Towing an Airstream with a Highlander Hybrid

[ljmiii]

Originally Posted by 2airishuman

[From 'If you've weighted your TV and trailer...' thread] toasty's dad has much the same trailer mass as you...but way more margin on his towing set up...we will get to that with the hihy

The 16' Bambi IS on the margin of the HiHy's official rating of 3500lbs max towing.

But that is that same 3500lb tow rating as the 6 cyl Highlander without the 343 ftlbs of torque from the HiHy's extra pair of electric motors. I don't know why the limit is the same...is it because of the Highlander's frame strength? Or that they don't want to stress the CVT transmission? Or that the 'Genuine' Toyota HiHy hitch is Class II? Or that with the HiHy's relatively short wheelbase they don't want people to get the idea that they can tow a long trailer? Or that Toyota is just being ultracautious about new tech in the field?

All I know is that I'm not willing to risk it by going over the 3500lb rating. And that all that 'extra' power makes towing the 16' Bambi with the HiHy quite nice.

[scottanlily]

A word of caution on the towing with this highlander ,it does indeed have good power and torque with the electric motor .It does not mean that you can
be pulling big trailers or going up hills with it floored and all .You have available power and while thats good ,this vehical is small and when you get
in a panic situation or manuver of some kind ,it will be obviouse just how small
it is ,that trailer can easily overpower the TV resulting in a jackknife of the
trailer and TV .so while the first outing was good and safe,Id be careful
about the power thing and the rest of the drivetrain on your vehical .toyota
Im sure does not figure this vehical will be towing 3 to 4 thousand pounds around .I think all your surmises in your thread are valid ljmiii ,theres a good reason that Toyotas hihy is class 2 ,and that should not be exceeded .The
power is not near as important here as many think ,careful setup ,proper
TV and safety are first .The thing is that because of the great power ,one
thinks then ,well I can go ahead and tow a bigger trailer and so on .Im
stressing safety always ,folks still will go ahead and go beyond whats safe.

Scott

[2airishuman]

Originally Posted by ljmiii

The 16' Bambi IS on the margin of the HiHy's official rating of 3500lbs max towing.

But that is that same 3500lb tow rating as the 6 cyl Highlander without the 343 ftlbs of torque from the HiHy's extra pair of electric motors. I don't know why the limit is the same...is it because of the Highlander's frame strength? Or that they don't want to stress the CVT transmission? Or that the 'Genuine' Toyota HiHy hitch is Class II? Or that with the HiHy's relatively short wheelbase they don't want people to get the idea that they can tow a long trailer? Or that Toyota is just being ultracautious about new tech in the field?

All I know is that I'm not willing to risk it by going over the 3500lb rating. And that all that 'extra' power makes towing the 16' Bambi with the HiHy quite nice.

hello again...

one quick thought...have you checked out toyota forums for the hihy? any help on towing issues? i'm sure a lot of creative folks are pressing the limits and have tips/tricks and resources for ya...

ok, here is the main reply...

'not willing to risk it' is the sort of thinking i like....

as for why the rating is unchanged for the hihy vs the standard model..

it could be any of the issues you've noted...

i will speculate on this issue...

my comments are not intended to belittle your tv or by extension you.

safety is my goal and yours 2 no doubt....

so lets start with the vehicle d.n.a. ...

it's a camry. it's a unibody. it's a fwd car based hi riding station wagon...

the camry was chosed 'car of the year' this week by some group and with good reason.

the highlander and sienna and lexus400 and the hybrid models are all based on this wonderful camry platform...

for reliability, comfort, economy, emissions, safety and hauling the family... it is top notch.

for towing it is very limited in any of the sytle offerings.

do you know the gcwr for the hihy? i couldn't find it but suspect a value of 9000lbs approx. and hope it isn't less.

curb weight is 4200lbs, gvwr 5600lbs so the payload is 1400lbs AND any vehicle options REDUCE payload and INCREASE curb weight...

rated for towing to 3500lbs. that is with one driver of 170lbs approx...

no passenger, no gear, no options, no reciever or hitch, and so on...

so in reality the 3500lbs towing capacity goes down with each item placed inside the hihy...

2 people a dog and a few toys, tools, and a big gulp....towing capacity drops to 3300 quickly....

IF the curb weight is really higher or your family weights more than 200lbs combined...

towing capacity goes down....

my understanding is the receiver mass MAX is approx 400lbs? even with a w/d hitch...

PLEASE CORRECT ANY INCORRECT NUMBERS or ratings i've noted....

you have gone UP on the receiver to a class III....

looks like there are class 3s with 400-600 lbs tongue capacities (w/d)

WHICH DID YOU OPT FOR? 400lb or 600lb...

now back to why the ratings aren't higher for the stronger power plant...

tightening the w/d spring bars produces torque, more torque than the actual tongue weight...

i've seen calculations that suggest this torque is 1.4-1.7 times the tongue mass...perhaps you've got more precise data...

and nick may know this info...

that torque is applied via the reciever to the frame...in your case a unibody. there IS no frame;

its a platform. no extra reinforcement like on the ridgeline or touareg...

one unibody platform designed to crumple safely on impact and so on...

even with a heftier receiver the bolts, bolt to the same unibody....

toyota has rated that unibody to handle 400lbs max...maybe they under rated it.

get a toyota engineer to say that...

so in my view even with a higher rated reciever, the limitation is the mounting area.

as for the other ratings issues and limitations on the hihy...tire rating, axle ratings, spring ratings and brake capacity? one really needs to know these limits too...

so to put it plainly forget the 80% many here swear by..

your trailer mass may already be over the 100% limit...

so may your actual hitch mass and likely the torque stress onto the unibody...

have you heard of can am, the folks in canada who do specialized towing setup for more unique situations, like towing with unibody cars?

they could likely fabricate a receiver to better distribute stress in the unibody, than a stardard bolt on model...

your other posts seem well constructed and reflect though and insight into your situations and again safety is the ultimate goal while enjoying the airstream...

so you may have already considered/solved everything noted above...

ok. one last thought and it's a question....

when slowing down the hihy initially uses regenerative braking right....

do the trailer brakes engage during this phase OR only after the hihy brakes actually engage?

i'd love to know this...

cheers
2air'

[ljmiii]

Originally Posted by scottanlily

You have available power and while that's good,this vehical is small and when you get in a panic situation or manuver of some kind, it will be obvious just how small it is...

Small for a tow vehicle in absolute terms, but not small relative to the trailer chosen.

Keep in mind that even an F350 Supercab long wheelbase dually is outweighed 3 to 2 by a 34' classic and the Ford's wheelbase is only 38% of the length of the AS. By comparison, the HiHy outweights the 16' Quiksilver 7 to 5 and it's wheelbase is 54% of the Bambi's length.

Which is not to say that I am unconcerned about jackknifeing. Just that I am unconcerned about the HiHy being small relative to a 16' Bambi.

[ljmiii]

Originally Posted by 2airishuman

one quick thought...have you checked out toyota forums for the hihy? any help on towing issues?

Yes...the reason for the original post was to give back to the communities that gave me so much information, to collect it all in one message, and to add my experiences.

Originally Posted by 2airishuman

curb weight is 4200lbs, gvwr 5600lbs so the payload is 1400lbs AND any vehicle options REDUCE payload and INCREASE curb weight...

No options on the HyHi limited. In my last post comparing the HiHy and non-Hi Hy I thought about balancing the HiHy's extra 310 lbs of weight against the extra 343 ftlbs of torque...but I have no way of knowing how much of those 310 lbs remain after the the non-Hi Hy's option weights are added back in.

Originally Posted by 2airishuman

my understanding is the receiver mass MAX is 400lbs even with a w/d hitch...
looks like there are class 3s with 400-600 lbs tongue capacities (w/d)
WHICH DID YOU OPT FOR? 400lb or 600lb...

Yes...and 400 lbs (it seemed wrong to get a heavier hitch receiver to support a tongue weight that the vehicle couldn't support)

Originally Posted by 2airishuman

have you heard of can am, the folks in canada who do specialized towing setup for more unique situations, like towing with unibody cars?

Yes, but they seem to be focused on solving problems of a different order of magnitude - Chyrsler and Volvo sedans pulling 27' and 28' Airstreams. The HiHy and Bambi are a match made in heaven compared to their TV/trailer pairings.

Originally Posted by 2airishuman

when slowing down the hihy initially uses regenerative braking right...do the trailer brakes engage during this phase OR only after the hihy brakes actually engage?

I don't know for certain. I do know that when I was calibrating my brake controller and I set it to max it completely felt like the trailer was braking the car. So the delay if it exists would seem to be undetectable.

[AlbertF]

Originally Posted by 2airishuman

tightening the w/d spring bars produces torque, more torque than the actual tongue weight...

i've seen calculations that suggest this torque is 1.4-1.7 times the tongue mass...perhaps you've got more precise data...

and nick may know this info...

that torque is applied via the reciever to the frame...in your case a unibody. there IS no frame;

its a platform. no extra reinforcement like on the ridgeline or touareg...
2air'

I've seen those calculations too, and created a little spread sheet. If the actual tongue weight is about 450 lbs (nearly 13% of 3500), the total tension on the bars would only be about 800 lbs. Most larger trailers require a tension of 1200 lbs plus if the wdh is actually levelling the TV.

Based on the calculations, a short rear overhang and a short trailer help a lot.

I'm not an expert, only trying to figure out what's happening, so it would be good to have feedback to understand this better. So here's my nickel's worth (2 cents adjusted for inflation). I'm also making some estimates re: rear overhang, distance from ball to trailer axle, etc.

The torsion bars pull down on the trailer A-frame. This has the effect of transferring some tongue weight to the trailer axle - the actual % varies with the length of the trailer.

While the tongue weight pushes down on the "back" of the receiver, the wdh pushes back up. It's clear that there is more force (800 lbs) pushing back up, and forcing the receiver down at the "front" end. The four bolts holding the receiver to the OEM attachment points have to deal with this. In this case, the stresses are probably a non-issue, as the loads are fairly modest. However, we can see where things might move, and this shows why a 6-point mounting with long brackets attaching the receiver to the tow vehicle is desirable. While I'm not aware of a manufactured alternative for the Highlander, you might compare a V-5 Valley Industries receiver to a GM factory receiver.

Can Am's approach (and I have looked at the underside of the 300C) is to use long centre receiver tubes in its custom receivers. These 2.5" tubes can be purchased in a number of different lengths up to 48" long. (The alternative is to weld an extension to an existing Class III or IV receiver.) The centre tube is attached as close to the rear axle as possible; often to the rear suspension subframe on vehicles with independent rear suspension. This approach is used to eliminate flexing of the receiver, but it's obvious that it spreads torsional loads through a much greater section of the frame and bodywork of a tow vehicle.

Based on the numbers, the load on the Highlander seems fairly modest. The structure will also be made of some form of HSLA steel which is something stronger than ordinary mild steel, although I don't know anything about the metallurgy. However, if the structure starts to exhibit damage around the attachment points, an extension would be something to think about.

[nickcrowhurst]

Originally Posted by 2airishuman

tightening the w/d spring bars produces torque, more torque than the actual tongue weight...

i've seen calculations that suggest this torque is 1.4-1.7 times the tongue mass...perhaps you've got more precise data...

and nick may know this info...

2air'

I discuss this at post 25 here:
http://www.airforums.com/forum...s-19236-2.html?

Nick

[Asianflava]

I'll throw my 2cents in since I tow with a 4-cyl Highlander. Granted, it's no Airstream, but I've towed my teardrop about 6000miles with this setup. The HL tows the teardrop fine but it only weighs 1500lbs loaded AND it is within the slipstream of the TV. It did great, Grapevine and Donner were no problem 110 degree heat no problem. I probably wouldn't want to tow anything much larger though.

About the weight ratings, it has been discussed on the teardrop board probably as many times as it has been here. One thing that comes up is that the US has conservative ratings for their vehicles. One example is the Toyota Echo. In Canada, it has a rating of 1000lbs (I think) in the US it flat out says towing is not recommended. Same car, different ratings. The Kluger (overseas name for Highlander) has the same ratings though.

For the Airstream that I'm picking this Christmas, I will have to use a 3/4-1 ton pickup.

[ljmiii]

Originally Posted by ljmiii

I won't be able to get out to a CAT scale until after Thanksgiving weekend but I'm really looking forward to seeing the results

Today I finally made it out to a scale. The answers are:

FA....RA....TV....TA...trailer total
2520 2140 4660 3080 3480 8140 separate
2560 2380 4940 3200................hooked up w/WD
...40...240..........120

I was surprised. The 'level' answer for the HiHy is indeed to distribute most of the tongue weight to the rear axles - only 40lbs on the front axle with 240lbs on the rear axle (and 120 lbs on the trailer axle).

Thanks again to everyone (particularly nickcrowhurst) for your advice.

[BillTex]

Just goes to show, there is always another perspective;

The Recorder

[Road Ruler]

Canada clamps down on gas guzzlers. Add $4,000. in TAX to the cost of the Hummer!

Hybrids get rebate.

Hybrid-car buyers get rebate

[BillTex]

Yes...this all goes to show, there are so many sides to every issue!
I still believe in "think globally, act locally" every little thing we each do, ultimately effects our environment. Whether you choose a Hybrid, Hummer, or tow with a bicycle!

[ljmiii]

Originally Posted by BillTex

Just goes to show, there is always another perspective;
The Recorder

Sadly, in only three short weeks the author's perspective is now more along the lines of "Student writer discovers failure to fact check can create instant fame (or was that infamy?)" He got caught relying on the report that CNW Marketing Research Inc put out in 2006 and spread like wildfire on the internet as 'Prius vs Hummer'.

Unfortunately for Mr. Demorro, the CNW Marketing report was debunked when it was found to contradict the results of automobile lifecycle environmental assessments of outfits like Carnegie Mellon University, Massachusetts Institute of Technology, and the Argonne National Laboratory (U of Chicago's DOE lab).


All of which is not to say that I believe hybrids are the solution to every problem. As I've noted in other posts, if you live in the American Southwest (eg high speed, low traffic, high temps) a TDI is a much better choice.

[Blu_Hwy_Lady]

Wow! BillTex that article was an eye-opener. I just don't understand why all the sides of a "solution" aren't presented. I always wondered about the disposal of the batteries after a hybrid "dies". Now I see that it is the manufacture of the batteries that is the real environmental bugaboo. Plus, I didn't realize that a hybrid had such a short life span. Think about the environmental impact of the manufacturing process for steel, plastic etc. for it to only last 100k miles. It gives me a whole new perspective on the fuel/energy savings issue. I got 340k miles out of my '83 Volvo (still runs just fine and I keep it for a "spare) and I've got close to 150k on my '99 Explorer and plan on getting at least 200k out of it. In the end, maybe only getting 19 mpg makes my vehicles more environmentally friendly than a Prius. Thanks for putting up that link.