Narrowing the track of a M116A3 trailer

[DSD277]

Rather than going into something blind, I thought to see if anyone has removed the spindles from a M116A3 to re-weld them into the stub axle after being shorten?
I am narrowing the track on a M116A3 to match up with my Pinzgauer ( roughly 10” narrower). I want to keep the raised center axle, hence need to cut the axle outside the spring perches on both sides, moving the hubs in approx 5”. Current spacing is approx 9 1/2" from the backing plat to the cross brace next to the spring. Plenty of room for cutting.

To answer questions before asked.
Cutting the track that much will still be a lot wider than to that of a M416 ( but the M116 bed)
Do not want to use dually rims
The raised axle is a nice match to the portals of the Pinz ( as the M116A3 is to the HMMWV)
The surge brakes is just a nice plus, but not necessary with the 6 wheel disc brakes of my Pinz.
My M116A3 actually has a narrower A2 bed (no fender extentions), so the tires and wheels will tuck nicely under the fenders

 

[jesusgatos]

Planning on doing this to one of my M116A3 trailers that I put an M1031 box on so HMMWV wheels/tires will tuck up into the wheelwells. Going to look into swapping an A2 axle first. Anybody know offhand what the difference in track-width is?

 

[Recovry4x4]

Planning on doing this to one of my M116A3 trailers that I put an M1031 box on so HMMWV wheels/tires will tuck up into the wheelwells. Going to look into swapping an A2 axle first. Anybody know offhand what the difference in track-width is?

The HMMWV rim and tire will clear the frame rail by about an inch with the A2 axle. I built a similar trailer but used the M887 SECM and the frame of the box was wider than the frame of the trailer and the HMMWV rolling stock wouldn't fit. Your SECM body may be different. Sectioning the outters of an A3 axle seems like a good idea and one I've considered.

 

[ChrisABQ07]

I see what you mean about working from the outer ends of the axle instead of the middle. It would require a major spring relocation.

 

[glassk]

M116A2E1
GENERAL
Angle of Departure ............................................................................................................30
°
Center of Gravity:
Empty .........................................................................................................................15.3 in. (38.86 cm)
Loaded........................................................................................................................8.3 in. (21.08 cm)
Shipping Volume of Chassis Trailer .................................................................................189 cu ft (5.29 cu m)
DIMENSIONS
Length ...........................................................................................................................145.7 in. (370.08 cm)
Width ...........................................................................................................................71.3 in. (181.1 cm)
Height of Chassis ...............................................................................................................30 in. (76.2 cm)
Tread ...........................................................................................................................71.3 in. (181.1 cm)






M116A3

GENERAL



Angle of Departure ............................................................................................................30

Center of Gravity:

Empty..........................................................................................................................16 in. (40.64 cm)

Loaded........................................................................................................................8.2 in. (20.83 cm)

Shipping Volume of Chassis Trailer .................................................................................189 cu ft (5.29 cu m)


DIMENSIONS



Length ...........................................................................................................................145.7 in. (370.08 cm)

Width ...........................................................................................................................81.5 in. (207.01 cm)

Height of Chassis ...............................................................................................................36 in. (91.44 cm)

Tread ...........................................................................................................................81.5 in. (207.01 cm)

so that Tread figure is about 10 inches from the A2 to A3,

 

[DSD277]

The A3 is the only variant M116 with a raised center axle, all the rest are straight (though the same reference conterdicts itself), and a piece of cake to cut and splice back together. If you don't intend to drive offroad, a straight axle is fine.

The track (tread) listed for the M116A2E1 is the same as the A3 , as is the trailer width. I was told the M116A2 had CUCV tires and rims, but it has a straight axles, so that takes us back to the A3 axles and it's wider track.
It all comes back to cutting 5" out of each the stub axles.

It seems I'll be using my axle to be a guinea pig to determine the most practical way to reduce the track, either by cutting a section out and slice back together with a sleeve, OR cut the stub the dimension I want and remove the spindle from the cut section and weld it back into the stub.

These pics are of the 2 M116A3's I have. As you can see, one is a modern A3 with the fender with extension is one piece. The other trailer was listed ( and the dataplate) as an A3 also, but has an A2 bed (no fender extensions), and there is no indication that there were any extensions. Everything else is A3 specs. It is this trailer I'm modding to take CUCV type rims. The beauty of my Pinzgauer is it is UK made and to NATO specs, and this trailer will fit perfectly in size and tracking (after the narrowing the axle)

 

[jesusgatos]

Good info. Thanks. Likely that we'll end up replacing the axles on 1-2 of our trailers with 6-lug civilian axles to match tow vehicles, so we'll have a few extra axles to fool around with. Shouldn't be too difficult, but I'll be watching to see how this goes. Thanks for sharing.

 

[DSD277]

Straight axles is the simplest way out... I'm not known for taking the "simple" way
But I did conceded early on NOT to change the hubs to TD Pinzgauer lug pattern... that by itself would have cost me 6x what the trailer did.
The tire in the last pic is a 265/75-16, just to get a general idea of what the trailer would look like. My final choice will be either 235/85-16 or 225/75-16.
After the axle is done, I plan to modified the wheelwell width to allow me to load my Haflinger onto it. And with the shorter tires, I can reduce the fenders from 11" to 4" and have the same internal clearances for spring compression and the axle bumps

 

[glassk]

The A3 is the only variant M116 with a raised center axle, all the rest are straight (though the same reference conterdicts itself), and a piece of cake to cut and splice back together. If you don't intend to drive offroad, a straight axle is fine.

The track (tread) listed for the M116A2E1 is the same as the A3 , as is the trailer width. I was told the M116A2 had CUCV tires and rims, but it has a straight axles, so that takes us back to the A3 axles and it's wider track.
It all comes back to cutting 5" out of each the stub axles.

It seems I'll be using my axle to be a guinea pig to determine the most practical way to reduce the track, either by cutting a section out and slice back together with a sleeve, OR cut the stub the dimension I want and remove the spindle from the cut section and weld it back into the stub.

These pics are of the 2 M116A3's I have. As you can see, one is a modern A3 with the fender with extension is one piece. The other trailer was listed ( and the dataplate) as an A3 also, but has an A2 bed (no fender extensions), and there is no indication that there were any extensions. Everything else is A3 specs. It is this trailer I'm modding to take CUCV type rims. The beauty of my Pinzgauer is it is UK made and to NATO specs, and this trailer will fit perfectly in size and tracking (after the narrowing the axle)

My deal is I have a M116A3 with fender ext and HMMWV wheels 16.5 8 Lug and I'm wanting regular 8 lug chevy wheels, so back spacing is my area of concern I guess,

I have a M116A1 removed BUD wheels axle and used a dropped with 6 lug hubs to match my pickup, think hub faces were 68 inches

 

[DSD277]

The 3rd pic is with a standard Dodge 8 lug rim (same as Ford and older GMC/Chevy). The older Chevy wheel should bolt right on and the correct backset. What a tire shop told me was that the newer Chevy/GMC rims are a metric pattern that is close, but not the same. I have not verified it... I should, I have a '09 Silverado too.

 

[glassk]

The 3rd pic is with a standard Dodge 8 lug rim (same as Ford and older GMC/Chevy). The older Chevy wheel should bolt right on and the correct backset. What a tire shop told me was that the newer Chevy/GMC rims are a metric pattern that is close, but not the same. I have not verified it... I should, I have a '09 Silverado too.

Getting two from a 2003 GMC 2500 that a friend has, so the dodge wheel is with out the extension, we will see

 

[Recovry4x4]

My deal is I have a M116A3 with fender ext and HMMWV wheels 16.5 8 Lug and I'm wanting regular 8 lug chevy wheels, so back spacing is my area of concern I guess,

I have a M116A1 removed BUD wheels axle and used a dropped with 6 lug hubs to match my pickup, think hub faces were 68 inches

I had a similar concern with my M101A3. That is what led me to look into sectioning the axle. I reluctantly bolted on standard M1008 stuff (6.5" wide factory rim) and it fits perfectly.

 

[glassk]

I had a similar concern with my M101A3. That is what led me to look into sectioning the axle. I reluctantly bolted on standard M1008 stuff (6.5" wide factory rim) and it fits perfectly.

My plan is put the MEP002A from this trailer on my M116A3 , Liked the fact that it had 3 inch frame no surge brakes being it is an M116A1, cons had those huge BUD wheels and did need to change the axle, also changed to a Collar Hitch and drop axle, with that came being able to use my factory wheels my spare will fit it and the track is the same as the truck,


Also looking at some bearing info on the M116A3, think the inside bearing matches a 9000 lbs outside bearing and outside from is same as an inside 7000 lbs one, talk about over built,

 

[harleyhouse]

You want a narrowed A3 axle with raised center section.
What about taking a narrower A2 axle and raising the center section inside the shock mounts like the A3 is?

As for 8 bolt wheels earlier before 2014 GM wheels are the ones to use.
The later dodge 8 bolt wheels have a deeper backspacing.

Post what you end up doing.

 

[86m1028]

As for 8 bolt wheels earlier before 2014 GM wheels are the ones to use.
The later dodge 8 bolt wheels have a deeper backspacing.

Post what you end up doing.

Actually its 2010 NOT 2014 when GM changed

 

[DSD277]

The Dodge rims seem to have the most offset short of using dually rims (the idea of tearing my shins on lug bolts everytime I'm near the trailer, just doesn't appeal to me )

Buying more axles really isn't an option. My biggest challenge at the moment is getting a work area.. The FDT and Pinzgauer occupy prime inside spaces I can't/won't give up and no more secure outside space until I sell something. ..

I have decided the route I'm going to follow that allows various "new directions" without any "ah crap!" .

I'll submit pics as I go along... just don't expect anything until I solve my main problem. .

 

[86m1028]

Yes the dodge wheels are wider but have more offset (tuck in more).
I have pics somewhere of a chevy wheel & a dodge wheel on an M1102.
I know, not the same trailer but it will give you a better idea.

 

[DSD277]

Yes the dodge wheels are wider but have more offset (tuck in more).
I have pics somewhere of a chevy wheel & a dodge wheel on an M1102.
I know, not the same trailer but it will give you a better idea.

I don't where you got the Dodge rim is wider? These rims I have are 6 1/2" wide. Narrow by all modern standards. Basic steel rim
The closest I could find to mimic the TD Pinz appearance without goting to a 5 or 6 bolt rim
And a pic of the HMMWV tire on the trailer before changed it. And can see in the background the same on a true A3 bed.
The standard A3 tread width is 81.5" which fits within the 84" wide A3. When I'm finsh, the tread I'll have is approx 72" within the 73.5" wide bed on my "not a true A3 bed".
Using the smaller and narrower 235/85 will allow me the option to modify the fender height/width at a future date for use to haul my Haflinger.
The 3rd pic is my old 712 with the trailer I was using 12 years ago. The 718 has far better brakes plus the trailer surge brakes aren't needed for the 1600lb Haffy.
I started this thread to see if anyone had gone through the process of narrowing an A3 axle. The rest of my trailer mods are going to be done on "ideas" to see how it comes out. Pretty much the way I went with the FDT, which surprisingly came out better than what I had imagined, and others said I couldn't do!( and I had my own doubts )
I've been running all the questions of bed height, ramps, loading/unloading the Haffy (safely), loaded trailer's center of gravity, and dozens of other items that factor in to the final useability. If it falls short of my total expectations, OK, it was a fun project and will still be a functional trailer and be a nice fit behind the Pinz..
I do know some of my limits, and won't try to make a M119 howitzer that would look sooo cool behind the Pinz or Supacat .

 

[ChrisABQ07]

Time for an update on your project. Any photos? Any complications?

 

[DSD277]

Sorry, I've been bouncing between different projects and haven't gone any further with narrowing the axle.