New Southern Il. Rule

VicS

Well-known Member
Location
SE Il.
New rule! All drawbars will be within 10 degrees of level. All classes. Thinking is if your hitch slopes down more than 10 degrees, gives you an unfair advantage. Would a mathematician please reply and tell me how a angling hitch makes a difference in solid steel? The meal was excellent. Thanks. Vic Simpson.
 
Angling down away from the tractor would give you a slight disadvantage, if the legal height was measured to the highest point as it should be. The highest point would be just next to the hook hole, so the chain will have less down pull.

Angling down towards the tractor will give no difference as the highest point will be the very end of the drawbar.

My hitch the hook point is a round bar so the angle of drawbar is irrelevant completely...

Sounds like another rule made because of a strong competitor?
 
Moresmoke is right. The angle of the drawbar makes absolutely no difference, and neither does the attachment point to the tractor. As long as everything is solidly mounted, all that matters is the height and the length.
 
That's different. Our club rules say our draw bars run as level as possible and parallel to ground.
 
The problem comes into play when the drawbar is very thick (up to max allowed)and has a lot of meat from the end of the pull hole to the end of the drawbar. In some cases when this maximum thickness drawbar is hiked up at a steep angle, it puts the chains hook in a different position compared to a drawbar that is perfectly level. Look at many of the professionally made easy-adjust drawbars and notice that they are often very much up in the tail. It just plain looks wrong, like the drawbar frame was positioned too low for the chassis/rear tire size. It's been done like that for a reason on some tractors.
 
I see what you are talking about but they are more worried about like a Allis that the hitch comes down at a say 45 dog angle.
 
As long as the hook point is measured to the highest and furthest forward spots that the hook touches it will make no difference.

You could have a pretzel shaped drawbar that came down forward at an angle and it would make no difference to the force applied to the tractor. The only thing that makes a difference is the actual points that the hook touches.
 
Moresmoke,I believe you are wrong as the attachment height point to the tractor is the main factor.We used to pull Wd45s back when,one pulled from the Snap Coupler bell and the other pulled from the tractor frame which was 30-36 inches high going back to 18 inches hook height at a VERY steep angle.It made as much as 200-250Lb.more needed in some classes on the front end. Works on the same principle as turn buckle rule on point height top point.On a long chain ??,but on a short (-30)chain a world of difference.Just my take over the yrs of what different attachment height points on the axle will or won't do.
 
One of you are talking about hitch point and one is talking about where the
draw bar bracket is mounted the way I am reading this. I don't see the angel of draw bar to ground makes any difference.
 
As long as the hook point is in the same spot, and fixed so it cannot move, there will be no difference in the force imparted against the tractor.
 
20 inches up from the ground and 18 inches back from the axil is the same on all tractors, and it doesn't matter where it attaches to the tractor. I pull an Allis and it like some other tractors has a high rear axil, this allows you to attach the hitch point higher. The only advantage is that your hitch is straighter with the chain and since the tensil strength metal is at it highest when it is being pulled apart (no bending). This allows you to build a very strong hitch but keep the weight down. That saved weight can be used else where on the tractor where it does you more good. If your club is going to have rules like this. Why not just build all the tractors exactly alike and just paint the tractor your favorite color. BOOOOORRRRIIINNNGGG.
 
D beatty, I think it's a great rule. Picture in your mind, if the angle of the hitch to the tractor is the same as the angle of the chain and hook to the tractor, it's the same thing as hooking the sled closer and higher, just makes the chain act a tad longer. I'll take a 9 inch longer chain for a 6 inch higher hitch point anytime, not to mention it's like being 4.24" closer. gm ;-)
 
Budanut, I've noticed that mostly WC's, (the guys that make natpa rules mostly?) have this aberration to their hitches. I can think of 4 that do and have done eerily well against other tractors when there was absolutely no reason they should have. gm
 
It's nothing but an optical illusion. A fixed point is a fixed point.

I'm a mechanical engineer, it's a simple statics 101 problem. Give me some dimensions and I can prove it with the math to show that there is no difference as long as the hitch is rigid in all directions. ---- First thing you do is draw the free body diagram for the hitch. (look it up and it might make sense, it's a pretty simple concept)

Like previously said, only advantage is in optimizing the design for strength to weight.
 

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