M-812 Engine and wheel size questions

[TnD]

I'm looking at getting a M-812 Bridge Truck for use in my business.

A bit of background on the application. I will be hauling loads in the 16-20K lb range max, possibly with a matching trailer with about 6K in the the trailer. Haul distances will be short. Approx 45-65 miles. The reason I feel I need a 6x6 is that the terrain I will be on is mountainous, logging roads, grades sometimes exceeding 30%, narrow switchbacks etc...

I plan on doing a full modern air brake conversion (trailer would be braked as well). Also adding a JakeBrake.

The truck will be set up with super singles.

The two questions I have:

#1. with the 1600 series tires will there still be enough room to run chains, or should I stick with 1400. Also will the 1600's limit me with the above stated loads on extremely steep terrain (I am almost always unloaded when going up the steepest grades)

#2 what improvements in fuel economy have people seen from turbocharging. (If you have figures for loaded vs unloaded that would be a huge bonus)

 

[KsM715]

Go with a 900 series cargo (I dont know the number right off hand) They already have full air brakes, a2's have 14 singles already. I would avoid the 16's they will kill any power you might have.

 

[porkysplace]

go with a 900 series cargo (i dont know the number right off hand) they already have full air brakes, a2's have 14 singles already. I would avoid the 16's they will kill any power you might have.

m945

 

[73m819]

REMEMBER a bridge truck is OVER WIDTH (about 9'6") and the 250 DOES NOT have pistion squiters

 

[TnD]

Didn't realize this about the over width....and as to the lack of.piston squirters....I thought this was the case only on the earliest of these engine?

 

[73m819]

Didn't realize this about the over width....and as to the lack of.piston squirters....I thought this was the case only on the earliest of these engine?

NO none of the 250s have them, not sure about the newer cunnins in the later 900s

 

[TnD]

I've seen other threads in which the 250's have been successfully turbocharged. I am still leaning toward the 812 as it is standard transmission rather than the Allison auto and there is the big point to consider of availability. I believe it is the 945 that is the equivalent of the 812....not sure how many there are out there. I know I can get 812 up here in Canada.

The width issue will need to addressed with either truck I would expect.

 

[TnD]

73M819...I've been looking closely at photos and it looks like the over width issue is only with a bridge section mounted. The pallet deck itself appears to just cover the tires, so no wider than a drop side.

Does anyone have any insight as to whether chains can be run on the rear with 1400's?

 

[73m819]

73M819...I've been looking closely at photos and it looks like the over width issue is only with a bridge section mounted. The pallet deck itself appears to just cover the tires, so no wider than a drop side.

Does anyone have any insight as to whether chains can be run on the rear with 1400's?

Wrong, it is OVER -WIDTH at the tires, 1400 x 20s mounted with the NEEDED spacers ARE almost 9'6" WIDE from out side of tire to out side of tire, in order to get standard width, the 1400s and spacers need to go, then 1100s/1200s installed.

I have been there hands on with a tape measure and I READ TMS

 

[seano11]

You don't want 1400s on these trucks. You will never get out of 3rd gear your best bet is to put 395s. Also the bridge trucks that are sold up here have been sitting forever because he can't sell them because he's asking way to much

 

[lakeydna]

Hey TnD I have 4 M931's in Devon, right by Edmonton. PM me for more details, also have a M812.

 

[lakeydna]

Also a bridge truck with singles and a different deck will be within width. Rear duals are 10' wide, chains won't clear on 1600's

 

[TnD]

Ahh I see said the blind man........well it appears that the old "picture is worth a thousand words", only holds true if you know what the **** you are looking at.

Don't want to run I to issues with over width, and needing to call for a.permit every time I go out, so need to find a way to work around that.

 

[M813A1]

You might consider getting a M814 Cargo it has the 20 foot cargo bed so it has the longer frame, if you are in the hills I would NOT recommend the 1400 or 1600 they will use up to much torque to turn them !! You can turn the fuel up some on the NHC 250 Cummins and not be in trouble with EGT, but would recommend a Pyrometer if you do turn up the fuel !! You might consider getting the 395's or even 1200 X 20 tires they are slightly larger and will not take to much power to turn and they will give a bit more road speed .. Also consider there is a M815 Bolster truck that is designed to haul long item like trees or poles when used with the Extendable M796 Bolster Trailer .. Good Luck on your search for the right truck.

 

[TnD]

I am taking in everyone's input and correction of my misconceptions.....one of the things that is a prime requirement is the ability to drop a pallet onto the ground for loading. So that does keep pulling me back to the 812.

That said...if I were to out one on Super Singles running 395's, how difficult would it be to narrow the stock cargo deck to 96" . The other alternative is to build my own cargo deck from scratch.

 

[lakeydna]

It is very hard to find a pallet and it would be hard to retain the latch pins at the end of the deck. You're better off making one. See pictures of a modified Gib pole and a permanent deck.

 

[lakeydna]

1600r20's on the truck - see the tight space between tires, not as tight as a M939 series but I'm sure the chains would not clear. Guess you'd have to try.

 

[TnD]

So did you weld your deck directly to the gib pole?

Making my own deck on a 812 and running 395's sounds like a reasonable option for what I'm doing. Was thinking I would need to modify the stock pallet deck anyway, so aside from material cost, its easier to start from scratch.

I know the 900's have improvements in some areas, however I definitely love the look of the 800's way better than the 900's

 

[seano11]

The 6x6 system on the 800s is useless your stuck before the front tires kick in your best bet is to get a 900 series

 

[TnD]

The 6x6 system on the 800s is useless your stuck before the front tires kick in your best bet is to get a 900 series

Would you be able to explain what the difference is...don't they both use a Rockwell T-138 t case?