How To Reduce Sag When Towing With A 2021 Toyota 4Runner Venture
Updated 12/22/2025 | Published 10/13/2024
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Question:
I have a question about my 2021 venture 4runner. I tow a small 15 foot aluminum boat. When attaching the boat my rear end starts to sag. I am looking at either sumo springs or timbren and was wondering if these will help my problem with the sag? Also which one you guys recommend.
asked by: Chet
Expert Reply:
Hi Chet,
Both Timbren And SuperSprings SumoSprings jounce springs would help with the sagging you're experiencing, but only one is going to give you a comfortable ride quality. You'll want to stay around the payload capacity of your 4Runner otherwise the springs you install can be too stiff and start affecting your unloaded ride quality in a negative way. Timbrens are great but are made for more heavy-duty use and would likely be too stiff for your intended use.
I recommend going with the SumoSprings Solo Custom Helper Springs # SS68DR. These 1,400lb capacity so they're well over what the tongue weight of the boat trailer would be and likely whatever else you'd load into the back of your 4Runner. These springs are designed to progressively stiffen up as weight is added so if you're not loading a lot or you're empty the first portion of the spring will lightly compress versus feeling like you hit a hard chunk of rubber.
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Robin H.
12/22/2025
Hey Chet, how did things turn out after adding the SumoSprings to your 4Runner? Did they help level out the rear when towing your boat? Your feedback could really help others dealing with the same sagging issue.