Which leaf springs to use?

Tacoma747

Tacoma747

Well-Known Member
Joined
Mar 20, 2005
Location
Winston-Salem
As some of you may know, I am building a bus for my sister to turn into a food truck. It had 1984 Chevy C30 dumptruck leaf springs in it (9 leaves + overload, 2.5" wide) in it, but I am wondering if they wouldn't ride like a brick. I have some springs out of a 2001 Dodge 3500 Dually (about 6" longer than the dumptruck springs, 3" wide, 3 'main leaves', one overload on bottom, and two 'overload/helper' springs above that ride on the rubber pads bolted to the frame).

I am kind of afraid the Dodge springs might ride on the helpers ALL the time, which would probably not give a very smooth ride either, plus they would wear out the rubber pads on the frame fast. I found somewhere online the payload of a Dodge 3500 was like 4900lbs? I thought it was a 1-ton truck which meant it could haul 1 ton in the bed, but payload would be 'in bed' weight right?

Gonna guess the back of the bus to weigh maybe 1000lbs more than the truck bed/back of the truck. The generator will be about 400lbs, then it will have about 400lbs of water (~50 gallons), ~250lbs of fuel, refrigerator (200lbs?) freezer (150lbs?), sink, water heater (~50lbs), spare tire, A/C unit, etc.

I will be to the point probably next week where I need to decide which springs I want to use, I thought about just using the 3" Dodge springs and putting in an add-a-leaf or two if need be.

Here is a link to the bus these are going under: http://www.nc4x4.com/forum/index.php?threads/1936-ford-school-bus-build-with-5-9-cummins.123342/
 
Chris_M said:
Airbags???
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I thought about that, actually bought a kit from a friend for $500, but the frame of the bus would have to be narrowed to make it fit, and I don't think she would want to spend the $$$ to get a new airbag setup. I don't want to hack the kit up I bought for $500, it will be a bolt-on kit for an Excursion of F-350, and is about $3500 new...

EDIT: I say the frame would need to be narrowed because bags will not fit on the outside of the framerail without hitting the tires. I guess some helper bags might be an option if the springs are not enough.
 
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What about taking out a few of the existing leaves and adding a cantilever for the airbags? With your plasma table a cantilever should be pretty easy. It would also give you the ability to dump the bags to lower it for easier loading and getting in and out.
 
If the payload capacity of a 1 ton truck were actually one ton, you wouldn't be able to haul a pallet of anything in the bed of a truck. I'm 84% sure that the springs in the back of a 3/4 ton 2nd gen are the same as the springs in the duallys and I can say that with a 3000lb pallet of salt in the back of mine it rides on the overloads. With a ton in the bed it rides real well.
 
If it were me, I'd stick with the GM springs. If they're too rough unloaded, you could always take out a leaf or two and if you run the airbags, you wouldn't much notice the missing load capacity.

BTW, I read that you said it's a smoker....if you need a hand tuning it to smoke much, much less, shoot me a PM. I fine tuned my truck to get very minimal smoke (more like a haze) during normal driving, even with the big injectors I'm running.
 
I called AutoSpring Co in Winston-Salem today, turns out they have books that tell what each spring is rated for. He told me an 8-leaf plus overload on the 84' chevy (he misunderstood when I said 9 +overload) was rated for 2200-2600 per leaf pack. He checked on the Dodge springs, and said they are rated for 3050 per pack, and that the 2-leaf helper springs add 1000 per pack. Guess that means I will stick with the Dodge springs, if I need an add-a-leaf made he said they run ~$125/pair, so that's not too bad. She likes the idea of airbags, but doesn't want to spend the extra $$ on them right now (I estimate about $500-$1000 if I build everything myself). Maybe some day down the road we will do airbags on front and rear so it can be slammed!
 
braxton357 said:
I see new towing/helper airbag setups going for 2-300 all of the time? You must be talking bout some fancy shit.
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Yea, helper bags might be an option, but I don't think she would want to spend the money on that when an add-a-leaf could be put in for cheaper. It will have 75% of the weight on it ALL the time, so it won't be running around 'empty' where a smoother ride might be nice. The only way I'd really want to consider an air-ride setup is if it were custom where it could be dropped on the ground. I am not a 'lowrider' person, but full air suspension should ride great, plus, being able to drop it on the ground would be cool at events and such.
 
What about a "helper" coil spring if you need more support? Sometimes people add them in between the perch on the leaf spring and frame, or even farther inboard if there is a good support crossbar.
I agree that helper airbags are probably the waiy o go. Full air would be pimpin' indeed but I could see it getting costly.
 
We used those same 1-ton 56 inch long chevy springs in the back of our k-5 unloaded it didn't ride too rough. Don't fix it if it ain't broken.
 
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