Packard Forum Index » Post-War (1946-54)

Thanks Fred. 42 psi will probably make my martini "shaken not stirred".

The Diamondback people told me to use 42 lbs. This is because they happen to have in stock the exact duplicate of my original tire size tire but in a radial. Had I been alert, I would have gotten a "fatter" radial tire. I think they look better.
The profile is pretty skinny. In other words if you look at it from the back it's a very narrow Tire. So I think that's why they suggested 42lb. Bicycle tires have extremely high pressure because they're so small.

Thanks Fred! I'm pretty good about keeping mine at 42 because tires are a very expensive item and I don't have to buy another one!

I was told by DB to keep their tires - Hankooks I bought for my 115C - at 36 psi. The reason given was to keep the sidewalls from flexing too much which would loosen the white walls.

The main advantage of higher pressures (especially for radials) is to lighten the steering at low speeds. It does work, and inflating radial tyres to say 42psi does not really cause any harm. Regardless of pressures, some radials are harder riding than traditional bias ply tyres so the ride will feel more uncomfortable - especially in a Packard.

I use Diamondback whitewalls (based on Toyo radials) on my 1941 120 Club Coupe. I run these at about 38psi, in deference to the bonded white sidewalls. That also reduces the steering effort at parking speeds, which is a nice benefit. The ride does not feel noticeably worse, maybe because many road surfaces today are better than in the day....

I adjusted my tires pressures for the coming winter and then the weather warmed up again. The ride is terrible even though the difference only is 10%.

I know those antique radials call for 50% more pressure than bias ply, but the extra wear on suspension parts is not worth it as far as I can reason especially given the limited supply of parts thereof.

If you run those pressures in Michigan where the roads are falling apart the car will not hold up. As well the frame itself is being subjected to increased strain and the rivets will start to loosen.