915a1 top speed

[gregary]

anybody know the top and or cruising speed of the915a1?

 

[Josh]

Yes

 

[NDT]

2000 RPM is 55 mph. This is best cruising speed for me, gives 7 mpg. I don't run against the governor because I have to pay to fix the Big Cam if it comes unglued.

 

[Bighurt]

I couldn't get mine to 55 without running against the govener and like NDT I prefer an operational unit.

50 was all I could muster, but I'm pretty sure my speedo is bad.

Tire size changes everything as well.

 

[M1075]

57mph

 

[tbci]

Singled mine out with 385/65/22.5 tires and wheels off of M989 ammo trailers and truck now cruises at 65 empty, 60 loaded according to GPS.

 

[Derrickl112]

Singled mine out with 385/65/22.5 tires and wheels off of M989 ammo trailers and truck now cruises at 65 empty, 60 loaded according to GPS.

But at what RPM?

 

[tbci]

No idea. Tach and speedo are busted and haven't had a chance to fix. Currently using TomTom for speedo.

Honestly, I just run it by sound and feel. Not very scientific but it'll have to do for now!

 

[Ferroequinologist]

mine will run 67mph if pushed to the floor empty. I think that's at 2350 RPM. I've run the tried and true 855 block and basic engine design in many different pieces of equipment. From a 1941 locomotive to my M915a1. Never had an issue with 2400rpm or less, as long as the engine was built/rebuilt right. I wouldn't sustain such high RPM for long periods though. Also going that fast just sucks the fuel down. I also can get 7mpg pulling my empty M967 trailer and keeping it around 55-60.

 

[73m819]

When I drove ZIGGYs 915/van trailer from NJ. to NE. and back, I could do 65 easy, hit 70 if I worked at it, till tried to suck the bottom out of the tank, then it was 60/62 easy and worked to 65 (filters), found that you can get 600 miles on a tank , NOT 601, put In right at 100 gal on that fill up, this was running very close to the peg (running hard)

 

[wreckerman893]

With the Allison the above is true.......with the CAT tranny and the engine turned up to 2350 you will embarass a lot of civy big rigs and piss off the Convoy Commander (ask me how I know).

I was clocked at 85 MPH in New Mexico by a deputy sherriff.......he didn't give me a ticket....he said he just stopped me to make sure his eyes weren't bad. Said the M915 was "the fastest dam Army truck I ever seen."

 

[quickfarms]

so the cat is faster than the allison.

 

[Andy1234]

The 7155 trans in the M915 is an overdrive transmission, whereas the Allison in the M915A1 is a direct drive (1:1) transmission, so the M915 is capable of higher speeds then the M915A1.

Andy

 

[ZiggyO]

Hello all,


Its funny: two of my m915a1's will do 65-70 like 73m819 said-- however my other two m915a1's will only go to about 62mph and stay there. Those last two trucks came from the same unit in NC so I wonder if they were both intentionally set that way........


Ziggy

 

[R Racing]

The Cat 7155 is actually a double over drive trans Being 15th and 16th are both overdrives .Its hard to tell with the 6:17 to 1 ratio in the m916s thru m920s but they still do 63-64 in that configuration.But I bet they fly in the m915s

 

[doghead]

Terminal velocity , 659 mph.

 

[Ressoldier]

I drove the 915's for years and most would do 62-65 being pushed, a few that would get a little closer to 70. They are geared and set up to be reliable and comfortable(power/ engine wear/ mileage[ not ride]) at 55mph. We did have a few that had the CAT 16speed in them and they would leave the rest in the dust doing 80-85 easy(found out same way Wrckerman did, also no ticket). In fact the Reserve Unit I drove them in finally started getting rid of them this year for the new A5's.

 

[wreckerman893]

The one I drove to GA from CA would pass everything except a fuel stop.

If you don't do much long haul driving with the single fuel tank is OK......for long haul you have to stop a lot more often than you do in a commercial rig.

 

[Monkeyboyarmy]

For you guys that are worried about the 2100 rpm limit, I have a friend that pulls with his truck and has the rpm set at 4000. At 60 pounds of boost and 1000 psi of rail pressure,he is getting about 1500 horse power. All stock bottom end.Even with steel pistons. He has used the same bearings for 3 years in a row now.But I do not know the limits of the allison transmission as far as rpm.

 

[wreckerman893]

1500 HP would destroy a stock transmission in short order.