Replacement Axle for a 2010 Heartland Bighorn 3670RL  

Question:

Expert Reply:

We do have an axle that will work for you. However, it's not a 8k axle and its only available as a 3.5k axle. Lippert axle kit part # LC45FC. Your current axle has a 68-1/2" spring center spread and a 87" hub face to hub face length. Something you could swap over to that would get you close to the 8k that you're looking for would be the Timbren Axle-Less kit part # TASR7KS01.

One major note about this system is it requires a crossbeam support. If your trailer frame doesn't have a crossmember in place, you can retrofit it with one, or you can add a support by running a piece of 2" x 3" steel tubing through the square holes that are existing on each assembly. You can also add a steel reinforcement bracket to the inside of your trailer frame.

These Timbren kits have built in suspension so It's an all in one so to say. It will be an overhaul of a swap over but a true game changer when it comes to the quality of the ride. I included some pictures below showing some views of how the Timbren kit would look like once installed.

The last thing I want to mention, since you are wanting to upgrade to a higher capacity axle, using a higher capacity axle wont increase the capacity of your camper. Your frame also has a rating and there isn't a way to increase that.

Why are you wanting to upgrade to a higher capacity axle?

expert reply by: Gwendolyn Y

0

Timbren
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Timbren
(click to enlarge)

Bill E.

2/24/2026

The Lippert axle kit part # LC45FC you recommended is for 3,500 lb axles. My camper has tandem 7,000 lb axles. Your suggestions won't work for my application. I want to upgrade to provide a measure of safety and reduce wear and tear since these campers generally run close to their max capacity.

Gwendolyn Y.

2/24/2026

@BillE I referenced the Lippert kit number since it was the only axle we carried that was as close to the size that you were looking for. A heavier axle may help a little bit since you could also upgrade your tires but it won't be that big of a difference. To get one that will fit and is rated for 8k, I recommend going to a local trailer shop so they can get one custom ordered for you. The best way to reduce wear and tear would be to upgrading the suspension. Getting upgraded equalizers to something like part # MR87ZR would be a better upgrade over all and help support your load and cushion the ride a lot. If you really want an overhaul then I recommend going with the Roadmaster Comfort Ride part # RM-2470-2580. The only issue you may run into using the Comfort Ride is the 8k kits would need a 3-1/2" round axle and 7k axles are traditionally 3" so you would still need new axles. Just some options.