Trailer axle rating

[THoltz]

If a trailer has tandem axles, each rated at 5200 lbs, does that mean that a GVWR for the trailer of 12,480 is in excess of what the axle capacity is? I know it seems like a dumb question, but these numbers are what is published in a brochure for Colorado 5th wheels. What gives?

 

[WestTN]

The truck will support some of the load.

 

[MAleshire]

Go to a truck scale and weight the load on the back axle of the truck. Then weigh the back axle load with the 5th wheel attached to the truck. Subtract the difference from the total weight of the 5th wheel to determine the load on the axles. It's important to do this so that you'll know how much air to carry in the 5th wheel tires. Biggest cause of tire failure on trailers is under inflation. Hope this helps.



Skip

 

[Curious Dave]

OK... Well... It is a bit of a mess the engineers have created with this subject. But here is what I have found out. The trailer mfg should have a listing for what they call "pin weight". That is the number that has been calculated that the truck has placed on it while towing said trailer. The pin weight is subtracted from the total weight of the trailer and the axles have been chosen to support what ever weight remains. So if you have 11,000 and they call for 1500 lbs. pin weight, that means you have 9500 lbs. being supported by the 2 axles that have a rating of 5200 each. That means that you can load 900 lbs of junk into your trailer before you are at the maximum carrying capacity of your trailers axles. This is not to mention the tires. They have a rating also. The problem I have with this is what exactly does the maximum weight rating for tires, axles, or springs mean? Is the number given a maximum weight at which failure occurs or is it a maximum weight that represents a certain percentage of safe loading.

 

[Curious Dave]

OK... Well... It is a bit of a mess the engineers have created with this subject. But here is what I have found out. The trailer mfg should have a listing for what they call "pin weight". That is the number that has been calculated that the truck has placed on it while towing said trailer. The pin weight is subtracted from the total weight of the trailer and the axles have been chosen to support what ever weight remains. So if you have 11,000 and they call for 1500 lbs. pin weight, that means you have 9500 lbs. being supported by the 2 axles that have a rating of 5200 each. That means that you can load 900 lbs of junk into your trailer before you are at the maximum carrying capacity of your trailers axles. This is not to mention the tires. They have a rating also. The problem I have with this is what exactly does the maximum weight rating for tires, axles, or springs mean? Is the number given a maximum weight at which failure occurs or is it a maximum weight that represents a certain percentage of safe loading?

 

[Matt400]

Is the number given a maximum weight at which failure occurs or is it a maximum weight that represents a certain percentage of safe loading?

Safe loading up to this amount & rated to carry safely.

 

[WestTN]

As far as that inflation presure goes, always put them at maximum. No trailer has much excess load capacity. There are too many combinations of suspension components.

 

[R C Cola]

Weight Issues

Weight rating on the sticker is the maximum loaded weight by law meaning that you can and probably will get a ticket if caught over that amount. Other issue is your safety, if the wheel, tire, axles, etc. are rated at a certain amount are you willing to risk your family by going over it. In a non-commercial situation the factories are trying to save money by shortchanging you on how much stuff you can haul inside. I would install larger axles with better tires and remove the sticker and take my chances (they look at and go by what the tire says on the side and know by the number of bolts what the axle is likely to hold. Again non-commercial only. The rest of us can get a ticket just for the sticker not being there.

 

[HBarlow]

GVWR and GAWRs are very different numbers. The axles are not required to support full GVWR because the tongue weight or kingpin weight is supported by the tow vehicle.



For conventional tongue pull trailers about 12-15% of gross is supported by the ball.



For fifth wheel trailers, about 20% of gross is supported by the fifth wheel.

 

[Curious Dave]

well... after 3 sets of bent axles, "w" shaped leaf springs, blow outs, and all of the impact on the truck, not to mention the intermittent response of the trailer brakes and blowing intersection... I decided to design my own layout and go with what made sense in the real world. I got rid of the factory tandem 6,000 setup with rigid pin box, and 16" wheels. I went over to a trail-aire pin box and 8,000 tandems with Rickson 19. 5's. No more problems... Imagine that. By the way... I had the trailer weighed and at no time was it over weight. I am also looking at the Keldermann air ride system just to make things a bit more plush.

 

[R C Cola]

Kelderman ?

On the truck or trailer ?

 

[Curious Dave]

Keldermann on the trailer. I thought about truck and trailer... But they tell me they do not recommend air bag assist with the rear air bag setup they have. I already have and need the assist with the load I carry on the rear. Unless I could use the assist bags with the bags they put on their rear system and eliminate the brackets I have. Then maybe 4 bags available when needed????? hmmmmm... ...