2008 3500 Srw Rear Axle Capacity

gaw · February 25, 2011

I am trying to figure out what the rear axle capacity and rear spring capacity are for this vehicle.

The sticker on the door says 6390. This is the tire capacity (265/70/17) not the axle or spring capacity.

Does anyone have an SRW with a higher rear axle capacity listed on the door jamb, and what are your tires.

I am trying to decide if putting higher capacity tires would allow me to carry heavier loads, or do I need to change the springs or axle. (which would not really be cost effective)

Thanks

markw8 · February 25, 2011

The actual axle rating is quite a bit higher than that. That being said, the rating on the door will never be higher than the oem tires are rated for on a srw truck. On my dually, I have more tire capacity than axle rating.

You can go to higher rated tires but it won't change the door sticker, and it can't be changed. The rear axle on my D/A dually is 8200#.

Mark

djmercer1 · February 25, 2011

The actual axle rating is quite a bit higher than that. That being said, the rating on the door will never be higher than the oem tires are rated for on a srw truck. On my dually, I have more tire capacity than axle rating.

You can go to higher rated tires but it won't change the door sticker, and it can't be changed. The rear axle on my D/A dually is 8200#.

Mark

i understand the issue, but think about it the other way: a guy puts p-rated tires on that same dually and has less tire than the gvwr... i understand the implications of assess gvwr, but there has to be a better way than a sticker from when the vehicle was manufacturer....

gaw · February 25, 2011

I was somewhat wondering, if I had gotten the 245/75/16 tires which would have a 6830 capacity, would the rear axle capacity be 6830.

On the dually, if the rear axle capacity is 8200, and the tires are really more, then the springs/axle capacity really is 8200.

On the SRW, I have the diesel with the AAM 11.5 rear axle. This is probably the same as the dually, but I am not sure. And I think it has a rating of over 10000. So the 8200 is more than likely the rear springs of the dually.

But is the SRW spring pack the same as the dually. If it is, then is it rated at 8200 and could I put 19.5" tires on to allow me to safely carry a higher payload.

markw8 · February 25, 2011

245-75-16e tires are rated 3064# each. The 8200# number is from my door sticker. The mfg. rating may very well be 10,000.

The Goverment requires the door sticker. This is what the mfg. states is the legal limits of the truck as built. The mfg. can't control what you do after the purchase. When I had my previous truck, a 2000,2500 EC 6.0. The gvwr was 8600. With my camper loaded for 2 weeks, full of gas and 2 people, it weighed 9810#. 4100 frt. 5710 rear. I was 1200# over the gvwr but not the tires or axles.

Mark

gaw · February 25, 2011

Sorry I meant 265/75/16, which is the stock tire size for the 3500 HD SRW.

I know that my rear axle capcity is limited by the tires, but what are the real axle and spring limits. If the spring limit was 6500, then putting on larger tires is somewhat of a waste without upgrading the springs.

markw8 · February 25, 2011

Sorry I meant 265/75/16, which is the stock tire size for the 3500 HD SRW.

I know that my rear axle capcity is limited by the tires, but what are the real axle and spring limits. If the spring limit was 6500, then putting on larger tires is somewhat of a waste without upgrading the springs.

What are you going to carry in the truck? I have a 3000#+ camper. I used Air Lift airbags on both trucks. They were a must on the 2500, not so much on the 3500. If your loads don't exceed 2500#, you should be good.

Mark

gaw · February 25, 2011

I am not too familiar with air bags, and how they work. I was hoping I did not need them.

Do the springs still compress and decompress when you have air bags? So do the springs still need to be able to handle the weight?

I have a car hauler trailer with a tongue weight in the 700-1000 lb range.

The actual payload capacity of my truck is 2500-2600 lbs (truck weight is 7300-7400, GVWR is 9900), with passengers and minimal other stuff.

I would like to put a camper in the back. Given the above number, I would want a camper with a max wet weight of 1500-1900 lbs, to keep things within GVWR. Maybe a dry weight of 1000-1400 lbs.

Although, it is possible to find a truck camper in the 1000-1400 lb range, the more desirable ones are 2000+ lbs dry.

I could find a 1000 lb camper and stay within my GVWR and make no modifications to the truck (this is what I will probably end up doing)

or

I could put higher capacity tires, and airbags, and maybe upgraded springs, and get a bigger camper.

markw8 · February 26, 2011

On my 2500 I would run about 50# in the airbags. This put the rear of the truck back near unloaded height. The springs were still very much being used. The bags would prevent bottoming in all but the worst cases. It also kept the headlights pointed the right way.

I ran the dually one season without the bags. It was ok, but felt it would be better to have them. I have the onboard compressor and cab controller. I run about 30#. This gets it back up a bit, and still lets the top helper leafs contact the stops. This helps control sway.

Some people don't like bags because they do or can leak. I everything is installed correctly, THEY will not LEAK.

Mark