Towing and rear suspension opinions needed

[squirel]

I am building a 67 short fleet. My plans are to use this truck for weekend cruising and pulling my holiday trailer. It is not lowered and has the coil spring rear end with a 12 bolt. The problem is the hitch weight of the trailer is 950 pounds and the dry weight is 7337 pounds. Will 3/4 tons springs be enough? I have looked at the helper air bags that fit inside the springs ( http://www.jcwhitney.com/1000-adjust.../p2005927.jcwx ) they do not make them for our trucks that I can find. Or do I ditch the springs for air bags ( http://www.airbagit.com/product-p/fbx-r-che-02.htm ) Or is there a different option any opinions would be appreciated. Thanks

[rsavage]

Why don't you check to see if Firestone makes some helper air bags that will work in conjunction with the stock coils? I've used them on my Dodge Ram and they work really well. Obviously, that is a leaf spring truck. 3/4 ton coil springs would probably do it, or some HD variable rate springs, but you are always going to sit higher in the rear when unloaded than you probably would want. Can you load the trailer to reduce the tongue weight somewhat? I'm sure you are using a weight distributing hitch.

[1968CHEVYC10]

you could get some of those half leaf helpers springs LMC has them

[Shyguy]

A lot of our trucks came with what I call over-load springs.

They mount behind the rear axle just about where the bumper mounts and go forward to the axle. They do not affect the ride until a load is put on.

I am sure many people have a set laying around.

If you are going to tow with a short fleet a load lever hitch with sway control would be advised. Trailer brake setup would also.

Danny

[squirel]

Thanks for the ideas guys I have looked into Firestone and they do not make anything that will work for the coil spring rear end. I think they did make them at one time but not anymore

I was not sure if the overload springs would work on the coil spring rear end does anyone have a picture of them on coil spring rear end.

I will check into the half leaf helpers springs from LMC when I get home tonight

Yes Shyguy I will have a load lever hitch with sway control I have been pulling this trailer with my 2007 GMC half ton and I could not see pulling it with out them it gets a little hairy in a cross winds.

[Cole Trickle]

Originally Posted by squirel

Thanks for the ideas guys I have looked into Firestone and they do not make anything that will work for the coil spring rear end. I think they did make them at one time but not anymore

I was not sure if the overload springs would work on the coil spring rear end does anyone have a picture of them on coil spring rear end.

I will check into the half leaf helpers springs from LMC when I get home tonight
Yes Shyguy I will have a load lever hitch with sway control I have been pulling this trailer with my 2007 GMC half ton and I could not see pulling it with out them it gets a little hairy in a cross winds.

I can take pictures of them on my truck tonight and post them if you still need them.

I am going to remove them and my hidden hitch as the truck will never tow anything and I don't want the extra weight.

[squirel]

That would be great I have seen them on leaf spring trucks but not on a coil spring rear end

[1968CHEVYC10]

Originally Posted by squirel

Thanks for the ideas guys I have looked into Firestone and they do not make anything that will work for the coil spring rear end. I think they did make them at one time but not anymore

I was not sure if the overload springs would work on the coil spring rear end does anyone have a picture of them on coil spring rear end.

I will check into the half leaf helpers springs from LMC when I get home tonight

Yes Shyguy I will have a load lever hitch with sway control I have been pulling this trailer with my 2007 GMC half ton and I could not see pulling it with out them it gets a little hairy in a cross winds.

sorry about the bad description, just couldn't remember what they were called shyguy got it right. overload springs are what I'm talking about.

[capev86]

any stock height 1/2 ton w/ rear coils.....cleanest looking, most effective route is to just swap in the 3/4 ton rear coils. my dad had a 72 burb 1/2 ton back in the 80's and he did the upgrade because the stock rear coils were shot. his truck had the overload leafs. after the swap the truck sat a bit like a hot rod / drag racer while unloaded but with our '71 holiday 23 footer w/ 800 pound tongue weight those overloads never came into play after that.

the 3/4 ton springs are 2000 lb rated per side instead of 1400 lb rated so that gives you an extra 1200 pounds of capacity. they will ride stiffer but not too bad since you are only stiffening up the rear where you need it. it will definitely help with body roll too. the overload springs were a novel idea, but don't add as much capacity and the truck has to sag a good deal before they even come into play. i recommend the 3/4 ton rears for any 1/2 ton truck hauling more than trophies. they were optional equipment on all coil rear trucks including the 2wd blazer....natural choice for a "tow package".

you can use lowering springs for a 3/4 ton if you have a mild drop but in your case stock springs would be best. i bought the 3/4 ton HD option rear coils (2750 lb per side) for my 72 burb 3/4 ton so that some day if i want to pull big toy haulers i can. but they are probably too stiff for right now and WAY too rough for a 1/2 ton axle. you will find those standard 3/4 ton coils are perfect with your big camper hitched up. no extra parts to maintain unlike and aux air bag system....just swap and go!

i'd also suggest you replace the rear trailing arm and track bar bushings with polyurethane ones. they are an inexpensive replacement for the stock worn out rubber.....cheap insurance to make sure there is no excess play in the back end of your tow rig. LMC carries the parts, but i had to go to CPP to get the poly kit for the bigger track bar on my 3/4 ton burb. trailing arms are the same.

[Longhorn Man]

new bushings are a must.
I would just get some helper air bags for in the coils. Air lift sells a set for monte carlos that fit right in. You'll need to order a couple extra pushings/isolators. I have a set in my burb and they are great. Stock/soft ride when deflated, and load capacity when filled.

[capev86]

i really don't think the 3/4 tons ride THAT much harsher than 1/2 tons. my 72 burb feels very much the same as my dad's 87 2wd 1/2 ton burb going down the road. and stiffer springs are so simple and clean looking. i just want to hook up and go and not worry about pumping up air springs. i like having a truck partly due to its towing capacity. and 1/2 ton rear springs suck when you try to do anything serious with it. i think all you have grown soft driving around in plush modern trucks. i bought my burb to take to car shows....yes.....but also to use as GM intended....as a truck....hauling stuff....towing trailers....the family piled in.....

LMC carries the 1/2HD / 3/4 ton spec springs for $70/pair. no extra parts are needed as it is a bolt in swap.

[squirel]

Thanks everyone that is a lot of great information (This site is great)

So here is the plan first new bushings then I am going to go with the 3/4 ton springs and see how they work $70 dolllar's is not that much money if I do not like it I can always go with the 1/2 ton springs I take out and the airbags I would only be out the 70 dollar's

Longhorn Man are these the airbags you used

[Cole Trickle]

Originally Posted by squirel

That would be great I have seen them on leaf spring trucks but not on a coil spring rear end

I like the air lift bag idea better but here are a couple pictures of the helper springs.

[capev86]

as i said....they are a neat idea.....but that is just an extra part that only comes into play with the suspension REALLY loaded and won't keep it level. he will be towing a heavy trailer and you want primary springs that will react instantly to the increased load. i think the helper leafs are ugly myself. as i said....on a stock height daily driver....get the 3/4 ton coils and be done with it. they are very livable and there is no need for "extra" springs with them. my dad's burb went from having them loaded (severe sag) to not needing them although he never bothered to remove them. LMC doesn't even carry stock height 1/2 ton rear coils anymore....with good reason!

Henry David Thoreau: "simplify, simplify, simplify"

Montgomery Scott: "the more they overtake the plumbing, the easier it is to stop up the drain"

[squirel]

Thanks for the pictures Cole Trickle
capev86 your right those are ugly and depending on how those brackets mount it is getting pretty tight back there with a fuel cell and a hitch anyways

[LONGHAIR]

I take it that a trailer that weighs more than 7000# has it's own brakes....be sure to maintain them properly and that the conncetions to the truck are good. It takes quite a bit to stop something that heavy. Nearly 1000# of tongue weight sounds a little out of bounds though?

[Cole Trickle]

Originally Posted by squirel

Thanks for the pictures Cole Trickle
capev86 your right those are ugly and depending on how those brackets mount it is getting pretty tight back there with a fuel cell and a hitch anyways

I agree thats why its all coming out.....

Some of the U bolts are really close together and one is kind of couging the spare.

No towing for Yeller any more. There is a pretty good chance I won't even run a spare tire. (Unless I need the back to come down a tad more when lowered)

[N2TRUX]

Originally Posted by Longhorn Man

new bushings are a must.
I would just get some helper air bags for in the coils. Air lift sells a set for monte carlos that fit right in. You'll need to order a couple extra pushings/isolators. I have a set in my burb and they are great. Stock/soft ride when deflated, and load capacity when filled.

I agree with Andy 100%. I have had this similar system a few times and it worked great. You get a stock ride with no load, and you can adjust your air pressure for the load that your pulling. Add a small compressor and a gauge and enjoy the ride.

[Cole Trickle]

Originally Posted by N2TRUX

I agree with Andy 100%. I have had this similar system a few times and it worked great. You get a stock ride with no load, and you can adjust your air pressure for the load that your pulling. Add a small compressor and a gauge and enjoy the ride.

I would say the only issue with a singler compressor and a T line to the helper air springs is that when you corner it could hurt your handling. When you load up a side it pushes the air to the other bag and makes a anti sway bar effect.

Probably not a huge deal in these trucks buit it wasn't a good thing in my 06 GTO. I used seperate lines/valves to avoid the issue.

[squirel]

Yes the trailer is dual axle and has brakes I have been towing it for the last two years. I found the biggest thing with towing big trailers is make sure you have good sway bars/load levers, brakes and never be in a hurry or your going to be the first to the accident scene. The reason for the big weight up front is due to the front slide out bedroom here is a picture with weights and measurements below.

[Cole Trickle]

Originally Posted by squirel

Yes the trailer is dual axle and has brakes I have been towing it for the last two years. I found the biggest thing with towing big trailers is make sure you have good sway bars/load levers, brakes and never be in a hurry or your going to be the first to the accident scene. The reason for the big weight up front is due to the front slide out bedroom here is a picture with weights and measurements below.

I don't know the details on your build but I just re read the weight of the trailer. Personally there is no way I would tow a 7500lb trailer with a 4,000lb truck built 40 years ago.

I have a 09 silverado and tow a 8500lb toy hauler and imho I'm overloaded even though the truck specs say it will tow 9K pounds. Its not the power thats the issue its the size of the truck in the event something went bad. A regular cab short bed with a short wheel base would never tow my trailer safely.

Be carefull and make sure you have alot of brakes....My uncle tried this build years ago with a long bed C20 with a monster 406ci moter. He used it 2x and sold it for a modern diesel becuse he said it was sketchy.

[StingRay]

My half ton has variable rate cargo coils and I can haul a 9000lb trailer no problem. It rides really nice with no load too. I have it loaded for 10% on the hitch so that's 900 lbs. The truck rides pretty close to level but with a little bit of rake left. The real problem here will be the short wheel base. You will probably find 5 K too much for a SWB. I've pulled 5K with our 4Runner and it was the scariest thing I've ever done for towing. You will need to make sure your load is very well balanced and I think you will find that unless you use a weight distributing hitch you won't be legal or safe so. Typically you are only allowed to tow the vehicles GVWR with a standard hitch and then double with weight dist., goose neck or 5th wheel. So the bars are more than just a good idea they are required at that weight in at least some places. Trailer brakes are an absolute must and failure to have them and the controller for them can get somebody killed at these kinds of weights.

[Ackattack]

I'll agree that I wouldn't to a trailer that big with a SWB 1/2 ton

But, if you do, in addition to the rear spring upgrade (I would go with helper bags or airbags). I would also add a rear sway bar and front one if you don't have one. It will help keep things under control a little more.

[1NiceLonghorn]

Moog offers a cargo-coil, variable-rate springs as an upgrade for vehicles that carry heavy loads. The cargo-coil, variable-rate springs change resistance as they compress and become progressively stiffer as the load increases. These springs are vinyl-coated for corrosion resistance and extended service life.

[71sierragrande]

Just an opinion, but I would never tow a trailer that weighed twice as much as the truck, regardless of spring or hitch setup.