Tire pressure

Pulling for first time this year with 13.6 38's instead of my 28's on a wd45. On a hard track what pressure seams to work the best on a hard clay track?

12 inch rim. Half tread. Non cut. 4500 and 5500 class. 3 mph

At those weights, probably not less than 10.

Tire pressure for pulling tires is about as loaded a questing as to what type of women one prefers or who builds the best P/U, you get as many answers as people you ask. In general if you have power and need traction go lower until the center of the tread quits biting and raises up (When you look back at your tracks after unhooking) When your lacking power raise the pressure to loose some grip.  A good start for bias ply tires is 1 PSI per 1000 pounds of tractor weight, then adjust as performance dictates. You want the tires to squat a little but not to buckle severely.

That age old theory of 1 psi per 1,000 pounds of weight works pretty well on a 24.5 or 30.5 x 32 tire.....nothing else.

I have no argument with the 1 psi per 1,000 lbs with the 24.5 or 30.5 x 32 tires......I'm just sayin that ain't the way to go with a 15.5 x 38 tire on a 3500 pound antique tractor. If it works for you great....I'd never advise someone to run that low(3 1/2 psi).

As I first stated: asking a question about tractor pulling will get you more answers than people you ask. I started pulling in the later part of the 60s and have had a winning record in every type of pulling I've ever been involved with. I use that as a baseline to get started with a combination I have no experience with, rarely do I vary far from that.  When I answer questions about what I'm doing pulling and how I win so much, nobody believes me anyway. Lower pressures can't be used if the rim is too wide for the tire.

AC puller I'm just curious as to how you pulled with 38's compared to 28's.I don't know how much you got in your engine to pull 5500 lb cause I've never seen one on 38's pull it. Like I said curious because I'm wanting 38's myself.

Pulled 4 times. 4000 open,5000 open, no rpm limit. Pull my cheater rod. And 4500& 5500 3mph. Have 23degree firestones about half tread. Plain 4-1/8 overbore and headwork. Don't think I did any better than my 28's. But need to play with weights. Little different animal now.

38's will almost always out distance a 28 of the same width if they are equal in wear/brand/sharpness. You're talking about "uncut" tires and that isn't very fair. Your 28's may simply have been sharper than the 38's. You can't compare a 28 Firestone F-151 to a junk Goodyear 38.

How wide of 38'sdo you use?

I run 15.5 x 38 on my 37 wc. I run 10 psi. I pull any where from 3800 to 6000 lb. Class. I have a 400 cube motor running 110 hp. Never out of power but hard to keep front down on good clay tracks. 2300rpms at around 4 mph.