tire pressures for 1957 eldorado ?

[paul57]

hi all , i have just replaced the odd pair of radials on the front of my '57 with a pair of used bias ply , thing is i now find the car wanders quite a bit and the ride seems pretty harsh  .
 i have tried to find some general data on the car but came up blank     could anyone point me to a site with some basic service data ?
what should the correct tire pressures be for my car ? the used ones are a temporary stop gap until i can save the 900 english pounds i need to replace the four tires i have at the moment , gulp !  unless someone has a set going cheap 

thanks in advance . paul ...

[Guidematic]

 What you are experiencing is typical of bias ply tires. Radials ride smoother and do not follow road imperfections.

 Follow the pressure specs on the side of the tire for the correct settings.

 Mike

[35-709]

If you still have radials on the back it will definitely make the car squirrely!  Ran into that years ago when I attempted to convert a '68 Chevy sedan of mine to radials thinking I could do 2 at a time as I saved the money.  I came up with the money for the other two pretty quickly!   

Geoff N.

[Otto Skorzeny]

Do not mix radials and bias plies. it is dangerous. Get a good set of one or the other.

Good bias plies will work fine on a car whose steering and suspension are in order. They'll follow grooves in the road but I've found they work very well for me on the highway. Correct pressure is also crucial.

[paul57]

think you misunderstood me , i had radials on the front and bias on the rears ,funnily enough the car drove great ...  i swapped over to bias on the fronts , i now have bias all round , still need to know what the tire pressures should be all the tire has written on it is do not inflate over 60 psi . i am running with 32psi at the moment but car feels awful to drive . think i will have to experiment with the pressures if no-one can tell me what they should be 

[Otto Skorzeny]

What kind of tires are they?  Are they all the same size and brand with similar amount of wear?

I had Firestone Champion  8.20x15. I kept them inflated  between 28 and 30psi.

[35-709]

We've had a tire pressure discussion here before that dragged on and on, mostly concerning radials which generally require more air pressure than a bias-ply.  That discussion only evidenced the fact that there are lots of opinions on the subject.  The 1956 Shop Manual recommendation on the tires available then on new Cadillacs was 24 pounds front and rear (not considering Commercial Chassis and Limos) which some tire conscious people back then thought was about 2 pounds low because the factory wanted a soft ride.  The 1965 manual calls for 26 pounds front and rear, these pressures are in line with what a bias-ply tire should use.  My recommendation?  26 pounds front and rear. 
RADIAL tires require more pressure and (depending on individual tastes) are usually in the 32 to 35 pound range for normal use.  IF you are carrying that kind of pressure in a bias-ply it will ride harshly, be more prone to following road imperfections, will wear prematurely in the middle, etc.
Geoff N.