Best Suspension Enhancement For 2021 Toyota 4Runner Sagging While Towing

Updated 07/23/2024 | Published 07/22/2024

Products Featured in This Question

Timbren Rear Suspension Enhancement System

(7173)

$269.36

SumoSprings Solo Custom Helper Springs - Rear Axle

(2510)

$278.99

Question:

I have a 2021 4Runner and I just added a box to the tongue that increased the tongue weight to 350lbs. 4Runners max tongue is 500lbs. The total trailer weight is 2800lbs. I’m experiencing enough rear sag to blind oncoming drivers with my low beams and also a lot of bouncing/rocking front to back on the 4Runner during specific types of bumpy highway road. I understand that I have a bit more tongue weight than I should. I’ve tried to balance it out as much as possible with putting the heavy objects behind the axel. I’m hoping I’m not totally screwed by adding this box. Would something like Timbrens help this?

asked by: Bryan

2021 Toyota 4Runner Towing Trailer
(click to enlarge)

Expert Reply:

Hey Bryan,

Thanks for the photo and specific info you gave, and if you're sagging to the point that it's affecting oncoming drivers you definitely need suspension enhancement. That much sag is actually going to affect your 4Runner as well because the back end will experience more wear, and your tires are going to go quicker. You mentioned Timbrens and while those will work, there's a better option, which are SumoSprings:

- SumoSprings Solo Custom Helper Springs # SS68DR

The # SS68DR will fit your 2021 Toyota 4Runner and I like them the most because they'll provide more than enough stability to handle the added tongue weight while you're towing, but won't make the ride super harsh like Timbrens can. Timbrens are made of a rubber that is very dense, and when you go over any type of bumpy road when unloaded, you are really going to feel them. The SumoSprings will compress more, so you will have a better ride.

expert reply by: Kyle S

Bryan

7/23/2024

Thank you! I noticed some talk concerning these in colder environments, which I’ll be often operating in. Near zero degrees is not uncommon. Is that something that changes your recommendation at all?

Kyle S.

7/23/2024

@Bryan Zero degrees is completely fine. The temperature would have to get to twenty-five degrees below zero to change how effective the # SS68DR would be for you; so unless you're pretty consistently at this temperature, you won't have any issues.