Drawbar length. Don't understand it.

Hey all,

I dabbled with antique tractor pulling with my '52 model A JD for a couple years when I was just getting out of highschool. this has been quite a few years ago. When you ask many in the pulling crowd for tips or advice, you get alot of opinions. One that I could never understand was why everyone ran their drawbar as close to the tractor as possible? In my mind, having the drawbar all the way out, with all the suitcase weights on the front would make the most sense for putting the most weight on the rear tires. Where am I going wrong with my thought process here.?

When I pulled my best pulls were with the drawbar in, and the suitcase weights mounted just ahead of the cyl block on the frame.

Back then I was just a young guy having fun. Now I'm married with 3 kids and thinking about getting the family involved. I pulled the carburator off the Model A today and went though it. it hasn't been started in about 6 years and has been outside (I know, shame on me) I think with a little will it'll be running again. It'd be fun to pull it and the MC in an exhibition class.

Thanks all.

DF
 

Many will tell you always always! keep your drawbar as short as allowed. You don't want to have a guy with a shorter drawbar spinning out in the same spot you did and going 3 inches further. HOWEVER, in a situation where you are weighted for your lightest class, and you are nose heavy, you can slide your drawbar back and transfer weight from the front to back, and go appreciably further with that weight transfer red to the rears.
 
Many times we forget that pulling is like no other use of the tractor,as we continue to move along down the track,more AND MORE weight is transferred to the back wheels,more traction,more downward pull is exerted,this is when we need to be weighted correctly with the draw bar short,not at 100 feet,most pulls are done after 200-280'. Also,many other factors are involved,hitch height,balance,tire size,air pressure,track soil type,wet,-dry,moist firm hard,all matter,some guys run the hitch back a little on poor tracks or with poor tires,but I will almost guarantee you that a seasoned active passionate puller will have the hitch short as possible to have that factor a constant ,move weights instead,that is why you hear so much about movable weight.Also a long not strong enough unsupported hitch will flex A LOT ! This is not a pure science,why we all like it so much,no set answers,not the same every time,or else it would be boring.Have fun with the family,we used to grill and pig out while waiting to pull,some friends would bring different stuff and we all gathered every weekend for fun and bonding.
 
I think one of the biggest factors that should help determine hitch distance from the rear axle is the length of the chain. One of the clubs I pull with use a long chain. I moved my hitch back about 6 inches and have gone much farther on average in all classes.
When I pull a short chain I need more weight up front now but I'm ok with that.
 
DF
Many clubs have pre-season tune up pulls, or fun pulls to try different combinations to see results. Also called test & tune in some areas. This is a good way to test your tractor with different setups. Might want to check the air intake stack on your A after setting outside as hornets like to build mud nests inside of it reducing air flow.
I had a friend that pulls Olivers believe the long drawbar story, but after 15 years pulling his drawbar is always in.
Have Fun!
Gary
 

With a Short Drawbar (Short Lever), the sled must pull down on the tractor maybe 3x heavier, before the tractor front starts to lift..
More weight on the front and it takes MORE to lift it..PLANTING the Tires that much deeper into the track..

It all depends on the Track..Loose, Damp, Hard, etc..and the type of Sled hitch (Length and Height)..

Remember, when the front lifts the Drawbar lowers and the sled gets harder to pull..You want to carry that drawbar as high as allowed as FAR as you can and not spin-out..

Ron..
 
You are right, a long drawbar should put more weight on the rear tires, enabling you to have a greater percentage on the front. Eugene Sellers wrote a article on the math, saying the same thing. He does win a lot. But not all the time! The truth is sometimes you have to get through a soft place. So you have to have more weight on rear. then when get to end don't have enough on the front. Last pull I went to was 2 days. Same classes both days. Friday I placed but didn't win. Came back Saturday and pulled out. Then dq.for speed in pulloff. Then won two more classes. The thing is Friday night at the Motel we decided the tires were cut wrong, and wrong brand. The track was the same both days, they never worked it up. Oh my drawbar is fixed at 18 in. and was as high as allowed 20 in. I guess what I am saying is. You never can tell what will work for you. But with a longer drawbar when the front end does come up the drawbar lowers more and it is all over!
 
Most tractors you can run 18 inch drawbar and have plenty of traction to lift the front. There are a few that you need more to get enough weight transfer to get things to lift. The longer the drawbar the greater the chance to mess up your balance. Running tires that are wider than necessary can cause the same problem. If you geteverything spot on you pull well, but a little bit off and you're out. Thats the problem I fight with the tractor I have, get it right and put on a good show, or be off a little and end up way in the back.
 
Consider this: your drawbar is acting as a lever. The longer it is the less amount of downpressure it takes to lift the load (frontend). A long bar will also pivot toward the ground faster:loosing sled downpressure. I only use a long bar if too heavy on nose with no weight. Loose track or long chain
 
I will add that though I have been pulling better with a longer hook point, its been harder to get the balance right. It was a bit of a learning curve.
 
(quoted from post at 18:50:06 04/20/15) You are right, a long drawbar should put more weight on the rear tires, enabling you to have a greater percentage on the front. Eugene Sellers wrote a article on the math, saying the same thing......"

I would like to read Eugene's article, I believe it was in the March of 2013 issue of Hook, according to my search. Is there some type of link to the article so I don't have to buy an entire subscription - I have more magazines now than I can read?

One thing in your post puzzles me: you state, "a long drawbar should put more weight on the rear tires..." Yes, the downforce from the sled chain acts through a longer lever arm. However, my thinking is, once the tractor has lifted the front wheels the weight on the rear tires should be the same regardless of drawbar length. This of course assumes the same height at the hitch point. Am I reading your post correctly...?
 
(quoted from post at 18:25:40 04/21/15)
(quoted from post at 18:50:06 04/20/15) You are right, a long drawbar should put more weight on the rear tires, enabling you to have a greater percentage on the front. Eugene Sellers wrote a article on the math, saying the same thing......"

I would like to read Eugene's article, I believe it was in the March of 2013 issue of Hook, according to my search. Is there some type of link to the article so I don't have to buy an entire subscription - I have more magazines now than I can read?

One thing in your post puzzles me: you state, "a long drawbar should put more weight on the rear tires..." Yes, the downforce from the sled chain acts through a longer lever arm. However, my thinking is, once the tractor has lifted the front wheels the weight on the rear tires should be the same regardless of drawbar length. This of course assumes the same height at the hitch point. Am I reading your post correctly...?

Ken you are right, but review the responses. You should see that nearly everyone is in agreement that nose heavy or soft track or even long chain, or combination of the above, is when it is advantageous to lengthen the drawbar. It can be pretty tough for the front end to come up at all if in the lightest class the tractor is three hundred pounds heavy on the front. Extra drawbar length can transfer that extra three hundred to the rear.
 

Yes exactly, it helps transfer weight, I understand that. "Transfer" is a better choice of words than "Add" weight.

Ken
 
I believe it will be more till the front
raises above the center of mass. One
reason to keep weights as low as can get
on the scale.
 

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