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Installed the 700R16AD Auburn Deluxe Radials last year on my 37 120C, they are a tight fit on the front and had to do a slight adjustment on both front fenders, the Radials made a big differance as the car really handles so much better compared to the Bias Ply tires.

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Everyone happy with the Diamondback Auburn radial tires? It seems like the other classic tires are made by Coker. Are the Diamondbacks a better tire than Coker? Being this '40 is destined to operate in some road rally events like Great Race, it might be driven a little harder than most 40 Packard out there. Would you say the DB Auburn 700-16 are a good choice or should I look for something different? Perhaps a light truck tire?
Joe, is your only preference with the 700-16 because it fits the side mount covers better than the 750-16? Or do you find a drivability difference?
(I still haven't decided whether I will be using the dual side mount or smooth fenders. Chances are both sets will be painted.)


thanks,
Mark

You do realize that different springs were used if side mounts were originally fitted, yes?

Mark, take Joe Santana's and Chuck's advice, go with Diamond Back bias-sized radials. You want a runner, but you'll never be happy with the "off" look of a 215/225 SUV radial. They won't look kosher in the fenders' opening. If you want an understated, softly elegant, international look, get Diamond Backs in black wall. Your car will be, after all, a serious road car, not another local car show/cars'n' coffee tart.

Though radials call for high pressure by about 8-10 lbs. over bias ply's 32 psi max cold, radials' sidewalls have more give than bias ply, so probably not much harder on your suspension components, but have yet to read any serious tech study or SAE-worthy reports on this.

It used to be said that radials, or at least belted radials, gave a harsher ride than bias tires. But many people are reporting better ride and handling with bias-look radials on older cars not originally designed for them. I would try to keep tire pressure at or below 30 PSI on 1930s thru mid 1950s cars. It is not necessary nor is it a good idea to run tires on passenger cars at the maximum pressure rating on the sidewall.
On the other hand, Packard recommended tire pressures as low as 22 PSI on late 1930s 120 cars. I run 24 to 26 PSI cold on my '37 120 conv. coupe with Firestone bias tires. That gives good results overall, and so far, tread wear seems to be normal at 3,000 + miles. The tires run only slightly above ambient temperature at sustained speeds around 50 MPH. I don't know whether the bias-look radials are belted or not, but I'd think a belted radial tire would need about 28 PSI cold on a 3600 lb car. Excessively low pressure might cause belt separation issues.

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My 40 did originally have dual side mounts. If I decide to not use them, we'll find out how high it sits without them. Springs aren't too pleasant to change, but can be done later if needed.


thanks,
Mark