Packard Forum Index » Pre-War (1899-1942)

Pressures on sidewalls are typically maximum pressure at maximum load. So far, at about 1200 miles, I'm showing no significant wear, but I've had pressure above 22 PSI cold most of the time. 25 PSI cold at 60 F seems to give good overall results. This car weighs about 3600 lb, and judging by the tire deformation at the ground, weight distribution is fairly equal front and rear. The engine is very heavy, but unlike more modern vehicles, most of the engine sits behind the front axle, rather than over it, and there is almost no front overhang.

I would check out Diamond Back tires, I have them on my 1936 120 and they are radials with the wide whitewalls. I restored a 1937 Buick a few years ago and used them, I have no complaints they ride nice.

Ended up ordering the Goodyear Deluxe 4 inch. white walls. (Kelsey tires had them in stock which is not the norm as I discovered) As soon as I get them on, I'll share pics. Thanks all.

Awesome! I have the Firestone 7.00-16s as well. I've enjoyed them, and they are wearing well after a few thousand miles. I too have found that on modern roads, the car does great at about 28-30 PSI. A friend with SIGNIFICANT old car experience actually recommends running bias ply tires at 40 PSI, but I've been happy with 30 as a middle ground.

Awesome! I have the Firestone 7.00-16s as well. I've enjoyed them, and they are wearing well after a few thousand miles. I too have found that on modern roads, the car does great at about 28-30 PSI. A friend with SIGNIFICANT old car experience actually recommends running bias ply tires at 40 PSI, but I've been happy with 30 as a middle ground.

40 PSI is way too much, unless you have a very heavy car running 6 or 8 ply tires.
It's probably better with an antique car that is driven often to run the tire pressure as low as is safe, and perhaps sacrifice a little gas mileage and tread life to preserve the car from as much road pounding as possible. If your car sits for long periods, airing the tires up to the maximum pressure shown on the sidewall may prevent flat-spotting, but I'd adjust the pressure before driving it. Ideally, we'd all have smooth roads to drive on.

From SL-VOL8NO2:

Came across these from service manual.

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The Gas Ration stickers of WWII had nothing to do with the availability of gas, but had to do with the availability of rubber. Best way to keep people from wearing out their tires was to restrict how much they could drive. Hence the gas rationing.

Given the recommendation of 22 PSI cold for the '37 120 coupe convertible, it appears that 26 PSI cold is about right for the driving I do on the roads I have to use. It gives good results and is consistent with the wartime recommendation. If I carried any significant load, I'd start with a higher cold pressure. Wild swings in temperature around here can affect significantly tire pressure. For instance, it was about 75 F here Saturday, and it's 65 F here at 4:30 AM Sunday morning, and it is predicted to be around 20 F here late Sunday night. I got good results running 23 year old tires at 24 to 26 PSI cold for about 12,000 miles. I drive at 45 to 55 MPH on the open road, and 30 MPH or less on the dirt roads. I use a dial type Milton gauge that appears to be fairly accurate, and it will consistently indicate pressure changes as small as 1/2 psi.