Increase axle rating on 1979?

[KYAirstream]

Although your under a 15% bump in capacity, whereas a 15% bump in capacity for me puts my 3200lb axles at 3680lbs.

Did Airstream realize over the years that 3200lb rated axles were under capacity for a 31 ft trailer? While your excella is heavier than mine, it doesn't seem to be that much heavier, so it makes me wonder if my 3200lb axles were marginal from the onset?

[4RXLA]

Seems to me like Airstream subtracted the tongue weight and let the axles cover the rest. I prefer the axles rated high enough to cover the entire weight of the trailer plus gear and fluids.

[4RXLA]

Here is what my trailer weighed in 2008 while still mothballed and mostly empty.

[Action]

Many trailer manufacturers will equip it in a manner that just covers the load with little to no margin. It keeps the costs down while competing for market share. Most buyers are not that educated and are looking at the shiney!!! The goal is camping not necessarily how one gets to the camp site.

>>>>>>>>Action

[TG Twinkie]

One must keep in mind.
Tongue weight is not carried by the axles.
The GVWR includes the weight of the axles and hardware including tires. The axles do not have to carry their weight. Only the weight of the coach and whatever is loaded.
If one has a coach with a 7,500# GVW. You could probably subtract a 750-900# tongue weight in addition to 400# or so of axle, tires etc.. Using the max weights of 900+400=1,300. Subtract that from the 7,500-1,300=6,200. Two 3,500# axles gives you 800# buffer.

[blkmagikca]

The ride is fine. I do have Centramatics which ensures that the wheel/hub/brake/tire assembly is dynamically balanced making for a smooth ride. Tires are inflated to 80 psi.

[Inland RV Center, In]

Originally Posted by KYAirstream

Although your under a 15% bump in capacity, whereas a 15% bump in capacity for me puts my 3200lb axles at 3680lbs.

Did Airstream realize over the years that 3200lb rated axles were under capacity for a 31 ft trailer? While your excella is heavier than mine, it doesn't seem to be that much heavier, so it makes me wonder if my 3200lb axles were marginal from the onset?

3200 pound axles for an average owner of a 31 foot Airstream (Old Excellas excepted) is fairly OK.

But, todays owners carry far more things, and stay on the road for longer periods of time.

Accordingly, the axle rating can be increased to 3500 pounds for the seldom users. Increasing to 4000 pounds is OK, BUT , the payload must also be increased, along with having the running gear absolutely balanced.

Part of that payload is full water. Total water weight for the later trailers, bumps 400 pounds. 50 gallons fresh, and 6 to 10 gallon water heaters, plus whats in the water lines.

Then add to that, at least a half tank of gray water and a half tank of black water, just to be safe.

Increasing axles from 3200 pounds to 4000 pounds REQUIRES that more attention be given to proper loading as well.

As an example, if 3200 pound axles are increased to 4000 pounds, and the trailer is towed with empty tanks and a light pay load, the ride will be much harsher than if loaded adequately.

The heavier the axle rating, the heavier the payload MUST BE. If not then damages will occur.

When replacing the older torsion axles, keep in mind the way you typically load the trailer, so that you can discuss your requirements with whom ever you choose to purchase axles from.

Axle ratings do not change the costs, but excessive ratings not using will certainly create repair bills.

Airstreams MUST HAVE a soft ride. Loading torsion axles correctly will provide that soft ride.

Andy

[KYAirstream]

Thanks for the replies.

Just to reiterate, carrying ZERO supplies and only full water and propane, per the CAT scales the trailer weighs in at 6660lbs with 660lbs tongue weight. If we can assume a deduction of 1060lbs (400 for axles and 660 for tongue weight), then each axle is carrying roughly 2800lbs.

When loaded with a weeks worth of supplies, the CAT scales show a trailer weight of 7500lbs with a tongue weight of 750lbs. A deduction of 1150lbs for tongue and axle weight suggests each axle is carrying approximately 3175lbs.

Given the above, what's the best axle rating to accommodate being fully loaded with supplies to last a week, as well as being loaded lighter for a weekend trip?

IF the assumption regarding axle weight is correct (approx 400lbs, or 200lbs each), then it seems like 3500lb rated axles would be plenty.