Dr Frankenstien gets his hands on a transit bus.

[natedog39]

I've been using the bus enough lately to prevent any real work from being done but that's ok, knocking on the door of 4,000 purely towing miles since June.

After weighing the beast I've been thinking a little more about what will happen when the new engine goes in.

Early on sombody here mentioned how the weight distribution would change after moving the rear axle back.
Also quite a bit of cantilever weight was removed when the old A/C unit was removed.

When I weighed the bus and camper the weight slip gave me axle weights as well as the total weight, as of right now the front end is putting 6,400 lbs on the ground.
The front axle is rated for 6,000 lbs
400 lbs doesn't concern me much right now, it would if the tires were overloaded but they're max load is 7,100 lbs.

An 8.3 Cummins weighs at least 700 lbs more than a 5.9 and at that point the tires will be overloaded.
That does concern me.

I was planning to replace the front springs anyway but I guess I'll be looking for a used 8,000 lb axle as well.
255-70-22.5 G rated tires have a capacity of over 10,000 lbs and are just an inch taller than the 8R-19.5 tires on it now.
That will leave me with spare wheels and tires for the rear too, that's a win there.
Not sure where I'll get 22.5 aluminum wheels though without breaking the bank.

[MTrider16]

What was the weight on the rear axel? You can only put as much torque on the ground as you have weight holding the axel down.

David

[djb_rh]

What was the rear weight situation? Why not consider moving the rear forward and/or the hitch back to lever some more off the front? That's what we do in the HDT world with 5ers and hauling decks and Smart cars on the back.


--Donnie

[Patrick46]

Originally Posted by djb_rh

What was the rear weight situation? Why not consider moving the rear forward and/or the hitch back to lever some more off the front? That's what we do in the HDT world with 5ers and hauling decks and Smart cars on the back.


--Donnie

Moving the rear axle foreward would be a TON more work then just relocating the 5th wheel hitch.

Actually, this is why the 5th wheels can slide on semi tractors, is so you can move the weight around to your liking.

but YES, that's exactally what I'd do too.

[natedog39]

Originally Posted by MTrider16

What was the weight on the rear axel? You can only put as much torque on the ground as you have weight holding the axel down.

David

7,700 lbs with the camper hooked up, which has a tongue weight of aproximately 2,500 lbs.

[natedog39]

Originally Posted by djb_rh

What was the rear weight situation? Why not consider moving the rear forward and/or the hitch back to lever some more off the front? That's what we do in the HDT world with 5ers and hauling decks and Smart cars on the back.


--Donnie

I doubt the front tires/axle are overloaded under any circumstance with an HDT. I also spent considerable time lengthening the wheelbase, there's no way I'm going backwards.
Also remember that I also use this thing without the camper.

Changing the front axle won't be too bad anyway, 8,000 lb springs are 3 inches wide (same as whats on it now) as long as the center to center distance is the same I can use the existing hanger brackets.
No problemo.

[DakarNick]

Originally Posted by Patrick46

Moving the rear axle foreward would be a TON more work then just relocating the 5th wheel hitch.

Actually, this is why the 5th wheels can slide on semi tractors, is so you can move the weight around to your liking.

but YES, that's exactally what I'd do too.

Of course it's more work but it's one of two options. I heard semi trailers can have around 10,000 pounds of pin weight. That needs to be over the rear axles. On an HDT and Nate's truck the pin weights are lower and can be cantilevered off the back to take weight off the front axle.

Nate, how far (in inches) back is the center of your hitch to center of your rear axle?

[natedog39]

Originally Posted by DakarNick

Of course it's more work but it's one of two options. I heard semi trailers can have around 10,000 pounds of pin weight. That needs to be over the rear axles. On an HDT and Nate's truck the pin weights are lower and can be cantilevered off the back to take weight off the front axle.

Nate, how far (in inches) back is the center of your hitch to center of your rear axle?

8 inches, and that's where it's stayin!

[djb_rh]

Originally Posted by natedog39

I doubt the front tires/axle are overloaded under any circumstance with an HDT. I also spent considerable time lengthening the wheelbase, there's no way I'm going backwards.
Also remember that I also use this thing without the camper.

Changing the front axle won't be too bad anyway, 8,000 lb springs are 3 inches wide (same as whats on it now) as long as the center to center distance is the same I can use the existing hanger brackets.
No problemo.

Just to clarify (I'm not trying to convince you, just getting facts straight), I'm talking mostly about HDTs being converted to private RV title and used to pull 5ers. Back when that practice first became en vogue, most folks were singling the HDTs. They were also choosing the biggest cab they could get for the room. And they ultimately gravitated toward Volvos for a variety of reasons. But Volvos are on the nose-heavy side for HDTs. And most folks early on were singling the rear axles out (that's less common today, but still done). And many started building hauling decks and putting Smart cars on the deck sideways between the cab and trailer. Even before the Smart car thing happened, though, most were putting the hitch as far back as they could just to help improve the ride quality since the rear suspension was never near fully loaded even with the heaviest of 5ers (6k pin weight range).

EVEN THEN, with that amount of leverage, if you singled mid or short, and had a Smart on a big steel deck, most Volvos were perilously close if not overweight on the front axle. Many folks were singling short or mid so the truck would turn as tight as possible. That was a holdover from the earlier folks NOT using Volvos, however. The Volvo was the truck many gravitated to BECAUSE it turns so well already compared to other trucks. But even folks singling long found that unless they extended the frame and REALLY put the pin way far back, they were still overweight on the front. So they tried that. And many found it worked REALLY well to have the pin further back by a lot (six feet is not uncommon, though some have gone eight or more). Off-tracking is reduced by a lot. But the best part is you can back the trailer a LOT better, which is an issue for a lot of the folks using these because they live in it full time and visit a lot of national parks and such.

These days most folks have simply figured out that the easy button is to just leave the truck tandem in the rear. Build a deck that's 5-10k in weight by itself. Add three feet in frame length to the back and mount your hitch there. Then you have room for a Smart or a couple motorcycles or a golf cart or whatever. Folks who want room for a "real" car have left the wheelbase alone and simply gone even further out the back with the frame, but things get weird as you approach that six foot number, I think. But it's been done.

But obviously the bus isn't an HDT, either. I'd think with 2500 in pin weight you could go back another foot or two with the hitch with no problem, but I'm not sure that would get your front axle weight where you want it anyway. *shrug*

I threw it out as an option in case the front axle upgrade doesn't end up as easy as you thought, mostly.

Originally Posted by DakarNick

Of course it's more work but it's one of two options. I heard semi trailers can have around 10,000 pounds of pin weight. That needs to be over the rear axles. On an HDT and Nate's truck the pin weights are lower and can be cantilevered off the back to take weight off the front axle.

Nate, how far (in inches) back is the center of your hitch to center of your rear axle?

Nick, a single tandem axle is typically 20k pounds. So dual tandems are 40k. So it's not uncommon for commercial trailers to have a 30k pin weight. A normal US commercial truck with a single steer axle, two drive axles, and a dual tandem trailer has a GVWR of 80k pounds.

So with even the heaviest of 5er trailers having 6-7k in pin weight, it's totally okay to move it back a good bit, even singled.

I'm on my second HDT with a frame stretch out the rear and hitch at the back, FWIW.


--Donnie

[Hardware02]

Donnie, do you have pics of your setup? (maybe it's already somewhere on this site and I've missed it)

[djb_rh]

Originally Posted by Hardware02

Donnie, do you have pics of your setup? (maybe it's already somewhere on this site and I've missed it)

The current truck just has a steel flatbed with the hitch in the back. The previous truck, which I got rid of when I no longer needed the Smart car, is here:









This deck was built with ramps for the rear so I could haul a Jeep on the deck longways, but without the gooseneck (but with a tag trailer).

Also note that this truck is a VNL670, which is the full height cab, but it's a foot shorter cab then *most* HDTs with a full sleeper, but with the same wheelbase. So less cab space, more deck space. That meant I didn't need to change the wheelbase and didn't have to extend the frame very much, either. Pictured is an air ride gooseneck hitch, but it's deflated. That's an air ride tag hitch on the back, too, in a 2.5" receiver.

And if you want to see build pics of a 45' coach on an HDT chassis, see my For Sale site for my other rig:

http://coach.donniebarnes.com


--Donnie

[ducnut]

Originally Posted by djb_rh

Nick, a single tandem axle is typically 20k pounds. So dual tandems are 40k. So it's not uncommon for commercial trailers to have a 30k pin weight. A normal US commercial truck with a single steer axle, two drive axles, and a dual tandem trailer has a GVWR of 80k pounds.

Weight limitations vary, by state and class of road. One should invest in a Motor Carrier Atlas, to be sure of limits for each state and road they plan to travel. Overweight tickets are big money.

[little foot]

looks good.

[MTrider16]

Nate your rig looks good. Can't wait to hear what it does with that 8.3 in it.

David

[natedog39]

Originally Posted by djb_rh

Just to clarify (I'm not trying to convince you, just getting facts straight), I'm talking mostly about HDTs being converted to private RV title and used to pull 5ers. Back when that practice first became en vogue, most folks were singling the HDTs. They were also choosing the biggest cab they could get for the room. And they ultimately gravitated toward Volvos for a variety of reasons. But Volvos are on the nose-heavy side for HDTs. And most folks early on were singling the rear axles out (that's less common today, but still done). And many started building hauling decks and putting Smart cars on the deck sideways between the cab and trailer. Even before the Smart car thing happened, though, most were putting the hitch as far back as they could just to help improve the ride quality since the rear suspension was never near fully loaded even with the heaviest of 5ers (6k pin weight range).

EVEN THEN, with that amount of leverage, if you singled mid or short, and had a Smart on a big steel deck, most Volvos were perilously close if not overweight on the front axle. Many folks were singling short or mid so the truck would turn as tight as possible. That was a holdover from the earlier folks NOT using Volvos, however. The Volvo was the truck many gravitated to BECAUSE it turns so well already compared to other trucks. But even folks singling long found that unless they extended the frame and REALLY put the pin way far back, they were still overweight on the front. So they tried that. And many found it worked REALLY well to have the pin further back by a lot (six feet is not uncommon, though some have gone eight or more). Off-tracking is reduced by a lot. But the best part is you can back the trailer a LOT better, which is an issue for a lot of the folks using these because they live in it full time and visit a lot of national parks and such.

These days most folks have simply figured out that the easy button is to just leave the truck tandem in the rear. Build a deck that's 5-10k in weight by itself. Add three feet in frame length to the back and mount your hitch there. Then you have room for a Smart or a couple motorcycles or a golf cart or whatever. Folks who want room for a "real" car have left the wheelbase alone and simply gone even further out the back with the frame, but things get weird as you approach that six foot number, I think. But it's been done.

But obviously the bus isn't an HDT, either. I'd think with 2500 in pin weight you could go back another foot or two with the hitch with no problem, but I'm not sure that would get your front axle weight where you want it anyway. *shrug*

I threw it out as an option in case the front axle upgrade doesn't end up as easy as you thought, mostly.



Nick, a single tandem axle is typically 20k pounds. So dual tandems are 40k. So it's not uncommon for commercial trailers to have a 30k pin weight. A normal US commercial truck with a single steer axle, two drive axles, and a dual tandem trailer has a GVWR of 80k pounds.

So with even the heaviest of 5er trailers having 6-7k in pin weight, it's totally okay to move it back a good bit, even singled.

I'm on my second HDT with a frame stretch out the rear and hitch at the back, FWIW.


--Donnie

I appreciate any input from inmate's here and welcome any idea's/advice.
Whether I follow them or not.
I think your right about moving the hitch not making much difference anyway.
Some of our half buses at work have 8,000 lb front axles and I've been taking measurements while they're up on the lift.
Haven't measured my rig yet but the springs seem to be centered on the frame rails, which are spaced the same.
I don't see the installation being a problem.

Feel free to post more pics of your rig, both past and present.
That setup looks awesome.