Ford C-900 question

[gasman]

would the newly reissued AMT Fruehauf long bed trailer be a viable trailer to be used on this truck. or would the trailer be too big for it.

[highway]

would the newly reissued AMT Fruehauf long bed trailer be a viable trailer to be used on this truck. or would the trailer be too big for it.

It would be fine Terry. The only thing I would suggest is if you are loading the trailer, keep the load "light", a heavier load like the three steel coils in the kit, would be too heavy for the single axle of the Ford. It would be overweight on that axle by DOT regulations.

[Aaronw]

It is axle weight that becomes the issue, 12,000 on the front, 20,000 each for the rear, so a 3 axle straight truck can have a total weight of 52,000lbs. Cement mixers are given an exception to allow 20,000 on the front axle too.

With trailers not all of that weight goes to the truck axles so a pair of shorter trailers will allow a 2 axle truck to carry the same load as a 3 axle and a large trailer assuming it has the power to pull it. I'm not sure how the transfer of the trailer weight to the tractors axles is calculated, but assume there is a basic formula of some sort. It does vary depending on how the weight is distributed on the trailer, so ultimately is determined on a truck scale.

[highway]

Highway, if you had [2] 27ft trailers with a c900 ford? Would that be too much weight?

What kind of weight is suitable for such a small truck?

No, Justin, twins are fine, because the dolly axle for the second trailer acts just the same as a tandem (dual set of axles) on the tractor.

As for weights, and this applies for your common everyday road truck, they go as follows:

Front steering axle: Max 12,000 pounds

Single axles, drive and trailer: Max 17,000 pounds

Tandem axle sets, drive and trailer: Max 34,000 pounds

These are also what determines the GVW (Gross Vehicle Weight) rating for trucks, the normal 5 axle trucks on the road is 80,000 pounds, where a truck like the C900 and the Freuhauf trailer would only have a GVW of 63,000 pounds. There are execptions to this, just like every rule. One I know of is on trailers with a spread axle tandem like most flatbeds nowadays, since my good friend drove spread axle flats hauling steel, the axle weight on a spread is 40,000 pounds maximum. The GVW is still 80,000 pounds, though, just because the spread axle allows 6,000 pounds more than a standard tandem, it does not increase the GVW.

Hopefully I didn't lose you with all that, but with the C900 as the example, the C900 could haul 80,000 pounds legally with the doubles. The only thing that effects the weight is the lack of a second drive axle, it could only legally haul 63,000 pounds with the Freuhauf trailer. The dolly between the double trailers is actually adding an axle to the setup, and therefor increasing the GVW.

[highway]

It is axle weight that becomes the issue, 12,000 on the front, 20,000 each for the rear, so a 3 axle straight truck can have a total weight of 52,000lbs. Cement mixers are given an exception to allow 20,000 on the front axle too.

With trailers not all of that weight goes to the truck axles so a pair of shorter trailers will allow a 2 axle truck to carry the same load as a 3 axle and a large trailer assuming it has the power to pull it. I'm not sure how the transfer of the trailer weight to the tractors axles is calculated, but assume there is a basic formula of some sort. It does vary depending on how the weight is distributed on the trailer, so ultimately is determined on a truck scale.

Aaron, I think in the respect of straight trucks, you are right with the 20,000 pounds on a rear axle, because the few straight trucks I drove did have a GVW of 32,000 pounds. I'm not sure if the same is true for a tractor with a single axle, though. I know the one single axle tractor I drove with a tandem axle box was 63,000 pounds gross weight, which equals the weights I explained in the post just after yours.

As for the transfer of weight from the trailer and tractor axles, I'm not really sure what you mean by it being calculated, but I can tell you how it is distributed. Trailers with a tandem axle, with the exception of tandem spread axles, are movable and sliding the axles forward (pushing the trailer backwards on the axles) distributes more of the weight to the trailer axles and takes weight off the drive axles of the tractor. The reverse is true for sliding the axles back toward the rear of the trailer, more weight is put on the drive axles and less is on the trailer axles. It also depends greatly on how the trailer is loaded too, like you said. Commonly for a single axle tractor, the trailer is loaded lighter in the front and more weight is distributed towards the rear of the trailerand the tandem axles. Usually the trailer tandems would be set as far forward as they can be slid, too.

[Aaronw]

I only drive straight trucks and the axle loadings are just one of those things that stuck in my mind from the test. It's not something I have to worry about in practical terms, since the loads are well within the limits.

What you are saying about the trailers is what I was getting at, adjusting the load to distribute the load between the trailer axles and the 5th wheel. I've never had to deal with that and assumed there was some formula so people knew where to put the axles and how to distribute the load in the trailer. It sounds like you are saying it is mostly experience and trial & error.

[highway]

I only drive straight trucks and the axle loadings are just one of those things that stuck in my mind from the test. It's not something I have to worry about in practical terms, since the loads are well within the limits.

What you are saying about the trailers is what I was getting at, adjusting the load to distribute the load between the trailer axles and the 5th wheel. I've never had to deal with that and assumed there was some formula so people knew where to put the axles and how to distribute the load in the trailer. It sounds like you are saying it is mostly experience and trial & error.

Yeah, I drove mostly tractor trailer, so that's why I had to think of the few straight trucks for their weights!

I sort of figured that was what you were thinking of, and you are right, it's mostly trial and error and experience to get a semi scaled out just right. It took a while, but I had always found if I set my fifth wheel (yes most of those slide back and forth too) so the front edge of the trailer was even with the front quarter fender mudflap, it set me up good to where I had a little over 11,500 pounds on the front steer axle and could slide the trailer axles to adjust the tractor drives and trailer. That was one thing I didn't mention in the other post, the fifth wheel position effects the weight, but it mostly transfers weight from the drive axles to the steer axle. I found on trucks where the fifth wheel wasn't movable, they were most always set where the trailer lined up just like the way I always set my fifth wheels.

There is, I guess, a little formula along with the axle weights, too. I was always told each hole in the fifth wheel slider was about 500 pounds of weight redistributed and each hole in the tandem slider rails were worth about 250 pounds. After a few years though, I could almost scale a truck by the seat of my pants, I could always tell before I ran it over a scale what changes had to be made just by the ride!