Bought the wrong truck

[john1981]

Originally Posted by kdauto

Your "advice" is downright dangerous. No one has shown any SRW axle rated in the 9000lb range, although they seem adamant to say so. No axle manufacturer has put that spec out AFAIK.
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id post a link but my web browser is acting up. try searching "dana spicer weight ratings" and it should turn up something for you. the thing is, these axles arent used just in trucks. dana 80s were definately used in forklifts and all other sorts of industrial applications. i dont advocate going over gawr at all because that goes from the grey area of whats safe to crossing the solid line of illegal. you can doctor a gcwr or gvwr on paper to make it legal. you cannot doctor whats on the door jamb as far as axle ratings and make that legal.

[KingKid]

If you like the LB my 2022 Ram diesel is gvwr is 12,300 lbs and my payload is 4,055 lbs and towing is 20,055lbs with the LB you will have more payload and I have a Laramine.

[JIMNLIN]

Originally Posted by KingKid

If you like the LB my 2022 Ram diesel is gvwr is 12,300 lbs and my payload is 4,055 lbs and towing is 20,055lbs with the LB you will have more payload and I have a Laramine.

Just like the OP your limited by the Rams 7000 rawr thats carrying all the pin weight plus other stuff in the bed.
Your trucks rear axle may weigh in the 3500 lb range. The 3500 srw Ram has the smallest rawr at 7000 lbs.
Math shows your trucks rear axle has around 3500 lbs left to carry pin weight plus the hitch plus other stuff in the bed.
Actual scale weight will give your trucks actual in the bed payloads.

Some F350 srw owners report 44xx lb gvwr based payload stickers. But their still limited to around 3600-3700 lbs by Fords 7230 rawr. Same story.... as scaled axle weights will tell the actual in the bed payloads on any size LDT.

[Rhagfo]

Well all this talk about the axle manufacturer weight rating. Keep I mind you still don’t know the limits of the trucks frame.

[rarebear.nm]

Weight carrying capacities are fixed by all the components, tires, wheels, axles, springs, frame etc. The weakest single link sets the limit.


I would have a hard time believing that truck manufactures do not over design and engineer these systems to allow for at least occasional overloads to some amount. I would love to hear from someone who is an engineer with real world experience in designing these systems. But likely they have signed an NDA and can't say much.



There is likely some percentage of built-n safety margin, how much I have no idea.

[4x4ord]

I wouldn’t go very far on a public road loaded like this but I’ve had 11000 lbs on the pin of my SRW F350 (so about double my rear axle weight rating)….. the nose of the truck was pointing to the moon but the tires didn’t actually look that bad….. nothing broke.

[KingKid]

Originally Posted by JIMNLIN

Just like the OP your limited by the Rams 7000 rawr thats carrying all the pin weight plus other stuff in the bed.
Your trucks rear axle may weigh in the 3500 lb range. The 3500 srw Ram has the smallest rawr at 7000 lbs.
Math shows your trucks rear axle has around 3500 lbs left to carry pin weight plus the hitch plus other stuff in the bed.
Actual scale weight will give your trucks actual in the bed payloads.

Some F350 srw owners report 44xx lb gvwr based payload stickers. But their still limited to around 3600-3700 lbs by Fords 7230 rawr. Same story.... as scaled axle weights will tell the actual in the bed payloads on any size LDT.

You are so right on this, that is the limited factor here, I was looking at getting a dually and could have when I bought this one but I don't need it because we bought a MH.

[kdauto]

Originally Posted by john1981

id post a link but my web browser is acting up. try searching "dana spicer weight ratings" and it should turn up something for you. the thing is, these axles arent used just in trucks. dana 80s were definately used in forklifts and all other sorts of industrial applications. i dont advocate going over gawr at all because that goes from the grey area of whats safe to crossing the solid line of illegal. you can doctor a gcwr or gvwr on paper to make it legal. you cannot doctor whats on the door jamb as far as axle ratings and make that legal.

Oh I've seen some of those links, but it's hard to get more confusing than that. There is no definitive ratiing on the entire assembly that I"ve seen. Are they talking about the ring and pinion only, the axle shafts only, the housing? I doubt a rear axle on an F350 SRW is mounted anywhere near the same way as it is on a forklift (never heard that one before BTW).

Thickness of the axle tubes, mounting hardware for the springs etc. all affect weight rating. For those that seem to think there's a magical 50% "fudge factor", I'd like to remind you of the Ford rear axle recall since the axle tubes are crushing and/or cracking. Doesn't sound all that strong to me.

Those advocating that everything's fine with hundreds or thousands of lbs overload, or trying to redesign a truck that's already at limits, but not addressing the basic structure of the axle housing, they are dreamers. At some point, the mods are more costly and way less efficient than getting the proper rig.

[carybosse]

I remember the 8 ton forklift we worked with when I was in college, we managed to twist the axle in two and literally shattered the axle shaft. It was neat to look at since it wasn't my checkbook to repair. Boss went to a place that sold truck axles to get the replacement part. (This was about 1980, so a few years ago.) Similarly went to those sources for new brake shoes (actually, I think he just had old shoes re-lined.) The fun part was turning the drum for those forklifts. He was too cheap to take it anywhere, I had to chuck them up in a lathe and turn them myself to clean them up.

I look at so many of these truck campers and think they are a disaster waiting to happen, way to top heavy, easy to roll. Not even getting to the payload concerns. There is no way the average Joe has any idea what each & every the design parameter the engineers considered when developing these heavy duty trucks. Trying to shade-tree mechanic upgrades to allow heavier loads is a recipe for disaster.

[john1981]

Originally Posted by kdauto

Oh I've seen some of those links, but it's hard to get more confusing than that. There is no definitive ratiing on the entire assembly that I"ve seen. Are they talking about the ring and pinion only, the axle shafts only, the housing? I doubt a rear axle on an F350 SRW is mounted anywhere near the same way as it is on a forklift (never heard that one before BTW). .

it honestly doesnt matter since the axle rating is the hard rating for the application. dana can rate it for a million lbs, if the pickups only got a 7k rawr, then thats your limit. no amount of dmv wizardry will change that. i was just pointing out that these ratings do exist outside of the rating that gm or ford put on them. fun fact, economy power king tractors used an automotive spicer rearend.

[JIMNLIN]

Axle mfg supply the whole axle housing assy including all the inside bearings/gears/etc.

Looking at Dana/Spicer shows the Dana 80 at 11000 lb ratings. Ford and Dodge has used them but derated with lower rated suspensions/tires/wheels.

The AAM 11.5" rear axle also rated at 10000 lbs used on GM 2500/3500 srw and drw. GM used tapered axle tubes with the 11.5" AAM with 4" out of the housing but tapers down to 3.5" at the outer ends. GM later went with the 4" straight tubes.
Older Dodge 2500/3500 srw and drw used it for years with a straight axle tubes. My '03 Dodge/Cummins has this axle but derates it to 6000 rawr.
Newer 3500 drw Rams have the uprated 11.8" AAM rear axle.

[Bedlam]

The 10.5" Visteon axle assemblies made at their Sterling, MI site are rated for 9750 lbs before getting put into Ford's F250 and getting lower rated parts added on.

[kdauto]

Originally Posted by Bedlam

The 10.5" Visteon axle assemblies made at their Sterling, MI site are rated for 9750 lbs before getting put into Ford's F250 and getting lower rated parts added on.

Yeah, but do you see what is included in their "axle assembly"? I couldn't find any definitive answers.

If they are rated that high, why did the tubes bend/crush/crack like that?

[KingKid]

But I do trust my setup to tow the Alliance 310RL.