The Stovebolt Site Forums The Parking Lot Big Bolts 1972 c50 suspension upgrades

Hello, i have a 1972 chevy c50 that i have been using/fixing/upgrading. Anyway my gvwr is 24,000lbs and my truck weighs about 9000-9500lbs depends on how much fuel I got and if I have a passenger. So I should be able to haul 7 tons according to the gvwr. However 5-6tons is really about all I can haul due to the sagging effect and my rear tires to fender clearance. But even with 5-6 tons, if the loader at quarry isnt a pro and puts the load to one side or the other, im leaning like a cholo. I recently put a "new" rear end on my truck I did have the h150 rear end, upgraded to the t170 rear end that is a two speed rear end that gave me more gears to play with and about 5-6mph increase. I can now drive 55ish on the highway, before my max speed was 50ish. And when I did this axle swap I got the bigger overload leaf pack from doner truck that had 3 leaves and my previous axle only had a single leaf for the overload. When I got this installed my truck(loaded) sagged less in the back but still sags but my tire to bed clearance is more open but if I hit a bump at highway speed it gets really close. I really would like to be able to haul the max load for my truck which was 24000lbs before the axle upgrade it might be more now with the heavier duty rear end but I'm still gonna go with the 24000lbs as the max capacity, that I still cant do. But I really would like to get to that safely, and I'm wondering how can I go about this goal effectively and somewhat cheap. I can fabricate stuff with welder and torch if need be, I just dont know anything about air suspension, or air brakes cuz I know bigger trucks run the brakes and suspension off air.

I've been looking into these air helper springs but not sure they meet my weight class. I've found them up to the one ton trucks which today some one ton trucks are basically the same weight class but not sure if it will work. Wondering if anyone out there has any experience with this kind of thing on a medium duty truck like mine that just has spring suspension?

Thanks for any and all info you can give!!

The 24,000 GVW rating (32,000 GCW) for your 1972 C50 is on the upper scale of what it was rated for, 20,000 GVW was standard issue. In order to achieve that rating you need the following optional upgrades;

9.00-20 10 PR front tires.
9.00-20 12 PR rear tires.
7,000 pound front axle (5,000 pound is standard issue).
17,000 pound rear axle (15,000 pound is standard issue).

Not knowing which exact model truck you have you could have the following rear leaf springs;

10-leaf 54" x 2.5", capacity 7,500 lbs each.
9-leaf 55" x 3", capacity 9,200 lbs each (I'm guessing this is what you have).

Your optional single auxiliary spring (33.5" x 3") adds 2320 lbs to each main spring pack.

Was you body mounted to allow full spring travel when fully loaded?

Have you had the quarry load you to 24,000 lbs as a test to see how close the tires come to the body? The last few thousand pounds may not change the ride height.

Mike B

I have:
295/75r22.5-fronts (brand new) f055 axle.

9.00-20-rears (good tread old tires came on axle) t-170 axle.

I'd have to check the leaves to see how many I have.

I have the 3-leaf auxiliary leaf pack 3inch wide, what is the rating on that?

As to the dump body mount, I dont believe it was mounted for full spring travel. I was thinking about getting lift blocks but that would raise my top heavy weight. But I dont take corners fast when I'm hauling... I try to avoid looking in the mirror at ppl riding my @$&.... but that's the only simple fix I can come up with becides removing the whole bed and adding 2 10-12ft pieces of steel channel/rectangle tube for a new "dump body frame/riser frame" or I could just torch off more of the bed side rails/edges for a deeper "fender flair" for clearance. But I'd rather avoid more torching to the truck.

Now to the quarry loading me up, I did one time get overloaded to 7.25 tons and I was leaning pretty hard cuz it wasnt centered perfectly. And it was really squatted. Dont remember if that was before the axle swap or not... I actually bottomed out a couple times and ripped off like 2 knobs of my tires grips on the side it was leaning to. And yes i was babying it the whole way home and it still was happening. But all in all the truck hauled it and dumped it fine. But I could hear my truck whispering to me not to do that again until I figure some things out!!! Lol.

front axle-f050 (mistyped first time) but it's the original and that code is in my glove box.

Rear axle- was the h-150 now I have the t-170 which is an option for my truck but I got it off a 69 c60. Cant find rating for it. And I lost the photo of that trucks glovebox codes. And it's been crushed since I got the rear end. It had a 366 engine in it that i really wish i had got.


The 3leave auxiliary pack came off the 1969 c60 donor truck.

Now to the bed height/spring work you speak of, what spring work do you mean could help? I was thinking those air helper springs might help me out with that issue and it would be somewhat easier cuz it's just an add-on. But not sure about weight ratings. But they would help with the leaning issues I think.

Now that you say that I probably should have dumped a couple loads that were uneven, but those guys in the loaders are pretty busy some days and that's usually when the sloppy loading happens. But the big rig trucks with air suspension never lean and I'm sure they arnt loading them gently cuz I've seen them loading semis and they are just scooping and dumping and scooping and dumping like 4 or 5 times for the big rigs, I barley get a half bucket full on those big wheel loaders they have. It's agood thing I have the 15foot flat/dump bed cuz I see ppl with the shorter beds getting loaded and the buckets are so wide they dump 1/4 of the load in bucket on ground behind their truck, seems like alot of waisted time pushing that back everytime you get a small truck in there.

Contact your local big truck spring shop and see if they can add a leaf or two to take care of the sag issue...might be cheaper than going big rig air bags.

Mike B