Tractor pulling and tire pressure
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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=15571
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Topic: Tractor pulling and tire pressure
Posted By: ChuckLuedtkeSEWI
Subject: Tractor pulling and tire pressure
Date Posted: 22 Jul 2010 at 6:13pm
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Pulled last night at the county fair and I got 7th out of 13. Not a bad showing but could have been better. I pulled my 45 diesel again, with one set of rear wheel weights and two suitcase weights stacked on the rear platform got me to the weight of 4500. I have enough weight that I could go up to the next class but that is 6000, and 60 hp, and I think I would get run over in that class. There isn't one in between. Track was clay and very spongy although not overly wet. Eliminator rear tires were really digging down in and for the antique classes which I was in, they kept the front sled wheels down so the sled part wasn't riding on the ground and then lowered it at the 150 mark. Most people died shortly thereafter, as it was so mushy. My question is, is there any general rule of thumb with tire pressure and track conditions? I lowered my tire pressure, but I think I might have went down to much. I think I was down to 7.5 when I pulled. The wife took part of a video and they didn't look to be bulging or torquing too bad, but she was way in front of where it started to struggle. I guess does it get to a point where the air pressure isn't enough to provide for good traction? I wish I would've started doing this years ago. There's alot to learn from this sport, but it sure is fun!!
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Replies:
Posted By: Mark D.
Date Posted: 22 Jul 2010 at 6:38pm
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Really, you want them as low as you can because this will increase the size of your footprint on the ground, therefore also increasing your traction.
That being said... it depends on how much your tractor is being pulled down on and the type of track your pulling on.
Here is how you know you went too low... You actually dont know for sure you were too low until your done with your pull and check the holes you spun out in. As you pull away from the sled check for a hump or "hill" in the middle of the tire track. If they are there, that means that your tires have too low of pressure and giving in the middle. Harder tracks will need more psi to resist the hump and softer tracks will take less. Remember, dont be scared of seeing the sidewalls ripple. Trust the holes at the end cause that is where you need the traction the most and your sidewalls are meant to torque and grab.
FYI - We run 12 psi on 24.5 Firestones on our Superfarm weighing 9300 lbs. and 10 psi on 18.4 Firestones on our Hot Farm weighing 8000 lbs. For a sandy track we go down 2 psi on each. Hope it helps!!
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Miss Behavin - D21 Super Farm
Xcessive Tinkering - 190 XT Hot Farm Puller
Watch on YouTube - http://www.youtube.com/watch?v=J2TX1Af7aoA
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Posted By: Dick L
Date Posted: 22 Jul 2010 at 6:51pm
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I would say that you wouldn't want to go any lower but for the 4500 class you were in the ball park. Hard to get a WD45 to do well in the 4500 class. It can be done but it will be a little heavy in the front. A tuff WD45 gas that I used to pull against in the 4500 pulled with what looked like close to 5 pounds. Tires would buckle real bad but he was always in my face against my Oliver 77. A fellow had a WD45 diesel that looked like it just came out of the factory. He tried every thing he could think of. I don't think he ever made up to third.
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Posted By: alliswd
Date Posted: 22 Jul 2010 at 7:30pm
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Hey Chuck! I was in that pull as well. I had the WD that finished 3rd. I ran 6 psi and had pretty good bite until the left side of the track went away. My biggest problem is trying to see this in the track before I get into it. Anybody have advice on that? This was only my 4th pull, and it is a lot of fun. See you at Ozaukee.
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Posted By: ChuckLuedtkeSEWI
Date Posted: 22 Jul 2010 at 8:05pm
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You do have a beautiful tractor. That track was real mush. It will be interesting to see how I do at Ozaukee. Last year, I was in fourth. I will check the ripple next time. Thanks for the tip Mark.
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Posted By: Larry(OH)
Date Posted: 22 Jul 2010 at 8:52pm
i go for a pound for every 1000# of weight usually works pretty good. I think the larger diameter tire, the more foot print. Take say a 14.9/28 and a 15.5/38 and roll across a spot where it leaves a mark. Next, measure out say 2 ft and see how many bars are on the ground in that 2 ft. My thought is the more bars on the ground, more traction, ALTHOUGH guys will run the smaller tires and use it as a lower gear ratio since they are smaller. I also watch the holes and see if its humped up or dug down and adjust accordingly
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'40 WC puller,'50 WD puller,'50 M puller '65 770 Ollie
*ALLIS EXPRESS contact*
I can explain it to you, BUT I cannot understand it for you!!
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Posted By: HaroldOmaha
Date Posted: 22 Jul 2010 at 10:39pm
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I always pull the next weight class above what weights I have on the tractor. You'd be surprised how many of the bigger tractors you can beat. I was 600 lbs light last week, missed 3 rd place by 1 " and beat 2 JD 60, SM IH, 400 IH, Minny U or UB
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Posted By: JNunn
Date Posted: 23 Jul 2010 at 5:35am
here is a good rule of thumb for tire pressure, when you are loaded down for whatever class you are pulling stand off to the sides of your tractor and look at the footprint...If you have 3 full bars flat on the ground thats about right. I run 5 psi. in my WC 11.4-28 and that works great
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WC, WD, WD45, WD45D, WD45PS, D17, B12, Two-Ten, 185, 710, and 7010
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Posted By: KevinC(MD)
Date Posted: 23 Jul 2010 at 9:22am
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I run 8.25 lbs of air in my WD 45. I pull at 3550 lbs with 13.6 X 28's. This pressure hooks good for me as torque tends to make the tread fold on a tight track. When conditions are wet or when pulling on an un-prepared or sandy/gravelly track, I air down to 6 to 7 lbs.
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Posted By: Boomer
Date Posted: 23 Jul 2010 at 11:05am
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I ran my stock WD45 in the stock pull last year in the 6500 pound class. This was my first pull. It was a blast, was a little nervous because there was a lot of wispering and glances at me and my tractor. Finally, somebody came up and said, "is that stock, sure don't see many of those in this class..." It was very intimidating going against 6 cylinders and bigger frame tractors. Bottom line, I made a decent showing. I am now building a WC unstyled puller...which will take me a few years to get it working, currenlty working on a Speed Patrol. Wife said to fix everything on the Speed Patrol, and get it painted up!
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Posted By: BrianC,Ont
Date Posted: 23 Jul 2010 at 11:24am
We found that 10 pounds worked better in the 16.9x28s on our D17. We used to run 5-8 psi and it always spun out. We talked to a guy at the pulls one day and he said that the pressure was to low and the tread was cupping in the middle. After airing up we got a lot more 2nd and 3rd, and finally won one. Now we are trying a set of 13.6x38 on it to see what it does.
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35WC on steel, B with belly mower, D17 puller, D15 Series II puller, D15 Series II with loader, 608 Lawn Tractor
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