Yeah we will see how it affects the ride.

I'm just hoping that it will get me thru the next 6+ months until I get an entire suspension and dump the front spacers

I’ve had my 20’ boat for 15 years and hauled it with 5 different vehicles. The T4R isn’t the worst, but it’s certainly not the best at hauling.

My trailer completely loaded with the boat, all the fishing crap, trolling motor and a full tank of gas is 4,260 pounds (certified truck scale) with a tongue weight of 298 pounds. My suspension is completely stock. The rear drops about 1 1/8” with the rig hitched up and looks about level with maybe a tiny bit of rake left.

I realize that travel trailers are completely different than boat trailers, but the level kit is really hurting you. I would probably start with airbags on the rear then consider a WD hitch. Best option is probably better springs, but that may end up making for a harsh ride when not hauling. If you want to solve a lot of the problem go back to the stock rake.

Good luck whatever you decide!

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You need a WD hitch. They are not to control sway, they put some of the load on the front of your tow vehicle, when adjusted properly. Tongue weight controls sway, it should be minimum 15% of what the trailer actually weighs loaded. 18-20% is better.

Sway control bars control sway, but they are a band-aid for an improper setup.

Further, if your poor 4runner looks like that with an empty trailer, wait till you load it with a thousand pounds of water, food, dishes, clothes, and everything else you think you need or will acquire.

A 4runner would be better off with a teardrop trailer or maybe a small tent trailer.

Just for some reference here:

Stock rear springs IIRC are about 180lb/in. Meaning they will compress 1 inch with every 180lb added. You have two in the rear. So you should expect 360lb of weight to compress the rear 1". If you have 500lb of gear in the back and another 400lb of tongue weight - you should expect the rear to drop about 2.5" And that's what it looks like you are experiencing.

Air helper springs will provide additional support as will stiffer springs. There is a big difference between the two however in that air springs are very progressive in spring rate (meaning they get a lot firmer as they compress) while coil springs are usually linear. So the ride quality is quite a bit different both loaded and unloaded.

I prefer the ride of springs generally, but I like air bags for towing or hauling because they actually will ride firmer than coil springs under heavier weight. I don't know that there is a perfect solution for every use. It's really hard to make something ride well both under heavy load and light load. I think if you're doing a lot of towing - I'd probably consider both a slightly taller/heavier rear spring (not extreme heavy) and air helper springs for when you're really loaded up.

Get your tongue weight measured and figure out how much weight you have in the back of your 4Runner. I would bet you need to redistribute your weight better.

Dobinson rear springs arrived today.
Looking forward to getting these on and seeing what changes!




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Springs installed!
Haven’t driven it yet so not sure how every day commute will be yet and I won’t be able to hook it to the trailer till next week but we are getting there!

Used the 10mm spacer for the kdss so I wouldn’t lean and it’s perfect




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Well they definitely helped balance it out with the front spacers, so it looks much better now!!

For those who ask again, it's C59-505 with PS59-4023 spacer

I would really suggest that your money would be better spent on a good, properly adjusted wd hitch. That way, you’ll preserve the feel of the stock suspension when not towing, which I expect is your normal situation.

Here’s a pic of my setup. Trailer weighs about 4K pounds all loaded. Very stable on the road, balanced and no airbags, non stock springs, etc. If you want to make a more important mod, I’d add a transmission oil cooler.

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It's not the suspension - get a WDH and airbags and you'll eliminate the droop immediately. Also it is a LOT safer for you and everyone else on the road - no sway issues - I tow a 23' TT 5000km a year with a hitch weight of around 500lbs and TT weight of 4000 lbs - no droop and no sway - I set the airbags to 25 psi, crank up the WDH and good to go. Then once the TT is at the site, the suspension (I have 5100's all round) is good to go for the trails, beaches etc and is not so firm it shakes everything around.

appreciate the response!
the wd setup wont eliminate my reverse rake due to the level kit in the front of my car so thats why i went with hd larger springs in the rear to offset that tongue weight

i have towed the trailer several times now and have zero sway or bobble..
this thread is really just about eliminating the sag that i have brought upon myself

and....

in full disclosure..
most of my sag dissapeared as soon as i removed those stupid 'TRD OFFROAD' emblems and the overland bound badge from my c pillar

:P

don't fool yourself with thinking the sway isn't an issue - think about a semi truck with a 53ft trailer passing you going 80 mph on the highway.........

i just installed these took 2 hours. $100.00 on Amazon.
what a difference, just got back today from a 1000 mile trip made it solid as a rock highly impressed. i also suggest a re curve 3 weight distribution hitch it is the bomb.
Video below:

YouTube

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I wonder if air bags would solve your problem!