Anyone running recaps?

What BBBill is talking about is slip angle and cornering force.

Since force (not cornering force) is measured as F = M x A, where M = mass and A = acceleration (metres/second(squared)), then the force applied to the tire increases exponentially as the speed increases (by the speed squared, therefore speed (acceleration) has more impact than mass).

Slow speed, tight radius turns, are where the tires on a spread are subject to the most side-loading due to slip angle. During moderate to higher speed turns the radius of the turn is large enough to not affect the spread's tires as much.

Intuitively, the steer tires get much higher side loading because they are being turned against the direction of travel at higher speeds and therefore at exponentially higher forces. They are also given the task of redirecting the entire mass in a new direction.

If a semi is loaded to maximum (12,000, 34,000 and 34,000), then the steer tires are loaded more heavily than trailer tires as well. Even if the spread has 40,000 on it, if the steer axle is at 12,000, those tires are more heavily loaded.

Someone smarter than me could provide more information and I'll bet there are published studies somewhere on this.

As always, YMMV.

 

I think we all understand what he's saying. But there is a difference between being drug around a corner and being directed around a corner.

Simpler way to put it..... going up a curvy road loaded at high speeds, which in reality won't be that high of a speed but you will easily get the point.

You need to keep in mind not all go by the weight standards you listed.

 

Wow, LNF, that was impressive. Knew someone would have the phisics of what seems just logical when you stop and think about it. The steers are used to change direction and are subject to a tremendous amount of side force. All other tires are following with much less side force.

The side abuse on the spread is going to be from tight, slow turns like backing and parking lot turns.

 

Put steer tires on a spread and see how long they last. If its easier to be on the trailer they should last longer. In case you dont know they wont last.

 

Excellent point! Wonder if that was in the study?

I've never seen a steer tire side roll like a spread and I've never seen one forced off a rim like I have a spread.

The force you guys are talking would be extreme and I mean something like road racing extreme not regular highway travel.

 

We've tried putting older steer tires on a spread to finish them out and it does exactly that......usually in less than a week.

Guess your excluding the steering wheel holders who do 40mph in parking lots.

There's one idiot I see almost daily who will grab 4 gears before his trailer makes it out the door, he probably participated in that tire study!

 

Is he an RJ youknowwho driver?????

 

Yep yellow Pete, ex Bowling driver.

 

I cringe everything I see him do that with no air in the bags... I run into him about everyday, he got busted last week.

 

Oh please explain!