle like a 4 Runner is heavy, and has good ground clearance too, which all helps as well. Agent_Outside has a good explanation of what happens when 4 WD is engaged. The big difference is tires, a good winter tire can make an unbelievable difference in any vehicle. A lot of guys think if they have a big luggy tire they’ll be good to go. Unfortunately, not so much, and that uniformed thinking will get you to the ditch or worse where I live in Canada in winter.
So, how do you decide when to engage 4 Hi? Only when it’s absolutely needed! Haha, that comes from experience, I guess. Just don’t try to take any tight turns when it’s engaged. Also, in icy snowy weather all vehicles depend on 4 very small pieces of rubber to hold them in place. Slow down, and drive according to the conditions, and arrive safe and sound, even if you’re late.
If the worst happens, be thankful you’re in one of the safest vehicles in the world with 8 air bags!

 

The constant conundrum. We get 100 inches of snow per year where I live (yes, in Arizona). Mountain-snowflake rated tires help a great deal. But the mud on the trails here and in southern Utah is slick-slick-slick, which argues in favor of dedicated M/Ts. Decisions, decisions.

 

Sorry to bump an old thread, found this searching online. I’m in the same boat 2020 SR5 premium and first real 4wd vehicle. Same tires actually as well haha

So the consensus seems to be it’s ok to use 4Hi in snow/ice on city streets if there’s snow on the ground that allows the tires to slip when taking a turn, let’s say from a stop sign but if the pavement is dry or the ground is just freshly plowed/sanded where no slip would occur, 2WD is better? Is that right?

I’ve watched a lot of off-roading videos online with the 4Runner and they use 4Hi and 4Lo on rocks and climbing hills where they come they shimmy the wheel back and forth full lock, it’s ok in this situation because rock allows for slippage, right?

 

All points correct.

 

I live in NYC and 4hi/4low doesn’t like tight turns at all other then off road I never use 4hi plus my wildpeaks really do a fabulous job in the tough stuff
Your next 4Runner should be a limited that 4wd system is constantly on different then all other versions on 4Runners

 

See I don’t think the wild peaks are that great. I’ve had some balance issues on them, I don’t think I would use them again. I just find that in the deep icy snow on the city streets around me that haven’t been plowed, 2wd is fine in a straight line but if I’m at a stop sign and have to turn left or right, 2WD slips pretty bad, as it should being a RWD rig. It makes sense to use 4Hi, I just wanted to understand when and when it wasn’t safe to do so.

 

The balance issue is tire pressure related there is 1000’s of replies on line of how finicky the 4Runners are on aftermarket tires NOT just falken
If you increase psi to close to 40 it usually eliminates the shimmy I had issues with my wildpeaks and my blizzaks both are now shimmy free at 38
J

 

Trust your gut feelings, the thing is it is very easy to go in or out of 4 high, you are not going to break it. Use it when you feel like you need it, then shift out when your comfortable. No need to over think it, enjoy your rig man.