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Tire Pressure for Reproduction Vintage Tires


WHSEWARD

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I have a set of 7.00 x 19 Bedford tires on my 31 Lincoln K. These are NOT the original tires, I believe they were bought new maybe three years ago. The Owner's Manual says 45 psig front and rear but I am a little reluctant to pump them up that high given that I am not sure about the present condition of the tubes. Presently I carry 40 psig front and back, and the car weighs 5500 lbs. I realize that underinflation is at least as dangerous as overinflation here, so my question is, what pressure do you guys carry in your vintage tires, and what would be a lower limit for 7.00 x 19 bias-ply tires on a 5500-lb car?

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  • 4 months later...
I have a set of 7.00 x 19 Bedford tires on my 31 Lincoln K. These are NOT the original tires, I believe they were bought new maybe three years ago. The Owner's Manual says 45 psig front and rear but I am a little reluctant to pump them up that high given that I am not sure about the present condition of the tubes. Presently I carry 40 psig front and back, and the car weighs 5500 lbs. I realize that underinflation is at least as dangerous as overinflation here, so my question is, what pressure do you guys carry in your vintage tires, and what would be a lower limit for 7.00 x 19 bias-ply tires on a 5500-lb car?

When I had 32-35 pounds in the 700x21" tires of my 1926 Packard, I noted that the center of the tread wore out at a fast rate, a sure sign of over inflation. Thereafter I ran at about 27 pounds front and rear and the wear pattern was much more uniform. This was on a Phaeton weighing in at about 4300 pounds. Plus I never drove much more than 35-40 mph.

So the best pressure is probably arrived at by similar experiment, erring on the side that underinflated tires will run hotter. So if you drive at highway speeds, better to wear out tires too soon than risk a blowout.

--Scott

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  • 3 weeks later...

I would recommend running 45-50psi. The condition of the tube has nothing to do with what pressure to run. The load capacity of tire is increased with higher pressures. I'll guarantee if you use an infrared 'laser' thermometer and take your tire's temperatures with both inflation pressures, the tires will be much cooler with the higher pressure.

Letting the tires get hot will destroy them and weaken them more and faster than anything else you can do to them.

I run 45-48psi in both my 600-22' in the series 80 cars, and 45-48psi in the 7.50-17" on my '33 836 Club Sedan. Both cars handle better and the tires run almost 50* cooler when the ambient temps are around 90-95*.

What type of wheels are on the '31 Lincoln K? are they drop center wire wheels? or a flat center rim with snap ring? Or a flat center split rim?

The Drop Center wheels put more stretch on the inner tube where it inflated into the drop center, This is the main place tubes fail.

GLong

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  • 3 weeks later...

If the dry weight of the car is 5500 lbs, then you need to add another 500 lbs (at least) for oil, gas, water and a typical passenger load. Compare this weight to the load rating of the tires at the maximum inflation pressure given by the tire manufacturer and the answer will become obvious.

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