Axle to Trailer Weight Ratio

[elmo_4_vt]

Silly question for the people on this board more knowledgeable about trailer equipment than I...

Right now I have a 1,900lb-ish (fully loaded) trailer and am using a 3500lb axle with Ford Ranger leaf springs and good shocks and I am pretty happy with it's performance on and off road. Problem is, I'm already thinking of what I'd like to build in the future and I keep coming back to how much weight I can put on a 3500lb axle for a trailer that I want to be capable off-road (bad dirt roads, not really rock crawling) before it will be too much for it. I've seen a couple of dual axle off-road camper trailers from Australia on here and I REALLY like the idea of them for family camping in remote areas, but they use an independent style suspension for all wheels. Because of my fab ability, I'd have to stick with some sort of a custom leaf spring, straight axle setup, and am wondering, how heavy I can go before I get into having to use two 3500lb axles to keep everything rolling right in rough terrain. There's not much of a chance I'll go over 3500lbs, but there is a good change I'll be around 2500lbs-3000lbs loaded based on how much my current setup weighs...

Also, will having the additional axle help or hurt manners while driving in the dirt on and on the street. I also have two utility trailers that I use for side jobs, one w/ two 3500lb axles, and one with one 2000lb axle. I've had three blowouts at different times (two on the highway), and an axle seize on the small 2000lb trailer, and I've never (knock on wood) had ANY issues with the larger trailer. I drive both around the same mileage, maybe more on the large trailer, keep both in good maintenance and shape. The small trailer was never overloaded when the incidents occurred, because I always use the bigger trailer if it's even close. Anymore, I'll use the larger trailer even to get a couple sheets of ply from the local box stores just because of the luck I've had with the smaller utility trailer. Does that make any sense, or do you think it's it just bad luck and in my head?

Thanks for any help/opinions/advice you can provide.

Don

 

[Martyn]

The bearings and races on a 3500 lb axle are much bigger than the 2000 lb axle and more suited to off-road travel.

The same can be said when comparing 3500 to 5000 lb axles as far as the bearings are concerned. The issue with going from 3500 - 5000 is that at the 5000 lb level things start to get massive in size and weight.

As far as load goes you want a 20% safety margin for off road use, it's a rule of thumb and not scientifically calculated. So a 3500 lb axle should be maxed out at 2800 lbs.

Blowouts are usually a tire issue. Trailer tires can be inferior in quality, they sit for long periods in the sun, they are use infrequently and hard, and the oils in the rubber tend not to flow. They also rot from the inside out, so they look fine from the outside. We just replaced all 4 tires on the AT flat bed, they looked wonderful externally but were potential hazards.

Seizing is a matter of bearing maintenance. We are all guilty of not greasing and adjusting the bearings on our trailers. It's the one moving part that needs attention and still we ignore it. If it's been a while since you checked them, remove the hub and pull the bearings. Check the races and bearing surfaces for wear, re-pack the bearings with grease, fit a new rear seal and pin, and adjust them. Alternatively buy a complete rebuild kit and replace the bearings and seals. The races usually are fine. See http://www.atreport.com/bearing&hub.html

 

[elmo_4_vt]

Thanks for the reply.. I guess I wasn't even thinking about the 5000lb axles. I could always use them, but I would probably have to get a spacer specially made to fit my 5 on 5.5" bolt pattern I have as I don't think I've seen the wheel/bolt pattern sizes for the 5000lb axle I've seen for the 3500lb axle.

As far as maintenance, I'm usually pretty good and will at least pack every axle once a year in the spring, but I don't doubt that I should have replace the bearings in the one that seized on me. As far as the blowouts, I guess it could have been the tires just wearing, but none of them were more than a year or two old. In my opinion, I just don't think the tire sizes, moving parts, and suspension of a 2000lb axles are up to 1000 mile trips at 70mph and a good loads on them...

As far as my future trailer, I guess I'll just build it around a single 3500lb axle, and if it's close, I can always move up to a 5000lb version, everything on the trailer should be transferable.

Thanks again for being a sounding board.

Don

 

[Martyn]

The 5on5 is not available in the 5000 lb axle.

The other thing to note is that the 3500 and 5000 lb spindles are not interchangeable, they use different size tube for the axle. So if you build a 3500 lb axle and then decide to upgrade to 5000 lbs it's a whole new axle.

 

[elmo_4_vt]

The 5on5 is not available in the 5000 lb axle.

The other thing to note is that the 3500 and 5000 lb spindles are not interchangeable, they use different size tube for the axle. So if you build a 3500 lb axle and then decide to upgrade to 5000 lbs it's a whole new axle.

I understand that the axle would be different, I meant the springs and shocks. What I was scared about is having to go from one to two 3500lb axles, which would require significant changes in the body, frame, and suspension. Going from the 3500lb axle to a 5000lb is only the axle itself and easily changed out in a day with the exception of the bolt pattern, which I could also take care of in advance if I have to go that way.

Thanks again,
Don

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