2500HD vs 3500

You are mistakien, The ONLY difference between them is tha the 3500 has 265E tires, one more leaf on either side and the label on the door. Axle, chassis and brakes are all the same. Add one leaf to either side and you will have the same truck and given that at 9900GVW that you will only need to put about 5900 lbs on rear axle (tire capacity for 245E is 6168 for the pair) with 4k or more on front axle (it will likely have more up front if it is a diesel which means even less in rear if you go by GVW rating) it is debatable if you even need the 265 tires. The 2500HD has less spring anyway than a 8600GVW OBS truck for a softer ride so it would be a wise addition. I have a

2000 OBS SRW K3500 andit is rated at 9200 too and it has more springs than the 2500HD does. During the winter I have had it over 5 tons more than once with plow and salt load with no problems at all and I have been doing it since 99.

----------------- The SnoMan

Both the Corp 14 bolt 10.5 and the AAM 11.5 SRW are good to about 4 tons as far as the axles themselves. The dualies has a different axle housing than the SRW and that may be where you are confused. Both the

2500 and 3500 SRWuse the exact same rear axle and brakes. The factory rating for the GAWR is based on the rating of the lowest rated componet which is usually the tires or the springs. A single 245R16 E has a rated capacity of 3084 lbs and a 265E is rated at about 3570 per tire. It get better yet because the 1500 HD has the same chassis and springs and tires as the 2500HD. The only difference is that it has a 9.5 inch rear axle rated at about 3 tons for the axle itself but it has the same springs, tranny, tires and engine (if you are talking 6.0) as the 2500HD yet it is oownly rated at 8600 GVW but truth be know it will care the same weight that a stock 2500HD will with same ease. Are you confused yet? BTW, I have GM dealer manuals and the parts I mention are the same but they are vauge about that in brochures because they want you to spring for the more expensive model. They do this to reduce parts needed and cut costs while boosting profits. Just go look at a 1500HD from side in rear and then a 2500 HD and it has the exact same springs as it is plain to see.

----------------- The SnoMan

Is it possible that the rear axle gear ratio also contributes to the axle capacity? IIRC, back in '04 when I bought my 2500HD with the diesel and Allison tranny the stock rear axle was 3.73:1, but the stock ratio on the

3500 with the same motor and tranny was 4.10. I'm sure that spring and tire load capacity have a major say in axle capacity, but perhaps the OP should look to see if the ratios are the same on the axles he's comparing between the trucks as well.

Cheers - Jonathan

Thanks for the info

Axle ratio only has some effect on effect GCWR, not the axles GAWR.

----------------- The SnoMan

The ONLY difference between the two trucks mentioned here is that the

2500HD has 4 leafs plus a booster on each side in rear and the 3500SRW has 5 leafs and a booster. Axles, brakes, engine tranny, and chassis are the same. The 3500SRW comess with 265 E tires too but in a Dmax EC you will hit 9900GVW before you will exceed the capacity of the 245E tires if you make your 2500 into a 3500 by adding on leaf to each side. The irony of all of this is that HD 2500 OBS truck that was rated at only 8600 GVW, had more springs in the rear than the new 2500HD dies. I have a 2000 K3500 SRW OBS (not a silverado) and it is rated 9200GVW but it too has more springs than the new 2500 HD rated at same weight. Things are not always as they seem and most do not dig into it and I do commend you for taking the time to try to make a informed decision and better understand it. A freind of mine wanted a 3500 SRW Dmax CC but we could not find one the way he wanted it so we built him one. He bought a 05 CC Dmax and we dropped the rear axle in my driveway and added a leaf to each side. It was quick work using air tools (about 1 hour for start to finish)

----------------- The SnoMan

In '01 and '06 all the Duramax came with a 3.73:1. I thought that was all any Duramax had.

Ron