SS on spread axle flat bed....

likely caused by the traction issue SS have. /<sarcasm off>

 

I'd venture to say you're wrong. If they didn't hold the weight they wouldn't be back there or on drive axles. Translation, if they couldn't carry the weight they wouldn't be used.

 

A well built trailer should be able to take the abuse without a dump valve. I've pulled a 1990's vintage Wilson curtain van that has spent its life doing brutal alley docks without a dump valve & it has held up just fine.

I also don't think duals vs singles should make any difference. The co. I'm currently leased to has been running wide base Michelins on spread axle curtain vans for at least 10 years with no problems. It's really in the hands of the operator, take your turns as wide & slow as possible & everything will be fine. For the first month I didn't have a dump switch in my truck & the tires survived just fine. A dump valve makes it way easier to back into tight docks though.....

 

Well, like I stated earlier, check with Keim TS about how they are doing with wide based rubber on spread axle flat beds. That is all they use.

 

Europeans use single tires on tridem axels and I'd say they run well. yep, when SS blows air lines, fenders, light may easily be damaged, more damage then from conventional tire, really.

Rim for SS is 20% heavier conventional rim, but there are two rims per axel only, so really SS saves weigh (unsuspended weight). and trailes on SS runs smoother.

 

I'm not saying they won't carry the weight but with a super single you have less rubber touching the road than you do with a set of duals. I don't care if the axle and tire are rated to carry 20,000lbs per axle, if you don't have enough rubber on the road you can't do it.

 

Back in Europe we use ss on 90% of trailers I would say and our weight limits are much higher than here, true there is less rubber on the road but that's the point of them, they are lighter overall , less rolling resistance so they save fuel and they brake better on slippery roads when empty

 

Why doesn't spread axle trailers have at least on axle that steering?
Tires and suspension components must suffer a lot from the punishing side forces.

 

It's easy, do the math.
Depending on what kind of tires you run a dual tire has an overall width of 10" take 10" X 2 & one set of duals has 20" compared to one super single that only has 17". Go measure your truck/trailer axle spacing and ask your friendly neighborhood DOT man how much you can carry per axle with duals on and then ask him how much with super singles on. You can NOT carry 20,000lbs per axle on a spread with super singles.

Or you can put all your axle measurements and tire sizes in this form and it will tell you how much you can carry & then tell me how you can carry 20,000lbs per axle with singles on. https://apps.sd.gov/applications/hy30commpermit/legalcal.asp