3 x 7k axle but only 20k GTW???

Great question as I've wondered the same thing. My RV has a GVWR of 19K, has 3-7K axles for a 21K rating and tires with a weight rating of 24.5K so go figure. My pin is at 19.5% of GVWR. Not sure where the weak link is, a factory rep told just to not exceed the axle rating if going over the 19K GVWR listed on my RV, of course he wouldn't put that in writing...lol!

Most toy haulers run 20-25% pin weight. So a 20,000GVW trailer will have 4000-5000 K on the pin and 15,000-16,000 lbs on the axles

The third axle is most likely to help spread the weight of whatever you put in the garage. On a non-toyhauler, the heaviest items are built into the trailer and will not be added by the owner. With the toyhauler you could end up adding an extra ton or ton and a half near the rear of the trailer. Might be too much concentrated weight for just 2 axles.

Thanks for the responses; the factory tires are g rated so a little over 4k each.

With a 3150 pin weight that leaves roughly 17k on the suspension components; spings and hangers etc. a two axle in the same model line has GvWR of 16500 pretty close to 7k an axle plus pin weight for the model... provided all things are equal just trying to figure out “why” the third axle only nets 3500lbs of added capacity to the trailer. Wondered if if it’s merely a regulatory thing? Have to classify differently over 20k? Meet other restrictions over 20k? Or if it’s actually a physical capability issue?

fj12ryder wrote:
"What is the weak link; pin, frame, hangers, other???"

Yes.

Could be any one of the above item or a few not mentioned like springs or tires.

GAWR and tire minimum capacity are listed on the side of the trailer on the Federal Certification Label.

My guess is the springs are matched to the GAWR. This is commonly done by RV builders

Probably due to tires. What is the load rating on the tire sidewalls? Anything less than 3K and there you are at 20K for max capacity.

Same reason the sum of your truck axle ratings is less then the trucks GVWR

hoopt01 wrote:
Looking at upgrading TT toyhauler for 5th wheel toy hauler (grand design momentum) specific floor plan still being debated. Anyhow, why... if it has three axles rated @ 7k each (not to mention pin weight) would it only be rated for 20k max? What is the weak link; pin, frame, hangers, other???

Well 3x 6k seems a bit light so they put on 7k. Seems well built to me.
GVWR is not always the sum of the axles plus the hitch or pin.

My Voltage has the same thing: 3x7000 pound axles and a 19,000 GVWR. Glad one of cares enough to pose the question.

"What is the weak link; pin, frame, hangers, other???"

Yes.