Thoughts on towing an 8000 pound trailer?

I wouldn't have been too concerned towing that, especially since that was with full tanks, but I probably would have stored the generator and whatever else I could in the trailer to try and get closer to rated payload.

 

Kparrow, this is a good example! Thanks for posting. Did you do a run that showed before weights for you truck and trailer separately?

 

@Malinois38 @PBNB Andy Thompson would get jeered right out of this forum for how he sets up tow rigs. He argues it’s reasonable to use half ton trucks even if the trailer’s tongue weight puts the truck over GVWR. His reasoning is that a half ton has a lower center of gravity, much lower curb weight, brakes nearly the same size as 3/4 ton brakes, and better handling due to IFS. He also says there is room between the sum of the axle ratings and the GVWR, which can be taken advantage of. He says not to get hung up on any one number but look at how everything works together. Here’s a screen shot from an article he wrote for RV Life:


Here is Andy’s argument from the article applied to my ‘21 Tundra, which has 1270 lb on the door jamb for payload and a GVWR of 7200 lb, for example:

“In theory, you should never carry more than 1270 lbs in this truck…or should you? The front and rear axles are rated to carry 4000lb and 4150lb, so the truck can carry 8150 lb if you could distribute the weight to the front wheels. …we [can] use a properly set-up weight distributing hitch that transfers some of the weight to the front axle.”​

This is basically why I’m fine with being over GVWR but under each axle’s rating.

 

That’s a very rational way of looking at it this topic.

 

Has OP tried towing that trailer yet? Curious?

 

There is only one problem with RV life style article. Center of gravity. It shows a 2wd ram truck pulling an airstream trailer. Most airstream trailer are, from what I have seen, are about 18" high from ground to frame. Most travel trailers, like mind , now days are 24" from the frame to off ground. Just a little more top heavy.

If I'm wrong about the airstream trailer, please let me know.

 

17 to 18” is probably correct for most. Mine has a 3” lift so about 21” now. Airstreams do keep their weight low which why they have a reputation as a very stable and towable trailer. They concentrated the heavier components near the floor or under it. Like the tanks.

I think Andy’s approach is to look at the tow vehicle and the trailer and then see if the hitch can do, with a emphasis on weight distribution. He has provided some upgrade solutions for stock hitches to improve weight transfer to the front axle.

You see him setting up cars to pull trailers as well as trucks and SUV’s. He takes a practical approach to towing which is why he has been so successful over the decades. We haven’t had any work done by him but I did reach out him when we got our former Ridgeline.

 

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Adding GAWRs is how medium & heavy duty trucks come up with a GVWR, but light-duty trucks have to meet additional ride/handling/performance standards.

For example, to meet current tow ratings a pickup must be able to maintain at minimum speed of 40mph up a ~5% grade for 11.4 miles running the A/C on high with ambient temperatures over 100 degrees without overheating, losing any fluids, throwing any trouble codes, etc. That same chassis with a smaller engine will be rated lower even though it can safely handle just as much weight - it just won't be as quick to do so.

 

still figuring out best way to load the new rig will certainly help

Not in my example from the first weights but I have another example for you. This was all the same trip. I know this is a 3rd gen towing question so I don’t want to intrude too much and feel free to roast me on my weights. I got a new trailer last year and this was early on in the season trying to dial weights and figure out best way to load the new rig combination. All weights are from the trip with the combo in this picture. All weights with full fuel tank



Fully loaded


Unloaded with all gear still in bed (kennels, rack, kayaks, dogs, generator)



Unloaded “normal” truck only




If my math is right, that means when I was loaded up with the trailer and gear, I had a total of:

Weight of truck / on truck = 7580lbs

Weight of trailer = 8340lbs

Tongue weight of trailer
7580 - 6720 = 860lbs

Gear in bed = 400lbs

Over GVWR / Payload = 480lbs
Not over any axle ratings

It’s easy to overload just keep that in mind. I’ve taken steps to account for it with a good hitch, airbags (doesn’t do anything for weight fyi, just nicer towing experience), E rated tires, and slotted cryo brake rotors with Hawk LTS pads. All that and I know that technically…it’s over.

I plan to weigh the rig again this year after balancing better with the experimenting I’ve done. We will also not be bringing any kayaks or bikes, just dogs/kennels on the first trip out because I’ll be at sites with power. That should help give me even better insights. I’m not new to towing or trailers, but finding the sweet spot of balance with my new rig is a lot of trial and error. I had my 24ft trailer dialed perfect, this one I’m almost there. Tongue weight is almost a perfect at just over 10%.

Feel free to roast me, criticize, etc. it’s how we all learn stuff and strive to do better. Hope this helps a bit!

 

Kevin, It seems to me that you are very aware of the important aspects of your rig.

I see that the front axle didn’t get much weight moved from the tongue. I wonder if the airbags are getting in the way of that? I would expect to see about 1/4 of the tongue weight moved to the front axle in a typical weight distribution application.

 

I would think that is actually more than likely happening. I don’t have a weigh with the trailer hooked up without the spring bars but I can tell you when I sat the trailer down in the driveway the truck almost touched the bump stops before I got airbags. The goal of weight distribution hitches is to get as close as you can back to unloaded weight on the front axle. Without the bars I would think the front axle would probably be around 3k lbs.

Typically if you overdistrubute the weight, the front axle will be heavier than it was unloaded and you will be pushing the front of the truck down more than unloaded which isn’t good. You’ll end up with not enough weight on the rear axle as well most likely.

After about 6 times adjusting the hitch and finding the right hitch head angle and heights, the truck returns basically to unloaded height in the front. It’s about a 1/2” difference if I remember right. Truck is level, trailer is level front to back. The bags I actually fill up after. They have the potential to take too much off for sure, but I run about 15 to 18lbs in them, which doesn’t lift the truck so much as it just prevents large bottom out on expansion joints or large bumps.

Hope that helps explain how the weight is being push back to the front axle. I plan to do that type of weigh this season when JP get the trailer hooked up to better understand the differences I’m dealing with and be able to see the amount of weight I’m really pushing forward with the hitch

 

I think the point of the weight distribution hitch is to send some of the weight forward to the front axle and back to the trailer axles. Your weight slips don’t show adequate transfer of weight to the front axle. As a previous poster alludes to, it’s likely your airbag setup fighting your weight distribution setup. Dialing the two in together will be challenging. I would be setting up the WDH first with no air in the bags. Make sure the trailer is level. Measure your front center hub to fender hight. Add the trailer with WDH and check front fender hight again. It should be the same or ideally lower than before, not higher. Then I would only add enough air to maybe raise the back 1/2” or so, just so I know I have a higher effective “spring rate” in the rear for bumps and such. Rewrite and adjust as necessary. Being over GVWR means you’re exceeding one of the systems in the truck. Could be cooling, could be braking, the Toyota engineers know which one as they set the number.

 

I am not too sure how busy your local CAT scale is but what if you were able to determine the load at the scale in real time. You could dial in the load transferred to the front axle and then start applying the air to the bags to see the front axle load change. You could dial in the weight distribution and air together. I think the results will be clear and you will see the weight distribution drop off. A quick check would be to see how easy the bars are to removed at the point where the airbags are pumped up to 15 - 18 psi. If the bars easily swing away, that would demonstrate that the airbags are winning!

If your hitch requires tilting the head to achieve more load, that could be a challenge while blocking the scales!

When my trailer is connected I did notice a few inches of droop in the rear when just on the ball, and the front was pointing up. I could feel the lightness in the steering. Then adding my weight distribution bars, the rear came up to level with the front came down so I was able to dial in the load. The truck sat level (the original factory rake was gone). Steering felt normal.

My trailer only adds 500 lbs to the tongue so I was surprised to see the rear sag so much. I guess that’s why they added the headlight adjustment controls in the cab! With WD, I can see a small load moved to the front but haven’t confirmed the number. Weight distribution also returns a portion back to the trailer axle so we need to be aware of the gross trailer weight as well.

 

You don't want the airbags to win on this one. You want the WDH doing the work. The airbags should supplement your trucks spring rate to prevent bottoming out and make the rear ride a little more controlled. You would likely see greater benefit with heavier setups, not 500# hitch weights.

 

Thanks KNABORES, In my case, I will be using Timbrens SES stops. They provide support when the rear is loaded. I am not too concerned about my truck as it runs level with the trailer and WDH but I am going to be adding a 1.75” levelling kit up front and expect that the truck will look overloaded with the extra 1.75” up front. These will push the rear back up closer to level. My WDH can be dialled in so I know that it is working. I hope this comes together and works. I will post on the results when I get to the changes done.

 

I suppose we can agree to disagree, because the documentation of hitches and many others state the point is to get weight back onto the front axle at or slightly over unloaded weight. The idea is to get the steers back to “stock” weights. Without the bars I would be taking 500lbs+ off the steers. When I get a chance to weigh the trailer without bars that will help confirm it. That means I’m putting all of that weight back on the front steers with the hitch that I otherwise would have taken off with the trailer. The rear a axle should carry a significant part of the extra and the steers should be as close to stock as normal has always been my understanding. The bars with the bags set to 15-18psi still have TONS of tension on them. Seems near perfect to me. Here’s a perfect article from an engineer for Progress who makes the equalizer hitch describing what I’m talking about.

https://www.cars.com/articles/half-...tribution-hitches-why-and-when-to-use-454793/

 

9400# Flagstaff dry weight, 37' long, 14k WDH, timbren SES, minimal cargo, no problems, BUT I am an experienced driver pulling heavy loads, the truck will handle it, religiously follow the set up of the weight distribution hitch, that's make or break IMO

 

50% weight return to the front wouldn't fly with me. As close to 100% as possible. Considering you now have to control the steering for more than twice the weight, I want all the weight on the front tires I started with, not less. On a scale I would want to see the same weight on the steer axle I started with, yours are pretty close (within 60lbs). If it tows great and handles well, you may be as close to dialed in for your rig as possible with your setup. Happy towing.

 

Screwy Louie, how do find the Timbren's?

 

Absolutely. As close to 100% as possible is my goal and 50% certainly wouldn’t fly with me. I’m using my bags solely to supplement the spring rate of the leafs that are no question worn out. Bags were less expensive and quicker install for now but the goal is eventually new leafs. Will be moving my lithium batteries from the front storage to the under bed storage just behind so that should shift weight just a little bit. Will have to do lots to trial and error on the scales once spring comes around and I’m gonna get it as close to 100% as possible. Happy towing for you too.

 

Have not yet as I have not bought that trailer yet.... still deciding on which one to buy. But I definitely let y'all know what I decide on and how it goes.
BTW thanks to all for the good inputs and I had no idea this thread would take on a life of it's own. This forum is awesome

 

@PBNB got them from etrailer.com, talked to one of the specialist, explained my situation and it's what they recommended.

 

You're hunting a Unicorn, and they don't exist. You're going to take an MPG hit for heavier tires. Compared to towing a trailer that is too large for the truck in the first place, the impact of the tires won't even be noticed.

Also, airbags don't help your suspension. They are cosmetic for sag and give the illusion that overloaded springs are fine. You'll be better off getting heavier duty springs and using a WDH.


None of the mods they suggested will help your braking ability, engine and transmission cooling ability, cornering ability, or the increased wear while you are overloaded. I'm sure you can add their suggestions and tow it for years and not have an issue, but neither did the guy with the in bed camper that broke his dodge in half. You need a bigger truck if you want to haul a house for camping. 1/2 tons work best for trailers that don't have slide outs and are under 24' in length, preferably under 22'.

 

These threads always go the same way.
“I wanna tow heavy. I mean reeeeeeeaaaaal heavy. Is my Tundra the right tool?
NO.
Okay, but what if I put on better tires?
NO.
Gotcha, I need airbags.
NO, you need a 3/4 ton.
But this guy on YouTube pulls a 5th wheel. Can and should are 2 different things.
There is no way to change your payload by adding things to your truck, it’s already been printed. You’re actually better off taking things off the truck to increase your payload. LT tires make towing heavy a more pleasant experience, but your factory tires can tow all the way up to your trucks ability and beyond. Well beyond your axle rating. Airbags are great for heavy things in the bed all the time, not as helpful when towing with a WDH. Be safe out there people. Don’t tow beyond your driving limits and don’t tow beyond your vehicles limits.

 

Y'all should see what people are towing over on ih8mud...

 

Your tires are good for over 4,900 (for the pair) on an axle rated for what, 4,150 lbs? Unless they're giving you issues somehow, I don't see much reason to change

Load E All terrains weighing <50 lbs
Bridgestone Dueler AT are rated for 3,195 (47 lbs)
Firestone Destination XT 3,195 (47 lbs) (severe snow service rated)
Firestone Transforce AT2 3,195 (46 lbs)
Goodyear Wrangler Workhorses are 3,195 (50 lbs) (severe snow service rated)

Load E dirt road & highway tires weighing <50 lbs
Bridgestone Dueler HT LT265s are 3,195 (46 lbs)
Michelin Defender LTX are rated for 3,195 (50 lbs) (low rolling resistance)

If mpg is important, LTX's are hard to beat. They ride great, wear great, and still do okay off road and in light snow. But they don't look aggressive.

The Wrangler Workhorses would get my nod if you wanted/needed something a little more aggressive off road but wanted to take as little of a hit from mpg as possible.