1959 GMC 2 ton bus - 4x4 swap

[shortbus4x4]

The ag DTs have some shorter fan hubs, I think there is some online info. Pulling trucks and tractors like the DTs. I know one company makes a serpentine belt system so you can fit the DT in a short space and still run the mechanical fan. Definitely try to make the mechanical fan work if at all possible.

CSD Dt360 Serpentine Belt Kit Coming Soon

Serpentine belt kit for a DT360. Get rid of that old V-Belt. Comes with everything needed except the alternator and A/C Compressor.

www.carsonstaufferdiesel.com

 

[thatbus]

Thanks for the tips, guys. Much appreciated. Heading down to the bus tomorrow to mess around with the fan and see what I can do...

 

[thatbus]

Not much of a status report; been working hard on this but it's all stuff that isn't worth photographing. Had to take time off after getting a bit of cut-off wheel in my eye... and I was even wearing safety glasses. Shit sucks. Axle was finished and upgraded to 35 spline. Engine is about to go in and the front of the frame is being painted beforehand. Rustoleum primer + Rustoleum tractor paint + Majic hardener. That's going well at least:

Went with the aluminum paint because it's easy to see oil leaks that way... more importantly, it was cheap.

Not an immediate problem, got time to think about it... but I'm wondering if recentered humvee wheels would be safe for a lot of on road miles, or if they'd weeble wobble too much. I'd like to push the rear axle width out a bit and am debating that over spacers.

 

[350TacoZilla]

I think if you press them in and weld them right they would be fine but then your stuck with having to run that 1 type of wheel in future vs stock take offs. Spacers have never given me an issue as long as they are torqued and I use a tiny drop of servicable locktite on the lugs that hold spacer to the axle not wheel to spacer.
If you are looking for a wheel and tire setup more for the RD 3rd gen ram wheels have over 6" of back spacing and are 17" so super common tire size to find.
The first one listed is the chrome style (I think the aluminum wheels have these same specs) and 2nd is the plain jane steel like the spares are.
Ram 03 steel--17x8 -- 6.19bs=1.81 stick out
Ram 03 steel--17x7.5 -- 6.02bs=1.48 stick out
H1 Mil steel--16.5x8.25 -- 7.00bs=1.25 stick out

 

[thatbus]

I think if you press them in and weld them right they would be fine but then your stuck with having to run that 1 type of wheel in future vs stock take offs. Spacers have never given me an issue as long as they are torqued and I use a tiny drop of servicable locktite on the lugs that hold spacer to the axle not wheel to spacer.
If you are looking for a wheel and tire setup more for the RD 3rd gen ram wheels have over 6" of back spacing and are 17" so super common tire size to find.
The first one listed is the chrome style (I think the aluminum wheels have these same specs) and 2nd is the plain jane steel like the spares are.
Ram 03 steel--17x8 -- 6.19bs=1.81 stick out
Ram 03 steel--17x7.5 -- 6.02bs=1.48 stick out
H1 Mil steel--16.5x8.25 -- 7.00bs=1.25 stick out

Thanks for all that info, much appreciated.

Thing is, I've got the most recent generation of humvee wheels and tires, and I like them a lot. They check a lot of boxes for me and I'd like to stick with those. I guess another option is finding 8x6.5 pattern 16.5" dually rims off of a Chevy motorhome, but then again they're not beadlock so maybe that's not so great.

Seems like someone else has already beat me to the punch with recentered H1 wheels on a bus that from what I saw, sees regular highway use... DRW humvee wheels could be interesting. waaaay more load capacity than I'd need with a Dana 80 though, without going to a bigger F106 rear end, or whatever else could fit 16.5" wheels around the brakes.

 

[Grendel]

Not many bigger axles will fit into a 16.5" wheel. It's the hub size.

 

[thatbus]

Not many bigger axles will fit into a 16.5" wheel. It's the hub size.

D80 and AAM 11.5/11.8/12.0 axles are the biggest then, I take it, without something custom, or without adapting wheel bolt pattern?

 

[Grendel]

D80 and AAM 11.5/11.8/12.0 axles are the biggest then, I take it, without something custom, or without adapting wheel bolt pattern?

Hub diameter on the bigger axles doesn't leave much room for 8 on 6.5, so, yes.

 

[thatbus]

Still having second thoughts about front axle weight, even in spite of half the answers in my previous thread saying I'd be fine. I like to overdo things when possible though...

I have a Dana 80 rear - supposedly from a 3500 DRW - that has a 35 spline carrier. I took an axle out, put it in my D60, and it fit just fine. I assume the reverse would work, meaning I could run 35 spline D60 inners, chop off the junk on the D80 there now, weld on some inner C's, and use the rest of my 35 spline Chevy outers/knuckles and stuff, for a complete steering axle? Just get custom length inners made and find a way to seal the axle tubes and I'm good to go? With a centered diff, this seems like it would work well.

Hell, I could sell the kingpin Chevy 60 minus the knuckles and hubs to some sucker for a grand and recoup my costs...

Is it worth the trouble? I like this idea because I have a planned overall weight for this build, and would like a bit more breathing room than 5500 on the front and 8500-9000 on the rear. As singles, the tires are rated for 9080lbs. 8500 on each axle would seem better. Unless mycurrent KP60 front would be fine with more with the way I've trussed it, and that makes the D80 idea pointless...

With my truss, my axle has a moment of inertia of 17"^4 versus 6.88"^4 for a Super 60 in the vertical direction. Mine is 247% stronger vertically. 56% weaker than a SD60 horizontally unless I add more truss. (Though I don't see how force in this direction is relevant unless I smash the wheels into a tree or rock ledge or whatever).

I know Isuzu NPR/NPS 4x4 trucks that come in around the same weight as my bus, when done up as campers, have a 9.25" ring gear that looks to be low pinion, so maybe I'm overthinking this. I don't hear of them blowing up diffs... Alternatively, I could just add a Jantz load bolt to the KP60 and be done with it. Thoughts on all this?

 

[Grendel]

I have a kingpin 14B front here, that would drop right in. New brakes would clear, too

 

[thatbus]

Got that engine in... well, most of the way:

It was a 12 hour job just sneaking it in there and go figure little parts sticking out here or there added on another hour or two, figuring out how to get around 'em. At the moment the turbo is inside the passenger footwell. Hope ya like warm toes!
It's now resting on the rear mounts and the front crossmember needs to be notched to clear the harmonic balancer.

Thank fuck for tractors and handwinches...

 

[YotaAtieToo]

Thanks for all that info, much appreciated.

Thing is, I've got the most recent generation of humvee wheels and tires, and I like them a lot. They check a lot of boxes for me and I'd like to stick with those. I guess another option is finding 8x6.5 pattern 16.5" dually rims off of a Chevy motorhome, but then again they're not beadlock so maybe that's not so great.

Seems like someone else has already beat me to the punch with recentered H1 wheels on a bus that from what I saw, sees regular highway use... DRW humvee wheels could be interesting. waaaay more load capacity than I'd need with a Dana 80 though, without going to a bigger F106 rear end, or whatever else could fit 16.5" wheels around the brakes.

I doubt those wheels would actually hold what those tires are rated for, just for looks really.

Still having second thoughts about front axle weight, even in spite of half the answers in my previous thread saying I'd be fine. I like to overdo things when possible though...

I have a Dana 80 rear - supposedly from a 3500 DRW - that has a 35 spline carrier. I took an axle out, put it in my D60, and it fit just fine. I assume the reverse would work, meaning I could run 35 spline D60 inners, chop off the junk on the D80 there now, weld on some inner C's, and use the rest of my 35 spline Chevy outers/knuckles and stuff, for a complete steering axle? Just get custom length inners made and find a way to seal the axle tubes and I'm good to go? With a centered diff, this seems like it would work well.

Hell, I could sell the kingpin Chevy 60 minus the knuckles and hubs to some sucker for a grand and recoup my costs...

Is it worth the trouble? I like this idea because I have a planned overall weight for this build, and would like a bit more breathing room than 5500 on the front and 8500-9000 on the rear. As singles, the tires are rated for 9080lbs. 8500 on each axle would seem better. Unless mycurrent KP60 front would be fine with more with the way I've trussed it, and that makes the D80 idea pointless...

With my truss, my axle has a moment of inertia of 17"^4 versus 6.88"^4 for a Super 60 in the vertical direction. Mine is 247% stronger vertically. 56% weaker than a SD60 horizontally unless I add more truss. (Though I don't see how force in this direction is relevant unless I smash the wheels into a tree or rock ledge or whatever).

I know Isuzu NPR/NPS 4x4 trucks that come in around the same weight as my bus, when done up as campers, have a 9.25" ring gear that looks to be low pinion, so maybe I'm overthinking this. I don't hear of them blowing up diffs... Alternatively, I could just add a Jantz load bolt to the KP60 and be done with it. Thoughts on all this?

People have done D80 fronts.

I think you're over thinking it. I run a 2019 F550 grossing 39k lbs with a trailer and never go much over 5200lbs on the front. 06h3 runs a cclb 16' flatbed F550 with a 1 ton hummer on the back and iirc runs about 5500lbs on the front.

I just can't see how you would be that heavy on the front end in this rig. Not to mention, I doubt the R&P would be the weak point anyway.

 

[thatbus]

I doubt those wheels would actually hold what those tires are rated for, just for looks really.



People have done D80 fronts.

I think you're over thinking it. I run a 2019 F550 grossing 39k lbs with a trailer and never go much over 5200lbs on the front. 06h3 runs a cclb 16' flatbed F550 with a 1 ton hummer on the back and iirc runs about 5500lbs on the front.

I just can't see how you would be that heavy on the front end in this rig. Not to mention, I doubt the R&P would be the weak point anyway.

Yeah, I think you're right about the overthinking it part. Habit of mine... But yeah I've decided to stick with the D60 front. I might install a Jantz loadbolt for extra, cheap insurance. After all this diff does live well in those Aussie offroad buses that come in at the same weight as my bus - and that's without any trussing/gusseting/etc...

I'll stick with the Humvee tires, as super singles I think. They do most of what I want. Gusseted Rogue Fab H1 centers are supposed to be stronger than the originals, but no idea what centers are in that pic though.

 

[thatbus]

Getting closer. Engine is in, transmission is in. The thick and short shaft is in... Next up is hoisting the transfer case into position. It's a T-136-27 drop case. On a 25 deg. angle (how it comes, ready to mount), I'll have 16" of ground clearance underneath. At a 45 deg. angle, I get 19" of ground clearance but the driveshaft will have a 5 to 7 deg. slope sideways from the passenger side of the transfer case (where the rear output is) to the centered rear axle yoke. Is this too much? I'd prefer to go with the 45 deg. transfer case clocking for better front driveshaft clearance and better breakover angle. Thoughts?

The other issue I have is with the balancer clearance. I have about 1/4" to 5/16" on each side with the engine sitting in its permanent position. Is that enough considering frame twist, engine movement under load, etc? Moving the engine far as I can with a cheater pipe, it won't touch anything, and it's close to the axis of rotation for the front bushings... Not much more I could cut out.

 

[350TacoZilla]

I know pics sometimes don't show the angle right but is there enough room to get the belts on and off? It would suck big time to be stranded trying to lift the engine enough to change a belt. Would you be able to hack that C section and add material till it looked like this?

 

[thatbus]

I know pics sometimes don't show the angle right but is there enough room to get the belts on and off? It would suck big time to be stranded trying to lift the engine enough to change a belt. Would you be able to hack that C section and add material till it looked like this?

Good call about the belts. I can just sneak one past the balancer but it's tight. I imagine as the bushings compress a bit over time it'll get worse. Yeah, I'll open it up a bit...

 

[shortbus4x4]

Good call about the belts. I can just sneak one past the balancer but it's tight. I imagine as the bushings compress a bit over time it'll get worse. Yeah, I'll open it up a bit...

Yes, the bushings will compress.

 

[bdkw1]

Does the T-case have an oil pump? Will the pick up still work laid over farther?

 

[thatbus]

Does the T-case have an oil pump? Will the pick up still work laid over farther?

It has no oil pump. I've seen the T136-27 used vertically in big mud trucks, which I'm intuitively thinking would be the most difficult to oil effectively as oil would have to fight gravity more than with a 25° or 45° clock? I'll still be clocking it in the same direction as it normally sits; towards passenger side.

 

[bdkw1]

I would say go for it then. DS angle will not be an issue. Just make sure you have the right amount of oil in it since the fill hole not be at the correct height anymore.

 

[thatbus]

I haven't had much of a chance to work on the bus. I did clearance the harmonic balancer more - much better now. Work keeps me busy. However, i did have a chance to weld up a battery fixture for the LiFePO4 cells. This will maintain some light compression on them which increases lifespan:

The top lip will help secure a piece of plexiglass over the terminals and provision BMS mounts. You don't want to drop a wrench over these at full charge; it's like a fuckin grenade going off...

Far as wheels and tires go; I may exchange my current Humvee 37's for something with a bit more load capacity. This is on the recommendations of several people who full-time in their expedition rigs. I bought them from a local business (militarytires.ca) and the owner said I could exchange them for a different set of tires if they didn't work for my build. 325/85R16's would be the ideal size I think, but they only have XML's in that size and I suspect they'd be horrible for fuel economy/tread life. I don't even know of another Canadian source for Conti MPT81's, XZLs, etc. in that size. Shipping from the US is prohibitively expensive, especially with the exchange rate.

I recalculated some weight stuff: With 500lbs of water and 300lbs of fuel, I come in at 10,500lbs wet curb weight +-100lbs.I expect the interior and solar to weigh 2500lbs-3500lbs. With a 20% extra margin, that's 3500+700=4200lbs at the absolute max. In reality I calculated 2,900lbs including a 20% margin, but hey, you always miss stuff...

The bus - fully converted - should come in between 13,000lbs and 14,700lbs. I suspect more like 13,400lbs.
With a 6000lb front axle weight - I really don't want to go heavier with a chevy kingpin 60, in spite of the upgrades I've done - that leaves me with with 18% rear tire capacity left in the most likely scenario. Like 4% in the worst case scenario. Is that fine? I don't want to cut it too close especially when weight shits a bunch, soon as you tilt the vehicle...

What I am considering doing is buying a new rear end - something from a bus, Ford F700, etc. - and running 43" 11R20 XZL's. This will allow me to carry plenty of weight in the rear, easily two tons more than what I had intended, which is really nice headroom to have. I can get plenty of those for cheap, all around the country, since our military's logistic trucks run them - so there's a steady supply. at home and on the road. The one problem with this is the Dana 60 front axle. Will 35 spline stuff hold up? Are stock KP60 12.75" brakes (albeit with a Bosch Hydromax booster) okay? I'll be adding a Jantz load bolt to mitigate ring gear deflection. It's not as if I'll be rock crawling the bus, but I also don't want to overextend the axle's abilities.

If I used an aluminum 20" dually wheel on the front axle, I could get the total weight of a 43" XZL tire/wheel down to 180lbs. By comparison, my 37" Humvee tires/wheels are 150lbs. Is a 6" and 30lb difference enough to cause serious problems?

Here's a mockup with an 8" roof raise, and 37" vs 43" tires (yeah, the 43" should be XZL's, I was too lazy to photoshop those in):

43":

37":

 

[Grendel]

I'd do a Spicer 130 and and add matching front hub adapters.

 

[thatbus]

I'd do a Spicer 130 and and add matching front hub adapters.

Yah I've always had my eye on the S130, S110, etc. Perfect in terms of GAWR and overall beef and with 20" wheels I could make them work. the local truck junkers also had some Rockwells and larger Spicers under F600's and B600's with the same 6 lug pattern as the 1100R20 XZL's wheels. Wonder if any of those have 4.56 gears... that'd be perfect.

Are Isuzu or Mitsubishi rear ends worth looking at? All I know is some have big 6 lug hubs and a 7700kg/17000lb rating. Don't know much otherwise...

 

[350TacoZilla]

If your looking for load carrying and tread life a commercial truck 22.5 tire is going to be best but suffer in offroad traction or snow\ice. If you are looking at the 11.r20 range of tires the goodyear G177 military used is a decent tire that rides bit better then the XZL-XML-XL lineup, adding small sipes to a G177 would probably net you a decent all around tire and they can be found pretty cheap surplus. They are rated at 7390lbs according to goodyear when used as a single so you could probably get away with a good aftermarket 20" aluminum wheel and singles if you end up with a wide enough rear axle.

 

[thatbus]

If your looking for load carrying and tread life a commercial truck 22.5 tire is going to be best but suffer in offroad traction or snow\ice. If you are looking at the 11.r20 range of tires the goodyear G177 military used is a decent tire that rides bit better then the XZL-XML-XL lineup, adding small sipes to a G177 would probably net you a decent all around tire and they can be found pretty cheap surplus. They are rated at 7390lbs according to goodyear when used as a single so you could probably get away with a good aftermarket 20" aluminum wheel and singles if you end up with a wide enough rear axle.

Thanks for reminding me of the G177... we use those up here so they're easy-ish to find surplus.

I've heard that aftermarket 20" aluminum rims have the wrong bead seat for military tires? that they come unseated easily because of the shape of the lip or something? Any truth to that, or where that reasoning is coming from??

For the front axle, I'd probably go with these for the sake of weight capacity being good enough, and being only 45-50 lbs themselves:

US Wheel Rat Rod 69 Wheel 20x8 8x6.5 (8x165.1) Unfinished Raw Steel -19 MM - DOORBUSTER PRICING! (not necessarily this offset)

WELD Off-Road W100 Dualie Inner 20X8.25 8X165.1 ET80 Gloss Black

Capital Auto Parts Has The Largest Selection Of WELD Off-Road W100 Dualie Inner Wheels Part Number - W10008280775 Wheel Size - 20X8.25 Bolt Pattern - 8X165.1 Large Selection Of WELD Off-Road W100 Dualie Inner Gloss Black Wheels In Canada

capitalautoparts.ca

Cali Offroad Summit-D 20x8.25 100 Matte Black | 9110D-2881MBI100 | Custom Offsets

These Cali Offroad Summit-D wheels feature a Matte Black finish and are sure to make your ride stand out! This particular wheel setup is in 20x8.25 with a 100 offset. The Cali Offroad Summit-D is a One Piece Alloy wheel that features exposed lugs. These beautiful 8 spoke wheels are available in...

www.customwheeloffset.com

 

[shortbus4x4]

Is the G177 a true military tire? I know I used to see them a lot on logging trucks and Forest Service fire rigs.

 

[Grendel]

It's true about mil tires on civvy rims. Lots of overlanders have complained about it. There's a guy making hefty rims in modern MDT patterns that can take Civvy or Mil (thicker) beads.


I am removing my MPT's from my IH project, to go civvy tires on civvy rims.

They'll go on MRAP rims, to dually the rear on my G506.

 

[350TacoZilla]

I think the confusion on bead is there are two styles of bead. If I'm remembering correctly MPT tires are a different style bead. I'm not saying the model of tire like continental mpt81 which adds to the confusion but an actual MPT tire.
For example michelin makes a 12.00r20 xl and also a 12.5r20 xl which uses mpt style bead. Add in the my phone wants to change "mpt" to "not" everytime I type it and it gets worse.
I would think any bead seating issues in general would just be down to the military tires having super stiff sidewall and not like to be aired down without being on a double headlock wheel.

 

[thatbus]

I think the confusion on bead is there are two styles of bead. If I'm remembering correctly MPT tires are a different style bead. I'm not saying the model of tire like continental mpt81 which adds to the confusion but an actual MPT tire.
For example michelin makes a 12.00r20 xl and also a 12.5r20 xl which uses mpt style bead. Add in the my phone wants to change "mpt" to "not" everytime I type it and it gets worse.
I would think any bead seating issues in general would just be down to the military tires having super stiff sidewall and not like to be aired down without being on a double headlock wheel.

It's true about mil tires on civvy rims. Lots of overlanders have complained about it. There's a guy making hefty rims in modern MDT patterns that can take Civvy or Mil (thicker) beads.


I am removing my MPT's from my IH project, to go civvy tires on civvy rims.

They'll go on MRAP rims, to dually the rear on my G506.

I think you're right TacoZilla... that this is specific to MPT/Multi-Purpose Tires. It sounds like that's where the bead difference is and thinking back, it seems every time I've heard this brought up, MPT tires were in the discussion. Guys over on Steel Soldiers say:

A 365/80R20 is supposed to be equivalent to a 14.5R20 in size and is, as such, a MPT bead tire, made for a MPT wheel. I think nearly all of the MRAP wheels are NPT bead wheels, made for NPT bead tires.

Here is how I understand it - An NPT or MPT tire can go on an MPT wheel, but only an NPT tire can go on NPT wheel. Any ".5" tire is a MPT tire.

Taking a quick look, it seems all the xx.50R20 tires are advertised as MPT; Mitas MPT-05, MPT80 and MPT81 Conti... And looking here too: Multi-Purpose Tires (MPT) | Industrial Tires Online

So I guess with a XZL or G177 11.00R20 I'd be fine on any of those rims I linked in my last post?

Any practical benefit to running typical m35 beadlock wheels on the rear, and just these aluminum rims up front? I guess I couldn't air down up front much, but could air the rear down?

 

[ridenby]

Only thing I can contribute, is that modern tubeless tires come off the wheel very easily when the pressure gets a little low-say 50psi vs 90psi.