Axle weight rating question

[AMink]

If GAW is 6000, that means the axle is rated to carry 6000#, correct? So if the truck is weighed and the scale shows 3000# on the axle you should have another 3000#. BUT, part of that 3000# IS the axle and everything else under the springs. Tires, wheels, brakes. That's a lot of weight the axle isn't actually carrying but is getting weighed. Just trying to wrap my head around why the axle itself is not taken out of the weight equation. More useless pondering in the middle of the night! Any insights? What am I missing?

 

[AH64ID]

Basically yes that is the gist of it.

The axle housing itself may not be supporting the weight; however, the wheel bearings are, the tires are, and the brakes are stopping it.

Generally speaking the GAWR is the lowest of the suspension, axle housing, bearing, brakes, tires, etc...

That is in generic terms. If your talking a SRW Ram 2500/3500 then it's not any of those And the axle, with proper wheels/tires, can be loaded much heavier.

 

[RVTRKN]

That is where research comes into play. The manufacture can claim a high GVWR, then when you do the math and find your surplus weight is only a 1000 pounds. The competitor can have a lower GVWR but have 2000 pounds surplus. That gives you a 1000 pound advantage, even though the GVWR is lower. Axle ratings is the true weight limits you must stay within. GVWR is only a manufacture number and is not recognized by DOT, but can void your warranty.

 

[GAmes]

DOT doesn't care about axle ratings either. If you will notice, your door sticker or trailer plaque will show (my D80 for example) GAWR 7500 pounds with tires 215/85R16D 65psi. Once I installed my E load rated tires, that sticker became moot, and trust me, I've crossed a lot of scales with more than 7500 pounds on the rear axle.

 

[AH64ID]

Here in Idaho all DOT cares about is registered weight and tire ratings, with the exception of TAG axle rating.

 

[GAmes]

A correction to my post is that DOT DOES care about GVWR. That is how they determine if the class of drivers license you have is adequate.

 

[AH64ID]

DOT doesn't care about GVWR here in Idaho.

GVWR hasn't meant anything in the states I have researched.

EDIT: Let me caveat that this is not for CDL's, just private use and RV's.

CDL's can include GVWR; however, it's only for licensing and not for actual weight limitations/regulations.

 

[GAmes]

Research TX, and any other state that limits GCWR on a standard DL to 26,000 pounds. The nice thing about CDLs is that every state is the same. Not so with non-commercial loads and RVs. Some states exempt RVs from GCWR limits, some require a non-commercial class A when the GCWR exceeds 26,000 (like TX). CA requires a non-commercial class A for 5ers over 15,000 GVWR and TTs over 10,000 GVWR regardless of the tow vehicle's GVWR. Some states are too lazy to implement a non-commercial class A DL and require a CDL-A for combos over 26,000, even if the rig isn't used for commerce. I believe you are mistaken about ID. According to their official website "A commercial vehicle, for driver-licensing purposes, is a
vehicle that either has a manufactured gross vehicle weight rating of 26,001 pounds or more". http://www.itd.idaho.gov/dmv/DriverServices/documents/driver_manual.pdf page 1-3. That tells me that if ID residents operate a vehicle over 26,000 GVWR they must have a class B DL and to operate a combo over 26,000 GCWR they must have a claas A DL. Apparently your state doesn't offer a non-commercail class A or B, so a CDL is required.

 

[AH64ID]

Look at the Idaho CDL exemptions. You will find RV's in there. I was looking at them today.

 

[GAmes]

That is what I get for only reading one document, but it still illustrates my point. ID defines RV as "vehicles used exclusively to transport personal possessions or family members for non-business or recreational purposes" which is the broadest definition of RV I have ever seen. The fact remains, even though GVWR might not be relevant for actual loading of a vehicle, it is the determining factor in DL class.

 

[zb39]

DOT doesn't care about axle ratings either. If you will notice, your door sticker or trailer plaque will show (my D80 for example) GAWR 7500 pounds with tires 215/85R16D 65psi. Once I installed my E load rated tires, that sticker became moot, and trust me, I've crossed a lot of scales with more than 7500 pounds on the rear axle.

So how far does this go........if I put 22.5 wheels and tires on my truck is my rear axle now good to 30k that is what the wheels and tires are good for. I know this is extreme but where does one draw the line when upgrading tires or both tires and wheels in regards to the sticker on the door for gross axle weight?? People seem to suggest all the time that the sticker is because of the tires. Maybe it is, I don't know. If it is, how far can you go?

 

[GAmes]

As far as DOT, probably the max. Single axle - 20,000 pounds Tandem axle group - 34,000 pounds. Their concern is highway structural damage, not structural damage to your vehicle.

 

[SnoKing]

Here is what is enforced at weigh stations across the country. State codes are parroted version of the Federal Bridge Weight Laws.

http://ops.fhwa.dot.gov/Freight/publications/brdg_frm_wghts/index.htm

A pickup truck would be hard pressed to exceed these weights.

Between 16", 17" 18" and 20" tires found on pickups in recent years, the 17" are the weight "dog" of the group with just over 3000 pound rating. In 16" one can easily use LT265/75R16E rated at 3415 each that came on a lot of the later 2nd gens. The third gens started the change to 17" wheels and lower rated tires.

OP has one of those 3rd gen trucks.

SNOKING

 

[AH64ID]

So how far does this go........if I put 22.5 wheels and tires on my truck is my rear axle now good to 30k that is what the wheels and tires are good for. I know this is extreme but where does one draw the line when upgrading tires or both tires and wheels in regards to the sticker on the door for gross axle weight?? People seem to suggest all the time that the sticker is because of the tires. Maybe it is, I don't know. If it is, how far can you go?

As it was stated DOT only cares about a couple things, that being said you can still get an unsafe ticket for 22.5's loaded to capacity on a Ranger.

Some common sense does need to be applied. On the 2500/3500 SRW Dodges the rear axle limit is based on tires. The axle/frame/suspension is far capable of carrying more. On a DRW the limit is not the tires.

When I decided to upgrade my truck to 19.5's I did a bunch of research on my truck. What I came up with was that my truck is nearly identical to a 3500 DRW with the exception of 4 things. First is the spacers on the front axle, which are not a factor in loading since both SRW/DRW FAWR's are identical. 2nd is the rear suspension. My 3500 SRW uses a 4/1 main leaf spring pack and the DRW uses a 3/1 that is stronger; however, it's only 7% stronger/stiffer so that, IMHO, in negligable and easily overcome with the airbags I have. The upper overloads are identical. 3rd is that one of the rear wheel bearings is larger on the DRW axle, but according to AAM this is only to support the wider stance of the dually tires and has nothing to do with the axle rating. The axle is rated for over 10,912 lbs in SRW or DRW configuration. 4th is the lack of tire rating.

The RAWR on a DRW with my frame is 9,350 lbs since that is lower than the tires and axle I made the assumption it is the frame/suspension limit and don't plan to exceed that, which I cannot anyways with my tires.

By using the 19.5's I have (245/75R19.5 LRG) I have 9,000lbs of GAWR and would use it if I needed to, thou I am generally in the ± 7,500lb range. I do try to keep the front axle around the FAWR of 5,200lbs but it's not always easy based on how these trucks are balanced with people and no cargo. I do have upgraded ball joints and wheel bearings so I don't worry about going up to 5,500 since it's not too often.

I guess to sum it up, if you plan to exceed the door sticker ratings be sure you do some research. It not only makes a safer/longer lasting truck but you may need to use it to explain your load to a LEO if he isn't sure it's safe.