Recommended Suspension Support for a Single Axle Travel Trailer

Updated 11/12/2025 | Published 11/11/2025

Products Featured in This Question

SumoSprings Trailer Helper Springs w/ Line Relocation Bracket - Single Axle - 3K to 5K - Underslung

(66)

$299.99

Correct Track Trailer Alignment and Lift Kit - Tandem Axle

(56)

$501.83

Timbren Trailer Suspension Enhancement System for Underslung Axles - 5,000 lbs

(1)

$398.07

SumoSprings Trailer Helper Springs w/ Line Relocation Bracket - Single Axle - 3K to 5K - Overslung

(310)

$267.99

Question:

Hi, Description says Required Clearance: Between top of spring plate and bottom of trailer frame: 6inch - 8-5/8, question is... when is this measurement taken, before or after jacking the trailer up? I have a 2019 Wolf Pup 16FQ and have seen several reviews from people who installed them on the same or near same travel trailer. However, my measurement from spring to frame as it sits not jacked up is about 5 5/8inch - 5 3/4. Maybe im measuring wrong, what/where is top of spring plate? Will these springs work? Thanks!

asked by: Cat

Expert Reply:

Hey Cat, thanks for the information. The SumoSprings Trailer Helper Springs w/ Line Relocation Bracket item # TSS-106-40, you were looking at, is designed for trailers that have their axle mounted above the leaf springs. From the information I can find online it looks like your trailer has the axle mounted below the leaf springs or overslung.

If your axle is mounted underneath your leaf spring, the SumoSprings item # TSS-106-40 won't work without modifying your suspension. You would need to install the Correct Track Trailer Alignment and Lift Kit item # RR23QX. This would lower your axle by 1-1/4" to give you enough clearance. Please note this will raise your trailer by 1-1/4".

The other option is to install the Timbren Trailer Suspension Enhancement System item # T92MR. This is similar to the SumoSprings item # TSS-106-40, however you only need 5-1/4" of clearance.

For an overslung axle you would need the SumoSprings Trailer Helper Springs w/ Line Relocation Bracket item # TSS-107-40. These springs have the same capacity, however they only require 5-5/16" - 6-1/2" of clearance.

I've attached a couple of pictures below so you can see the difference between underslung and overslung and what this springs look like when they're installed.

Is your axle mounted above or below your leaf springs?

You can add this information and any other questions you have where it says Reply to Jerred H and I'll be happy to answer them.

expert reply by: Jerred H

Overslung
(click to enlarge)

Underslung
(click to enlarge)

Cat

11/12/2025

I have a single underslung axle, springs are under axle, the TSS-106-40 sounds like the correct kit. I spoke to Sumo Springs and they said to take clearance measurements from top of springs to frame, not from spring plate to frame (as you're instructions state). Please confirm how to measure clearance.. Also, What model Timbren would I need for 3000k-5000k underslung axle springs? Thanks

Jerred H.

11/12/2025

@Cat For the item # TSS-106-40 the top of the spring pack to the bottom of the frame would be the distance you would want to measure for an underslung axle. The location of the spring plate is irrelevant in this configuration and I'll try to get that wording changed. The Timbren Trailer Suspension Enhancement System for Underslung Axles item # T92MR are what you need for a 5,000 lbs trailer. These measure 5-1/4" so you need at least that much clearance.