Draw bar length January 09, 2020 02:02PM
If you need more traction would a longer draw bar help much.
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Re: Draw bar length January 09, 2020 02:48PM
Yes
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Re: Draw bar length January 09, 2020 04:18PM
No
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Re: Draw bar length January 09, 2020 04:34PM
Both answers are correct but it will take a novel to explain the circumstances where an 18 inch long drawbar is better, or worse, than say a 24-26 inch drawbar.
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Re: Draw bar length January 10, 2020 01:09AM
Like most things in Life, pulling is not a "PURE SCIENCE",no one answer fits all the time,like many discussions on here, opinions run rampant,more so than fact.Many reasons exist for our wanting to pull in the first place,- just like why some preform differently than others.Life is a series of choices.Rules of physics and geometry apply and sometimes not so much.
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Re: Draw bar length January 10, 2020 01:21AM
There is no maximum length of the drawbar however there is a minimum length. So if you lift the front end of your vehicle the longer the drawbar the less draft you will have, thus less downward pull on the rear tires. As the angle of the chain decreases the draft also decreases and traction is lessened.


Dick Morgan

www.PULLOFF.com
Independent Pulling News



Edited 1 time(s). Last edit at 01/10/2020 01:24AM by Dick Morgan.
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Re: Draw bar length January 10, 2020 02:17AM
Trial and error. You need to find the sweet spot for your tractor.
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Re: Draw bar length, to Dick January 10, 2020 05:28PM
Dick, just because the hitch gets longer, doesn't change the CHAIN angle. Hitch would still be at same HEIGHT as the short hitch, just puts hook point further away from axle CL.
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Re: Draw bar length, to Dick January 10, 2020 07:43PM
however -when longer hitch is used,any pressure on the longer lever moves it lower faster than shorter,even just tightening chain
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Re: Draw bar length, to Dick January 10, 2020 10:29PM
I believe that on a nose heavy antique tractor like my w-9 a longer hitch helps I regretted ever cutting mine off
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Re: Draw bar length, to Dick January 11, 2020 01:12AM
Thank you for pointing that out. My point was that if or when the front of the vehicle comes off the ground then the angle of the hitch will change. However if the front of the vehicle does not come off the ground then the angle will be the same.


Dick Morgan

www.PULLOFF.com
Independent Pulling News
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Re: Draw bar length, to Dick January 11, 2020 05:38AM
Many other factors are important,much and or more than just initial hitch height, tire pressure,drawbar support,strength of said drawbar,bending and stress causes forces greater than we know to work on hitch,tires,and more,simply spinning down three - four or more inches changes all above mentioned, and all sled are not created equal,many have chain hooked to absolute lowest point possible,- others not so much and chain length varies as does the wind bloweth. Overall length of main frame of tractor and transmission weight varies greatly,look at some very interesting posts on here about that subject. IF IT WERE EASY, - I WOULD WIN MORE,AS WOULD WE ALL !!!!!!!!
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Re: Draw bar length, to Dick January 11, 2020 07:33AM
Correct, the downward component of the the angled chain load (the sled) will act on the long drawbar much like a cheater bar and will work to lift the front of the vehicle (imagine if the drawbar were 20 feet long, you'd be able to almost step on the end of it and raise the front end). It's essentially the same as reducing the number of front weights you have.

Once the front end is in the air and the hitch is in the dirt all the physics change. That's why it's not an easy yes or no answer.
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Re: Draw bar length, to Dick January 11, 2020 10:17AM
On the note of sleds. I believe NTPA specifies chain length to be used on a given level of sled. Maybe a sled owner could clarify.
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Re: Draw bar length, to Dick January 12, 2020 02:12AM
I believe 40" +/- 1/2" is the spec on chain length.
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Re: Draw bar length, to Dick January 12, 2020 02:16AM
46" +/- 1/2" on big sleds.
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Re: Draw bar length, to Dick January 12, 2020 09:10AM
yep, thanks.
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Re: Draw bar length, to Dick January 11, 2020 10:25AM
A tractor with a lot of movable weight could really use the leverage from the longer draw bar it would be just like cheating adding extra weight to the front and picking it up putting it on the rear tires
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Re: Draw bar length January 11, 2020 12:13PM
has nobody pulled out a stuck tractor or a car or truck stuck in the ditch? Have you guys actually ever hooked a chain to anything other than a sled? I'd draw you a free body diagram but most of you wouldnt understand it. A longer drawbar has the same effect as a longer chain. you want the shortest chain and drawbar possible. the only exception is in an example like bbailey mentioned where the tractor is just way too front heavy [very rare]. id suggest that the drawbar would be the absolute last alternative and if you can't get the tractor to hook up then theres much to be changed in your setup before drawbar.
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Re: Draw bar length January 11, 2020 01:12PM
Wow you are way way off on that. A longer chain decreases the angle of the chain going up to the hitch and results in less pulldown on the back of the tractor and less lift on the front of the sled pan. Drawbar length has no effect on the chain angle or amount of pulldown/lift. It does have the same effect on the tractor as using a bigger pry bar on something. The longer your drawbar is the more weight you need up front on your tractor. The longer the chain the less weight you need on the front.
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Re: Draw bar length January 11, 2020 01:15PM
Drawbar length does have an effect on the angle IF you lift/raise the front end.


Dick Morgan

www.PULLOFF.com
Independent Pulling News
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Re: Draw bar length January 11, 2020 01:17PM
Correct, I'm just stating it from the standpoint of hooking up to the sled.
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Re: Draw bar length January 11, 2020 02:08PM
Ntpa and PPL and I am sure many other groups and clubs have a set standard chain length,- however many brush pulls,local small clubs, county fairs and such use under sized sleds to stop heavy tractors and trucks, - so the lazy easy way is to raise and lengthen chain.
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Re: Draw bar length January 12, 2020 12:23AM
I for one would like to see a free body diagram, I haven't had to do one since Engineering school, 40 years ago. Don't forget this is not a static system, it is a dynamic system, so your free body diagram should have variables for the forces and angles.

Rich PE
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Re: Draw bar length January 12, 2020 12:57AM
My grampa always said the closer you hooked the team ,the more they cloud pull
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Re: Draw bar length January 12, 2020 03:29AM
GLennMc,- your grandpa was a smart man,no need for engineering school or diagrams,common sense and experience tells,shows and teaches practicality when they give us limits in pulling,rules to follow,understanding how the utilization of said rules and limits can help none our game,not all tracks, sleds and or dirt type are created equal. I have lowered my hitch often when using a gear I figure might pull me down me too quickly,have installed mid mount weight brackets to help keep my error limited to 50%.And I believe that NTPA has a rule about draw bar angle also.When we setup a pulling unit to hook ,we do it so it is most perfect for the later stages of the pull,not at 50 feet,not at 150 or 190,-- but at the point the sled's friction starts to over take our traction and perfect balance,power and speed.Reading the track and gleaning from tractors and classes before we pull is our only "HOT LAPS"
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Re: Draw bar length January 12, 2020 03:40AM
NTPA rules on hitch angle is 15 degrees.
One thing to note,,,,,, for years everyone paid attention to hitch angle as it was always angled down to the rear.
For a while now, some vehicles have the angle so hitch is lower at the front. And none of those vehicles do bad.
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Re: Draw bar length January 12, 2020 07:54AM
I had a tractor that had hitch like that due to low rear end, I always thought that it seemed well suited to good transfer.
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