Model X tow capacity is too low for me

[Seesaw]

5000 pounds is impressive, about double than what I was expecting.

 

[JRP3]

Keep in mind that to tow 10,000 lbs requires MUCH more than just an electric motor and a battery capable of doing it. The chassis and suspension have to be designed and engineered specifically for towing to handle that much weight, with all the compromises that involves. We're talking body-on-frame with leaf springs, and more than likely, heavy duty front suspension like a one ton diesel truck has.

Not that your general premise is wrong but the Ford F150, a half ton truck with coil over front suspension, is rated for 12,000 lb towing in certain configurations: http://www.ford.com/trucks/f150/specifications/towing/

 

[bwa]

It's more complicated...

Originally Posted by Panu

According to wikipedia class III towing capability means:

It's more complicated...
And I think this is where benzer's confusion comes...
Trailer Hitches, Hitch Accessories, Hitch Wiring
Class III

1. Class III hitches are weight carrying (WC) and also are weight distributing (WD) depending on the vehicle and hitch specifications.
2. Not all Class III hitches are rated to be both. See the specific hitch for that information.
3. Class III hitches used as weight carrying are rated up to 6000 lbs. gross trailer weight (GTW) with a maximum trailer tongue weight (TW) of 600 lbs.
4. Class III hitches used for weight distributing are rated up to 10,000 lbs. gross trailer weight (GTW) with a maximum trailer tongue weight (TW) of 1000 lbs.
5. A Class III hitch usually has a 2" square receiver opening.
6. A higher class drawbar does not increase the towing capacity of the hitch. To use this class of hitch for weight distribution requires a weight distribution system.
7. Class III hitches attach to the vehicle frame only.

Some info on weight carrying vs weight distributing hitches.


“Weight Carrying” refers to the amount of load a receiver hitch is capable of carrying when used as a “deadweight” hitch — that is, using only a standard utility ball mount to connect the hitch to the trailer. “Weight Distributing” is the rating used to describe the capacity of that same receiver hitch when used in conjunction with a weight-distributing hitch kit, which increases the hitch’s capacity, because it spreads some of the weight of the trailer out over the tow vehicle’s, and a trailer’s suspension and tires, as opposed to concentrating it at the hitch and trailer coupler. Typically, a receiver’s Weight Carrying load rating is much less than its Weight Distributing rating: For example, a Class III receiver might be rated to carry 5,000 lbs. as a Weight Carrying hitch, and 10,000 lbs. when used with a Weight Distributing hitch.
​

Aha, so, theoretically:

+ Somebody COULD offer a distributing hitch augmentation
... + This could be Tesla
... + This could be someone else, under Tesla warrantee
... - This could be someone else, not under Tesla warrantee
... - This could be legal, or illegal
- Maybe we contemplate the possibility of someone offering this, but no one ever does.

Part of what they're saying by distributing the load more is that you get more load on the trailer's wheels. So, for instance, if you had a multi-axle trailer where most or nearly all of the weight of the trailer (dead or live) is on its own axles, then just pulling and pushing the trailer around is maybe easier and maybe safer than holding massive portions of the trailer's weight up (kind of like a train, where the locomotive doesn't carry the weight of the train (besides itself), just pulls and pushes it).

If the weight of the tractor is insufficient, it would be run over by the trailer when the tractor tried to maneuver (e.g., stop, emergency turns).

Now, if they could put a Tesla motor and software in the trailer axles itself, it becomes a different beast entirely! They'd have to call it "an articulated vehicle" at that point, for regulatory purposes, I have a feeling, because I doubt laws are even written for that. Or just call the motors "special brakes" and ignore them, even though they make the trailer go forward and regenerate energy. They could even laden the trailer with Tesla batteries to make up for aerodynamic losses.

A curtain between the body of the X and the trailer for a trailer wind-designed and at similar profile to the X would help with aerodynamics (look at all the aerodynamic enhancements on tractor-trailer combos on US-CA-I-5 in the central valley). The trailer and front vehicle could share battery resources, or keep them to themselves.

But none of that has been announced by Tesla, so it's just all silliness at this point. Like putting helium (or hydrogen) in the trailer (it wouldn't work, by the way --- I calculated it one day).

 

[Zoomit]

I would not expect anyone, Tesla or otherwise, to be able to modify a vehicle like this to handle a weight distribution hitch. The capability is integral to the original design. Think about taking a pipe, putting it in the hitch receiver, and trying to smash the FRONT tires into the road. That's a unique load case that needs to be considered during the unibody structural design process. There is some inherent ability for the body to transfer that load but it may not be able to withstand all of it without still meeting structural margins.

This video is a good 1 minute intro to what a weight distribution hitch does:

 

[jhs_7645]

I would not expect anyone, Tesla or otherwise, to be able to modify a vehicle like this to handle a weight distribution hitch. The capability is integral to the original design. Think about taking a pipe, putting it in the hitch receiver, and trying to smash the FRONT tires into the road. That's a unique load case that needs to be considered during the unibody structural design process. There is some inherent ability for the body to transfer that load but it may not be able to withstand all of it without still meeting structural margins.

This video is a good 1 minute intro to what a weight distribution hitch does:

If I understand what's happening here, we're really just talking about distributing the tongue weight to both wheels. shifting 600 lbs to distributing 300 to each axle? I honestly think that an SUV with a 1200 lb battery that's build into the frame can probably withstand that. It's really just probably a matter of testing/certification.

 

[bwa]

I would not expect anyone, Tesla or otherwise, to be able to modify a vehicle like this to handle a weight distribution hitch. The capability is integral to the original design. Think about taking a pipe, putting it in the hitch receiver, and trying to smash the FRONT tires into the road. That's a unique load case that needs to be considered during the unibody structural design process. There is some inherent ability for the body to transfer that load but it may not be able to withstand all of it without still meeting structural margins.

This video is a good 1 minute intro to what a weight distribution hitch does:

Awesome. Never knew that existed. Here's a longer version that really shows it, too (I'd recommend watching both):

How to use a weight distribution hitch - YouTube

I agree with your "integral to the original design" remark. Obviously, the leverage system this distribution hitch uses puts a lot of force on the fulcrum points. No way a 5,000# tongue weight limit designed vehicle would allow a heavier fulcrum point without proper engineering. BTW, the strong metal that must be used in a distribution hitch must weigh a lot, too.

If the trailer had an articulated front axle (either fifth wheel or some type of steering apparatus) and a rear axle that together held the entire weight of the trailer by itself (not on the tongue) and the tongue only had to pull and push and not carry any weight except for the connection armature and non-straight situations (turns, cresting hills and the bottom of valleys), then the engineering would be different. Is that even legal to carry (a multi-axle trailer that carries its own weight front & back completely stable on a class C driver's license vehicle)? I have a class A driver's license and those vehicles allow that, so I'm ignorant on smaller trailer combos. And what would the engineering implications be? I have no idea: a 5,900# pulling vehicle might not have enough control over a 10,000# trailer in this combination even though it's not carrying its downward weight. Also, the force 10,000# puts on the tongue pulling backward (and forward in breaking maneuvers) might be too much even though it's not putting downward force. Besides, could the Model X even stop safely in this setup?

 

[swaltner]

@bwa, thanks for that second video. I had seen references to the WD hitches, googled them in the past and saw pictures of how the looked, but didn't understand how they were different. I hadn't seen an explanation of how the bars attached, so it was very confusing on what was going on with them. This video shows how they are installed and makes it easy to visualize how they're different. Thank you.

 

[bws]

Thanks. Just judging by the size of the space versus the size of the size I am confident my oversized two horse trailer could fit through there.

I would not count on many of these for some time. This June we took a 5100 mile road trip in our Tesla, traveling from San Jose, CA east on 80 to Salt Lake City, then down to 70 to Denver, over to SD (Mt Rushmore), then west along 90 to WA and then back south to CA. The Rocklin Supercharger was the only one I can remember that was like this (and it is located at a Tesla Store). Most of the locations require backing in to a spot that is on the edge of a parking lot. Less than 1/4 of them had one (or sometimes two) pull forward spots. We did not stop at every supercharger, on our path, so we could have missed some others that are pull forward, but the majority are not.

 

[AlMc]

I would not count on many of these for some time. This June we took a 5100 mile road trip in our Tesla, traveling from San Jose, CA east on 80 to Salt Lake City, then down to 70 to Denver, over to SD (Mt Rushmore), then west along 90 to WA and then back south to CA. The Rocklin Supercharger was the only one I can remember that was like this (and it is located at a Tesla Store). Most of the locations require backing in to a spot that is on the edge of a parking lot. Less than 1/4 of them had one (or sometimes two) pull forward spots. We did not stop at every supercharger, on our path, so we could have missed some others that are pull forward, but the majority are not.

Thanks. Not counting on it at all in my household

 

[benzer]

Has anyone discussed the all important wheelbase to rear overhang ratio?

Towing Test: Mercedes
GLK 250 BlueTEC

http://rvlifemag.dgtlpub.com/issues/2013-05-31/pdf/rvlifestyle_2013-05-31.pdf (page 6)


also see:

2010 VW Touareg TDI

"In terms of finding a tow vehicle you can live with everyday, the Touareg is tough to beat, and very likely unbeatable. For example, it’s a snap to whip into tight parking places at the grocery store, thanks to its short front and rear overhangs and a 112.4-inch wheelbase. The variable assist steering system is buttery smooth, with lots of boost at parking lot speeds, but nice and taught on the freeway."




Here is an excerpt from a posting from CANAM RV in London ONT Canada (full posting follows excerpt):

"The Exceptional vehicle of this group is the Mercedes R Class. Though similar to the rest it has 124.5” wheelbase with a very short rear overhang and though not sprung overly stiff the incredibly short overhang to wheelbase ratio makes it very stable. Friends that we travel with tow their 34’ Airstream with an R class."




(full post) *** Note the interesting history on weight distribution hitches and how this history affects WDH ratings on german vehicles today


Diesel SUV’s

We have a lot of calls from people who want to tow with one of the diesel SUV’s; the Volkswagen Touareg, BMW X5, Mercedes ML, GL & R Class. Besides all being from Germany they all perform quite similarly. They all have 3.0 Litre Diesel engines producing over 400 lbs. of torque mated to 6-8 speed transmissions. They have plenty of power to tow almost any trailer, though if you are spending that much on a vehicle to get better fuel mileage you would probably want to mate them to a relatively aerodynamic trailer.

Besides having a great deal of torque and a great drivetrain these are some of the best handling tow vehicles available. They all have independent suspension, precise steering and short rear overhangs. The models with Air Suspension are tuned to be softer riding so they are not quite as stable but still quite good. The Exceptional vehicle of this group is the Mercedes R Class. Though similar to the rest it has 124.5” wheelbase with a very short rear overhang and though not sprung overly stiff the incredibly short overhang to wheelbase ratio makes it very stable. Friends that we travel with tow their 34’ Airstream with an R class. Last summer I drove it from Boston to the centre of New York State on a mix of interstate and hilly two lane roads. At the end I really did not want to give the keys back.

Though the R class is hands down the best tow vehicle of the bunch it has the lowest tow rating at 3500 lbs. I guess since it is the most van like of the group Mercedes figured they would give it a van tow rating. The rest are rated in the 7000 pound range with one very confusing problem. They all advise against using a weight distribution hitch hence all the calls. Certainly there is no way to tow a 7000 pound trailer safely or comfortably without using weight distribution so how could these very sophisticated vehicle manufactures have those high tow ratings while opposing the use of weight distribution hitches? The answer is a long story.

The weight distribution hitch was invented by a Blacksmith M.H. Mathison in California in the early 1950’s. His invention was an immediate hit and suddenly he had a very fast growing business. He expanded rapidly in California and then built a second factory in Indiana, I met Mr. Mathison when I was just a kid, he opened a factory in London Ontario, my father’s partner Al Hamill lent him the money for the deposit on the land because the seller would not wait for a wire transfer which in those days took a couple of weeks. Unfortunately for European RV’rs he also thought it would be a good idea to sell hitches in Europe so he flew over to check out the trailers there. What he discovered were very light but flimsy trailers using mechanical surge brakes with chassis far too weak to withstand the pressure from weight distribution. However he noticed that most of the chassis were made by one company so he went to visit them. He suggested that if they were to install electric brakes (weight distribution does not work with surge brakes) and make the “A” frames stronger they could use his weight distribution systems, the trailers could be larger and stronger with more amenities which in his mind would be good for the industry.

However the chassis company saw it differently they thought if weight distribution hitches became accepted then nothing would be stopping people from importing the much cheaper trailers from the USA and they would lose their chassis business. The result was the chassis company took the protectionist route and managed to get electric brakes and weight distribution hitches outlawed in seven major European countries. So to this day even with all their advanced cars trailers in Europe are towed with brakes using the same technology as a Model “A” Ford and hitches from the same era. These diesel SUV’s come from Germany the engineers come from there as well, they have no exposure to weight distribution hitches so they do not really understand them. You will never get an engineer to endorse something they do not understand. Still in fairness most Domestic car builders don’t truly understand how to set up a weight distribution hitch.

Often people interpret the recommendation against weight distribution to mean that the body structure is not strong enough to withstand the force of the hitch. This is not the case at all these SUV’s all have very solid body structures; they are among the strongest vehicles on the road. However like many vehicles their hitches leave a little to be desired. Until 2011 the Mercedes hitch was very weak and we saw many broken ones, the new Mercedes, BMW and Touareg hitches are better and are likely fine with many lighter trailers. The hitch designs still make me a little nervous as they use two long ears from the hitch receiver tube that weld to a round cross tube several inches above. When we set these vehicles up we do extend the hitches up to a structural member between the back wheels. I do know there are large numbers of people who are towing with the Touareg & BMW without the strengthening. The R Class does not come with a factory hitch but there is a relatively weak bolt on Class 3 that definitely requires strengthening.

Still if you want amazing fuel economy none of these are likely the best tow vehicle. The 3.0 litre diesel is also available in the BMW 3 series sedan where it delivers truly amazing fuel economy. Interestingly as we are starting to see more diesels the fuel economy of gas engines is getting closer. This summer when traveling the Ford Echo-boost in the Taurus was only 15% behind the Mercedes in fuel economy. The new Chevy Traverse with the direct injection 3.6 Litre is pretty close in fuel economy it does not have the massive torque of the diesel or the Echo-boost but a lot less expensive. At the moment Chrysler likely has the most fuel efficient large V/6 engine in their new 3.6 Litre mated to an 8 speed transmission. In 2013 you will be able to get Jeep’s Durango’s and Chrysler 300’s all with a 3.0 Litre diesel or the 3.6 gasoline. It will be interesting to see how these compare when they arrive.

 

[benzer]

If the trailer had an articulated front axle (either fifth wheel or some type of steering apparatus) and a rear axle that together held the entire weight of the trailer by itself (not on the tongue) and the tongue only had to pull and push and not carry any weight except for the connection armature and non-straight situations (turns, cresting hills and the bottom of valleys), then the engineering would be different.

you mean something like this?

Tow All 5th Wheel Trailers - YouTube

 

[Lyon]

Here is an excerpt from a posting from CANAM RV in London ONT Canada (full posting follows excerpt):[/B][/U]
[/FONT]
"The Exceptional vehicle of this group is the Mercedes R Class. Though similar to the rest it has 124.5” wheelbase with a very short rear overhang and though not sprung overly stiff the incredibly short overhang to wheelbase ratio makes it very stable. Friends that we travel with tow their 34’ Airstream with an R class."

These guys are something of a legend in the Airstream world and a never ending source of argument on airforums.com. Basically the arguments go in three directions:

1) These guys are looney tunes, don't have engineering degrees and would love to weld something up for you to sell you an Airstream. You can only tow within 10% of the manufacturer's specs. I must have a 3/4 ton diesel.

2) Well, what they say makes sense but I'm uncomfortable with the notion of towing a 10,000 30' Airstream Classic with a Ford Taurus so I'll get an F-150.

3) They've never had an accident that I know of and it all kind of makes sense, plus I really don't want to drive a truck, so I'm going to get my Honda Odyssey fitted out with a new hitch and transmission cooler and go tow at more than double what Honda says I can tow with it.

It's like the Hatfields and McCoys at times and more than one thread has been closed as a result.

I generally fall in the middle. To be frank, some dude at a service center cutting steel and welding up a hitch for me doesn't instill a lot of confidence in me but I would LOVE to be the plaintiff's attorney for the person who gets hurt when that rig has an accident (which will happen at some point). Also, I tend to be more trusting of the vehicle engineers who assemble these things. I think Tesla would LOVE to advertise a 10,000lbs towing capacity for Model X. They have no large truck sales to jeopardize so that argument gets no traction. Also, these guys are smart and have, you know, actual engineering and physics degrees and stuff.

 

[JRP3]

I once drilled a hole in the bumper of a Chevy Citation to mount a ball and tow my 18ft speed boat. Many things are possible, though maybe not advisable :biggrin:

 

[mknox]

I once drilled a hole in the bumper of a Chevy Citation to mount a ball and tow my 18ft speed boat. Many things are possible, though maybe not advisable :biggrin:

Nice. I had a bumper mounted hitch on my 1980 Chrysler Cordoba. Problem was, it was one of those bumpers mounted on shock absorbers. One time when I saw the whole rear bumper sag when I hitched up the boat, I immediately had a Class III frame hitch installed. Visions of my boat, trailer and bumper upside down in a ditch was not an appealing thought.

 

[FlasherZ]

Nice. I had a bumper mounted hitch on my 1980 Chrysler Cordoba.

With soft Corinthian leather! Ricardo Montalban sure knew how to sell them. And the Cordobas were called the *small* Chryslers...

My parents pulled a 1960's Shasta (complete with wings) with that car on a class 3 hitch attached. (EDIT: 1975 model!)

 

[mknox]

And the Cordobas were called the *small* Chryslers...

They were in the now extinct mid-size class called "two door specialty hardtop" along with the likes of the Pontiac Grand Prix, Olds Cutlass, Ford Thunderbird, Mercury Cougar and so forth. My 1980 was the first year of the "downsized" Cordoba, but it was still pretty big by today's standards. I remember my mother looking at the 1975 Cordoba when it came out and saying she thought it was a nice size for "around town". She was driving an Olds Ninety Eight at the time. I bought mine brand new for $8,800.00 and sold it six years later to a guy at work who begged me for it for $6,000.00. The only problem I ever had with it was a "weak" starter motor that cost me $50 to replace.

 

[Red Sage]

The chassis and suspension have to be designed and engineered specifically for towing to handle that much weight, with all the compromises that involves. We're talking body-on-frame with leaf springs, and more than likely, heavy duty front suspension like a one ton diesel truck has.

I seriously doubt that is the only way to manage the feat. I guarantee that if a Tesla Motors pickup truck is released, it will have a 15,000 lbs towing capacity with unibody construction and fully independent suspension. There will be no leaf springs, live axle, or separate bed. Though it may well retain a flared rear for a dually appearance. And after years of Ford using the material for their trucks, and the long collaboration with Alcoa that Tesla enjoys, it will likely be of fully aluminum construction. The Model X may well be the harbinger of things to come in more ways than one.

 

[JRP3]

However the Ford still uses a steel frame, not aluminum.

 

[Red Sage]

Hence, Engineering.

 

[JRP3]

Sure, but there comes a point of diminishing returns. Steel frames and solid axles are used because it's easy to get the necessary load bearing capacity from them. The F150 is the most popular selling pickup truck and it does not have 15K towing capability. Over engineering a Tesla Pickup Truck to reach a tiny niche of use capability does not seem like a rational use of design, and would probably not result in an affordable vehicle for the general F150 buying crowd.