What is Needed to Install 8k Roadmaster Comfort Ride System on 7k 3 inch Axles

Updated 05/10/2025 | Published 03/13/2025

Products Featured in This Question

Roadmaster Comfort Ride Leaf Spring Suspension Kit w/ Shock Absorbers - Tandem 7K Trailer Axles

(146)

$1875.00

Roadmaster Comfort Ride Leaf Spring Suspension Kit w/ Shocks - Tandem 8K, 3" Trailer Axles

(146)

$1875.00

Replacement Tie Plate for Roadmaster Comfort Ride Suspension System - For 3" Axles - Qty 1

$123.25

Replacement Tie Plate for Roadmaster Comfort Ride Suspension System - For 3" Axles - Qty 1

$123.25

Question:

I’m looking To upgrade to the roadmaster comfort ride w/shocks with 8K springs for 3 inch axle tube to fit my 2020 grand design solitude 375res with tandem 7k 3 inch axle tube. My question is what U-bolt kit do I need to purchase to put that road master kit on my 5th wheel?

asked by: Dave

Expert Reply:

Hey Dave, since you have 7k axles I would recommend just going with the 7k tandem Roadmaster Comfort Ride part # RM-2460-2570 as it's the correct rating and has correct size components.

But if you wanted to go with the 8k kit part # RM-2460-2580 you would also need to go with the 3 inch diameter axle tie plates part # RM54GR and # RM22MR so that it can attach to your axle diameter. Are you wearing out your 7k springs pretty quickly?

expert reply by: Jameson C

Dave

3/14/2025

Yes my 7k springs keep flattening out. I’m on my second set and I am not over loaded. So I believe the 8K springs will benefit the problem. Can you Explain these plates to me better please. There is no images to see exactly what you are saying they do and there are 2 different part numbers so which one are you referencing? And how many plates to install the entire kit?. Also in the roadmaster kit description it doesn’t list anything about needing to add these plates. Do these plates come with the correct U bolts to install everything? Because you didn’t answer my original question on what u bolt kit to get.

Jameson C.

3/17/2025

@Dave You can reuse your current U-bolts you have now as long as they are in good shape as these kits do not include them or require new ones. For a tandem axle trailer you'd need 2 of each of the plates. They essentially become the u-bolt plate that you have now except they have a bracket the shock attaches to. Are your current U-bolts in need of replacing?

Steve L.

4/25/2025

@JamesonC I just installed the Roadmaster system on 7K, 3” axles with the 8k springs on a ‘24 Montana. I was not able to reuse the unbolts as they were not long enough. We needed a min length of 8” and were very difficult to find for same day pickup. We ended up having a trailer shop make us custom grade 5 bolts. Much better quality than the original. I suggest you always recommend that new bolts always be installed. Bolts should not be used anyway due to the torquing requirements a probable stretch they have already undergone.

Jameson C.

4/28/2025

@SteveL That's really good feedback! Sorry about the extra hassle. U-bolts generally aren't torque to yield though like what you mentioned. Torque to yield bolts are designed to stretch and only be used the one time whereas U-bolts aren't designed like that for trailers from what we offer.