tow package question?

[ThePair]

Hm, I had no difficulty getting mine set up. There are threads about this; it all seems to be related to the manufacturer and the length of the WDH bars. I'm sure there's a link to what I'm using, but if you can't locate it, I can dig up the information.

[T and C]

I just thought I would share my experience with helper springs on my old 1961 F-100 pickup. It had a 292 v8, a granny low transmission, a limited slip rear end, and a huge dump truck radiator.

I knew nothing about payloads, towing capacities, or about anything else regarding hauling or towing. I was 24 at the time.

I bought an overhead camper from my uncle. I have no idea what it weighed, but when my headlights pointed at the stars it was evident that it weighed too much. So, I headed down to Sears and bought a set of helper springs. That solved the sagging and sway problems just fine.

You know I was stressing that rear axle badly. However, it "took it" and never gave me any trouble. However, one day when I was driving through Salem, Oregon I began to detect through the steering that I had a flat.

When I pulled over I discovered that my left rear rim had split, the inner tube had bulged through the crack, and the sharp edge had sliced the tube. I just put the spare on and went on down the road. I bought another rim in some small town up the road. I continued to drive that truck for another 10 years and for at least another 100,000 miles. In 1975 I sold it to a friend who had a job setting up storage sheds for the manufacturer. He carried the sheds in the bed of that old F-100. He had the same split rim problem, and bought two aftermarket rims to replace the stock ones. Eventually the rear axle gave up the ghost. He replaced it with a stock Ford one and kept on working.

From this experience I concluded that there is quite a "fudge factor" in the weight ratings on pickup trucks, or at least Ford p/u trucks. Seems to me that the published ratings are there for liability and warranty purposes. I have never heard of a hitch falling off from too much tongue weight, or rear axles failing quickly from overload. I have heard of leaf springs breaking though. It is fairly common.

So, I figure my air bags relieve the spring stress, and I don't worry much about the TM tongue weight or the stuff I throw in the back of my F-150.

Tom

[ELM-JLM]

I have to agree with Tom! I have used coil helper springs for years with no ill effects. I towed a 21'boat (old & heavy) with a 73 Ford F100! If the rig wasn't close to normal ride height the front end would be all over the road! Our trip to Alaska in July and August went beautifully with the simple installation of a pair of 1500 lb coil helper springs! We are towing with a 2011 Silverado 1500 with factory tow pkg. The ride height is dead on when hitched and ready to go! I removed the two propane tanks and carry them in the bed of the truck so I could add a trailer tongue tool box! We don't pack the TrailManor very heavy but the truck is loaded! To make a long story short, We never once worried about our rig under any circumstance we encountered! I rotated the tires on the truck when we got home (no abnormal wear) and while jacked up slid the springs out!

I can tow with either my Chevy or GMC and I do not need a WDH. Sag measured at the rear bumper of the truck is about 5/8 inch. I have never measured the rise at the front bumper.

The factory has advised me that because I have large trucks I would not need a WDH.

However, when I load a 500 pound ATV in the back of the Chevy and connect the TM, there is so much sag that I can not remove the front wheel from the TM. A WDH might have helped, but I mad a guess that I was overweight or darn close to it. So we added a second larger truck.

I can load a 750 pound ATV in the GMC and have no problem with the TM removing the TM wheel. The GMC, being a 2500HD instead of a 1500HD, has stiffer suspension and higher ride height.

The only problem I have when towing with my configuration is the gas bill.

[Mr. Adventure]

I'll be very surprised if the Tundra does not have a substantial overload on the rear axle in recycleguy's proposed configuration unless a WDH is used. The problem with headlights in the sky is the loss of steering and braking, besides the headlight issue. The permissible load is determined by the owner's manual, the doorpost sticker, and ultimately, the scale.

One of the good things about the vehicles of the good old days is that they often had wide fudge factors because the designers had to guess a lot about things that are figured out accurately with computers today. One of the bad things about vehicles in the good old days is that they were necessarily built upon a lot of guesses.

Extra springs and airbag support might actually add capacity to the rear axle, but only if the rear end components are strong enough to handle it. And given that today's vehicles are designed to tighter specs than the good old days, it's possible the limits of those components are closer to the ratings than things used to be.

But here's the interesting engineering question about Tom's story of the old pickup camper and the axle/steel wheel failures: Did the failure events prove the risks of the overload, or did the many tens of thousands of miles between them support the conclusion that the overload was no big deal?

In the good old days there were some subtle changes that were not always visible.

My father-in-law placed a factory order for a (then) new 1971 Chevy 1/2 ton truck.

But he ordered it with 3/4 ton rear springs.

He knew he would be carrying a small camper and towing a light boat.

To the casual observer, it was a 1/2 ton truck.

[T and C]

Mr. Adventure

But here's the interesting engineering question about Tom's story of the old pickup camper and the axle/steel wheel failures: Did the failure events prove the risks of the overload, or did the many tens of thousands of miles between them support the conclusion that the overload was no big deal?

You are quite correct about computers being more precise. However, in the era before computers engineers worked with stress calculations all the time. I once worked with a lady who spent the latter part of WW2 doing stress calculations for Martin aircraft. Imagine a bomber taking off with a full load of bombs and then the wings folding up at the end of the runway, blowing the air base to bits. They knew exactly how to prevent this.

As to "proof" of anything, my "experiment" was inconclusive. The sample was simply too small to conclude any probabilities. But a common sense evaluation told me two things:

1. The weak link on my setup was the stock rims. Two split rims in years of use show at least that we were close to the limits of the rims. The aftermarket rims seem to have solved that aspect of the overload problem.

2. The main place the overload would have stressed the axle is on the bearings and hubs. These never gave out. So I would conclude, on a purely common sense basis, that I was well within the limits there. The truck had about 135,000 miles on it when I sold it to my friend, but I don't know how many miles it had on it when the differential gave out. But notice, it was not the bearings but the differential that gave out. The differential bears no weight.

So, I don't think I was taking any unnecessary risks.

Tom

My situation was very similar to Tom's. But inmy case the rear bearing went out after about a year and the rear axle slid out. Luckily I was traveling at low speed in town and was alerted to it by a pedestrian.

I would not want that to happen at speed hauling a trailer. So I'm much more careful about GAWR and GVWR these days.

[T and C]

Originally Posted by brulaz

My situation was very similar to Tom's. But inmy case the rear bearing went out after about a year and the rear axle slid out. Luckily I was traveling at low speed in town and was alerted to it by a pedestrian.

I would not want that to happen at speed hauling a trailer. So I'm much more careful about GAWR and GVWR these days.

Brulaz,

How's that ecoboost working out for towing and gas mileage?

Tom

Tom,

The F150 Ecoboost gives us about the same mileage towing our Elkmont as the old Tacoma (12mpg), but is almost twice the truck in payload and low-end torque. It makes for a great TV.

Will write more in a new thread when we get to Florida, maybe tomorrow.