Truck rolled/slid backwards while parked on hill

[GarageMahal]

Physics would say that’s not a factor.

Really... more weight + same contact area (resistance) = more likely to move

Simple physics experiment: take an empty container, put it on a steep slope, slowly add weight and see what happens.

My money is on the additional ton of weight.

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[Maquis]

Really... more weight + same contact area (resistance) = more likely to move

Simple physics experiment: take an empty container, put it on a steep slope, slowly add weight and see what happens.

My money is on the additional ton of weight.

The key is “steep”. At a 45 degree slope, the required force to overcome the friction increases at the same rate as the gravitational force as you add mass. At anything less than 45, the frictional component increases more than the gravitational force. I can’t believe his driveway slope is over 45 degrees.

 

[RickLightning]

Why did his other trucks never do this? As Rick said others have had the same issue. There must be something happening here that is different

Dumb luck.

My Mazda did it in 1994, once. The right conditions existed.

 

[Amps]

Dumb luck.

My Mazda did it in 1994, once. The right conditions existed.

I woke up one morning to someone blowing a horn from the street in front of my house. My red 1963 Chevy C-10 was against the curb on the opposite side and pretty much blocking the street. It was parked on an incline "on" the snow after I moved it from being parked "in" the snow.

 

[Monkey]

Is this something specific to the way the "park" works on the electric motors as it doesn't have a park in transmission?

The electronic parking brake in modern ICE vehicles and what we find in EVs / the Lightning, is the same. In the Lightning or other EVs it automatically engages when the truck is parked and disengages when you put it in drive. In an ICE vehicle, the EPB locks 2 wheels -- typically the front. EV's lock 2 wheels, usually the front. Manual transmission vehicles can be engaged in-gear to add the transmission/engine as additional measure against rolling. Auto transmissions do have a parking pawl. Which clamps the transmission when it is in park. These are almost always inferior to the parking brake. -- Park on a hill with a loaded trailer and just use the parking pawl, you're asking for trouble. However, in a full-time AWD or 4WD the parking pawl and transmission can offer resistance on all 4 wheels.

What we're seeing here with your truck is the front wheels, locked in park, lost grip on your driveway and slid and were undoubtedly locked and never rolling the whole time the truck moved. There are videos online of other cars/trucks doing this on slick driveways. Not in any way an EV thing, yet seems to get a lot of EV attention when it happens... Weight and weight distribution can be a factor, especially as the driveway becomes steeper. in an ICE with the engine and center of mass located more front-biased toward the front-locked wheels, makes a difference. In an EV with more mass and more evenly distributed between locked front and the rear unlocked wheels also makes a difference.

But as others have pointed out in this thread, it's more about ideal conditions than anything.

 

[jimfigler]

Maybe EV tire design?

 

[Freddyfresh]

My car rolled down the driveway. It did not slide. It happend twice. Once each winter. Ford is looking into it. As there first response was stupid. It said owner needs to engage parking break. But the car does it on its own. So there are looking for a fix.

 

[Freddyfresh]

Yes, others have had this happen, due to ice building up under the tires. Beyond setting the parking brake, as you did, or chocking the wheels, there is little you can do to stop it.

My car rolled down. Did not slide down the hill.

 

[RickLightning]

My car rolled down the driveway. It did not slide. It happend twice. Once each winter. Ford is looking into it. As there first response was stupid. It said owner needs to engage parking break. But the car does it on its own. So there are looking for a fix.

brake...

Someone had their Mach-E do this, twice, and it's clear the back tires are turning, not sliding.

 

[Freddyfresh]

When in park, there's a pawl that slaps itself right into the motor. Your wheels did not turn- the truck slid on ice.

My car rolled did not slide. This happened in January this year. Ford is looking into it. Here is part of the ring camera video it captures just part of it.

 

[MillieChliette]

My car rolled did not slide. This happened in January this year. Ford is looking into it. Here is part of the ring camera video it captures just part of it.

You can clearly see the rear wheel NOT spin in your own video.

 

[Freddyfresh]

My car rolled did not slide. This happened in January this year. Ford is looking into it. Here is part of the ring camera video it captures just part of it.

Your right

 

[GoodSam]

Rear has the parking pawl, front is able to roll? Does not look like much slope to get a slide going. Since the windshield is clear, must be someone inside ? Must have parked on slippery stuff and looks like a low spot was right behind the rear wheels? Evidently, if emergency brake was on, it does not affect the front wheels.

 

[KickingGas]

My 2019 Dodge Challenger slid once. I was at my parents house shoveling their driveway. Happened sort of in slow motion - I could see it sliding and I instinctively jumped in it, started it, and got it going just before it before it slid into traffic. It was AWD and I was able to drive it up into their garage easily. I really do love my truck, but not that much... Anyway, I had a clear view of the tires and they were definitely sliding, not rolling. Really hope this doesn't happen with my Lightning!!

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