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All Parts Needed to Upgrade a 3,500 lbs 86-1/2" Hub Face Axle to a 6,000 lbs Axle  

Updated 03/22/2026 | Published 03/20/2026



Question:

Hello, I have a 2025 Forrest River CKT24RRTBL-94 black label toy hauler, I would like to upgrade the 2- 3.5k Terran axles with a Dexter 5k or 6k replacement or similar. I like to be overkill for peace of mind on trips. I’m not confident with the current setup if I were to load a 1500lb+ sxs. The hardware has already shown a good amount of salt corrosion from manufacturing transportation I’m assuming. What would be the best route to go for pretty much replacing everything related to the axles and suspension? Suggestions and Full list of parts and ’s would be awesome Trailer Info- Dry weight: 6342 Gvwr: 8189lbs Gawr: 3500lbs Each axle Tongue weight empty: ~1100lbs My current axles read: TERRAN PART : ST35B-C-S-86.5-68.5-US-6102-7111-E CUST. PART : 3.5K 86.5/68.5 BRAKE 545 Thank you for your time

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Expert Reply:

Hey William, thank you so much for all of the information!

To replace your axles, I recommend the Trailer Axle w/ Electric Brakes item # e73SR. This is a 6,000 lbs axle that come ready to install with pre-greased hubs and electric brake assemblies. The hubs have a 6 on 5-1/2 lug nut pattern so you will need to replace your stock wheels as well. The 5,000 lbs and 6,000 lbs axles have a different spindle size and there's no options for a 5 on 4-1/2 hub.

Please note that the item # e73SR axle has an 86-1/2" hub face dimension. This is the length of the axle with the hubs. It'll match your current ones perfectly. We do not have one with 68-1/2" spring seat mounts so you'll need to purchase two of the Spring Seat item # TRSS300 per axle and have them installed.

You'll also need two sets of the U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles item # APUBR-8. These are 3" U-bolts designed for axles like item # e73SR.

The leaf spring dimensions were not listed on your axle tag. 3,500 lbs axles typically use 25-1/4" long leaf springs. The 5-Leaf Double-Eye Spring for 6,000-lb Trailer Axles item # e34SR would be the best replacement option. I highly recommend measuring one of your leaf springs from the center to the center of the mounting bolts with the weight off of that side of the suspension to confirm exactly what size is on your Toy Hauler. If you get a different measurement put it below where it says Add comment and I'll find a different leaf spring for you.

When you swap out your leaf springs, you'll also want to switch out your hardware as those wet bolts are only meant to be torqued down once. You'll want to pick a kit with the closest size to your current shackle straps.

The MORryde Suspension Upgrade Kit for Tandem Axle Trailers item # MR46ZR is for 2-1/4" shackles or item # MR76ZR is for 3-1/8" shackles. These kits are the top of the line and come with bronze bushings, wet bolts and shackle straps. The wet bolts can be easily serviced with the built in grease zerks. If you keep these wet bolts and bushings lubricated they'll last longer than your leaf springs and you won't have to worry about corrosion.

The last component you'll need is an upgraded equalizer. Your current factory one most likely going to be rated high enough to handle the over overkill setup you're looking for.

I recommend one of the MORryde equalizers like item # MR27ZR. You'll need to take a couple of measurements off of one of your current equalizers so we can find the right one. If you'll look at the picture attached below you'll see an 8" horizontal and 3-1/2" vertical measurements. If you could put that information below where it says Add Comment, I'll be able to find the correct one.

What kind of SxS do you have?


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Jerred H
MR27ZR
MR27ZR
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