Undersized axles?

Trailer is perfectly level. I do have outside kitchen behind axles. Full fridge, 3 bikes on the back. All tanks empty.

This is good stuff to think about BEFORE buying a trailer.

therink wrote:
ok, so I hit the scales (loaded and about to go camping):

Truck and trailer (GCW) - 20,120
Trailer rear axle - 5,060
Trailer front axle - 4,740
Pin weight - 2,480
Trailer weight (GCW)- 12,280
Trailer GVWR - 12,400

Truck weighed (GCW - unhitched) - 7,840
Truck weighed (GCW - hitched) - 10,320
Truck GVWR - 10,800

So I am within the trailer axle rating specs of 5,200 ea (barely). I am also well within the truck GVWR. I only have 120 lbs left on trailer payload. Time to go camping.
Steve

Is your trailer sitting pin high? I would try and level it out a bit if possible. 320lbs difference between the front and rear axle seems like alot.

ok, so I hit the scales (loaded and about to go camping):

Truck and trailer (GCW) - 20,120
Trailer rear axle - 5,060
Trailer front axle - 4,740
Pin weight - 2,480
Trailer weight (GCW)- 12,280
Trailer GVWR - 12,400

Truck weighed (GCW - unhitched) - 7,840
Truck weighed (GCW - hitched) - 10,320
Truck GVWR - 10,800

So I am within the trailer axle rating specs of 5,200 ea (barely). I am also well within the truck GVWR. I only have 120 lbs left on trailer payload. Time to go camping.
Steve

mapguy wrote:

FastEagle wrote:

mapguy wrote:


3. Safety margins are not "build-in" by most OEM RV builders. In fact -if you like to travel with potable water, more than one battery and LPG in the tanks - you risk being overweight.

The next paragraph is an out of context sentence from NHTSA regulations. The applicability means when such a system is installed.

“If applicable, the weight of full propane tanks must be included in the RV's UVW and the weight of on-board potable water must be treated as cargo.”

FastEagle

Nit-pic

Fine point

Propane calculation is always part of carrying capacity @ stated gvwr.

The proper term would be UVW.

FE

FastEagle wrote:

mapguy wrote:


3. Safety margins are not "build-in" by most OEM RV builders. In fact -if you like to travel with potable water, more than one battery and LPG in the tanks - you risk being overweight.

The next paragraph is an out of context sentence from NHTSA regulations. The applicability means when such a system is installed.

“If applicable, the weight of full propane tanks must be included in the RV's UVW and the weight of on-board potable water must be treated as cargo.”

FastEagle

Nit-pic

Fine point

Propane calculation is always part of carrying capacity @ stated gvwr.

mapguy wrote:


3. Safety margins are not "build-in" by most OEM RV builders. In fact -if you like to travel with potable water, more than one battery and LPG in the tanks - you risk being overweight.

The next paragraph is an out of context sentence from NHTSA regulations. The applicability means when such a system is installed.

“If applicable, the weight of full propane tanks must be included in the RV's UVW and the weight of on-board potable water must be treated as cargo.”

FastEagle

therink wrote:
I have a Keystone Sydney 340fbh fifth wheel with 5,200 lb axles ( 6 lug wheels) 12,400 gvwr, dry weight of 10,600, leaving payload of 1,800lbs.
If I calculate 20% of Gvwr on the axles, the Gross axle load should be 9,920 or 4,960 per axle. Isn't this cutting it close. Also, I believe 1,800 payload is quite weak for a fiver this size.
Opinions?

1. What are the GAWR on the Federal Certification Tag? Sum of GAWR plus hitch weight is minimum GVWR for an RV of your vintage to meet Federal Standards for first retail sale.
2. On paper the OEM way is legal and specified in their sales documentation.
3. Safety margins are not "build-in" by most OEM RV builders. In fact -if you like to travel with potable water, more than one battery and LPG in the tanks - you risk being overweight.
4. Part of the reason why tires are a problem on larger RV's -no safety margin -run components at maximum capacity without thought to lifetime -except warranty term.

FastEagle wrote:

therink wrote:
I have a Keystone Sydney 340fbh fifth wheel with 5,200 lb axles ( 6 lug wheels) 12,400 gvwr, dry weight of 10,600, leaving payload of 1,800lbs.
If I calculate 20% of Gvwr on the axles, the Gross axle load should be 9,920 or 4,960 per axle. Isn't this cutting it close. Also, I believe 1,800 payload is quite weak for a fiver this size.
Opinions?

Here is how I figured your weights using Keystone’s specs. They predicted a shipping weight of 10,544#. That would include all factory standards. To that they used 1856# of available cargo weight to establish a GVWR of 12,400#. By regulations they must set a hitch weight. In doing so it becomes the sounding board for determining the vehicle’s GAWR. So when we deduct the 2000# hitch weight from the 12,400# GVWR we get 10,400# supported by the axles. Thus two 5200# axles.

A double check of their specs can be done by adding the hitch weight to the GAWR. According to current regulations that answer must equal or be greater than GVWR.

So, on paper you have a cargo capacity of 1856# before dealer installed options. If your cargo label has a +/- 100# figure (before dealer options) I would say that is a good ballpark figure.

The following statement is verbatim from a NHTSA Q&A document.

“The FMVSS have requirements for the manufacturer to use proper tires and rims for the gross axle weight rating (GAWR) and the gross vehicle weight rating (GVWR). The manufacturer may determine the GVWR by adding cargo capacity (if any) to the curb weight of the vehicle as manufactured. The wise consumer, before purchase, will determine if the vehicle has sufficient cargo capacity to carry the weight of water, additional equipment (such as televisions, and microwave ovens), and luggage. The manufacturer’s certification label must show the GVWR. The GVWR must not be exceeded by overloading the vehicle. There is little the government can do to assist a consumer who has purchased a vehicle that has insufficient cargo capacity for its intended use.”

FastEagle

Thanks for the information. I will hit the scale tomorrow. I'm probably good, but still wish I had heavier axles for comfort factor.
Steve

therink wrote:
I have a Keystone Sydney 340fbh fifth wheel with 5,200 lb axles ( 6 lug wheels) 12,400 gvwr, dry weight of 10,600, leaving payload of 1,800lbs.
If I calculate 20% of Gvwr on the axles, the Gross axle load should be 9,920 or 4,960 per axle. Isn't this cutting it close. Also, I believe 1,800 payload is quite weak for a fiver this size.
Opinions?

Here is how I figured your weights using Keystone’s specs. They predicted a shipping weight of 10,544#. That would include all factory standards. To that they used 1856# of available cargo weight to establish a GVWR of 12,400#. By regulations they must set a hitch weight. In doing so it becomes the sounding board for determining the vehicle’s GAWR. So when we deduct the 2000# hitch weight from the 12,400# GVWR we get 10,400# supported by the axles. Thus two 5200# axles.

A double check of their specs can be done by adding the hitch weight to the GAWR. According to current regulations that answer must equal or be greater than GVWR.

So, on paper you have a cargo capacity of 1856# before dealer installed options. If your cargo label has a +/- 100# figure (before dealer options) I would say that is a good ballpark figure.

The following statement is verbatim from a NHTSA Q&A document.

“The FMVSS have requirements for the manufacturer to use proper tires and rims for the gross axle weight rating (GAWR) and the gross vehicle weight rating (GVWR). The manufacturer may determine the GVWR by adding cargo capacity (if any) to the curb weight of the vehicle as manufactured. The wise consumer, before purchase, will determine if the vehicle has sufficient cargo capacity to carry the weight of water, additional equipment (such as televisions, and microwave ovens), and luggage. The manufacturer’s certification label must show the GVWR. The GVWR must not be exceeded by overloading the vehicle. There is little the government can do to assist a consumer who has purchased a vehicle that has insufficient cargo capacity for its intended use.”

FastEagle