Easy way to lower of M105A2?

[wsmith350]

Hello I'm new to the forum here, so bear with me. I have recently purchased a M105A2 to use as a general utility trailer. I'm looking for unique ways to lower the trailer down to a more usable height without sacrificing the look. I want to put smaller tires/wheels on it. From what I understand, the Izuzu NPR (Chevy w3500) uses a 16" wheel with a 6x8.75 bolt circle. Has anyone here had any experience with this? Thanks

 

[3dAngus]

I have not, but I have put M1061 tires on them. They are also 6 bold rims. I keep forgetting the name of the other trailer, but it is like a munition trailer or something that has the same wheels that will lower it some.
I have heard of some people putting the springs under the axle, in lieu of above it to lower it. I have not checked into this.
Seems like it might not carry as much load safely doing that.

 

[m16ty]

I doubt the 16" wheel you speak of will clear the brake drums without mounting them "backwards". The easiest thing to do is find some M1061 wheels and tires like 3dAngus said.

 

[wsmith350]

The M105a2 has a 10k axle and a double stack of springs. Without at least removing the upper stack, I don't think there is room for the axle. I am also trying to get away from the split rims.

 

[CCS0185]

Bearing seizure

I have recently seized the bearing on my trailer while driving it home from auction because of high speeds. It occurs to me that you may have the same problem if you reduce the circumference of the tire, whereby causing the rotations to increase at slower speeds. You may consider leaving the tires alone and putting an inverted drop-hitch on the towing vehicle?

 

[wsmith350]

I have recently seized the bearing on my trailer while driving it home from auction because of high speeds. It occurs to me that you may have the same problem if you reduce the circumference of the tire, whereby causing the rotations to increase at slower speeds. You may consider leaving the tires alone and putting an inverted drop-hitch on the towing vehicle?

I considered the issues that come with the increased axle speed. The particular trailer that I have had only 30 miles on it since the government had it referbed in 2007. The axle grease was still fresh, so I left it alone for now. I do have plans to replace it with modern synthetic grease once I have some down time. As far as lowering it, I just put 16.5 isuzu wheels on it. I opted to modify the Pintle hitch so that it sits close to level with my truck. It's at a job now, but once it's empty I'll post some pics of the hitch modification. I'll be it not the prettiest, but very reversible and functional.

 

[quickfarms]

How are you going to actuate the brakes?

 

[wsmith350]

I installed a tie down model 66 surge brake actuator. $99 from eastern marine.

 

[3dAngus]

I have recently seized the bearing on my trailer while driving it home from auction because of high speeds. It occurs to me that you may have the same problem if you reduce the circumference of the tire, whereby causing the rotations to increase at slower speeds. You may consider leaving the tires alone and putting an inverted drop-hitch on the towing vehicle?

Not likely your trailer seized bearings due to high speeds. These guys are tougher then what any civy trailer is.
Your problem was dry grease, exasperated by water or a broken seal, but definitely dry grease or absence of it.
If properly packed with grease, and in good condition, these trailers can go 80mph and no issue to bearings.
The issue would be safety, due to tires or load, but definitely NOT bearings, and as such, I still would not recommend driving at such a high speed.
Hope this helps.

 

[patracy]

Not likely your trailer seized bearings due to high speeds. These guys are tougher then what any civy trailer is.
Your problem was dry grease, exasperated by water or a broken seal, but definitely dry grease or absence of it.
If properly packed with grease, and in good condition, these trailers can go 80mph and no issue to bearings.
The issue would be safety, due to tires or load, but definitely NOT bearings, and as such, I still would not recommend driving at such a high speed.
Hope this helps.

I'm going to guess that was the cause as well. I've been lucky with all my trailers, but it still lingers in my mind that I might have an issue someday. I've towed my M105 at 65 MPH before for some distance.

Now to the RPM question at hand. A M105 trailer came with 9.00's on it. Those measure about 39" tall. Or 61" in circumference.

All this is based at 60mph (1 mile a minute)
V = 1 mile/min = 5280 ft/min
RPM = 5280*12/61 = 1039 rpm

Now, let's take that M1061 tire in comparison. They measure about 32" tall which means a circumference of 50.25"
RPM = 5280*12/50.25 = 1261 rpm

So that means that the bolster tires would spin the bearings 222rpm higher. Or 21.36% faster.

I know personally I've pulled a M105 at 65mph for a long distance several times with no ill effects and the hubs didn't get warm. That's only 9% faster than 60mph. But still 11% away from the bolster trailer tires running the same RPM at 60mph. I would say, and this is purely my opinion, that the bolster tires could be ran on a M105 with no ill effects IF proper PMCS is done on the hubs. But dragging one home without a good check out might lead to disaster. (Yes, I've dragged a few trailers home without PMCS, however, I pull over frequently to check the hub temps)

 

[Sephirothq]

Or you could swap the axle out and put a atandard 8 lug trailer axle in it's place.