M105A2 gets a 2.5" lift

[tcruwithme]

Earlier this year, I put 395/85R20 XZL tires on my M105 with recentered HEMTT wheels done by Stazworks in Wisconsin. I did this so that I would have two spares for my M35A2, and so that the trailer sat more level with the truck - now that the truck has those same wheels & tires on it.

So, today I put a 2.5" lift on the trailer to get more clearance with the 46" tires. Everything worked out great, so I thought I should share my story and a few pictures. First off, I didn't see any other threads for people that have already done this. I am not an engineer, machinist, or mechanic - so I was trying to use common sense. Here's what I did ...

I measured the existing u-bolts and the diameter of the axle. Then, I made this fancy schematic.



I should have been more clear in that the measurements should have indicated from center of hole to center of hole. I brought this to my local machine shop to have them drill and round the edges of a block of aluminum 2.5" thick by 5" wide by 7" long. I wish I knew someone with a drill press and belt sander - that would have saved me a couple of dollars. I also wish that I took the springs and u-bolts apart before I had those blocks machined ...



The holes in the center were done after the fact. They needed a 1.25" diameter hole drilled 0.25" deep into the block. Then, there needed to be a 9/16" hole drilled in the center of that down another 0.5" (0.75" down from the surface). That way, the bolt on the bottom of the spring would sit in this depression. Here's how everything looked before the lift:



Here's how those same measurements looked after the 2.5" blocks were put in:



Here's what the new u-bolts and blocks look like. I got extra long u-bolts in case I wanted to put another block in there to lift it a little more. There's room for another 2" block with 0.25" of bolt left on top.



And here's what the truck with trailer looks like now. It's a little more level, but the ground it's on there is not perfectly flat.



So, my next move is to cut out the wheel fenders on the outside of the trailer, and get them replaced with some wider fenders to cover up those wide tiers. That's it for this project.

~ Thad Carlson, Eagan, MN

 

[juanprado]

Just remember the trailer has even a higher center of gravity now in case you put a heavy load in there.

I learned the hard way what a 500 gallon water bladder can throw a m105a2 trailer on it side in a heart beat going 5-10 mph on a soft road when I hit a rut.......

no harm, no fowl. Just bent my uprights on one side and tweaked the front fence and bows, A 105 looks gynormous when flipped on its side

 

[rustystud]

You would have had better luck going with steel rather then aluminum ( probably cheaper too ). The aluminum will wear where the springs set on them. Over time this will cause your U-bolts to loosen up. The trailer looks nice though !

 

[Rmtaunton]

Looks great

 

[tcruwithme]

Thanks for the input everyone. Now that I got them in once, it will only take 45 minutes or so to switch them out. My u-bolts have two coats of paint on them, and the springs and axle seat also had a good coat of CARC on them. I'll keep an eye on it to see if moving to steel is appropriate.

The new tires and rims are wider, and they weigh twice as much as the original ones. I think the center of gravity will be about the same with the increased height but wider tires with more weight out towards the edges of the trailer. I'll keep that in mind if I get in any sketchy situations. I agree that the standard M105 platform would be too high to haul large amounts of liquid. That would be scary indeed.

Next up is wider fender wells and mud flaps/splash guards. I already put marker lights, delineator plates, and a lighted license plate holder on it.