Tesla and its vehicles are a polarizing topic in the automotive world. The company has its die hard fans that will go to the mat over even the slightest issue, and they believe that Tesla can do no wrong. On the other side, there are those that can see mistakes and flaws in Tesla’s vehicles and shout them from the rooftops. Thus, when video hit the Internet showing a Tesla Cybertruck attempting and failing to climb a snowy slope, the rage machine on both sides kicked into overdrive. Today, we’re going to dive in and examine what was really going on.
The videos were posted to Instagram by one Matt Chambers, who noted that it was actually a video shot by a friend of his who helped with the recovery. The Cybertruck is branded as an “RC”, or “Release Candidate” model, with stickers on the side denoting that it’s an engineering prototype. We see the truck attempting to climb a steep slope near a pine forest at the Corral Hollow OHV Trail, with a Christmas tree loaded in the bed. It helplessly spins its wheels and makes little forward progress, and is eventually pulled back on to a flat trail by a Ford.
Ultimately, from what we’re told about the incident, and what we can see ourselves, there are a number of factors at play behind the Cybertruck getting stranded in this situation. Let’s tick them off one by one.
The first thing to reckon with is the slope. Video and photos are often a poor indication of just how steep a slope is, but there are certain context clues that tell us that the truck is contending with a fairly decent incline. If you look at the people in the background of the shot, you can get an idea of the angle of the terrain. It’s not an impassable slope, by any means, but steeper inclines do rob a vehicle of grip.
Steep Slopes Are Hard To Climb, Especially If Traction Is Low
This is fairly obvious, but let’s get into it; it’s all about friction and that friend of ours from physics, the normal force. (What follows is a heavily simplified explanation; for a deeper one, dive into some beginner’s physics and engineering courses).
The more friction between a tire and a surface, the more power you can put down to move in the direction you want to go. The amount of friction available can be determined by an equation where the friction force equals the coefficient of friction multiplied by the normal force. Ultimately, the coefficient of friction is determined by the surfaces involved – in this case, rubber and snow – and is affected by things like wetness, surface contact, and so on. If the coefficient is zero, there is no friction at all between the two surfaces in question. Higher coefficients are indicative of more available grip. Rubber on asphalt in the dry can have a coefficient around 0.7 in typical cases. Obviously, in the case of rubber on ice, which is much slipperier, the coefficient can be as low as 0.15.
However, the coefficient only tells half the story. You can have a good coefficient of friction, but if the normal force is low, you won’t have much friction, and thus grip, anyway. For our cases, the normal force is always perpendicular to the surface on which a vehicle rests. It’s the equal and opposite force to that of the car’s mass being pulled down by gravity. As the gravity pulls the car towards the ground, the ground exerts an equal and opposite force in return. This is what stops your car falling through to the center of the Earth.
The problem is that on a slope, gravity keeps pulling straight down, but the normal force remains perpendicular to the slope. What this means is that the normal force ends up equal to only a fraction of the gravitational force, and the steeper the slope, the smaller that fraction is. Effectively, the component of the gravitational force that is perpendicular to the slope generates the normal force, which helps with grip, while the rest is tugging the vehicle down the hill.
[Ed Note: Just as important as the drop in normal force (and thus friction) is the fact that the force due to gravity — which is giant given the vehicle’s girth — has a significant component pulling the truck down the slope (m*g*sin of the angle). This means that tractive forces pushing the truck uphill will have to overcome that plus the other opposing forces that would exist on a flat grade like rolling resistance, bearing resistance, etc. -DT].
The Tires Clearly Weren’t Ideal
With the physics out of the way, we should move on to the specifics of the situation. It’s plainly apparent that the Cybertruck doesn’t have the right tires for the situation. It looks to be wearing a relatively tame set of all seasons which are never going to be the best kit for snow, dirt, and mud.
Beyond their lack of aggressive tread, all seasons generally use rubber compounds that aren’t super grippy in low temperatures, either. When things get really cold, the rubber tends to become harder and less compliant, so it can’t mold to a surface as effectively and generates less grip. Winter tires are specifically designed to remain more supple in lower temperatures to avoid this.
My Autopian colleague Pete performed some Google magic and discovered this forum post, which shows the tire above is almost certainly a Goodyear Wrangler Territory MT, as previously seen on Cybertrucks in the wild. It’s an all-season, all-terrain tire. In other words, it’s a jack of all trades, but a master of none.
Here’s an example of a Goodyear Wrangler Territory (left). More aggressive tread designs such as the Dunlop Grandtrek SJ6 (center), Falken Wildpeak AT3W, or one of Goodyear’s more heavily lugged Wrangler models would have helped the Cybertruck – or any other truck – find more grip on that snowy slope. Production Cybertrucks are to be shod with the Pirelli Scorpion ATR, which is known for good performance in snow.
Along with the impact of tire choice, we can further speculate that tire pressure played a role. Dropping tire pressures is a simple way to get more grip, particularly in softer surfaces. As tire pressure goes down, the contact patch on the tire increases in size. This is because as a greater surface area of tire is required to support the vehicle’s weight with less air pressure in the tire. You want more rubber in contact with the ground trying to find some purchase and something to grab on to, to help pull the car along. By airing down the tires, you spread the vehicle’s weight over a greater area of rubber, and increase the chance of the tires gripping and moving the car, rather than simply slipping and spinning. A great example is the way that tank tracks take this to the extreme, creating excellent grip by spreading a vehicle’s weight across a long, wide tread.
In snow, airing down for a larger contact patch can be particularly helpful. It tends to help the tire “float” over a wider patch of snow because the tire’s load is spread over a greater area. This is desirable compared to seeing a higher-inflated tire punch through and sink into the slush. It’s very similar to how things work when sand driving.
[Ed Note: I haven’t had a tun of success airing down in the snow, though admittedly I haven’t done it a ton. -DT].
The Prototype Traction Control System Likely Needs A Few Updates
We can also see the Cybertruck, which is all-wheel-drive, is failing to put its power down. It’s spinning wheels both front and rear. According to the posts, this was in part due to a software issue which disabled the ability of the rear brakes to act as a locking differential. We don’t know exactly what drivetrain configuration this pre-release version of the Cybertruck had, but let’s explore the topic of why this can cause problems offroad.
Vehicles with open differentials face a common problem when tackling difficult terrain. An open differential transmits torque equally to both wheels. This becomes a problem when one wheel is on a slippery surface or dangling in the air without contact to the ground. This is because the further limitation of the open differential is that it can only deliver as much torque as the wheel with the least grip can take. Thus, if one wheel is spinning freely and putting down virtually no torque to the ground, the other wheel will get the same tiny amount of torque, and the car will go nowhere.
In the case of the Cybertruck seen here, it appears it may be suffering this problem. Some off-roaders get around this flaw by using the brakes. Hitting the brakes creates some resistance for a wheel dangling in the air, allowing it to accept more torque. This higher torque can be transferred to both wheels, hopefully providing some forward motion. Some modern vehicles use computer systems as a sort of “faux-locker” to selectively brake the wheels independently to generate this effect and allow forward motion. For example, the wheel spinning freely can have its brake engaged to create some resistance, allowing the differential to send more torque to both wheels. It’s not as good as a real locking differential, but it can sometimes make enough difference to get your vehicle out of a tight spot. In this case, though, reports from the ground are that a software issue disabled this feature on the Cybertruck.
It’s worth noting, though, that production Cybertrucks may not be victim to the same circumstance. As reported by Drew Baglino, Tesla’s SVP of Powertrain and Energy, production dual-motor Cybertrucks come with differential locks front and rear. A locked differential effectively allows 100% of torque to be transferred to a single wheel on an axle. It doesn’t matter if one wheel loses grip or has no contact with the ground; full torque can be sent to the other wheel to provide propulsion. In the case of the tri-motor Cybertruck, there is only a front differential lock. However, that’s because each rear wheel gets its own independent motor, and thus there is no need for a rear differential at all.
Front diff locker for tri, front & rear locker for dual.
— Drew Baglino (@baglino) December 1, 2023
Locking diffs would have probably been a great boon in this case. Combined with the prodigious low-down torque available from the truck’s electric motors, it may have had more luck crawling up the slippery slope without needlessly spinning its wheels.
Of course, it bears noting that we don’t have all the information. It’s possible that this slope is steeper than it looks, and slipperier than it looks, and that it may have been difficult for even a better-equipped Cybertruck to get up without issue. What would really fill us in is if we had footage of another truck in the same conditions doing a better job. Regardless, there’s still plenty that could have improved the Cybertruck’s chances, as discussed.
Just to be clear… this is a Super Duty and NOT advertising. Glad a @Ford owner was there to help. https://t.co/Rr78EY9k2T
— Jim Farley (@jimfarley98) December 13, 2023
Hilariously, this pre-production truck had one more flaw that complicated everything. It had zero recovery points fitted, and thus had to be recovered via a tow rope wrapped around the suspension. This is not ideal, and suggests the team involved with testing the truck had not properly prepared perfectly. If anything, you’d expect a prototype to have recovery gear available at all times given the higher likelihood of something breaking or failing.
Overall, the video doesn’t mean the Cybertruck is awful off-road. To avoid a similar situation yourself, make sure you’ve got snow tires, and that they’re appropriately inflated to optimize the conditions. Remember that going up a steep slope cuts your grip, and consider if you can safely find a way to make it up a lower grade instead. Engage diff locks if you have them, or any traction control or faux-locker aids that your truck might come with. And, if all else fails, make sure you’ve got the right recovery gear to make towing your truck out easy. Happy wheeling out there!
An unbiased and informative Tesla article. I can really appreciate that. Thank you.
What they should be ashamed of was being off the trail. Just what we need, more irresponsible off roading getting a ton of press.
Basic ass Superduty 4X4’s often have the same issue, not lockers, Hard Street AT tires, with too much air and a huge Gross Vehicle Weight to contend with.
Put a Rivan, The Hummer, and even the portly Lightning on the same trail and let’s talk after. I think the Rivan is probably going to with the day as long as the stock road tires are not spec’d
Man, that is one long winded apology for a Tesla vehicle.
I think the problem is the color – it’s not a little red truck hawwlin’ a Christmas Tree.
It’s nice to see a CyberTruck carrying its maximum payload, even if it is a “Release Candidate”.*
As much as I favor progress and electric vehicles, the CT is way, way down there on my list of favorite vehicles. A converted Toyota Hilux 4X4 would be much preferable.
*Release Candidate sounds like a prisoner up for parole consideration.
I have to say there was at most a lite dusting of snow. Meaning nothing of consequence but also no mud because there was any snow mud would freeze.
No. So much no. Ground stays warmer under the snow. Bottom layer is like insulation. Very common to have snow and mud and ice (on rocks or pavement) all in the same place.
No because snow is at freezing. If ground is warmer the snow melts. The ground must get to freezing for snow to lay. And this is clearly laying snow.
Helpful tip if it starts to snow as soon as the snow stops melting sweep the snow off and you will not have a layer of ice stuck to your sidewalk or driveway.
That’s not the whole story.
https://nsidc.org/learn/parts-cryosphere/snow/science-snow#:~:text=However%2C%20the%20snow%20can%20still,the%20conditions%20are%20just%20right.
Okay per the article it can snow a few degrees above zero if the conditions are exactly right.
All true, and I seem to remember you are a fellow western PA person. The top of the ground is freezing, but once through that crust is goey mud.
Yes western PA. AND yes depending on weather and temperature and time of year the undercrust can get gooey. But without decent rain or a decent warm patch the ground I have seen is like concrete. But then again the Cybersuck does weigh as much as a small moon orbiting Uranus!
If the Cybertruck was not being constantly hyped as an invincible, unstoppable transport for the post apocalyptic future and didn’t look like a child’s doodle made real we wouldn’t be so harsh and mock it at every turn. If a Rivian or an F150 Lightning gets stuck, or has a $41,000 collision repair estimate it gets handled fairly because Rivian and Ford market their vehicles as electric trucks and not as all conquering symbols of virility.
tl:dr it’s not the vehicle, it’s the marketing
Well let’s give the Cybersuck it’s due. At least it is drawing car hating video playing 20 year old children into the car loving world.
That right there is exactly why they SHOULD be ashamed. The rest of this is spot on with the physics and what-not, but the complete lack of preparation in recovery points and poor tire choice is why they should feel bad. This could have happened in any vehicle, so the blame is not on the vehicle but on the operator(s).
being a “release candidate”, it’s possible they were using it to test the traction control system, the same as that previous video.
put non-ideal tires on it, drive it down a hill where you expect it to get stuck, then lead-foot the accelerator and see if, or more likely, how badly the traction control fails at its job.
normal companies would do this well before releasing the model, on their own closed test track, but due to silicon-valley-brain, they’re leaving it to the last minute and probably intending to fix it with an OTA update.
You are contending that they intended to get stuck? If that’s the case, then the lack of recovery points is even more shameful.
And silicon-valley-brain is also a great reason for shame.
Define “Released”. How many are really in the wild?
“According to The Verge, Musk confirmed in January that the Cybertruck won’t enter full volume production until sometime in 2024, but early manufacturing efforts were slated to begin this summer.”
Right now it’s press vehicles and a few FOE’s (Friends of Elon)
From Teslas CT release party recently I want to say there were at least 10?* at the event, that have now been officially sold, All (I think) to Teala employees.
Much like with the release of the M3 6 years ago they are intentionally selling the 1st ones to Tesla employees as a way to gather some real world feedback before selling to the general public.
I can understand the strategy, for all the attention Tesla gets its easy to forget this auto company that is only 20 years old and the CT is only their 6th unique vehicle
At the same time… I can 100% understand criticism of “is it even really for sale if only xx have been “sold” and those sold were to friends/family?”
And I agree, I expect these 1st units had a hell of a lot more hands on production than later units will have as production ramps up in 2024.
That said I think it is anyone’s guess what production ramp up will look like and if Tesla can get to 250k units produced per year or more like was projected at the release party
*to be fair along the lines of making vehicles evs especially since all the tech is so new is hard… how many ev Humvees has GM sold since they’ve been in production over a year now? 30?
I think we agree – Tesla is actually doing things correctly in pre-release-releasing some vehicles for real world testing before they get too deep into mass production. Japan (Toyota specifically?) used to do this by releasing limited numbers of specific vehicles in Japan where they could closely monitor them and fix any design flaws before sending the model to the U.S. – thus cementing their quality reputation. GM, on the other hand is infamous for using first and second year buyers as beta testers.
I amsure these buyers whose job, future, and financial stability rely on success also give great reviews.
Yep hesitation to give critical feedback about a product your company has produced is certainly a real risk. Ive heard Tesla has built a culture of candid honesty (about short comings), but even unconscious hesitation to critize is real.
I don’t have in depth knowledge but from what I have read here and elsewhere Tesla pretty much lies about everything.i may be wrong.
Elon himself seems to be a rather complex person. I don’t know of any other leader quite like him in both positive and negative ways. I mean what person (even among the richest 50 people in the world), are regularly working +100 hr work weeks?
Do I think that’s a good idea?
Hell no.
The ‘lies’ of Tesla mostly seem to stem from Elon himself being incredibly optimistic for what he wants his products to achieve and when it comes to some hard specs like range Teslas regularly fall a little short.
Although on the flip side Tesla right now has M3s avaliable for $35k even without the $7500 tax credit. Now is that going to change in literally a couple of weeks when the calendar rolls over to 2024? Hell yes it will.
I also don’t know that his insistence on being Tesla’s CEO (or “TechnoKing”) makes sense either, why not find someone to assist and take over the role of CEO like he did with SpaceX? It seems like his personal psych. in how he sees himself is Way too wrapped up in this particular company.
Well IMHO the regular auto manufacturers are really slow moving hard to change behemoths. Elon is willing to change as soon as he sees something he likes better. Another person would not be able to do that to Elons satisfaction. Now is this a good thing or a bad thing? YES
Excuse my ignorance but I was wondering with the enormous thrust capacity of an EV how do they control traction? Is it just too much power to attain grip?
EV motors are leaps and bounds more responsive than ice and with sensors any wheel slip can be detected (and responded to) literally at least hundreds of times per second.
This is precisely how/why an aev rock crawler makes a Ton of sense between to ability to control power to each wheel plus it could be set up with in wheel motors and you could even have a hollow bar between the wheels to make for an ‘axel’ without having the complication of reduction gears reducing efficiency between front, center and rear mechanical differentials;
Of course batteries are still (relatively to gas), incredibly energy light, so perhaps (for now), an on board ice as an ev generator (which could be run on alcohol, ethanol or gasoline) still makes sense).
Thanks for the knowledge
It is not the Cyber Truck that I make fun of, it’s Elon’s arrogance and a presumption of superiority that I enjoy seeing being taken down a notch every once in a while. ⸌(ㆆ‿ㆆ)⸍
Porque no los dos?
The main question is why is the vehicle off the road in the first place? As far as airing down in the snow, in deep snow going from 25 to 12 psi is like going from 2wd to 4wd, it is super helpful and usually is the difference between struggling to not get stuck and driving through without issue.
I’ve never owned anything with lockers, but my experience in sub $500 80s Subarus absolutely supports airing down for snow*. And, a couple years back in a heavy snow changing to sleet, my Bugeye wrx was a chore to drive at 30psi in my new WinterForce tires. Took them down to 25 and it was again joyful.
*for a given value of snow: over 10” those poor underpowered things just couldn’t push much: they’d start plowing, and when it got over the bumper they just couldn’t do it.
Did we ever find out why the Cybertruck was on the side of the “steep snowy hill” in the first place? It’s probably a clue as to why everyone is making fun of it.
Because the person decided to steal a Christmas tree and didn’t want to walk down and back up the hill with his loot.
You are on to something there. I don’t see a Forest Service tag attached to it.
Yup. They were off trail and should be shamed relentlessly
To me this just shows the first limitation of anyone’s offroad ability that many seem to forget: Don’t drive into what you can’t drive out of.
I joke about passing stuck Jeeps in the mountains in my Subaru but it isn’t because my Crosstrek is some offroad marvel. It’s because I know what it can and can’t do and base my decisions on that.
Not here to defend or bury the Tesla…..just largely to point out the driver did something ill thought out and needed help.
This. I’ve taken Subarus into places people just stare at me for. Only had to be pulled out twice: once very early into them in a 2wd and again only because I had a buddy with me when I wanted to try something I was pretty sure I couldn’t do but I had backup.
and I always carry straps & a small shovel & proper clothing/boots to walk out—plus a couple 50 bills to entice a Good Ol’ Boy to pull my silly arse out if I do go too far
In college I had a MKI GTI (84′). Two friends and I drove it from IA to TX (S. Padre). Somewhere in I think S. Kansas I-35 was being shut down due to a spring snow storm. For a few hundred miles the the interstate felt like we were (light) off roading based on how bumpy it was from snow and ice.
We saw many, many full size 4×4 pickup trucks literally spinning all 4 wheels on interstate on-ramps, while my little fwd GTI easily could make stops & get back on our way…
The difference was I still had my winter tires (blizzaks) on 🙂
2015 or so I was on 220 in my 85 300TD through snow starting around 6-7” and getting deeper every mile (was almost 10” when I got home some 40 miles later) I went north. Truck tires on stock bunt wheels on the back, cruising easily about 35mph. Came upon a lifted brodozer with massive chrome stack & really wide mud boggers doing maybe 25ish. Passing him pissed Mr Man off no end: for the next mile or so I would hear his diesel turbo spin up, then see his headlights swinging wildly, then he’d slow it down a bit—then try again.
I just plodded along in my cozy cocoon listening to Hearts of Space on npr & chuckling contentedly
Haha that is delightful
There seems to be a massively misplaced amount of confidence in stocks 4×4 drivers and the abilities of their vehicles.
I’m a big proponent of the fundamentals, maximizing traction, increase contact patch and (usually) minimizing weight when it comes to getting through snow on bad roads.
Off road I think these same simple rules apply, though I’d add decent approach, break over and departure angles. And progressively using 2wd, then 4 wd high and lastly (last resort) 4wd low.
Of course ice engine AWD and ev AWD change things…
Having no recovery points is certainly something to be ashamed of!
I don’t care what automobile you’re building or how much it weighs, it needs at least one recovery point in the front and one in the rear.
IMHO said recovery points should be strong enough to handle use with a recovery rope at the minimum.
Agreed. I also think that every car should come with a hitch, even cars that have no business towing. It’s just useful to have, as a recovery point or bike rack mounting or whatever. It’s not like tow hooks or hitch receivers really involve major design compromises.
Clearly you’ve never tried to add a rear tow point to a series 1 Lotus Elise. There is very little structure behind the rear suspension, and what structure there is is boxed in with fragile GRP and 2mm aluminium diffuser panels. Also centre exit exhausts.
I know, niche car.
Similar thing with aluminum cars like the first gen Honda insight, noone makes an aluminum hitch receiver.
That being said every vehicle should have recovery points that are at least strong enough to handle a recovery with a recovery rope.
If we’re going to bring up towing, I could tell a long winded tale about towing a Triumph TR3 from Kansas to CA with a ’78 Chevy Monte Carlo through lots of snow up around Albuquerque,