2008 Toyota Highlander V6 towing 16'ft. Casita SD?

[koy]

Thank-you,patrick for your advice. I thought about ordering a transmission cooler online and have a independent auto shop install it for me. what do you think ?

[gordon2]

Originally Posted by koy

Thank-you,patrick for your advice. I thought about ordering a transmission cooler online and have a independent auto shop install it for me. what do you think ?

I would go to the shop first and make sure they can fit the one you plan to order. That is if I were to use that 08 Highlander at all.

[John in Santa Cruz]

Originally Posted by mizterwizard

There is nothing magical about towing ratings. The factory picks a number based on intuition, expectation of owner use/abuse and very little science. ....

not at all true, since the new SAE J2807 standards were adopted 5 or so years ago.

SAE J2807 Tow Tests - The Standard

this is also why quite a few vehicles were derated when these were adopted, as they simply didn't have the power to climb at the required speeds and accelerations.

[Humblepaul]

https://www.etrailer.com/question-36270.html You can tow up to 5K with some modifications.

[mizterwizard]

Originally Posted by John in Santa Cruz

not at all true, since the new SAE J2807 standards were adopted 5 or so years ago.

SAE J2807 Tow Tests - The Standard

this is also why quite a few vehicles were derated when these were adopted, as they simply didn't have the power to climb at the required speeds and accelerations.

This is a quote from the article cited:

Maximum trailer tow ratings have been a bit of a mystery over the years. Manufacturers each had their own somewhat secret ways of determining how much weight their diesel vehicles could safely tow, but there was no universal testing standard for all of them to follow.

That sounds pretty much like what I said, I think.

There is a competition between the various vehicle manufactures to out spec the other guys each year. Towing ability is one of the main areas of competition. Someone will come out with the highest towing rating one year and the next year everyone else will catch up or more likely surpass them. All without a single change in the structure of the vehicle. It's been going on for decades.

Today's compact trucks have higher ratings than full sized trucks from 30 years ago because of the constant battle to have the highest number. As a consequence, the trucks themselves have gotten ever larger and heavier.

If a rating is quoted as being in compliance with a standard of measurement then at least it will have some validity. But, another quote:

The chassis content required (suspension, steering, brakes, and so on) is “immaterial to this section as long as it does not affect propulsion/powertrain selection or final drive ratio.” This became a bit of a loophole when manufacturers passed the test using vehicles “equipped” with bumper and spare tire delete options meant for work trucks, but after that became public, everyone seemed to straighten up their acts and stopped taking advantage of this non-requirement.

From this we see that even with a standard, the manufacturers are not above stripping a truck to get a better number. A chassis/cab model could be tested and the result could be used for the comparison number.

Maybe there is a little more in the number than I indicated but my point was that a number, any number, is more like the pirate's code than like the speed of light.

https://www.youtube.com/watchv=WJVBvvS57j0

Even with the existence of a standard, towing ratings are still not absolute. If they were then they wouldn't be in round numbers. The standard is for comparison and as a guideline. It is not a limitation.

I have in my shop at this moment a truck with air bags to hold the suspension up because it hauls and tows way more than it is supposed to. Many RV tow vehicles are like this. Equalizing hitches, suspension upgrades and many other mods exist so that people can tow more than the rating of their vehicles.

https://www.youtube.com/watch?v=kzfND5fcpB4

[steve dunham]

Originally Posted by mizterwizard

I have in my shop at this moment a truck with air bags to hold the suspension up because it hauls and tows way more than it is supposed to. Many RV tow vehicles are like this. Equalizing hitches, suspension upgrades and many other mods exist so that people can tow more than the rating of their vehicles.

Can or should , the terms are not synonymous.
Upgrading the hitch , suspension , cooling , etc , etc doesn’t do a thing for braking ability .
If you want to tow beyond a vehicle’s ratings so be it , encouraging others to follow is another story .

[gordon2]

Originally Posted by steve dunham

...doesn’t do a thing for braking ability .
....

I was under the impression that trailer brakes, when adequately sized, adjusted and maintained, basically put no more load or stress on the tow vehicle then if the trailer did not exist at all. That is to say that the trailer's brakes stop the trailer without any more or any less use of the tug's brakes. Of course not all rigs are properly set up an maintained but if they are, then the braking ability of the tug becomes a moot point as far as adding a trailer is concerned. So if the tow rating is assuming that the trailer brakes are not sufficient, then there are many other assumptions one could make that would affect tow rating. For example, towing on gravel, extreme grades, bad tires, bad electrical connection, etc.. In some of those cases the tow rating might be reduced to near zero.

[mizterwizard]

Originally Posted by gordon2

I was under the impression that trailer brakes, when adequately sized, adjusted and maintained, basically put no more load or stress on the tow vehicle then if the trailer did not exist at all. That is to say that the trailer's brakes stop the trailer without any more or any less use of the tug's brakes. Of course not all rigs are properly set up an maintained but if they are, then the braking ability of the tug becomes a moot point as far as adding a trailer is concerned. So if the tow rating is assuming that the trailer brakes are not sufficient, then there are many other assumptions one could make that would affect tow rating. For example, towing on gravel, extreme grades, bad tires, bad electrical connection, etc.. In some of those cases the tow rating might be reduced to near zero.

I think it is beyond useless at this point to discuss towing capabilities any further. This is one of those topics like the best oil, the best politician, the best religion or the prettiest girl. I know the answer to all of these. So do you. They just aren't the same answers and they never will be.

I knew a lady who towed her travel trailer where ever she went because the vacuum boost for her brakes wasn't working and the trailer was how she stopped the car. She also had an equalizing hitch which kept the rear of her car from sagging because the air suspension was blown out. I doubt any one here would condone such a setup but it worked for her.

Some people actually stop ever 100 miles to check their tires, lug nuts and wheel bearings and replace their tires every 5 years regardless of tread thickness. Just like all of the "experts" advise.

There is a wide range of what people are comfortable with. And yet we don't have RVs exploding all over the place. I guess we are a lucky bunch.

[Kip in Ga.]

Originally Posted by gordon2

I was under the impression that trailer brakes, when adequately sized, adjusted and maintained, basically put no more load or stress on the tow vehicle then if the trailer did not exist at all. That is to say that the trailer's brakes stop the trailer without any more or any less use of the tug's brakes. [/B] Of course not all rigs are properly set up an maintained but if they are, then the braking ability of the tug becomes a moot point as far as adding a trailer is concerned. So if the tow rating is assuming that the trailer brakes are not sufficient, then there are many other assumptions one could make that would affect tow rating. For example, towing on gravel, extreme grades, bad tires, bad electrical connection, etc.. In some of those cases the tow rating might be reduced to near zero.

Gorgon I do tend to agree with the highlighted area above. And I don't understand why it isn't true. But it isn't. It has to do with total mass of the tug/trailer combo.

Of course the combo will stop better when all brakes are in good shape, and properly set trailer brake controller, than if everything is not in good working order.

I personally like a large margin of safety. 50% or better. If the trailer and vehicle real world load is 2000#, I want the tug to be rated at 3000# or better.

I started towing boats around 1965 or so, and campers around mid '70s.
Seen a lot, heard a lot, and experienced a lot. Things can and eventually will happen that we never planned on and were not prepared for.

At or very near the top of the list is not having enough Tug.

"Just because we can, doesn't mean we should!"

Gordon, You wrote: "So if the tow rating is assuming that the trailer brakes are not sufficient, then there are many other assumptions one could make that would affect tow rating. For example, towing on gravel, extreme grades, bad tires, bad electrical connection, etc.. In some of those cases the tow rating might be reduced to near zero."

Good points, those things can indeed happen . Thus the need to have a good margin of power and safety with the tug. Plenty of power for those unexpected extreme grades, 4WD or AWD for unexpected poor traction, and enough sense to have good tires and check out electrical before every trip. Being as prepared as we can.

kip

[mizterwizard]

I guess I just can't leave this alone.

Originally Posted by Kip in Ga.

And I don't understand why it isn't true. But it isn't. It has to do with total mass of the tug/trailer combo. kip

Mass and weight are interchangeable in a uniform gravitational field. Only the garbage constant changes. I'm with Gordon 100%. It's either science or opinion. Opinions are worth hearing but science is more persuasive.

Originally Posted by Kip in Ga.

I personally like a large margin of safety. 50% or better. If the trailer and vehicle real world load is 2000#, I want the tug to be rated at 3000# or better. kip

I took a machine shop class once. One of the things they talked about was sticking with the specification. The example was that an engineer designed a part that needed to be welded. He analyzed the stress, calculated the needed weld size and added in a safety factor to come up with a 1/4" weld. He passed his design up to the chief engineer. During his review the chief engineer decided to make the weld 5/16" just to be safe. He passed the blue prints on to the shop foreman who looked at it an crossed out the 5/16" spec and made it 3/8", just to be safe. He gave the project to a welder who decided to do an extra specially good job and made the weld 1/2". This process resulted in wasted resources and a part that was heavier than it needed to be. The point was to stick with the specification, not alter it just because.

Continental tires used to go to motorcycle rallies to do demonstrations of how good their tires are. They would walk through the parking area, find the most worn continental tire they could and offer the owner a new tire for their old one. Then they would mount it up on a rim and inflate it. The tire was intended to hold 40 PSI but somewhere north of 85 PSI the tire would jump the rim. They would then reinstall it, air it up and show that the tire,though worn out, was still good.

Draw your own conclusions but I believe there is already considerable safety margin built into most tow ratings.

Originally Posted by Kip in Ga.

Things can and eventually will happen that we never planned on and were not prepared for. kip

I couldn't agree more but then that is why safety margins are already built in. Given the resources I think most of us would have a 1 ton 4X4 diesel truck to tow our FGRVs but this thread is about whether a certain vehicle can reasonably tow a certain trailer. The answer is yes. The extended answer is that some prep will improve the experience. The useless answer is that things can go wrong and all preparations you can make are almost enough.

Originally Posted by Kip in Ga.

B]"Just because we can, doesn't mean we should!"[/B]
kip

Can is science. Should is opinion. Just keep that in mind. There will always be someone who says you shouldn't do that, what ever it is.

Originally Posted by Kip in Ga.

Good points, those things can indeed happen . Thus the need to have a good margin of power and safety with the tug. Plenty of power for those unexpected extreme grades, 4WD or AWD for unexpected poor traction, and enough sense to have good tires and check out electrical before every trip. Being as prepared as we can. kip

Kenworth is the answer but only an all wheel drive Kenworth with a professional driver and onboard mechanic, both with current extensive certifications.

[ShelbyM]

Originally Posted by mizterwizard

I guess I just can't leave this alone....
Draw your own conclusions but I believe there is already considerable safety margin built into most tow ratings.

And yet, your post #34, "There is nothing magical about towing ratings. The factory picks a number based on intuition, expectation of owner use/abuse and very little science." Yes, probably should have left it alone.

[Glenn Baglo]

Originally Posted by ShelbyM

And yet, your post #34, "There is nothing magical about towing ratings. The factory picks a number based on intuition, expectation of owner use/abuse and very little science." Yes, probably should have left it alone.

That's where I stopped reading the arguments as I expected the rest would also be baseless.

[Kip in Ga.]

Originally Posted by mizterwizard

I guess I just can't leave this alone.

Mass and weight are interchangeable in a uniform gravitational field. Only the garbage constant changes. I'm with Gordon 100%. It's either science or opinion. Opinions are worth hearing but science is more persuasive.

Do you have any science to back up that statement, or is it just your opinion? You ignored a very important aspect. EXPERIENCE!

You went to considerable effort tearing my post apart. So I will defend my positions with experience of towing 56+/- years.

Even though an object is able to stop in a given distance , the distance will increase if that object is coupled to other "Like" objects. A tug will stop in a given distance, and a trailer with brakes will stop in a given distance. Coupled together, the distance will most likely be greater than either alone. Consider a train. The more coupled mass the greater the stopping distance.

I took a machine shop class once. One of the things they talked about was sticking with the specification. The example was that an engineer designed a part that needed to be welded. He analyzed the stress, calculated the needed weld size and added in a safety factor to come up with a 1/4" weld. He passed his design up to the chief engineer. During his review the chief engineer decided to make the weld 5/16" just to be safe. He passed the blue prints on to the shop foreman who looked at it an crossed out the 5/16" spec and made it 3/8", just to be safe. He gave the project to a welder who decided to do an extra specially good job and made the weld 1/2". This process resulted in wasted resources and a part that was heavier than it needed to be. The point was to stick with the specification, not alter it just because.

There have been a lot of catastrophes attributed to poor engineering decisions. Personally If given the opportunity, I would go with stronger, within reason. .

Continental tires used to go to motorcycle rallies to do demonstrations of how good their tires are. They would walk through the parking area, find the most worn continental tire they could and offer the owner a new tire for their old one. Then they would mount it up on a rim and inflate it. The tire was intended to hold 40 PSI but somewhere north of 85 PSI the tire would jump the rim. They would then reinstall it, air it up and show that the tire,though worn out, was still good.

And yet many of us have observed and heard of perfectly appearing tires virtually exploding. Especially on trailers. If not prepared with a spare tire, the folks would be in a very bad place. From witnesses and owners the tires were rated higher than the load. How could that be??? Where was the safety margin you believe is there? You will find that many experienced camper owners have gone to higher rated tires,

Draw your own conclusions but I believe there is already considerable safety margin built into most tow ratings.

I believe they meet dictated requirements and that is all. Being prepared for the unexpected is our responsibility.

I couldn't agree more but then that is why safety margins are already built in. Given the resources I think most of us would have a 1 ton 4X4 diesel truck to tow our FGRVs but this thread is about whether a certain vehicle can reasonably tow a certain trailer. The answer is yes. The extended answer is that some prep will improve the experience. The useless answer is that things can go wrong and all preparations you can make are almost enough.

I will take any prep I can that may help our journey to be safer and or more enjoyable. I have never seen or heard any factory literature for vehicle ratings, stating the vehicle will safely do more than their published rating.

Can is science. Should is opinion. Just keep that in mind. There will always be someone who says you shouldn't do that, what ever it is.


Can is often born from ignorance or stupidity. Should is often an opinion that the ignorant or stupid need to carefully consider. Example: On these forums, folks have said they tow their 16 + foot campers without brakes. That is the advice they are giving the person that asked if they should have trailer brakes.

Good news is that ignorance can be fixed. Stupid is mostly permanent.


Kenworth is the answer but only an all wheel drive Kenworth with a professional driver and onboard mechanic, both with current extensive certifications.

Thanks for the exercise.

[John in Santa Cruz]

Originally Posted by mizterwizard

I took a machine shop class once. One of the things they talked about was sticking with the specification. The example was that an engineer designed a part that needed to be welded. He analyzed the stress, calculated the needed weld size and added in a safety factor to come up with a 1/4" weld. He passed his design up to the chief engineer. During his review the chief engineer decided to make the weld 5/16" just to be safe. He passed the blue prints on to the shop foreman who looked at it an crossed out the 5/16" spec and made it 3/8", just to be safe. He gave the project to a welder who decided to do an extra specially good job and made the weld 1/2". .

...then the manufacturing bean counters reduced it to a 3/16" weld to save $0.05 per unit.

[thrifty bill]

Originally Posted by John in Santa Cruz

...then the manufacturing bean counters reduced it to a 3/16" weld to save $0.05 per unit.

We had that point in every project design, it was called “value engineering” but actually it was all about taking cost out and eliminating scope creep.

[mizterwizard]

Originally Posted by John in Santa Cruz

...then the manufacturing bean counters reduced it to a 3/16" weld to save $0.05 per unit.

I like that one.

[cpaharley2008]

Speaking of bean counters, the current Highlander has a temporary spare, to save $$ and weight, I'd check the spare on your Highlander, temporary spares are not intended for towing.

[mizterwizard]

Originally Posted by Jim Norman

Speaking of bean counters, the current Highlander has a temporary spare, to save $$ and weight, I'd check the spare on your Highlander, temporary spares are not intended for towing.

Very good point.

One way to get around it would be to carry a AAA card in your wallet. Then you could delete the spare and tire tools all together.

That wouldn't be my way though. I take along 100+ lbs of tools where ever I go. I hate to be at anyone's mercy, including Murphy and his laws.

https://murphys-laws.com/

If I ever happen to use the spare tire, I feel totally exposed until I get the flat fixed. I see people running around on donuts all of the time and I wonder how they can stand the tension.

If worse came to worse you could put a donut on the front and move that tire to the flat but that would just be to get you to the next town. Donuts should never be used on a drive axle when pared with a normal tire because they are smaller in diameter and the mismatch from side to side would overwork the differential.

Of course some would say that you shouldn't use a compact spare at all on a towing vehicle because it doesn't have a towing rating, etc. Hence the AAA card.

So, by a show of hands, who here knows how much pressure is in their spare tire, both truck and trailer? I though so.

[John in Santa Cruz]

i checked all my spares earlier this summer, probably time to check them again. but I carry a Viair inflator/compressor... along with about 100 lbs of tools.

[gordon2]

Originally Posted by mizterwizard

....
So, by a show of hands, who here knows how much pressure is in their spare tire, both truck and trailer? I though so.

Originally Posted by John in Santa Cruz

i checked all my spares earlier this summer, probably time to check them again. but I carry a Viair inflator/compressor... along with about 100 lbs of tools.

IKR, who cares how much air is in the spare. Everyone should carry a compressor. I carry two.. one that inflates fast and an older / slower one as a backup. And I deflate my spare to 10-15 psi to prolong its life.

https://www.goodyearrvtires.com/tire-storage.aspx
Tire Storage