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keiser31

34x4 1/2 NON SKID tire size air pressure?

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I am working on a 1913 Cartercar with 34x4 1/2 NON SKID tires and need to know how much air pressure to put in them and what direction they should read from. Anybody know??

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My buddy has a CarterCar and I believe he keeps 50# air in his tires. You should be able to read them while standing in front of the car.

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That is correct, you should be able to read the tires, standing like the car is getting ready to run over you.....

And they are high pressure tires, as the tire patch that contacts the ground is supposed to be relatively small.

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And remember, the pressure in the tires is equal to the non skid pressure on the ground, per square inch.........................

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Back to the air pressure question - those are clincher tires and they use a lot of air pressure to help hold them on the rim. Too little and they will "creep" and you'll end up pinching valve stems and possibly cutting the tube. I like to run around 60lbs pressure in my T.

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Amen, Terry....the tendency is to think "well, it doesn't need that much pressure", but your comment is correct...one has to get out of the 30 psi modern tire pressure thinking...

The fascinating thing is that, in the period, these tires and tubes failed constantly, and one had to pump up the pressure on the side of the road by hand. That's why the engine driven air pumps were a popular accessory on the early cars........

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All the charts both period and modern that I have seen(and I have most certainly not seen them all) recommend for high pressure tires 15# per inch of cross section. For the 4 1/2 inch tire the pressure would be 4.5 X 15# or about 68#. On my car with 36 X 41/2 I run 70#, On my 35 X 5 I run on 75#. My Model T with 3 inch tires on the front carry 45#. I do believe that the age of the tire should be considered when inflating them, the older the tire a little less pressure may prevent a problem.--Bob

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Wow, that's a great gem of information, 15# per inch of cross section. I'll file that next to the fact that tire size tells you rim size (thus, a 36 x 4.5 has a rim that is 36 - (2x4.5), or 27 inches)

I agree with higher pressures.

There's been a lot of discussion on tire age, but any tire over 10 years old on an antique car, or over 5 years old on a modern car, truck, or trailer, is dangerous.

Going to Hershey this year, towing a trailer on I81, content that all the tires were less than 8 years old on my trailer, I here a "boom" and one tire comes apart. And yes, it was properly inflated, I'd checked pressures before the trip.

Tires are cheap, compared to a loss of control....

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My 34 x 4 1/2 Firestone NON SKID tires are straight side ( Dunlop) not clinchers. The 15# guideline is very good across the board but perhaps low on narrow tires and high for wide ones.

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