I thought we had antilock brakes

[hacer]

I was driving 45 - 50 today in the left lane [later changed to right lane] passing a very large truck, when he suddenly moved into my lane, either he did not see me or was pre-occupied. In any case i hit the brakes hard to fall behind him and the wheels locked and I skidded. It felt like the back is what locked up but I can't be sure. Has anyone else had the wheels lock up?

You're not supposed to pass on the right. The tire marks in the picture show the car steered left towards the truck that was veering into your lane. This is another thing that makes the photo disagree with the description. These tire marks aren't from the described event. Maybe the ABS worked so well that there were barely any marks when you went back to find them so you erroneously thought these were your marks.

 

[Skysurfer]

You're not supposed to pass on the right. The tire marks in the picture show the car steered left towards the truck that was veering into your lane. This is another thing that makes the photo disagree with the description. These tire marks aren't from the described event. Maybe the ABS worked so well that there were barely any marks when you went back to find them so you erroneously thought these were your marks.

I think that is the most likely scenario. The event probably happened on or near those marks and they were mistaken for ones left by their vehicle. Curious to see what the service center says though.

 

[Nikola M3]

WOW, some of you guys are not much help. I posted this because it defies reasonable logic, to you AND me also.

Maybe I will meet some of you posters and you will get to know me personally and not doubt what I say. P85_DA knows who I am, he knows I am genuine. My info is not showing because there are some weird folks on the forums. When you meet me in person I will share all.

Tomorrow I will try to find some loose dirt to test on. I realize dry pavement would be best but I don't want to damage the tires any more than is necessary. If I can find a satisfactory place I will do a low speed, depending how much room there is, panic stop and get some more photos to post. It may shed some light on what is happening.

The wife is not liking this idea but I think it might be helpful to some of you and I am also interested in the results.

 

[Nikola M3]

You're not supposed to pass on the right. The tire marks in the picture show the car steered left towards the truck that was veering into your lane. This is another thing that makes the photo disagree with the description. These tire marks aren't from the described event. Maybe the ABS worked so well that there were barely any marks when you went back to find them so you erroneously thought these were your marks.

Hacer,

With all due respect you weren't there so REALLY?

The truck was one of those tank trucks that sucks out septic tanks. There was 2 lanes going my direction. He was on the left doing about 20, and wandering in his lane. In hind sight he was probably texting or dozing, I just wanted to be past him in a safer part of the road where he wasn't. I am driving a car that has this awesome ability to rocket past in an instant. As I punched to pass him he moved quickly into my lane. That is when I hit the brakes. He obviously realized he was drifting because he jerked the truck back after he crossed into my lane by 2 - 3 feet. I doubt he even saw me because I never got closer than a car length to his rear. After his "move" his driving got real steady and I passed normally.

 

[erthquake]

There are plenty of low traffic two lane roads in and around Cathedral City and Palm Springs. Setup an iPhone on a tripod and have a friend operate it in slo-mo my mode. Set the the phone back away from the street a bit so it has a wide field of view. Wait until traffic is clear and then drive at 35 mph or so and do a panic brake in front of the camera.

That should be plenty of speed to test the ABS and if the wheels do lock you won't wear them down much and shouldn't do any damage.

Try to recreate the sudden acceleration and braking scenario that you described above.

Even hand holding the iPhone should be adequate in daylight.

 

[Jdcorbitt3]

I was driving 45 - 50 today in the left lane passing a very large truck, when he suddenly moved into my lane, either he did not see me or was pre-occupied. In any case i hit the brakes hard to fall behind him and the wheels locked and I skidded. It felt like the back is what locked up but I can't be sure. Has anyone else had the wheels lock up?

View attachment 314160

Nikola.

Sorry, but those are acceleration skid marks from a standing start. Notice the drift from center to right due to camber in the road. They are not from your braking event. Yours are around, but a wheel in motion going into lockup goes from light to dark. Even aircraft skid marks, where there is no rotation, transitioning to pavement have a lead to the darkest part of initial skid. The beginning of the skid has a starting point perpendicular to the road, which, indicates 0 forward velocity at the beginning of the skid.

John

 

[sperkin]

Nikola.

Sorry, but those are acceleration skid marks from a standing start. Notice the drift from center to right due to camber in the road. They are not from your braking event. Yours are around, but a wheel in motion going into lockup goes from light to dark. Even aircraft skid marks, where there is no rotation, transitioning to pavement have a lead to the darkest part of initial skid. The beginning of the skid has a starting point perpendicular to the road, which, indicates 0 forward velocity at the beginning of the skid.

John

Looking closer at the picture on a PC now, and I have to agree, they were from a burn out.

 

[hacer]

Hacer,

With all due respect you weren't there so REALLY?

The truck was one of those tank trucks that sucks out septic tanks. There was 2 lanes going my direction. He was on the left doing about 20, and wandering in his lane. In hind sight he was probably texting or dozing, I just wanted to be past him in a safer part of the road where he wasn't. I am driving a car that has this awesome ability to rocket past in an instant. As I punched to pass him he moved quickly into my lane. That is when I hit the brakes. He obviously realized he was drifting because he jerked the truck back after he crossed into my lane by 2 - 3 feet. I doubt he even saw me because I never got closer than a car length to his rear. After his "move" his driving got real steady and I passed normally.

I mean no disrespect and I was not there. I'm only trying to reconcile what you say with the picture that you posted. Those tire marks curve leftward as they progress forward (just look at the picture). Leftward is towards the left lane, and thus towards the truck in your description above: "He was on the left ". I assumed that besides slamming on the brakes that you did NOT also steer towards the vehicle that you might hit. But maybe that is what you did. I just thought it was more plausible that when you went back you found the wrong marks.

The tread pattern of the tires are clearly visible in the photo so we can plainly see that the skidding was always along the direction of the tire, never sideways to it. If you steered right, the skid marks cannot be from your front tires because those tires would aim right. Neither could they come from the back-tires skidding with the back-end sliding out, because although this would leave skid marks that move left, they would have to show sideways skidding to the tread, but the photo doesn't show that.

Memory is a funny thing; especially in panic situations people tend to form strong impressions that lead them to think their memory is clear but unfortunately they are often wrong impressions of what actually happened False memories. Perhaps these skid marks are from a "burn out" where you "punched to pass", instead of the moment later when you slammed on the brakes and the loss of control you felt was during the burnout period of the event because the acceleration caused a slight leftward pull to the steering that you didn't counter under the heavy acceleration. That goes against your memory (and thus statements) of what happened, but fits with the photograph pretty well.

This is not any attack or disrespect to you, false memories can happen to anyone myself included; they are a scientific fact of the way our brains work. I am not claiming that you are lying or purposefully making anything up.

 

[Nikola M3]

I went back to the skid marks and set the car on the marks, the tires did not line up, see pics. I even checked to see if the front tires were a fit, nada.

Sooooo, I owe a big apology to all of you. It is like Hacer explained it or similar. I did not see any other significant marks in the area so I can’t explain what I felt, and obviously those marks whether acceleration, braking, wrong direction, etc, are not from my car.

For another test I found an area off the main road that was for construction vehicles with a layer of sand on the pavement. I tried twice to slide the car with full locked brakes. During the braking It did slide and release several times while I held the brake full down. I can’t be sure if it was the ABS working or the inconsistency of the sand on the pavement. There was not enough definition on the pavement / sand to draw a conclusion.

 

[animorph]

Thanks for hanging in there and the new info!

 

[silentsnow31802]

I never realized how wide those hips were. MMmmMmm

 

[LargeHamCollider]

I'm just happy to know you were honestly mistaken and not *yet another* concern troll trying to tarnish Tesla's rep.

 

[Nikola M3]

I'm just happy to know you were honestly mistaken and not *yet another* concern troll trying to tarnish Tesla's rep.

Troll, not likely, I love this car, everything about it. I'll show you my plates when they come in.

 

[Thomas Edison]

I went back to the skid marks and set the car on the marks, the tires did not line up, see pics. I even checked to see if the front tires were a fit, nada.

Sooooo, I owe a big apology to all of you. It is like Hacer explained it or similar. I did not see any other significant marks in the area so I can’t explain what I felt, and obviously those marks whether acceleration, braking, wrong direction, etc, are not from my car.

For another test I found an area off the main road that was for construction vehicles with a layer of sand on the pavement. I tried twice to slide the car with full locked brakes. During the braking It did slide and release several times while I held the brake full down. I can’t be sure if it was the ABS working or the inconsistency of the sand on the pavement. There was not enough definition on the pavement / sand to draw a conclusion.


View attachment 315586 View attachment 315586 View attachment 315588

 

[techmaven]

For another test I found an area off the main road that was for construction vehicles with a layer of sand on the pavement. I tried twice to slide the car with full locked brakes. During the braking It did slide and release several times while I held the brake full down. I can’t be sure if it was the ABS working or the inconsistency of the sand on the pavement. There was not enough definition on the pavement / sand to draw a conclusion.

So next time it rains, take the car to a deserted parking lot and do a controlled panic brake test. It should definitely pulsate. You don't want any question in your mind on what to do in a panic situation. Test it and put it to rest either way.