Upgraded Axles and Disc Brakes for 2021 Grand Design Imagine 21BHE

Updated 08/06/2026 | Published 07/31/2026

Products Featured in This Question

Lippert Trailer Axle Beam with Super Lube Spindles - 86.5" Long - 2,500 lbs to 3,500 lbs

(11)

$250.00

DeeMaxx Disc Brake Kit w/ Actuator for Tandem Axle Trailers - 10" Hub/Rotor - 5 on 4-1/2 - 3.5K

(29)

$2559.96

Dexter Trailer Springs Over-Under Conversion Kit

(855)

$75.93

Question:

Hello, I’m reaching out for guidance on upgrading the axle and brake system on my travel trailer. I own a 2021 Grand Design Imagine 21BHE, which currently uses a Lippert Components 3,000 lb axle Item V000247046, Cust Part 120276 with electric drum brakes. I’m interested in upgrading to a 3,500 lb axle equipped with a disc brake kit, and I would like to confirm all parts required for a complete and correct conversion. Specifically, I need to know: The correct 3.5K axle assembly compatible with my trailer The appropriate disc brake kit for that axle Whether my existing leaf springs must be replaced, and if so, which leaf springs you recommend Any additional components needed hubs, bearings, brake lines, brackets, hardware, etc. Any fitment considerations specific to the 2021 Imagine 21BHE frame or suspension If possible, please provide part numbers and links for all required items. Thank you for your help — I appreciate your expertise in making sure this upgrade is done correctly. Best regards, Tomasz

asked by: Tomasz L

Expert Reply:

Hello Tomasz! Thanks for providing all of that information. Your 2021 Grand Design Imagine 21BHE uses an 86-1/2" long axle with a 68-1/2" spring center measurement. For a 3,500 lb axle that matches you need the Lippert Trailer Axle Beam # LC63PK.

This comes in the underslung configuration, so you will also need the Dexter Trailer Springs Over-Under Conversion Kit # K71-384-00 to mount your leaf springs on top of the axle. You can replace the leaf springs if they're worn, but if they're in good shape it is not necessary. I would need to know the length of your existing leaf springs to find a replacement, see the article further down on this page which explains how to measure.

Then for disk brakes I recommend the DeeMaxx Disc Brake Kit w/ Actuator for Tandem Axle Trailers # DE84NR. This is a complete kit so it comes with everything you need to convert from electric to disc brakes on your trailer. The actuator, brake lines, hub/rotor, bearings and seals are all included.

Where are you headed with the Imagine once you upgrade the axles and add your new brake system?

expert reply by: Robin H

DeeMaxx Disc Brake Kit
(click to enlarge)

Tomasz L.

8/5/2026

Don't you need a higher rating springs if upgrading from 3k to 3.5k axles?

Robin H.

8/6/2026

@TomaszL you do not. You can certainly add them if you want to, but you aren't changing the rating on your trailer. You can add all of the higher rated components in the world and it won't change your GVWR. In the end, your frame will be the limiting factor. They may hold up better over time but you can't increase your trailer capacity.