M923A2 Doing 80 MPH!!

[turnkey]

So going 80mph is no big deal....But can a MV pull into a A&W and get window service or at the sonic??? That's the big question of the day...Now to bottleleg dinner with the wife at the local Taco Bell in the Big baby our M35A2 with all the goodies inside. Oh by the way was that 80mph or 80kph don't remember.

 

[ke5eua]

I took a het to sonic and McDonald's

 

[Swamp Donkey]

I regularly go to the local Dairy Queen drive-thru in my M923. They let the tall girl hand me my food though, lol. If she's not there then I have to get out.

I make it there doing 55...

That's the speed rating of my truck based on the tires I've chosen to use. I bought my truck to go where I want, pull what I want and make my boys smile (heavy emphasis on the last one). I understand what I bought and use it accordingly. If I wanted to do 80 mph I'd of bought a Corvette.

We don't have roads around here that can legally be driven going 80mph anyways...

I worked Fire / Rescue for 16 years. I have a very keen understanding of what speed can do to the human body, no matter what the vehicle. Nuff said.

 

[DavidWymore]

...and then there's tire age. Makes a huge difference. Most people don't know how to read date codes.

You roll a deuce or a five, you're a wet spot where the cab used to be.

 

[Dieseljeeper]

My gxr1000 will cruise all day at 130+. That doesn't mean it is a good idea

 

[Robo McDuff]

I am a safety first person also, but just for the sake of devil\s advocate and pure curiosity.

I am not familiar with the 900 series but to me they always sounded more like a normal road/highway truck than the good old "real " 5-tons like the M50s and the M800s. Even when in the 1980s in the USA and Canada, I saw Freightliners and Kenworths occasionally doing such speeds. The more modern trucks have formal top speeds mentioned of over 80 mph.

So let's start with a few "if" things. Presumably the M900s have dual air brake system. So IF the guy has tires approved for such speeds and IF the guy is driving in Texas along the 130 or on other highways where such speeds are allowed, and IF he is driving with properly inflated tires and IF he is hauling empty, are there any other mechanical arguments (and see disclaimer below) why a M900 should not drive those speeds while commercial trucks can do so mechanically and legally?????

Disclaimer: there are some situations where driving on endless straight highways with low traffic and good view and road surface, I might eventually agree with rigs driving 80 mph, but only if .., if .., if..., and if ..., (including a very warm place freezing over). On the other hand, the 50 - 55 mph for old MV trucks is appropriate, but for a much more modern truck (less than 20 years) using new (less than 6 year old) tires, it is unrealistic slow and way below the SAFE mechanical capacity of the vehicle. Beware, I am not talking about the !@#$@#!$ inexperienced driver and if it is advisable to go over that speed with an MV attracting a lot of attention anyway. I am asking a purely mechanical question here.

But 14 states now have speed limits of 75, 80, even 85 mph along parts of Texas 130 southeast of Austin.

 

[porkysplace]

I am a safety first person also, but just for the sake of devil\s advocate and pure curiosity.

I am not familiar with the 900 series but to me they always sounded more like a normal road/highway truck than the good old "real " 5-tons like the M50s and the M800s. Even when in the 1980s in the USA and Canada, I saw Freightliners and Kenworths occasionally doing such speeds. The more modern trucks have formal top speeds mentioned of over 80 mph.

So let's start with a few "if" things. Presumably the M900s have dual air brake system. So IF the guy has tires approved for such speeds and IF the guy is driving in Texas along the 130 or on other highways where such speeds are allowed, and IF he is driving with properly inflated tires and IF he is hauling empty, are there any other mechanical arguments (and see disclaimer below) why a M900 should not drive those speeds while commercial trucks can do so mechanically and legally?????

Disclaimer: there are some situations where driving on endless straight highways with low traffic and good view and road surface, I might eventually agree with rigs driving 80 mph, but only if .., if .., if..., and if ..., (including a very warm place freezing over). On the other hand, the 50 - 55 mph for old MV trucks is appropriate, but for a much more modern truck (less than 20 years) using new (less than 6 year old) tires, it is unrealistic slow and way below the SAFE mechanical capacity of the vehicle. Beware, I am not talking about the !@#$@#!$ inexperienced driver and if it is advisable to go over that speed with an MV attracting a lot of attention anyway. I am asking a purely mechanical question here.

The 939 series truck are still designed as Off-Road tactical trucks with a high center of gravity and a completely different suspension and handling characteristics than commercial trucks .

 

[Robo McDuff]

OK, that makes sense.

I was looking on the M915 series (Freightliner) and there it said

The M915 is almost a carbon copy of the commercial tractor-trailer truck and weighs 14 tons.

However, on the M939 series, to which the M923 apparently belongs, it mentions

The M939 truck was introduced in 1983. It's a general-purpose military vehicle, primarily designed for tactical, off-road use, with a top speed of 65 mph and an automatic transmission.

So an M915 rig could go quicker safely, but an M923 doing over 70 mph is way beyond its safety margin, not only or not necessarily because of the tires (they could have been upgraded for that speed) but because the total build of the thing is not suitable for such speeds.

For those also confused: the M915 through to M920 are "M915 series", while trucks as of the M923 through to M939 are of the M939 series?!

Whatever, if that is the case, case closed as far as I am concerned. The driver is a total and dangerous idiot who should be fined severely and get a lot of penalty points for driving offenses.

 

[98G]

My gxr1000 will cruise all day at 130+. That doesn't mean it is a good idea

Your gixxer will stop from 130mph in less distance than the 5ton trucks will stop from 70mph. Just saying...

 

[tobyS]

Can we talk about making a rat rod to cruise at that speed safely (when legal)? Like using 4x2 configuration, lower, air ride front and rear end. Google military rat rod images for the basic idea. How about a bus as a donor (ratio in the 3.7 area) ? (or trade and use the 6 x6 on the bus), (I'm not that motivated) but wonder about a highway cruiser). Here, this could be my sleeper.

 

[wreckerman893]

So let's start with a few "if" things.

IF your Aunt Freida had balls she'd be your Uncle Fred.

IF frogs had wings they wouldn't bump their a$$es so much.

IF the dog hadn't stopped to crap he would have caught the rabbit.

 

[painter paul]

I'm curious about the Army (or BMY actually) putting 63 mph on the dash as max on my M936A2 if the 1400x20's have a 55 mph speed rating!!??

 

[red]

The tires speed rating is figured with the tires at maximum pressure and load.

 

[painter paul]

Yes, I understand that but my question still remains!!

 

[red]

Calculating it off of the RPM's and gearing.

I know in Iraq we usually drove our MRAP at 60-65mph (speed limiter at 65). Only tire failure we had was when the truck got airborne.

 

[patracy]

I'm betting those trucks didn't have 10-20 year old tires on them when deployed?

 

[red]

No, newer tires rolling at 55k pounds.

 

[todds112]

Calculating it off of the RPM's and gearing.

I know in Iraq we usually drove our MRAP at 60-65mph (speed limiter at 65). Only tire failure we had was when the truck got airborne.
View attachment 568842

Sorry to hi-jack, but what are the long swooping metal poles that start from the left side of the grill. Some kind of antenna? Looks like every accessory and light possible is bolted on those things! AWESOME.

 

[The King Machine]

This happened to a friend just this past weekend

Front tire not even close to it's rated load capacity, aired down for the logging road, and doing under 50km per hour. Tires are old but with very low miles on them.

The side wall completely blew out, fist size hole. Driver noticed a couple minutes before it blew that something didn't feel right. He most likely had those minutes due to the low air pressure in the tire.

 

[gottaluvit]

Driving my 5 ton, I like to do it like it was made to do. Slow and easy. My personal top speed is and will always be 45 mph in this high-bumpered vehicle. When I was in Germany in 1985 I drove an 800 series 5 ton which sat lower than the 929 I have now. I was driving in downtown Frankfurt hauling garbage from a large civilian event (think it was Octoberfest) to the local landfill ( for PR reasons, no doubt) when all at once we were stopped at a redlight and some German person got out of the car behind us and started telling us in German that we hit a vehicle back a few blocks. My sergeant told me to follow him and sure enough there was a mercedes with a completely ran over hood. I was in the right lane of two lanes turning left at an intersection and accidentally cut the (unpainted lanes) turn short and ran right over the front of that car with my rear axles. Me nor my squad leader heard or felt a thing. I got fined 100 marks and the car driver got fined 400 for intentionally trying to dip into dod funds. Made me realize the danger of that behemoth and my current truck is even higher. It is always nice to lay your head on the pillow at the end of the day and go right to sleep knowing you harmed or killed nobody with stupid behavior!