QuestionQUESTION: I have a '48 Packard that has a set of dry rotted, tires. They are 9.00x15 size and I like the taller profile and narrow tread look. They are labeled as 4 ply nylon...Sears brand..1900 lb rating.
Can I replace these with a similar looking modern blackwall tire? I'm pretty sure these are non-radial tires on the car now, and if the old Packard engineers designed this car's suspension prior to radial tires being common...will radial tires change the "feel" of the ride?
I hesitate to look at the prices from the antique car tire sellers...and am hoping for a more affordable fix to this issue.
Is there a modern cross ref size to match this tire?
Thanks for any help you can offer.
Bill in TX
ANSWER: Bill,
According to Tire Guides, a 1948 Packard came in 3 different types:
A Custom 8 with 7.00-16's inflated to 26 psi front and rear.
A Standard 8 with 6.50-16's inflated to 26 psi front, 28 psi rear with a option of 7.60-15's inflated to 24 psi front and rear.
A Super 8 with 7.00-16's inflated to 26 psi front and rear with an option of 7.60-15's inflated to 24 psi front and rear.
You obvious do not have the standard rims - and perhaps you have the optional rims - and they were 5.5F type rims - meaning they are 5 ½" wide with an F type flange.
Just for reference, modern day tires use a J type flange (0.689" height) and F type flanges (0.875" height) are not used.
A 7.60-15 has a load carrying capacity of 1090# at 24 psi. This type of tire was called an "Extra Low Pressure Tire". The diameter is unspecified in the old books on the subject, but if I remember correctly, these were 90 aspect ratio, so with a 7.6" section width, the section height would be 6.84" making the overall diameter 28.68"
Interestingly, a 9.00-15 is a newer style tire than the 7.60-15 and was called a "low section Height Tire". It had a load carrying capacity of 1900# at 32 psi, and at 24 psi it was rated at 1620#. It fit on a 6JJ type rim. The overal1 diameter was 29.50" with a section width of 8.50", making the aspect ratio 85%.
The problem is that modern tires are much lower in aspect ratio and the result is that they require a wider rim. 75 series tires are gradually disappearing and those that are remaining are kind of designed for pickups, vans, and SUV's.
But a P215/75R15 is 8.50" wide, fits on 5½" to 7" rims, has an overall diameter of 27.68" with a load carrying capacity of 1742# at 35 psi.
A P225/75R15 is 8.78" wide, fits on 6" to 7½" rims, has an overall diameter of 28.31" with a load carrying capacity of 1874# at 35 psi.
I think you can use either of those.
Will the ride change? It is debatable as it is more dependent on the current tire and how it compares - which is not something I am willing to guess at.
---------- FOLLOW-UP ----------
QUESTION: Thanks for the great info....but I also neglected to ask if you thought my old 15" rims, as long as they aren't rusty, would work with tubeless modern tires without an issue?
thanks again, sir..!!
AnswerBill,
I suspect that the 9.00-15's are tubeless - and if they are, then there shouldn't be an issue.
But if they are tubetype, this is going create all kinds of problems. You'll need to get a properly sized tube and a perhaps a flap, and Coker Tire ought to be able to supply those.
