is shorter hitch better?
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Topic: is shorter hitch better?
Posted By: allis6080
Subject: is shorter hitch better?
Date Posted: 04 Sep 2014 at 7:19am
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I am pulling a d17 and I can't seem to get the front end off the ground or even light when pulling. Got all my weight on the rear ( pie weights) I am thinking of building a adjustable hitch. And am wondering if I should shorten the draw bar too. I am pulling on a tacky track in the 5000 lb class ------------- 6060 s\n 5016 1947 JD B |
Replies:
Posted By: thendrix
Date Posted: 04 Sep 2014 at 8:53am
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A shorter hitch would make a smaller lever so if you're trying to get the front end of the ground, no a longer hitch would do more to achieve this. This is a geometric thought. Someone with pulling experience may have a different answer ------------- "Farming is a business that makes a Las Vegas craps table look like a regular paycheck" Ronald Reagan |
Posted By: DaSquatch
Date Posted: 04 Sep 2014 at 9:07am
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You've just asked one of the questions that makes tractor pulling a sport, not just an engine building competition! Here's how I see it, with the caveat that I have no experience in anything except stock pulling with speed limits, where traction trumps momentum. And, others will disagree, so take it for what it's worth!
1- the sled "knows" how far it can be pulled with the hook at a given height, with a given amount of forward pressure. Nothing else matters to the sled.
2- The sled will pull further, for a given amount of forward pressure, with the hook at the highest point. (there is a limit, but it would be much higher than any legal hitch height).
3- The recipe for greatest downward pressure on the tires, and thus best traction, is with the hitch as high and as far back as possible (legal) that it can be, with the amount of front weight needed to keep the front wheels just barely on the ground at the end of the pull.
So always run the hitch way back and high, load the front and go, right? Well, no. Remember point 2? The farther back and high the hitch, the more the hitch will drop when loaded. This is a huge variable. Tires, tire pressure, track conditions, the lenght of the chain on the sled, and more will affect how much height will be lost. And how much more difficult the sled will be to pull with a lowered hitch is variable by sled and track, as well.
Finding the correct balance for YOUR tractor on any given day is the trick. If, as you say, you cannot even begin to lighten your front end at the end of a pull, and cannot move more weight rearward, I would try a longer hitch, and keep it as high as legal.
Power matters too. Traction, by definition, robs power. And, more downward pressure must also, though I know of no way to measure it. Bearing drag and axle deflection must make it harder to turn, I think. But the point is, if you're always spinning at the end of the pull, you can afford to lose more power to downward force. If you're stalling the engine without spinning, will it pull farther with less downward force?
If it was easy, it wouldn't be any fun!
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Posted By: WF owner
Date Posted: 04 Sep 2014 at 9:09am
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Theoretically, the closer you hitch to something, the easier it pulls. That's why everyone wants a short drawbar. Getting the tractor balanced is the most important part of tractor pulling. Too little front end weight means the front end comes up and you lose weight transfer. Too much front end weight and the tractor spins because of a lack of weight on the drive wheels. My opinion is that the drawbar setup is the most important part of successfully pulling a stock tractor (Maybe that's why I haven't had a very good summer!) There is no right or wrong. I pulled on a stone dust with no front weights (WD45 in the 3500 and 4500 lb. classes). I couldn't come close to getting the front end light I dropped the air pressure in the tires (16.9x28) and pulled on 2 clay tracks. With 650 lbs. on the front (in the 4500), it got high enough that it scared me and I stopped. There are so many variables. How much air in your tires? I am running about 8 lbs. (I have gone as low as 5.5) and they seem to bite good. If your tires aren't getting a bite, you will never get the front end light. Usually, a shorter drawbar means less weight transfer, which equals a heavier front end. It's all leverage. Unless you can get more traction to lighten up the front end, I would probably try a slightly longer drawbar, to try to get the front end light. |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 9:17am
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My thought was to lengthrn it also but everyone says to shorten it as was said easier to pull not transfer weight were I need it I'm not losing power by no means even 2nd ge My other thought was to have a hitch that didn't use snap coupler bell.to move hitch point more toward rear but not sure if cast housing could handle weight load. ------------- 6060 s\n 5016 1947 JD B |
Posted By: WF owner
Date Posted: 04 Sep 2014 at 9:56am
| What are you running for tires and how much air? Is there any calcium chloride in your tires (front or rear)? |
Posted By: cms
Date Posted: 04 Sep 2014 at 10:23am
| The snap couple is working like it was designed, to keep the front wheel down. We had a wc that we moved the hitch and hook it like a snap couple hitch and it keep front down. It work good for first gear but we were running higher speed so we moved the hitch back. |
Posted By: bsallis180
Date Posted: 04 Sep 2014 at 10:23am
| In my mind the shorter the hitch the better. For one there are normally rules for a hitch minnumim from axel to rear, never a maximum. For example: you grab a broom in the middle and try to pick up the end you sweep with vs. pick up very end of the broom " oppiset the Brussel" and pick up. Much harder if I have explained that right. Our rules and 15" from center of axel back |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 10:45am
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Cms do you have pics. Of your hitch? ------------- 6060 s\n 5016 1947 JD B |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 11:01am
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Wfowner 16.9 28 Goodyear's 40% tread no fluid in any ------------- 6060 s\n 5016 1947 JD B |
Posted By: cms
Date Posted: 04 Sep 2014 at 11:01am
| I can get some. I don't know how to add pictures to web site but can email or text if you like. Or if some one can help me add pictures. |
Posted By: thendrix
Date Posted: 04 Sep 2014 at 11:45am
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Fluid in the rears would definitely help with traction. That's the reason for it ------------- "Farming is a business that makes a Las Vegas craps table look like a regular paycheck" Ronald Reagan |
Posted By: XT in pa
Date Posted: 04 Sep 2014 at 11:51am
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Good years might be an issue ! My 17 that I farm with has a short hitch just used the 4 3/4 bolts under rock shaft housing. I pull it from 4500 up to 7500 and 4500 is the only class I don't have to put weight up front. I have power steering also. My tractor pulls pretty good for all that it is. ------------- 190XT,D17and 7045 |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 11:53am
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That's why I have pie weights on too ------------- 6060 s\n 5016 1947 JD B |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 12:05pm
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Xt can you send me pics of your hitch? ------------- 6060 s\n 5016 1947 JD B |
Posted By: WF owner
Date Posted: 04 Sep 2014 at 4:25pm
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My experience with fluid in the back tires when pulling was that it caused the tractor to "chatter". The reason people use it is cheap weight. I know no one who runs competitively that uses fluid in the rear tires. I, too, run Goodyears. I have the old 45 degree Traction Sure Grips. How much air are you running? Have someone watch your tires next time you pull, to see if you are getting any sidewall flex. I was amazed at the difference when I dropped the air pressure. For starters, I would try 8 psi. I know they have been around since I was pulling in the 70's, but I have a contraption (for lack of a better word) that consists of two clip on chucks, with some old air line connected to a Tee. I have a tire valve coming out of the Tee. I clip the chuck on both rear tires at the same time and add or remove air from both tires at the same time by using the valve at the tee. It makes sure I have equal pressure in the tires. For the $10 in parts and some old air line, it works great. |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 5:18pm
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I am running 6lbs in the rear.I know they were rippeling while I was pulling. ------------- 6060 s\n 5016 1947 JD B |
Posted By: 2wise4agm
Date Posted: 04 Sep 2014 at 5:23pm
| Tires and tire pressure!!! More important than HP on a farm stock puller with a speed limit IMO! I had some tires with REALLY hard sidewalls and consistantly got my tail kicked for over a year. Same situation as you; Couldn't even think about getting the front end light on any track! Switched to different rubber and started playing with my pressure and I'm always in the top 2 or 3 now. No other changes. |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 5:46pm
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I under stand that I am getting side wall flex. I have been pulling for quite a few years I've only been pulling this d17 for 3 years now. Just inquiring about a hitch ------------- 6060 s\n 5016 1947 JD B |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 5:51pm
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After reading how I typed that I just want to say I appreciate everyone's input on this subject. ------------- 6060 s\n 5016 1947 JD B |
Posted By: WF owner
Date Posted: 04 Sep 2014 at 6:15pm
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I've been pulling off and on since 1972. I think I did better then than I do now! Good luck and sorry about rambling on! |
Posted By: DrAllis
Date Posted: 04 Sep 2014 at 6:35pm
| Sounds like your not doing so well with what you've got set-up now, so take notes here and pretty much ignore those who have never pulled. You want your "hitch point" as short as allowed by Rules AND as high as allowed by Rules. These numbers are usually 20 inches high maximum and 18 inches short minimum from the center of the rear wheels. This is I'm sure MUCH shorter than you are now. The hitch point is defined as the point the sled hook pulls against. Using a floppy twisted clevis is stupid. Bolt it solid with lots of flat washers so it can't sag. Better yet, have a welded pulling eye or a 1 inch thick plate with at least a 3 inch hole burned in it. Maintain that height under load at all costs, so bolt things solid. Tire pressure as low as you're running isn't in my play book. I'd be probably at 10 psi to start. The firmer the track, the higher the air pressure (up to a point). I'd never go more than 12 psi on your tires. Too soft just sees to it your drawbar sinks lower and easier under load. A D-17 NF on a good biting track at 5,000 lbs weight should be able to lift the front wheels off the ground. I'd sure not pull one with a wide front end. Also, any good tuned D-17 should always be able to run 2nd gear low side in most conditions or the high side of 1st gear minimum. If you are running slower, you need to shift up. I get the feeling your drawbar is at 18 inches high and 26 or more inches long. You won't win much like that. |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 6:51pm
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Dr. you nailed my set up. I have a good machined hitch point 1" thick 3" hole exetera. The point you made about tire pressure to low is a very good point. My hole point was about hitch length always more than one way to look at things there are theory's and proven ways I'm just trying to go with what is the best way. ------------- 6060 s\n 5016 1947 JD B |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 6:54pm
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I do have a narrow front on this tractor and is well tuned also. ------------- 6060 s\n 5016 1947 JD B |
Posted By: DrAllis
Date Posted: 04 Sep 2014 at 7:00pm
| Let's just say, you somehow make a great pull and fall into the rear wheel spin-out holes of the guy in first place and spin yours out. He still wins. His "hitch-point" was 18 inches back from the center of the rear wheels and yours was longer than that. |
Posted By: allis6080
Date Posted: 04 Sep 2014 at 7:11pm
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Very good point Dr.! Great way to explain it also! ------------- 6060 s\n 5016 1947 JD B |
Posted By: Lonn
Date Posted: 09 Sep 2014 at 11:44am
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Too low air pressure causes the center of your tire face to buckle up and that puts less rubber on the track. Depends on tire if it's a soft tire and type of track. Look after you pull while they unhook you to see if your tire foot print has a bit of a hill in the center. If it does you are buckling too much. Another thing with a 17 in a true farm stock class is that if your front is getting too light you need to drop your throttle down quickly (not too low or you will stall, experience will find that sweet spot) and before the front touches the ground on the way down give the throttle a crack at wide open and as the front end goes up throttle down again and repeat until it just doesn't work anymore. I call it leap frogging down the track and it'll gain you lots of ground and most other stock tractors do not have the torque and governor to do this. Record the weight you used and where you used it, the tire pressure and type of track (dirt, clay gravel) and if it is wet or dry. Record if you were light or heavy in the front. So next time on that track you can make adjustments. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: studer automotive
Date Posted: 09 Sep 2014 at 8:50pm
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Listen to the experienced pullers. Why do you think there is a drawbar height limit& a limit how far forward the drawbar can be..... ------------- a-c 185-d y/r cab turbo soon 99 f-250 7.3 4x4 86 mustang5.0 owned since 8/93 |
Posted By: Big Orange
Date Posted: 09 Sep 2014 at 10:26pm
| The distance from the hitch point to the drawbar support is very important, as well as the angle of the drawbar, front to rear. It's all about leverage. Also the front of the tractor needs to be as low as possible. GOOD LUCK |
Posted By: Charlie175
Date Posted: 10 Sep 2014 at 5:51am
Yes!  ------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Big Orange wrote:Posted By: DrAllis
Date Posted: 10 Sep 2014 at 6:51am
| Not really and no. It's all about the actual hitch point/pull point. The drawbar support located close to the pulling point is a good idea, but in the end has no extra (or less) effect on downward pull. The only time it does, is when the drawbar beam is so weak in design that the flexing of it lowers the hitch point. The angle of the drawbar pulling beam also has zero effect on anything as long as it is bolted solid and cannot move up or down under direct pull. This is an old wives tale. Occasionally you'll see someone who has an adjustable 3point hitch top link located in a vertical fashion going directly up from the drawbar to a high place under the seat to control the height of the drawbar beam. All they are dong is seeing an immediate tractor tip-over if the drawbar lets go at the wrong place down below. There is no pull advantage. The drawbar when bolted SOLID is an integral part of the chassis and the angle it is at means nothing.......as long as it's bolted solid with zero movement. And there will be those who will argue this until he77 freezes over. |
Posted By: NEVER green
Date Posted: 10 Sep 2014 at 8:08am
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MY view is, the shorter the hitch the closer the axle is to the front of the sled. This creates a steeper angle on the chain thus taking weight off front of sled and adding it to hitch. ------------- 2-8050 1-7080 6080 D-19 modelE & A 7040 R50 |
Posted By: Charlie175
Date Posted: 10 Sep 2014 at 8:43am
Eh? The math is the same. The chain length and height do not change, so the angle is the same regardless of the hitch length. The applied down force does change in relation to the balance point of the tractor. ------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Posted By: Charlie175
Date Posted: 10 Sep 2014 at 8:47am
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Maybe this shows it http://smg.photobucket.com/user/RangerCharlie/media/angle_zps70c5a14f.jpg.html" rel="nofollow">  ------------- Charlie '48 B, '51 CA, '56 WD45 '61 D17, '63 D12, '65 D10 , '68 One-Ninety XTD |
Posted By: missicbc
Date Posted: 15 Sep 2014 at 5:20am
| This is a geometric thought. Someone with http://www.fut15coins.com/" rel="nofollow - Fut 15 Coins pulling experience may have a different answer |