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

Howdy Packard Fans,

Pretty sure new tires are in order soon. I currently have "Coker Classic" 4-Ply WWW L78-15 on my 2272 and spent a little time on the Diamond Back site as they seem to have nothing but satisfied customers. Using their nifty size chart, I get the idea that my current tires are about an inch taller than stock.

I thought I'd call on the collective wisdom here on whether to stick with what would now be a 235-75R15 or return to a 225-etc. Anyone able to double-check my understanding of these tire sizes off the top of their head?

Heck, anyone want to just point me to the right Diamond Backs for my car? I gotta say all the family talk on their website and the chatter about why their tires are the best... well I just ate that right up.

I'm looking forward to being able to track a straight line with this beast of a car.

Michal

The original tire size on your 22nd series Super was 7.60 x 15; an alpha-series "L" is MUCH too wide, I'm surprised that it even fits in the rear fender well.

The generally accepted radial replacement for 7.60 x 15 is 225/75R15, 235's may also give interference with the rear fender clearances.

You seem to suggest your car has poor road manners. Keep in mind that may be the result of a worn and misaligned front suspension and if so, just changing to radial tires won't solve that, though it may mask it to some extent.

I spent many weeks last year researching the tires to put on my 23rd series sedan. Here are the issues:

1. My Packard has the standard 3.9 rear axle ratio and does not have overdrive. The tire outside diameter must by large enough to allow cruising on the freeway without over-revving the engine. A modern low-profile radial is several inches smaller diameter than original and raises the rpm by about 10%.
2. A modern low-profile radial that has the right outside diameter is too wide to fit in the rear fender well. Small diameter tires are the only choice that fit the car.
3. Low fat tires look wrong on a 1950 car.
4. Bias ply tires of the correct dimensions are available, but they cause the car to wander on the freeway. I wanted the improved stability of radials.
5. The tread pattern of a modern tire looks incorrect for 1950 car.

I ended up with Diamondback radials, even though they were the most expensive tires option. They met all my requirements and I am very happy with them. Tires matter a lot so the extra money was well worth it.

I put 235/75R/15's on my '50 Custom . The fit in the trunk well is tight! I had no problems with clearance in any of the fender wells. I got the 3.5 inch wide Diamond Back whitewalls and went with the extra cost raised 'Beauty Ring'. When I got the car it had what I believe was an original factory tire in the trunk which had a 4 inch whitewall.

I agree with Dave (Owen) that mis-alignment problems can cause wandering. I also think very old bias ply tires can contribute to the problem. I had severe wandering problems when I first got the car. I was constantly tensed over the steering wheel as the car followed every imperfection in the road. The car had bias ply tires that I suspect were over 20 years old. The difference I experienced with radials was amazing. I also had my shocks rebuilt as they wouldn't hold fluid for more than a few days.

Note: the original tire for the Custom was a 15 X 8.20

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OEM tire size on Custom 8s was larger than Super Eights or Eights, 8.20 x 15.

Thanks O_D, I think we both included that bit of info at exactly the same time.

Thanks for the guidance everyone. Now we've racked this car several times and the front end looks healthy. I will check on the fluid in the shocks but I'm convinced tires are the next step. Makes sense that my current tires are much too wide; it was a bear getting the passenger rear off & on. Had to darn near deflate it. Looks like I'll be placing an order with Diamond Back soon...

Michal

Another issue may be important. On my Packard the lateral clearance on the rear tires was different from right to left. That could be caused by tolerances related to body mounting on the frame. I had my rear end aligned and the Panhard rod rebuilt, so it was not caused by worn out suspension. If your car has unsymmetrical clearance like mine it deserves checking of the clearance on both sides, not just one side. On my car there was no possible way a 235/75 tire would fit at the rear on both sides.

Fred,

What size tires did you end up with?

-Mike

The tires on my 23rd series Packard are 700R-15 from Diamondback Tires. They replace the dimensions and the appearance of the original 760x15 tires as closely as possible, but they are radials. I am very happy with them even though the cost for 4 tires was near $1100. I have some wear in the front end and the car tracks nicely down the freeway. The original tire OD allows a safe 60-65 mph cruising speed without overdrive.