Balancing Axle Weights

How important is it to have balanced weights on the drive axle and the trailer axle?

Tonight, I weighed out a reefer load and here are my numbers:

Steer weight: 11,040

Drive weight: 30,480

Trailer weight: 33,660

Gross weight: 75,180

Should I have made an adjustment to get the drive weight and the trailer weight closer to each other? I’ve heard conflicting opinions on this. If it’s legal, just go with it? Or fine tune the axle weights?

It's legal, so you could run with it. However, it's better to have more weight on your drives then on your trailers...especially in winter. If that was my load, I would be moving back 5 or 6 holes from where the pins are now.

Laura

If I can I like them balanced, it's legal and you could run. I'd do 4 or 5 holes back as well. My uneducated guess is that it's designed to be able to Balance the load on the axles.

From a safety and ride comfortability standpoint its very important to have balanced axle weights. You always want the drive axles to be slightly heavier than the trailer axles if at all possible. In addition to this, your Steer axle is too light. I always keep mine right at 12,000 but first double check the rating on the steer tires. Remember you can only reach 80,000 gross if your Steer Axle weighs 12,000 (12+34+34) so you are essentially limiting yourself to 79,000 gross by having your steers at 11,000lb unnecessarily.

How much weight shifts per pin depends on the distance between each pin. I generally average it out to be 500lb per pin.

Here is your current weight:

Steer weight: 11,040

Drive weight: 30,480

Trailer weight: 33,660

I would move my fifth wheel to add weight to the Steer Axle first making your new weight:

Steer weight: 12,040

Drive weight: 29,480

Trailer weight: 33,660

Now I would move the tandems 5 pins away from the Drive Axle to provide more weight to the Drive Axle. At 500lb per pin that would make a 2,500lb difference. Leaving you with:

Steer weight: 12,040

Drive weight: 31,980

Trailer weight: 31,160

Of course, do make sure that you are legal with your tandem placement for any states you are driving through.

I would always aim to balance yourself as much as possible for the sake of safety. It's difficult to do this in the LTL world because a lot of our tractors are single axle so we are limited to 20,000 on the Drive Axle. We find ourselves loaded at 18,000 on the Drive Axle and 33,000 on the Trailer Axle when hauling a longbox. Its not a comfortable ride to say the least but this is where experience helps.

Thanks for all the great info on this..

As it is now, my trailer axle has 3,180 lbs more than my drive axle. Here is my process for deciding how many pins to move the tandems. I take the total difference and divide it in half. That number is 1,590 lbs. I do this because when I slide my tandems back, it will shift 500 lbs from the light axle to the heavier axle. So, it really makes a 1000 lb. difference per hole moved. In this case, I would move back 3 pins to get things balanced. (1,590 divided by 500 = approximately 3 pins).

As far as the steer weight, I am a little light there. But I’m only 1/4 full on fuel so when I adjust my tandems and fuel up this morning, I should be closer to 12,000 on the steer axle.

When I get re-weighed, I’ll post the new numbers.

For me, some of my decision making depends on where I’m going. While I’d like a little more on the drives, if I’m going through small towns and tight turns on a route I’ve traveled before, I’d probably leave ‘em where you started. If I’m traveling I-20 or I-10 across Louisiana, I might stretch the tandems farther back in hopes of smoothing the ride.

😎

From a safety and ride comfortability standpoint its very important to have balanced axle weights. You always want the drive axles to be slightly heavier than the trailer axles if at all possible. In addition to this, your Steer axle is too light. I always keep mine right at 12,000 but first double check the rating on the steer tires. Remember you can only reach 80,000 gross if your Steer Axle weighs 12,000 (12+34+34) so you are essentially limiting yourself to 79,000 gross by having your steers at 11,000lb unnecessarily.

How much weight shifts per pin depends on the distance between each pin. I generally average it out to be 500lb per pin.

Here is your current weight:

Steer weight: 11,040

Drive weight: 30,480

Trailer weight: 33,660

I would move my fifth wheel to add weight to the Steer Axle first making your new weight:

Steer weight: 12,040

Drive weight: 29,480

Trailer weight: 33,660

Now I would move the tandems 5 pins away from the Drive Axle to provide more weight to the Drive Axle. At 500lb per pin that would make a 2,500lb difference. Leaving you with:

Steer weight: 12,040

Drive weight: 31,980

Trailer weight: 31,160

Of course, do make sure that you are legal with your tandem placement for any states you are driving through.

I would always aim to balance yourself as much as possible for the sake of safety. It's difficult to do this in the LTL world because a lot of our tractors are single axle so we are limited to 20,000 on the Drive Axle. We find ourselves loaded at 18,000 on the Drive Axle and 33,000 on the Trailer Axle when hauling a longbox. Its not a comfortable ride to say the least but this is where experience helps.

Would you suggest doing anything other that moving trailer tandems for trucks with a fifth wheel that can't be moved?

Bruce, I’d definitely work on a fifth wheel setting that moves more weight to your steer axle. You’re too light on the steers. Rule of thumb, fifth wheel should be centered between your drive axles, that’s a good start. This is a “set-it” and “forget-it” for the fifth wheel.

As Daniel said, you’re giving away 1k of payload the way it is now and check the steer tire max. weight.

My personal preference is to run as close to balanced as possible, with a bit more weight on the drives. Yes, for safety, but your ride will be much smoother. Again personal preference.

As it is now, my trailer axle has 3,180 lbs more than my drive axle.

That amount of difference is trivial. It will not have any effect on anything.

Honestly, I've heard a lot of claims over the years from drivers that they can detect when there's a set of axles overweight or if the weight balance between the drives and trailer tandems is off. They claim they can feel the difference. Of course, if I asked any of them to put some money on it and do a blind test to see if they're right, they'd be smart to run like hell. It's all baloney.

Ideally, you want slightly more weight on your drives than your trailer tires, but you will not notice a difference like the one you have. My biggest concern would be that 33,600 is so close to 34,000 that I might want to move it a hole or two just to get away from that limit. But again, even that is trivial.

In the grand scheme, just get your drives and tandems fairly well-balanced, make sure you're legal and get rolling.

Bruce, I’d definitely work on a fifth wheel setting that moves more weight to your steer axle. You’re too light on the steers.

I forgot to mention in my last reply that I agree with this. Daniel mentioned it. You want that steer axle as close to 12,000 as you can get it. That will allow for more weight to be carried and it will be safer because you're giving your steer tires more weight, which means better traction.

Would you suggest doing anything other that moving trailer tandems for trucks with a fifth wheel that can't be moved?

There won't be anything you can do. Fixed 5th wheels are designed so that you'll be very close to 12,000 on the steer axles. That's the only reason to adjust the 5th wheel is to get the proper weight on the steer axles.