Matching a TM to a 2014 Highlander

[mecicon]

Originally Posted by Padgett

OK my heep is the best tow car I have ever had (and started towing race cars in 1970.

290 hp/260 lb-ft & 114.9" wb but just as important regarding sway is a 4475 lb curb weight, 50/50 weight distribution, and 38" from center of rear axle to hitch (shorter is good). It also has traction and sway controls.

It has "enough" power to stay out of Power Enrichment at 65 on Florida roads so gets 17-18 mpg on 87 PON.

You have seen my opinon about WDHs before but just lets say that anything that adds or transfers weight to the 3.5k rated TM axle is anathema to me.

Your anecdotal information does not address the concern(s) of the OP.

WDH also transfers weight to the steering axle as well.

[Redtail Cruiser]

Not using a WDH on a marginal TV is much more dangerous than adding weight to the TM axle. I'm not sure of the percentages, but I would guess that a larger number of owners use a WDH, than don't. I have only heard of one axle failure (Tampajohn) and his was a result of a deep pothole. If axles were failing on a regular basis, this argument might have some traction, but I believe it is a non-issue. WDH's are a necessity on TV's that have under a 5000 LB tow capacity.

[tentcamper]

There has always been two camps on the TV's. Larger is better and the more fuel conservative smaller TV. Both like their TV's and think they do a great job for the load they haul. Both seem to get the job done. The larger is better has the bragging right for climbing mountains faster. Both can maintain a safe speed by downshifting on downgrades with out using their brakes. The larger TV have larger engine braking displacement but the weigh is more and need more engine braking to maintain the speed.

So in my view it is all your personal preference. They both work well. Just make sure your numbers are within the manufactures specifications or make the right modifications to compensate for the numbers.

Most TM owners have WDH's. Many are most likely not needed, or are substitutes for rear springs. The primary determining factor for WDH use to be, how much rise you had on the front end when the trailer is connected without a WDH. Somewhere in the past 20-25 years the hitch shop sales person shifted from adding rear springs to substituting additional springs with a WDH. But if you are going to error, error on the side of having a WDH, its the safer error.

[Padgett]

Is the old issue of "if you have to ask, then do this." My feeling is that until recently TM shall we say "skated a bit on margins". It is not just the axle but also the tires particularly since I found the second sticker on mine to inflate the tires 5 psi over the maximum.

So one question I have never seen asked is "Whether people with stock tires and WDHs experience more tire failures than others ?"

Will admit I tend to overdesign everything I do and follow the Harley principle of "if it breaks, make it stronger." Comes partly from a career designing engine and flight controls.

Now what you have when you drop the tongue on a hitch is a see-saw. Many people say it is the wheelbase that is important and that is one arm of the see-saw but the other which is mostly ignored is the distance from the rear axle to the hitch ball (why motor home tractors are short-tailed). Just a quick SWAG give a minimum ratio of 3:1 (WB/HA) HA-hitch arm. With 3:1 then a 600LB TW will lift the front with a force of 200 lb. 2:1 (long tail) would raise the front with 400 lbs.

OK descriptions of exactly how a WDH works are hard to come by but what it looks like is if you drop a link below the tongue and attach the other end to the hitch and tighten a turnbuckle. The force is inline with the hitch so has little effect on the TV but tries to force the trailer down. This translates the 600 lbs downward force to a 400 lb down on the receiver and the remainder to a horizontal vector. The 600 lbs is still there and the total force on the hit has increased a bit, just transformed into two vectors that reduce the downward force on the receiver and is why the receiver part of a WDH is so strong (and why you should disconnect if turning tightly, the force on the outside assembly would increase dramatically.).

This has the counter benefit that with two bars at an angle, if the trailer starts to sway the force on the inner bar decreases and the outer bar increases dampening the sway.

[wtxnitz]

Thanks for all the input. Now to answer a few questions.
Yes, the TV is determined. A 2014 Toyota Highlander Limited V6 AWD
the towing package is standard.

A few spec from the owner's manual
Trailer brakes are required 1000 lbs and above.
anti- sway required 2000 lbs and above.
WDH required 5000 lbs and above, BUT that's weird, since max tow wt. is 5000 lbs.
Max hitch wt is 500 lbs.
from the door sticker:
gvwr 6000 lb
gawr front 2955 lb
rear 3505 lb
total cargo and passengers 1385 lbs
Max tongue wt 500 lbs
GSU55L-ARTGKA GCWR 9940 LBS TWR 5000 LBS

from the discussions here and elsewhere, I am convinced we need trailer brakes, anti-sway and an WDH. It also seems even though we think we'd like a 3124, it is too close to the limit. It looks like a 2922 gives a better margin. It looks lile MarkoPolo's issues with sway were solved with and anti-sway hitch.

MP, do you have any weights for your 2922 fully loaded?

So back to the original thrust of the thread, what real world weights have people seen in the other models? The comparisons with comparable TV's is also quite valuable. Just the TV is set for now.

Thanks for this great discussion. I'm learning a lot.

[Bill]

wtxnitz -

I did not know the meaning of "GSU55L-ARTGKA", so I googled it. One of the hits was

http://www.toyota.com/t3Portal/docum.../sec_04-01.pdf

This is apparently part of a Toyota manual (Owner's Manual?) for the Highlander. This is one of the best pieces of documentation I have ever seen, and I admire Toyota for it. Lots of info, easy to understand. One thing caught my eye. On page 209 I find

TWR (Trailer Weight Rating)
The maximum allowable gross trailer weight. The gross trailer weight is the sum of the trailer weight and the weight of the cargo in the trailer.
. TWR is calculated assuming base vehicle with one driver, one front passenger, towing package (if available), hitch and hitch systems (if required).
. Additional optional equipment, passengers and cargo in the vehicle will reduce the trailer weight rating so as not to exceed GCWR, GVWR and GAWR.

The terms GCWR, GVWR, and GAWR are also clearly explained.

In other words, allowable trailer weight assumes a set of base conditions in the tow vehicle (one driver, one passenger, hitch and hitch system, no cargo). If you add more passengers, or some cargo to the tow vehicle, then you must reduce the trailer weight rating, but only until you bring the GCWR, GVWR, and GAWR back within spec. This is different from other manufactuers' statements, in which you must reduce trailer weight rating ing pound-for-pound for the entire weight of extra passengers and cargo in the tow vehilce.

This has not been my understanding in the past, so I stand corrected. It has also not been the expressed opinion of members who have maintained that NO reduction in trailer weight is required.

Another note of interest is on page 214, where it says that if you use a WDH, you should adjust it to return the front end to the same weight and height as before. No mention of air bags or helper springs.

We learn something every day on this forum. Thanks for your post!

Bill

[Padgett]

Think I finally figured out how to visualize a WHH. Visualize a 2" square bar weded to your hitch bar (with the ball on it) and dropping down about a foot. Now picture welding a similar bar to the trailer tongue about 3 feet back from the ball also dropping down.

Now picture a really big pair of pliers squeezing those two bars together. There is a rotational moment on both the TV and the TM. This rotational moment is resisted by the trailer frame and axle at one end and the whole TV on the other resulting in additional load on the front which reduces the force on the rear. Tongue weight is now the sum of the forces, the tongue weight pushing down and the rotational for pushing up at the rear.

So the TM axle is now carring the sum of the actual weight on the axle plus the rotational moment while the TV levels. Wonderfull so long as you do not exceed the TM axle and tire ratings..

Think I'll stick to methods that do not have any added force sums on the TM.

ps really good explination is here.

pps stating 2012 all vehicles sold in America have had to have Electronic Stability Control (ESC aka TC) which usually includes anti-sway.

[wtxnitz]

Originally Posted by Bill

wtxnitz -

I did not know the meaning of "GSU55L-ARTGKA", so I googled it. One of the hits was

Bill

sorry. yes, that is the model identifier from Toyota.

The owner's manual does have a lot of good info, but it is horrible to access online or through the app. It is a collection of pdfs, not a single pdf. That would be ok - there is a searchable index - but there is no way to jump to a specific page from said index to the correct section pdf. On top of that, the individual pdf titles have no reference to page numbers they contain. The titles are often cryptic and seemingly unrelated. such as load information is, I believe, in the pdf labeled "Keys and Luggage"

the Highlander does not have any air leveling or adjustable ride height, as far as I know.

The discussion on tongue wt version hitch load has me a bit confused, with respect to using a WDH. The Toyota spec says "Max. Tongue Wt. 500 lbs." Assuming a loaded 2922 runs around 4000 lbs. A 15% tongue load is 600 lbs. Obviously, without WDH, we break the bank. I understand the WDH torques the hitch to distribute weight off the TV rear axle and onto the TV front axle and TT axle. Say 200 lbs worth. Things are better, but is the load on the tongue now ok? It that now equivalent to 400 lbs undistributed?

[wtxnitz]

Originally Posted by Padgett

pps stating 2012 all vehicles sold in America have had to have Electronic Stability Control (ESC aka TC) which usually includes anti-sway.

It is true our Highlander has all kinds of safety handling systems. I'm not sure they are designed to handle towed vehicles. I don't recall any specific mention of "trailer anti-sway", so I assume it doesn't have it. I'll have to do some research. I know Ford commercials do boast specifically about trailer anti-sway. I assume silence means "no" Still, a good point to check out. Thanks.

[Padgett]

To really understand what a vehicle is you really need at least three documents and may want to have more:
Must have:
Owner's Manual
Factory Shop Manual
Build Sheet (for your car)
Nice are:
Specifications sheet
New Car Brochure

For example in my build sheet is listed:
Rain Brake Support
Ready Alert Braking
Electronic Stability Control
Hill Start Assist
Traction Control
Trailer Sway Damping

Now which is standard and which came with the towing package is not known but one point is that a lot more comes with a factory towing package than just a hitch. I can say that as of the 2012 model year NHTSA requires "Stability Control" on all US sold vehicles. Everything in the list above is part of the computer programming.

Point I am making here is that everything mentioned in my resource list above is on my computer (actually on several) and was part of the reason for selecting my TV even though at the time I had only a tow dolly.

BTW my factory service manual came on a CD and was over eleven thousand files. Makes sense as that way they can have generic boilerplate for all cars and just add the bits that are model specific. The owner's manual is a single .pdf file.