Is the "Bridge Trucks" rated correct at only 5-ton

[Towman2277]

Hey all!! As some may know, my "Steel Soldier" is a M-139 Bridge Truck, rated at 5-tons, built by IHC. My question is the rating of 5-tons, is that accurate, or maybe under-rated?? I have seen several 5-tons, and my suspension is much more than the ones I have came close to. I hauled a Caterpillar genset that weighed approx. 19,000 lbs yesterday, and it squated my truck once loaded VERY LITTLE! Once we lifted the Genset, we backed a AM general 5-ton (1970) under it, and set the load down. I thought that suspension was gonna just keep giving and giving downwards until the tires touched the bed!! It was a huge difference then the load placed on my truck. I recognized that I have several more leafs in the springs also, so I was just wondering if this could have been a heavier rated truck??- than the average 5-ton. Thanks for your input!!

 

[DDoyle]

RE: Is the "Bridge Trucks" rated correct at only 5

Yes, its off-road rating is 5 tons - but if you look at the designated load for the M328 (the bridge truck - a M139 is truly only a cab and chassis) - the gross weight of the truck is almost the same as a five-ton wrecker - that is to say, the truck is overloaded all the time, and sprung accordingly.

Hope this helps,
David Doyle

 

[M1075]

RE: Is the "Bridge Trucks" rated correct at only 5

It used to be the military load ratings were under the 'worst conditions' with usually double that capacity on highway. I think the M939 series 5 tons don't have the increased highway rating. Only the basic, worst case rating provided. The suspension on your bridge truck can definitely carry more weight than the standard 5 ton and could probably carry 10-15 ton. Horsepower and brakes could be an issue though.

 

[emmado22]

RE: Is the "Bridge Trucks" rated correct at only 5

900 series 5 tons can carry 5 tons off road, and 10 tons on road.

 

[M1075]

Here is what I found in the -10 manual:

"The 5-ton load limit rating of M939/A1/A2 series vehicles does not mean
these vehicles are limited to 5-ton payloads. A vehicle rating only indicates the
maximum amount of cargo weight the vehicle axles and frame can withstand when
operating under the worst cross-country conditions."

 

[Towman2277]

Hey, Thanks alot guys. I really appreciate your help with helping me figure this out! This winter I plan on pulling the 602 gasser and installing a cummins 250 with alot of power upgrades. That will be my next line of questions!!

 

[jh1990]

I've always wondered that especially right after we got our deuce. You kno these trucks look a lot beefer to be rated at what they are. More power is always a good thing.

 

[emmado22]

I was told by the Project Managers from TACOM forboth Medium and Heavy trucks that all cargo type trucks are rated at worst off road conditions, and you can double it for highway use.

 

[DDoyle]

I suspect that you can purchase an 800-series bridge transporter, or bridge erection truck, cheaper than repowering the M328. While I haven't done it, logically the designers didn't lengthen the engine compartment when they went to the NHC-250 without good reason - so I would imagine you'll need to do the same (though a 6CTA will fit in the G744 engine compartment).

From the very unscientific testing that has been done around these parts - you won't get more power from Cummns than you do the Continental - but you will get more speed and better fuel economy.

Somewhere around here I have the HP/torque curves on these engine......

Best,
David Doyle

 

[OPCOM]

The curves for the engines would be of alot of interest. Can you post them?
Thanks,
PJ

 

[ida34]

I drove a 900 series in the first gulf war and the ratings were just like every other medium to heavy duty truck. Five tons during operations over unimproved roads and trails and 10 tons over regular roads. By unimproved I mean trails and off road. Unless they have changed things dramatically they are good for 20,000 on highway. The chart given looked like an unimpoved road chart and their should be another for the highway load limits. Later when I am home I will see about checking the whole -10 to confirm. The quote above seems to confirm that the "best scenario" on highway rating would be higher since it concluded that the 5 ton rating was a worst case scenario and the vehicles are not limited to the 5 ton rating.

 

[Towman2277]

If I could purchase a bridge truck around this area (Alabama) in decent, driveable shape w/ the diesel for around $1600.00, I would go that route. The truck that I would pull the Cummins 250 from and transplant into mine, is hit hard in the rear, runs excellent, and I can get it for $1000.00, and thats a steal around here!! I believe my truck to be in excellent shape compared to others around this area, and it's "Extremely Heavy Duty" im my eyes, so I'll just keep mine, and If my gassser 602 goes south, i'll transplant before I rebuild. I'm going to do some simple weight tests this week, to see how much I believe safely I can haul on-road and off-road, i'll post any interesting results. When I hauled the 19,000 lb. genset, it hauled it remarkably, with me only adjusting for safe stopping distance......and the side "Cable Ratchet Straps" work excellent for securing a load!!

 

[DDoyle]

lots of folks seem to be afraid of the bridge trucks because of their size, and they seem to go cheaper than regular 5 tons....so you may just find one in your price range!

Best,
David

 

[Towman2277]

Thanks alot DDoyle amd everyone, whats great about this site, is everyone helping everyone accomplish their personal goals towards their own "Steel Soldiers", Thanks.

 

[m139h2otruck]

Bridge Trucks

In our state, you can't get normal plates for the bridge trucks as they are over width, and need a special permit (more money) and time restrictions for operations (no nights and weekends). This is why we had to remove the duals from the back of our M139 water truck and run singles, the duels were 9½ feet wide and the law only allows 8½ feet for normal operations. Not counting the mirrors, the truck is now just 8'-5½" wide± at the tank. Rear hubs were flipped and the factory spacers installed on the outside of the hub flange to help "center" the rear tires behind the fronts. It's not perfect, but close. Standard wheels are very deep dish and the front hubs have to run a thick (5-6") spacer to miss the tierod end with the wheel/tire.

Looking at our parts book from Memphis Equipment, there is only two types of rear springs for the 5 tons, normal and wrecker. The Army TM manual also show only one true spring for the rear, but the fronts are different for the M139 with one more leaf (which ours has). The water tank now on the truck has to weigh much less than the bridge body but 4,000 gallons of water does add up (33,000#+) and the truck handles it as if it were only 3,300#! Just would not want to run down the road full of water, would never get out of 3rd gear.

 

[M1075]

RE: Bridge Trucks

Hey H20, can you post or send me a picture of your truck? I'd like to see it.

 

[m.walker]

RE: Bridge Trucks

I think we all would like to see it !!!

 

[m139h2otruck]

Pictures

Sorry for not having any pictures right now, but I tend to be "challanged" when it comes to this stuff. The truck is currently back (installed new clutch in 12 hours,2 men, last Saturday) at a job site being used, and I will try to get some pictures today under sunny conditions with the sprayers working. Never been able to load the photos into the computer and then to a message board! Will try again or have my son load them and e-mail back to me. We have a trucking operation running removing 80,000 cy of sand at this job, and all the trucker types love the h20 truck!