First Jerry rig everything, now mark rober 🧐

[cybercricket]

My practicality concern is axle loading on a Beast + Range Extender + 11k trailer while lacking weight distribution guidance from Tesla.

Perhaps it's not an issue now that the Range Extender is cancelled

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[cybercricket]

But that's not what's being discussed, it's the safety factor rating.

Well, perhaps you have the definitions handy. What is the safety factor number in this context.

 

[mongo]

Perhaps it's not an issue now that the Range Extender is cancelled

Has Tesla said it's canceled, or is that just the conclusion people are jumping to due to removal from the configurator?

 

[cybercricket]

Has Tesla said it's canceled, or is that just the conclusion people are jumping to due to removal from the configurator?

To my knowledge Tesla hasn't commented on it in the recent months.

 

[BannedByTMC]

Well, perhaps you have the definitions handy. What is the safety factor number in this context.

Read mongo's posts.

 

[cybercricket]

Read mongo's posts.

@mongo is citing the regulatory documents that don't directly define the safety factor as a term, but rather deal with the raw numbers. If one criticizes a high level Tesla engineer for improperly making a claim, then perhaps one could also point to where the term in question is defined within the regulatory documents.

 

[mongo]

@mongo is citing the regulatory documents that don't directly define the safety factor as a term, but rather deal with the raw numbers. If one criticizes a high level Tesla engineer for improperly making a claim, then perhaps one could also point to where the term in question is defined within the regulatory documents.

Can we agree the hitch will see more than 1,100 pounds vertical loading in normal use and therefore agree 1,100 is not the correct number to base a safety/ headroom factor off of?
If you want closer to reality numbers, the European standard models the worst case trailer inertia and truck suspension dynamics (then applies a factor to it...).

 

[cybercricket]

Can we agree the hitch will see more than 1,100 pounds vertical loading in normal use and therefore agree 1,100 is not the correct number to base a safety/ headroom factor off of?
If you want closer to reality numbers, the European standard models the worst case trailer inertia and truck suspension dynamics (then applies a factor to it...).

Even this simple question is rather tricky. I agree with you that the peak loads may be in excess of 1,100lb, but it's going to be less than 1% (arbitrary small number) of the time. Thus is it appropriate to call it "normal use" ? And again, I don't question the numbers but rather the terminology. If the docs you cited don't use the terminology such as "safety / headroom factor" then you'd have to cite another authority to prove Wes wrong. If that's just your interpretation, then it's just as good as mine.

 

[mongo]

Even this simple question is rather tricky. I agree with you that the peak loads may be in excess of 1,100lb, but it's going to be less than 1% (arbitrary small number) of the time. Thus is it appropriate to call it "normal use" ? And again, I don't question the numbers but rather the terminology. If the docs you cited don't use the terminology such as "safety / headroom factor" then you'd have to cite another authority to prove Wes wrong. If that's just your interpretation, then it's just as good as mine.

Are you saying less than 1% of people will have a trailer with 1,100 tongue weight, or that the hitch will see more than 1,100 pounds vertical loading less than 1% of the time?
Either case is irrelevant, just wondering.
Safety factor is based on design loads for strength. I suppose it may be based on expected use for fatigue.

Tesla says the truck is built to handle an 11k trailer with 1,100 tongue weight in expected driving conditions. That means it can handle 1,100 + dynamic load of an 11k trailer. Therefore, expected forces are greater than 1,100 and it should be designed to handle some amount of force greater than that 1,100 + dynamic value. The difference between the expected max force and the designed strength is the safety margin if ignoring fatigue. Including lifetime fatigue, the value would be something like half the inital strength.

If one says a there is a safety factor of 10x on tongue weight, is that really saying the truck could handle an 110k trailer with 11k tongue, at least vertically?

 

[Deleted member 22486]

Lidar can just give additional information to the GSD computer. Additional to the cameras. It’s that simple. It’s also that simple that the big reason Elon doesn’t want to do that is because it costs more money to do so. It costs more money to purchase a sensor and it costs more money to do sensor fusion compute-wise. Arguably if you can do that you get a better system, but he’s not going to do that unless some of those cost go away. So debating this is almost pointless.

 

[Deleted member 22486]

Let's be honest, sometimes you post dumb stuff. What has a better chance of reflecting from a solid in a fog and in the presence of ambient light and then registered by a sensor: broad (both shape and spectrum) beams from the headlights, or a narrow (again shape and spectrum) beam from a laser ? Also who is paying for installing streetlights in every shithole in America ?

Dumb stuff? I think we all do that from time to time, but it’s OK. And honestly, her last point isn’t dumb but most decidedly your last post is cruel and you don’t need to do that. You could’ve left out that comment and still made your point.

 

[Deleted member 22486]

Even this simple question is rather tricky. I agree with you that the peak loads may be in excess of 1,100lb, but it's going to be less than 1% (arbitrary small number) of the time. Thus is it appropriate to call it "normal use" ? And again, I don't question the numbers but rather the terminology. If the docs you cited don't use the terminology such as "safety / headroom factor" then you'd have to cite another authority to prove Wes wrong. If that's just your interpretation, then it's just as good as mine.

The Society of Automotive Engineers (SAE) guidelines typically suggest that the vertical load on a trailer hitch should not exceed 10% of the trailer’s gross weight. For an 11,000-pound trailer, this would mean a maximum vertical load of 1,100 pounds on the hitch point. Specific standards like SAE J2807 emphasize testing with tongue weights at 10% of the trailer weight for conventional towing. Real-world scenarios, however, may require hitches to withstand dynamic forces beyond static ratings, especially during braking or road irregularities. Those real world scenarios involve some of the very things that Jason talked about in his video. He noted in the video that most manufacturers, including RAM, test tongue weights at 15%, not 10%, of the trailer weight for conventional towing in order to accommodate for some of these dynamic forces. He also said that there are some real world scenarios where the entire weight of the trailer could be transferred to a vertical load for a brief period of time (and demonstrating at mathematically, showed how that could happen). Then there’s the whole discussion about how brittle aluminum vs steel and how the fatigue rating is very different between the two materials.

All good reasons why I believe his analysis to be a thorough one.

So even though many of us thought Jerry‘s video was bullshit at first… it has SOME validity to it.

 

[CyberGus]

is that really saying the truck could handle an 110k trailer with 11k tongue, at least vertically?

I expect a YouTube video on this shortly

 

[CyberGus]

Sorta, the requirement has some safety/ fatigue factor over expected force, but expected force must be greater than 1,100 due to dynamic loading. So failing at 2,200 is definitely not a 2x safety factor, nor is 10,400 a 10x factor.

Right, the specification for "5x of tongue weight" isn't the safety margin, it's the minimum requirement.

 

[mongo]

Right, the specification for "5x of tongue weight" isn't the safety margin, it's the minimum requirement.

Yah, but I think the argument is that we don't have the data to say that the 5x itself isn't 4x expected load with a 1x margin on top.
The UNECE 55 methodology pulls in more physics, and applies factors to it which may include safety margin.

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