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Old 09-08-2019, 07:50 AM   #1
bobnelms
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Is Axle, Spring, and Tire Upgrade Enough?

Hello all,

A few years ago we purchased a used 2016 Keystone Cougar 5th wheel -- 37 foot. We've had a few issues -- fire on a wheel bearing and also a blowout.

After visiting the CAT scales, we are NOT overweight -- but only have 120 lbs per axle leeway.

So here's my question...

If I upgrade the axle to bear more weight, as well as the springs and tires to match, will I be okay?

Another way of asking the question is this.... May I exceed the rated cargo capacity of this RV (currently about 1500 lbs I believe) by upgrading the axle, springs, and tires OR are there other considerations?

Thanks ahead of time.
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Old 09-08-2019, 09:16 AM   #2
JRTJH
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Any trailer is constructed with "maximum ratings" on all the systems that make up the trailer. The tires, the springs, the axle beam, the bearings, the frame rails, the cross members that hold the frame rails in alignment, the A-frame (on travel trailers), the pin box (on fifth wheels) all can, depending on their ratings, limit the maximum trailer GVW capacity (not the rating, the actual capacity to carry a load)...

So, essentially, your trailer is very much like a chain. Its maximum capacity is limited by the weakest link. In your case, if the axles are replaced with 'stronger ones" then you'll be limited by the next "weakest link". What is that? It varies from trailer model to trailer model, so the engineering that went into building your trailer will dictate whether you can "increase the payload by increasing the axle rating.

Without getting into the legalities of such a modification to a travel trailer, on vehicles, there is a "hard and fast rule" that suspension upgrades DO NOT increase the vehicle capacity beyond the factory applied rating. The only way to increase the actual rating is to have a licensed vehicle modification company accomplish the work and certify their improvements with a new "vehicle certification decal/sticker" with the new ratings.

It boils down to: Yes you can put bigger axles under your trailer to eliminate axle strain and improve the axle capacity. That may or may not increase the overall trailer capacity depending on whether additional weight would stress some other trailer component beyond it's capacity and cause trailer failure in another area of the construction.
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Old 09-08-2019, 09:22 AM   #3
hankpage
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If you are looking to increase by 1000 lbs. I would definitely say not good since the chassis has limits also and the hitch weight will effect the payload of your TV. If you are just looking for a little safety margin increase I think it might be a good investment. Also consider there may be an increase in height which will change overhead clearance and center of gravity. JM2¢, Hank
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Old 09-08-2019, 09:39 AM   #4
travelin texans
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If you really want to help the overall suspension, contact MorRyde & check out their IS, independent suspension, upgrade with disc brakes. That's about a $7k upgrade for both but money well spent. They weigh your RV & determine the best weight rating setup for you on the suspension. The disc brakes are night/day difference in braking over the drum brakes, can actually feel the RV slowing the tow vehicle & I'm confident you could actually stop the rig in an emergency situation. I also upgraded to Sailun 17.5" H rated tires & wheels, thereby pretty much bulletproofing the suspension with these upgrades.
If for now you'd just want the disc brakes & tire/wheel package contact Performance Trailer Braking, they come to you if you chose to have them do the install, which by the way they do an exceptional job.
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Old 09-08-2019, 12:04 PM   #5
CWtheMan
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A NHTSA quote: "The FMVSS have requirements for the manufacturer to use proper tires and rims for the gross axle weight rating (GAWR) and the gross vehicle weight rating (GVWR). The manufacturer may determine the GVWR by adding cargo capacity (if any) to the curb weight of the vehicle as manufactured. The wise consumer, before purchase, will determine if the vehicle has sufficient cargo capacity to carry the weight of water, additional equipment (such as televisions, and microwave ovens), and luggage. The manufacturer’s certification label must show the GVWR. The GVWR must not be exceeded by overloading the vehicle. There is little the government can do to assist a consumer who has purchased a vehicle that has insufficient cargo capacity for its intended use."

Usually the procedure to modify your current trailer to carry an extra 1000# will be much more expensive than trading for one that will suite your load demands.

The attached reference is complicated and refers to other documents. But the gist you are looking for is there.

https://www.law.cornell.edu/cfr/text/49/part-567
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Old 09-08-2019, 12:10 PM   #6
Roscommon48
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i'd just redo the springs and upgrade tires. your issue with the fire is very unusual as far as i can tell.
of course the IS is out there if you want to spend another $7K
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