M931A1 carrying capacity.

[Redbaron1]

I am new here. Looking at a 931a1 to build into a flotation tired manure hauler. I am wondering how it would handle a 3000 imp gallon manure tank (30,000 lbs), also considering that it would add some weight to the front axle. Was going to build with 3 axletech 4000's which are rated for 20,000 lbs each, but ran into supply issues on them. I have been told that the 5 ton axles are just as strong by some and not by others. If anyone has actual experience with carrying a load such as this and if I am going to run into problems or not, that'd be great. I am thinking the steers are the weakest? Neighbor has a 931a1 for sale, so considering it. If I go with it, I am also considering changing out the rearmost axle for a steer axle so as not to tear up grassland. If anyone has input on this it is much appreciated.

 

[simp5782]

Semi trucks run 34,000lbs on their drive axles normally as a max with a max on 20,000 on the steer in the 5 tons case. 5 ton is around 9500 or so oh the steer empty. It will handle it. Just be sure to weld some safety bars on the torque rods

 

[Jbulach]

What size floats are you going to run, and what kind of ground speed you wanting while spreading?

 

[Redbaron1]

Semi trucks run 34,000lbs on their drive axles normally as a max with a max on 20,000 on the steer in the 5 tons case. 5 ton is around 9500 or so oh the steer empty. It will handle it. Just be sure to weld some safety bars on the torque rods

Thanks. I am planning for around 18,000 on front axle. Converting front suspension to air bag and torsion arms. So you don't think that will be too hard on kingpins, etc?

 

[Redbaron1]

What size floats are you going to run, and what kind of ground speed you wanting while spreading?

I will be running something like BKT FL635's. (750/45R22.5). Max speed loaded about 40 km/hr, field speed 5 km/hr.

 

[simp5782]

Thanks. I am planning for around 18,000 on front axle. Converting front suspension to air bag and torsion arms. So you don't think that will be too hard on kingpins, etc?

You will have to upgrade the front tires. Wheels on a 931a1 are only rated for 9,000lbs each. Along with the tires. Hemtt wheels are rated for 13,000lbs each. 395/85/r20 Michelin XZLs are rated for 11,700 ea. The 14.00s are only 9000lb rated

 

[Redbaron1]

You will have to upgrade the front tires. Wheels on a 931a1 are only rated for 9,000lbs each. Along with the tires. Hemtt wheels are rated for 13,000lbs each. 395/85/r20 Michelin XZLs are rated for 11,700 ea. The 14.00s are only 9000lb rated

I will have custom 24" wide x 22.5" rims with BKT FL635's (750/45R22.5) tires which are rated for 12,410 lbs each at 46 psi/30 mph.

 

[Redbaron1]

I will have custom 24" wide x 22.5" rims with BKT FL635's (750/45R22.5) tires which are rated for 12,410 lbs each at 46 psi/30 mph.

I am only concerned that it may be too hard on steering joints on these axles if they aren't built for 20,000 lbs. (breaking or wearing excessively) Have you had experience with say an 18,000 lb load on these front axles constantly?

 

[Redbaron1]

Semi trucks run 34,000lbs on their drive axles normally as a max with a max on 20,000 on the steer in the 5 tons case. 5 ton is around 9500 or so oh the steer empty. It will handle it. Just be sure to weld some safety bars on the torque rods

What are the safety bars for? Do the torque rods need beefing up?

 

[Glenngineer]

Thanks. I am planning for around 18,000 on front axle. Converting front suspension to air bag and torsion arms. So you don't think that will be too hard on kingpins, etc?

I think with a short wheel base you will overload your rear axles before the front is a problem

 

[simp5782]

What are the safety bars for? Do the torque rods need beefing up?

I have worn the heavy duty torque rods that Erik's surplus makes. They arent worth it.

Torque rod bushings are rubber. the fatigue and stress under load. A welded bar across the back of it keeps them from falling completely off in a bushing failure.

 

[Redbaron1]

I think with a short wheel base you will overload your rear axles before the front is a problem

I will be turfing the cab. I have a combine cab which is going in front of the engine, so tank can go as far forward as I want, right up to the back of the engine. It will realistically be back a bit from engine, but over trans anyways. Wherever I get perfect weight distribution. Hence I need to know what the front axle can handle. There will also be a loading boom side cab up front, which weighs about 1000 lbs. So anyways, the goal is to put 18,000 per axle = 54,000 lbs total on three. If it's not recommended though, I need another plan. I am also toying with the idea of putting another front axle in front of front axle under cab. 8 wheel drive. That would solve weight issue I am sure. But if 18,000 per axle is fine, then it is simpler. thanks for your considerations.

 

[simp5782]

Follow the bridge formula

 

[Glenngineer]

I will be turfing the cab. I have a combine cab which is going in front of the engine, so tank can go as far forward as I want, right up to the back of the engine. It will realistically be back a bit from engine, but over trans anyways. Wherever I get perfect weight distribution. Hence I need to know what the front axle can handle. There will also be a loading boom side cab up front, which weighs about 1000 lbs. So anyways, the goal is to put 18,000 per axle = 54,000 lbs total on three. If it's not recommended though, I need another plan. I am also toying with the idea of putting another front axle in front of front axle under cab. 8 wheel drive. That would solve weight issue I am sure. But if 18,000 per axle is fine, then it is simpler. thanks for your considerations.

I am in contact with a rep from meritor military division trying to get the proper capacity ratings from them for the axles on my M931A1 ,I will post that info if I am successful .

 

[Redbaron1]

I have worn the heavy duty torque rods that Erik's surplus makes. They arent worth it.

Torque rod bushings are rubber. the fatigue and stress under load. A welded bar across the back of it keeps them from falling completely off in a bushing failure.

Ah, I see. Good to know. The front axle would be converted to air ride, so I would build that all new. But I assume the same issue exists with rear axle torque arms?

 

[Glenngineer]

Ah, I see. Good to know. The front axle would be converted to air ride, so I would build that all new. But I assume the same issue exists with rear axle torque arms?

The ultimate would be to an Rayden air ride in the rear ,in my opinion it gives the best of all worlds in a tandem suspension. Made in Alberta for the oil patch.

 

[Redbaron1]

I am in contact with a rep from meritor military division trying to get the proper capacity ratings from them for the axles on my M931A1 ,I will post that info if I am successful .

Much appreciated!

 

[Redbaron1]

The ultimate would be to an Rayden air ride in the rear ,in my opinion it gives the best of all worlds in a tandem suspension. Made in Alberta for the oil patch.

I am not familiar with that, but I'll look it up. I was thinking of leaving the rear tandem suspension setup as is. Looks pretty beefy, and I'll be riding up front. But I haven't nailed that part down yet. First I need to be sure axles are heavy enough. Like I said, I was going to go with the A4000's, since they are rated for 20k, steer tighter, and have air diff lockers, but they are getting harder to find at the moment, so keeping my options open.

 

[Redbaron1]

I am not familiar with that, but I'll look it up. I was thinking of leaving the rear tandem suspension setup as is. Looks pretty beefy, and I'll be riding up front. But I haven't nailed that part down yet. First I need to be sure axles are heavy enough. Like I said, I was going to go with the A4000's, since they are rated for 20k, steer tighter, and have air diff lockers, but they are getting harder to find at the moment, so keeping my options open.

I see the Rayden principle. I have seen that before. Very stable looking set-up. I beefed up an air ride system on my current rig which works pretty well, but I had to chain it down to prevent roll - wore too many bushings out, lol.

 

[Redbaron1]

I see the Rayden principle. I have seen that before. Very stable looking set-up. I beefed up an air ride system on my current rig which works pretty well, but I had to chain it down to prevent roll - wore too many bushings out, lol.

Do you know if Rayden make a system that bolts onto the 931a1?