When and how much to slide axles??

Okay, here I am again. I have a really important question. If you're reading this, please answer as soon as possible.

Here it is. When adjusting and sliding tandems, how do you know which hole to put it in? If the load is heavy or the axle is heavy, how do you adjust the tandems without moving the fifth wheel? (The fifth wheels don't move, in this case.) Do you slide forward or backward? How do you determine which hole to put the tandems into? If it is too light, which way do you slide it? Basically, could use a good crash course in sliding tandems here. We don't know how to determine where and how much to slide tandems (which hole to put them into). I know I sound like the newbie I am here...please excuse it...

 

I've never had sliding tandems as I'm a flatbedder. Iirc though the rule of thumb is 500 lbs is shifted per hole moved in either direction. Moving forward takes weight off drives and puts it on trailer. Moving backwards does the opposite.

 

ok..i wont go into length

have you scaled out load?

 

Please give your axle weights and we can advise you

 

when sliding your trailer tandems, figure about 200-250 lbs per hole.if you weighed your truck and your trailer wheels are weighing heavy at 35,000 lbs, you would need to move your tandems back about 4 holes and then reweigh it. if your tractor tandems are weighing 35,000, slide your trailer tandems forward 4 holes and reweigh. sliding your trailer tandems forward takes weight off the tractor and puts it on the trailer. sliding your trailer tandems back puts weight on your tractor tandems and takes it off the trailer.

 

Good Job .............................

 

This is about as basic as I can illustrate the issue in "simple terms" and assumes the cargo volume/weight is all loaded evenly. Now for an exercise, looking at the trailer illustrated, imagine if the rear 33% of the cargo volume, comprised 50% of the cargo weight ... this would amplify the weight effects of any changes to the pivot point. Point is, if rear 1/3 is "heavy", each hole will move x weight off/onto the nose. If rear 1/3 is "light", each hole will move y weight off/onto the nose. So there is no hard and fast rules as to how much each hole will change weight configuration. Each load is different in most cases in terms of weight distribution. But the physics are the same. It's about the weight that is "behind the pivot point" that effects the weight at the nose. For the purposes of this exercise, don't concern yourself with steer weight, only concern yourself with how much weight is at the trailer front, based on the trailer tandems position.

You're essentially dealing with a fulcrum.

 

Actually the weight per hole varies depending on how far apart the wholes are. Some are about 200lbs while others are further apart and would be closer to 400lbs or so.

 

I hope you are asking these questions in trucking school and not out on your own yet.
If you are... poo poo on you and the company you're with.

I learned this my first week in CDL school.

The way I remembered it is well ... truck driving everything is opposite world. Just like in backing.

Sooo if I have too much weight on my tandems.. I bring the tandems back to more the weight up.
If there's too much weight on my drives I more my tandems up to being more weight back.

As far as how much... well it helps to pay attention to how the trailer was loaded before you close the doors.
How many hole.. usually I guesstimate 1 hole for every 300-400 pounds
Usually I'm at 78-79 k to begin with anyway if I gotta deal with sliding.
less freight weight would be less per hole also.

fun fun

 

Always slide toward the overweight spot. Yeah, usually 250-350 lbs per hole. Scale and rescale till you get it right.