over on RAWR occassionally

[howardwheeler]

I have reweighed my truck and fifth wheel setup fully loaded to the max of what I could reasonably expect to carry. I am not over my GVWR but am over by 400 lbs. on my rear axle. What remedial action could I take or, if I am stubborn, what would the long term effect be on the rear axle? We are talking about twice a year being in this situation for a few thousand miles.

[45Ricochet]

jerem0621 wrote:

45Ricochet wrote:

rhagfo wrote:

Keep in mind the F350 is SRW, not going to have a 9,000# axle rating, more like 6,100 to at most 7,000#.

Same axle as a DRW Ford so it IS rated at something over 9k, only the tires are holding it back from it's full potential.

Pretty sure the DRW has a Dana 80 and the SRW has a Sterling 10.5.

Huh, who would have ever guessed Ford would have gone back in time :B
I'll admit I'm not up to date on Ford's, but I just figured they all used Dana's.
LINK

[blt2ski]

I would say the issue is the springs, not the tires. Being over on the springs is not as bad as being over on the tire from my experience. I would toy with adding a leaf to the spring pack, air bags, or completly redoing the spring pack would be my first thought and preference. BUT< that is also the how I use my truck, better to have springs generally speaking than air bags. For some that carry truck campers, air bags would be a better option.

For the OP....not sure I would worry about it, since he has a 350, the issue of the overheating RA as mentioned by one that had a 1500, is probably not going to happen.

Enjoy the truck, make sure you have a paid for tag that is greater than what you are grossing at, as that will be the issue you will have if pulled over, more than being over the manufacturs ratings. At least that has been the case for me here in Wa st.

Marty

[JIMNLIN]

rhagfo wrote:
This is the result of the GVWR being tighter to the total GAWR of the truck. Now days that is running between 90% to 95% of the total GAWR, so it is possible to exceed the GRAWR without exceeding the GVWR

Good point.

This pops up especially on some F150 models with the high GVWRs.

Now the '13 3500 Dodge SRW has a whoppin' 12400 GVWR and 7000 RAWR. I see rear axle over load written all over this truck when RV folks use GVWR to figure a payload.

The '12 F350 SRW has a 6290 RAWR and 6730 RAWR and 7000 RAWR packages depending on truck selection. The OP has the 3750 lb rated tires so I assume his truck has the 7000 RAWR package.

[rhagfo]

45Ricochet wrote:

rhagfo wrote:

Keep in mind the F350 is SRW, not going to have a 9,000# axle rating, more like 6,100 to at most 7,000#.

Same axle as a DRW Ford so it IS rated at something over 9k, only the tires are holding it back from it's full potential.

Exactly, it is tires the control the axle rating on both the SRW and DRW, not the axle itself.

I believe that a gas, SRW F350 can be within the GVWR and over on the rear axle.

[jerem0621]

45Ricochet wrote:

rhagfo wrote:

Keep in mind the F350 is SRW, not going to have a 9,000# axle rating, more like 6,100 to at most 7,000#.

Same axle as a DRW Ford so it IS rated at something over 9k, only the tires are holding it back from it's full potential.

Pretty sure the DRW has a Dana 80 and the SRW has a Sterling 10.5.

[skyhammer]

You are correct about the 350 SRW now using a Sterling axle, by manual says 7180lbs, close enough.
My DRW uses a Dana 80 axle, Dana rates it as 11,000lbs but Ford derates it to 9650lbs.
For 2013, Ford increased the GVWR a little. The DRW is now 14,000lbs up from 13,300lbs. I don't know what the SRW's new GVWR is now, but it has also increased a little.

[4x4ord]

The rear axle rating on my 2011 is actually the rear spring rating and its 7000 lbs, The axle is made by Sterling and is rated by them at I believe 9750 lbs.
The GVWR in 2011 was and I believe still is 11500.
My empty truck weight with only the driver and one passenger is 8500lbs.
The empty rear axle weight is 3600.
So on my 2011 F350 SRW 3800 lbs of pin weight would overload my rear springs (RAWR) by 400 lbs and I would be over on my gvwr by 800 lbs. I wouldn't loose any sleep over it.

[45Ricochet]

I did think of the hitch placement but I had heard the Fords come drilled from the factory :H I would think most folks would save a bit or two and use the excising holes. Some scaled weights would be nice to have :W

[NC_Hauler]

rjstractor wrote:

NC Hauler wrote:
OK, I'm confused...He stated he's NOT over his GVWR (gross vehicle weight), but IS over his RAWR by 400#

Did anyone not catch this...If he is over his RAWR he's WAAYYY over his GVWR..unless he meant he wasn't over the trucks GCWR...but again, I get the impression that he IS over his trucks RAWR, but because his tires will handle more weight, he should be ok

Not necessarily over on his GVWR. The GVWR on a newer SRW F350 is 11,500. So, if he is 400 over on RAW, is he is running less than 4K on his front axle he could be less than GVWR. Granted, that is pretty light on the front end. I myself am surprised no one asked where the kingpin placement is in relation to the centerline of the rear axle. If it's too far back he could be unloading the front axle, and if that's the case moving it forward to just ahead of the rear axle could solve all his weight problems.

OK, you may be on to something and I should have thought it out a bit more. He could be over RAWR and not be over GVWR..my bad....(been a long last 3 day's13 hr day's at work:))...

BUT, that would bother me to think I'm overloading my RAWR by 400#..doesn't sound safe. You also may be on to something about his hitch mounting..if not in the correct position, could wreck havoc on pin weight putting more on the axle.

Thanks for helping me get back on track.....

[rjstractor]

NC Hauler wrote:
OK, I'm confused...He stated he's NOT over his GVWR (gross vehicle weight), but IS over his RAWR by 400#

Did anyone not catch this...If he is over his RAWR he's WAAYYY over his GVWR..unless he meant he wasn't over the trucks GCWR...but again, I get the impression that he IS over his trucks RAWR, but because his tires will handle more weight, he should be ok

Not necessarily over on his GVWR. The GVWR on a newer SRW F350 is 11,500. So, if he is 400 over on RAW, is he is running less than 4K on his front axle he could be less than GVWR. Granted, that is pretty light on the front end. I myself am surprised no one asked where the kingpin placement is in relation to the centerline of the rear axle. If it's too far back he could be unloading the front axle, and if that's the case moving it forward to just ahead of the rear axle could solve all his weight problems.

[45Ricochet]

rhagfo wrote:

Keep in mind the F350 is SRW, not going to have a 9,000# axle rating, more like 6,100 to at most 7,000#.

Same axle as a DRW Ford so it IS rated at something over 9k, only the tires are holding it back from it's full potential.

[goducks10]

howardwheeler wrote:
I have a 2012 F 350 Powerstroke SRW.

I was typing while you were answering:)

[NC_Hauler]

rhagfo wrote:

45Ricochet wrote:
I was a bit confused also Jim with the weights and ratings :H
That rear axle rating should be more like 9000 lbs I would think. The only limiting factor is the tires. I agree even the guys that use axle rating instead of GVWR usually don't go over their RAWR. In general a newer Ford F350 should be maxed out at about 3k lbs of pin weight.

This is the result of the GVWR being tighter to the total GAWR of the truck. Now days that is running between 90% to 95% of the total GAWR, so it is possible to exceed the GRAWR without exceeding the GVWR.

Keep in mind the F350 is SRW, not going to have a 9,000# axle rating, more like 6,100 to at most 7,000#.

Never heard of exceeding RAWR without exceeding GVWR...and by 400# at that..per the OP, but hey, learn something new everyday...at my age, that's good, bummer is, I forget two old things:)

My RAWR is 9750#..so if I weighed my truck, ie, like checking pin weight with 5er hooked up, and I exceeded my rear axle weight by 400#, (weight being 10,150#, setting on the rear alxe,though GVWR is 14,000#), I'll be ok, because I'm only exceeding RAWR by 250# AND, if my Tires will handle 10,200#, I'd be ok anyway no matter what...yeah, I get it.....

[rhagfo]

45Ricochet wrote:
I was a bit confused also Jim with the weights and ratings :H
That rear axle rating should be more like 9000 lbs I would think. The only limiting factor is the tires. I agree even the guys that use axle rating instead of GVWR usually don't go over their RAWR. In general a newer Ford F350 should be maxed out at about 3k lbs of pin weight.

This is the result of the GVWR being tighter to the total GAWR of the truck. Now days that is running between 90% to 95% of the total GAWR, so it is possible to exceed the GRAWR without exceeding the GVWR.

Keep in mind the F350 is SRW, not going to have a 9,000# axle rating, more like 6,100 to at most 7,000#.