Why M939A0 and M939A1?

Another question I have had for sometime in regard to the M939 series trucks. As seen with the M35A2 to M35A3, the "upgrade" included super singles. It was my understanding the military was going to convert the A0's to the A1 configuration (maybe I'm wrong). I see several later modelled 939's sporting the Goodyear G177's. Is there a reason why the military has the regular dual setup and the super singles? I would think the military would want a standardized configuration. Were the dual kept around for trucks who's primary function was for highway type transportation?
Personally, I do like the looks of the A1. However, I like the redundancy the duals provide.

Less tires = less stuff to break = less parts needed to be carried by the supply guys

In my BN, and from what I could see at my time at Hood, there was no "send me a A0 for highway use, not an A1 with super singles" It was "send me a cargo 5 ton".

The did try to standardize. The A1 and A2 have the same tire.

Trying to retrofit a zillion A0's to A1 tire config = big $$$$$$$$$$$ for no real tangible reason at that time.

I may be off on this but I had been told/read somewhere that although the super singles were both good and bad, a big reason they went with the duals again was that with this series being on super singles it put the center of gravity way up there and road manors were less than ideal IE- guys had a tendency to roll the truck and they felt this was to much of a risk especially on public roads. Not sure if this was the answer you may have been looking for in regards to your question

I have never heard that the Army made any attempt to upgrade M939A0 series trucks to A1. If they would have done this to the M939 series trucks, they would have done it with the M809 series trucks in inventory, too. The USMC did, but I don't believe the Army did. A particular unit may have, but I don't think it was widespread if they did. If you follow the trucks coming out, I don't believe I've seen any with A0 dataplates with singles. This would have been particularly obvious with the M939A0 trucks coming out that have been rebuilt.

Here's an eye opener:
[SIZE=+1]
U.S. General Accounting Office
Military safety: Army M939 5-ton truck accident history and planned modifications
Publication Date April, 1999
Physical Description 19 pp. [/SIZE]

Just curious, does anyone know when they started production on the M939A1's? In my research, I'm finding mostly mid-80's production A1's ('85, '86). I'm looking at buying an A0 and converting it to an A1. Why? Because I want to be able to register the truck as a Collector Vehicle/Historical Vehicle. In WA State, the vehicle needs to be at least 30 years old.

Katahdin said:

Here's an eye opener:

[SIZE=+1]U.S. General Accounting Office[/SIZE][SIZE=+1]
[SIZE=+1]Military safety: Army M939 5-ton truck accident history and planned modifications[/SIZE]
[SIZE=+1]Publication Date April, 1999[/SIZE]
[SIZE=+1]Physical Description 19 pp. [/SIZE][/SIZE]

Click to expand...

Rollover cab protection? What does that look like? Picked up an M925 yesterday that was rebuilt at Red River Apr09. Has a hardtop I didn't notice a ROPS.

That was just "planned" modifications... It didnt happen.

The facts about the G177s" is" duels are more road worthy and last longer on roads also,But simply put ... stability was the key here and the main reason behind the G177s, Driver error was reasoned for many accidents in conus when drivers hitting 55 mph and nailing the brakes with the super singles and went hoping off the road, many units that are / were state side and used there trucks for what they are intended for received the g177 upgrade, along with the anti loc brake system at the same time, Like all military, one can find a truck that may have no antiloc brakes with g177s but as a rule they will go together,upgrading an Ao as u are calling it to an A1 is just bigger tires, there were no i am aware of times the 939 series trucks were upgraded to be a number up, they just went in for anti loc brakes and many times g177s, They could have also retained the 1400s.Also it must be noted that the 939 series first run had NDCCs and most of those got G177 tires and anti loc brakes , but there were some trucks in the A1 that went to g177s , like I said , if they were used over the road alot, they would have been switched over, there was no world wide mandate for any of this, more just by unit and amount of over the road use.

emmado22 said:

That was just "planned" modifications... It didnt happen.

Click to expand...

100% correct I saved the anitoc brake explanation for this quote, they never went with anything more that antiloc brakes for the accident problem because it was driver error, BUT the antiloc brakes sure did alot to help also,And yes antiloc was an additional point made in testing to help these trucks over the road with the big tires, AND Along with additional driver training with the larger tires that were new to the drivers at the time, ALSO no need for any more upgrades because this worked and the accidents all but stopped, Oh and one cant forget the 40 MPH limit in country was also implemented when driving these trucks, and of course helped alot, another reason the guys who want to go over 60 should be nervous when running the 14 or 1600 tires, Uncle sam says 40 is the last official safe speed , But we all go faster , but the day one brakes loose i will say it is not going to be easy to bring her back and maybe impossible, just an fyi, Its a true tactical vehicle as most of us know.

Interesting

I recently picked up a M936. I didn't go with a A1 because of a cost standpoint. The truck will be used in my business and the bottom like counts. I sure do like the looks of the big super singles but the fact is they won't last as long on the road and will cost some big bucks to replace when they do wear out.

I'm brain-wrestling with the idea of singling out my new M923 while i'm waiting for EUC clearance. I sure like the looks of the singles on the A1 and A2, but maybe I should learn to love the wheels that come with the truck. I don't know exactly what tires are on it (yeah, I know, I played the GL picture lottery, stupid me!), but I think they looks kinda like the G177 (?) tires that I've seen discussed in some of the SS threads I've been studying. I'm still a bit baffled by the different single tire and wheel combinations that folks are using on the 5-tons, and I'd sure like to see a concise summary of the different tire and rim dimensions available, what combinations work with each other, and so forth. Basic stuff like a clear answer for the outer diameter of the 14x20 tires on stock A1/A2 trucks still eludes me.

having a few thousand miles on my M923A1 now, I can see why a lot of young men had accidents. I have significant prior expeience with dump trucks and heavy equipment and the 5 ton with sigles still makes me a bit nervous. I had a stop light turn a little fast and had to jam on the breaks which activated the ABS, I could feel, I would have lost the rear end of the truck had ABS not been installed. As for on road use, my truck has lockers and if the road is the slightest bit wet, It will get sideways fast, on tight turns. I have to drive it extra slow on wet pavement, I am curious how it will do in the snow.

On the flip side, when I'm off road, the lockers give me true 6 wheel pulling and could rip the foundation off a house in low gear.

Like the above report said, these things were made more for off road use but ended up on the hwy. Glad to see the military identified the problem and corrected it rather than pretent it doesn't exist.

wsucougarx said:

Just curious, does anyone know when they started production on the M939A1's? In my research, I'm finding mostly mid-80's production A1's ('85, '86). I'm looking at buying an A0 and converting it to an A1. Why? Because I want to be able to register the truck as a Collector Vehicle/Historical Vehicle. In WA State, the vehicle needs to be at least 30 years old.

Click to expand...

I was a Inf Bn Support PL at Ft Lewis (ID) in 1986-87. All the Infantry Bn in 9ID recieved new M923A1 and M927A1 in spring 86 (May 1886 as I recall). (Turned in 813s). This was dring the "High Tech Test Bed" time and 9ID was high priority for new equipment. Supposed to have been first large issue. The Support Bn had recently recieved M923/927 (dual NDT).

As I recall 9ID received of M927A1 w/winch issued in lue of M925A1. In anycase there were a BUNCH of XLWB on hand.

My drivers were really impressed with speed of the 923A1 compare to "old" 813s. Light load of Class V 65mph on I90 going to Yakima. No antilock in those days.