New tires vs old tires

PretendFarmer

Well-known Member
I have 12.4-38 rear tires on my H. These tires have to be at least 25 years old as there is a lot of dry rot and almost no tread left. Rubber is very hard.
Just this morning I was trying to reseat the bead on one of them because it loosened up during tractor pulling. I used bead sealer. When I aired it up to 35psi it blew off the rim. Upon examining the bead I noticed a slice in the bead. This is probably how it popped off the rim. Looked to be existing damage.
So now a fellow puller has offered me a nearly new set of tires. I believe they are 11.2-38. My thought is they should mount on my rims fine.
Do they measure tires different now than 25 years ago? He says by looking at them they appear to be the same size. Does anyone think going from 12.4-38 to 11.2-38 will make a negative difference in pulling? Going from a tire with almost no tread to ones with great tread might help as most tracks around here aren't super hard.
 
I know it is pricey, but if I were pulling at least somewhat
regularly I would use new tires. They take a lot of torque
hooked to the sled.
 


Tires I'm getting are essentially new. I'm kind of surprised the old ones held as long as they did. My tractor has a low gear option and when it would hook up good in heavy classes those things would wrinkle something serious.
 
the old size number for the 12.4x38 is 11x38 and the old number for the 11.2x38 is 10x38.You were luck you didn't get hurt 35 lbs is a lot of pressure for that tire. When they mounted my 15.5x38 the tire dealer would not put over 20 lbs to seat tires after seated they said to bring them down to pressure I was useing .
 
They did change the sizing system, but your old 12.4's and the new 11.2's use the same newer system.

Those new unworn tires probably do look about the same size as the old bald ones. That's because they're not worn out. New 12.4's would be a bit bigger than new 11.2's.

Frankly if someone offered me a smoking deal on an "almost right" set of good tires and I needed them... I wouldn't hesitate.

IMHO, try them and see how they work. Worst case you can easily sell them to someone with an H that needs rear tires and doesn't care about pulling, and possibly even make a little money.
 
(quoted from post at 05:22:42 08/26/14)
I will do that. Thanks. I thought 35 psi was the pressure to seat the bead. 20 is adequate?

Consult with the owners manual. 12 to 15 psi would be about right.

Also, if you stand the new 11.2 up beside the old 12.4, you will find the 11.2 to be much smaller. I would not want anything less than the 12.4 on an H.
 

I'm having the firestone shop mount them.
Side by side the 11.2's don't look much smaller if any at all just a bit skinnier. I'll try them out anyways.
 
If your old tires are only 25 years old they are using the "new" measurement system. The "new" system has been around about 40 years (or more).
 

The 11.2's are smaller and your speed will be affected. Also you will have less width for traction. The tire profile is different. I always pull better with an old road worn tire. I run a psi equal to the class I am pulling in. In the 6000 lb class I run 6 psi, in an 8000 lb class I run 8 psi. This allows the tire to crush out to it's widest when it is under a load.
 
I wouldn't think youd want to run any higher than 7lbs in your tires,maybe even 6lbs.its slow going antique stoneboat pulling,medium grade tracks..
 

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