M931 driveablity

[Carlo]

What is top speed on an m931 with a 250na cummins ? Realistically
How driveable is one on the highway say a two or three hour trip ?

I drove my 931 from Holland over the alps back home to Italy and got good milage. I filled up when I left and had fuel to spare when I got home. I ran it 90 to 100 km per hour.

 

[hotbox]

The cummins/allison combo is no hotrod, but a **** of alot better than my deuce's multifuel! I cruise at 60 mph on the highway with duals. Currently putting a set of singles together, but don't plan on driving any faster. It took a while to get use to the brakes coupled with the automatic tranny. It takes an easy smooth foot not to jerk the truck during downshifts. The only problem I have with my 5 ton is my face hurts from smiling so much when I drive it!

 

[Rambling Wreck]

Any top speed info on the A1 variant? Also, Did the A1/A2's get ABS brakes?

 

[quickfarms]

Any top speed info on the A1 variant? Also, Did the A1/A2's get ABS brakes?

The speed rating of the tires is more of a factor than the truck.

Experienced drivers do not need abs.

 

[Rambling Wreck]

The speed rating of the tires is more of a factor than the truck.

Experienced drivers do not need abs.

We all need abs. It would be hard to sit up without them (whether you are an experienced driver or not).

I am well aware of tire ratings. My question was more to the point of, since the A1/A2 variants have super singles, is there a greater realization in top speed, regardless of tire rating. Conversely, driving within the stated limitations of the singled out tire, is there a noticeable reduction in RPM's at cruising speed when compared to the earlier versions?

The reason that I asked about ABS brakes is that there are so many horror stories about accidents with these trucks. The root cause seems to be that the earlier versions didn't have ABS. That is why I was curious if when they switched to the A1/A2 models if they came with ABS brakes.

 

[trukhead]

TWO very simple ways to fix the reverse low range transfer case breakage problem
1--- Drive the truck like YOU own it and YOU have to pay to fix it, NOT like if you break it, someone else (tax payer) will fix it.
2--- Disconnect the automatic front wheel engagment when going into low.

It eaiser to put a lockout for low reverse and stickers saying "DO NOT PUT INTO REVERSE LOW" then to train young GI truck driver how to drive a big truck.
The problem is that the truck goes from 2 axle drive in high to 3 axle drive in low, the young GI truck driver thinks that there is only ONE throttle postion most of the time and that is on the floor boards, the truck is having trouble in high so he drops to low, since it is now in low, it will need ALL the power it can get, so NOW all 3 axles are pulling with traction and with a lot of instant horsepower, SOMETHING HAS TO GIVE, the transfer case TAKES THE HIT.

Bet I could break something putting any 5t into low forward/reverse, crank the rpms up and dump the clutch, the ONLY difference here between the 900s and the older 5ts is the when starting out with a clutch you have to eze into it on the throttle, where a automatic you can just floor it and go.

Question, If I have a M931A2 in low range and I'll putzin around on flat slippery wet ground but not sinking in mud, just slippery ground, May I put the tractor in reverse and not shift out of low range? I'm not on the throttle much above and idle, enough to move the truck and load. No floor boarding the accelerator just babying it to get the job done.
Geez these are big trucks!

 

[GHall]

We all need abs. It would be hard to sit up without them (whether you are an experienced driver or not).

I am well aware of tire ratings. My question was more to the point of, since the A1/A2 variants have super singles, is there a greater realization in top speed, regardless of tire rating. Conversely, driving within the stated limitations of the singled out tire, is there a noticeable reduction in RPM's at cruising speed when compared to the earlier versions?

The reason that I asked about ABS brakes is that there are so many horror stories about accidents with these trucks. The root cause seems to be that the earlier versions didn't have ABS. That is why I was curious if when they switched to the A1/A2 models if they came with ABS brakes.

Yes sir, it will lower rpm a good bit at 55 MPH. I think mine at 1700 is about 52-54 MPH. I also believe the A-1-2 models have ABS for the most part with few exceptions..

 

[Rambling Wreck]

Yes sir, it will lower rpm a good bit at 55 MPH. I think mine at 1700 is about 52-54 MPH. I also believe the A-1-2 models have ABS for the most part with few exceptions..

Thank you so much for the straight forward answers.

 

[Castle Bravo]

I think all the Army M939 trucks have ABS, and with that comes non-NDCC tires. (Almost always 11R20 Goodyear G177s) I have seen two Navy trucks without ABS and with 11.00x20 NDCCs. Not sure about USMC M939s and I don't know if there are USAF M939s.

 

[Carlo]

I think all the Army M939 trucks have ABS, and with that comes non-NDCC tires. (Almost always 11R20 Goodyear G177s) I have seen two Navy trucks without ABS and with 11.00x20 NDCCs. Not sure about USMC M939s and I don't know if there are USAF M939s.

NICE 916! I would like to have the 3 axle some day and run singles.

 

[Rambling Wreck]

I think all the Army M939 trucks have ABS, and with that comes non-NDCC tires. (Almost always 11R20 Goodyear G177s) I have seen two Navy trucks without ABS and with 11.00x20 NDCCs. Not sure about USMC M939s and I don't know if there are USAF M939s.

I was wondering what are the common tires on the singled out A1/A2 models. They look like 16.00-20 Goodyear AT A2's. Can someone please verify which tires they use and what the speed rating is?

 

[commandojeff]

14.00. Same as every A1 model 939. Those are Goodyears.

 

[Rambling Wreck]

14.00. Same as every A1 model 939. Those are Goodyears.

Thanks. Do you know what their speed rating is?

 

[patracy]

Thanks. Do you know what their speed rating is?

55mph.

http://www.goodyear.com/truck/pdf/radialretserv/LoadRatingsInflData.pdf

 

[Rambling Wreck]

55mph.

http://www.goodyear.com/truck/pdf/radialretserv/LoadRatingsInflData.pdf

Thanks patracy. I researched it a little further and found the same thing. Good link to Goodyear tire info

The Goodyear MV-T have a higher speed rating but I am no tire expert and don't know if they would fit these rims or perhaps M35A3 rims.


Edit:
Link to Michelin tire info

 

[patracy]

The MVTs will mount on a A3 wheel. They're not *supposed* to mount on a A3 wheel, but they'll mount. And I know a lot of people have put a lot of trouble free miles on them. (John has, I know personally) It's due to the bead and wheel lip design.

 

[Castle Bravo]

Usually it seems like the M939A1s and A2s have Goodyear AT2As, Michelin XLs, or Michelin XZLs. Sometimes you see what looks like a 4th tire pattern, but it is a retread Goodyear AT2A, I think. They look like an angular Michelin XL of sorts.

 

[Carlo]

The longest distance I have drove any of my 900 series trucks is northern Germany to my shop at 1,900 kms. After 3 hours you cant find a place to move in the seat that you find right. You start bending your right foot in strange angles to step on the gas. Noise is not to bad on a A2 but the A1 is another story. Oh dont forget rain. The rain starts finding its way in and then you see some dripping down into the gauge cluster and you wonder will this short anything out? AND not to forget if the door seals are worn the air coming in can be a pain plus the noise. On a positive side fuel use was not bad running at 90 kph.

 

[olewhiskey]

My 939 A2 likes 49-52mph and 55-56, no problem, I have found starting it out in 4th, and shifting to 5th on level ground it runs and upshifts best.

Sitting up so high and looking way down the road it drives and handles pretty dang good, I like driving it a whole lot better than my Deuces.

 

[trukhead]

The reason you can't shift a 939 into reverse in low range is simple. The torque converter multiplies the torque sent through the driveline. Something is going to give and in the M939 series, it's the transfer case. In the M809 series, same basic driveline layout, they have a clutch which can't mulitiply the torque. Same motor in most cases', I understand that the A2's have the 8.3 6CTA Cummins but the basics still apply. A torque converter will apply more force on the input shaft than a clutch for getting things moving when something is "stuck" or "doesn't want to move"

The M939 will move fine in reverse as long as it's rolling free and there's not a load connected. It can roll free in reverse if a load it attached as well, but if it can't move it backwards connected in High Range, you'll kill it if you reverse it in low range.

After getting to take my fresh M931A2 out for my first drive today, !! I enjoy the truck more in low range going forward, I like to hear the turbo spool up and whistle and feel the truck shifting through the gears. So when it comes time to go in reverse, I make sure the axle switch says "OUT" and I just let the "creep" of the engine idle move the truck in reverse, I might give it ever so slightly, a bit of accelerator but the truck is on solid ground and very easy to "roll" with the said above creep.

So if I stay out of the mud and keep off the accelerator heavily in reverse low range, I should avoid splitting the transfer case and life driving the M931A2 will be golden, all rainbow stew and unicorns, fuzzy kittens and frolicking puppy dogs, just a plain happy experience.