Desoto tires

[John32369]

I have a 46 Desoto sedan that had been sitting in a barn for 30 years before I got it. The Tires are dry rotten and I need to replace them. It has H78-15 sized tires  on it.  I see the modern size of these is P225/75R15 or P235/70R15.  What is the difference and which is better?  

[Plymouthy Adams]

225/75 and 235/70 are basically two ways of expressing the same height of the tire albeit at different cross section/width....once you establish your base diamter of the tire for proper fit and look... you go up one side in width you go down one size in ratio to basically stay the same diameter..

[John32369]

I'm assuming they would have tubes in them correct?

[BobT-47P15]

I would imagine that when new, that DeSoto had the old tire sizing such as  225x15......the old bias ply

skinny tire size.   I have run 215x 15s on my 47 Plymouth.     ..     Nowadays, if you want to use modern

radials instead of bias ply (they offer better drivability, don't follow the ruts in the road, etc) .  There are numerous

tire sizes and styles in both non radial and radial, offered by several vendors such as Coker Tire, Universal Tire, Diamond Back and others.  

If you want a wide whitewall,  you can find various widths of white also.  It is my opinion, based on certain observations, that you need to buy a tire that is just a bit more expensive than the cheapest WWW offered.  About a year ago, I purchased

from Coker Tire a set of four "B F Goodrich Silvertown"  radials, size P215/75R15, with a whitewall width of 2 1/2 inches.....

at a cost of around $250 each (plus tax and shipping if you have them sent to you).  I saved shipping and hauled them

home myself from the Carlisle, PA swap meet.  These tires are a wider tread design, like modern cars.  They can be

used tubeless, but I use tubes because they are mounted on old Chrysler wire wheels.  

However......for my spare tire, I bought one of the new "bias ply look" radials...........so it would fit into my spare tire

well as it is more narrow tread like the old model tires.   The size I'm using is listed as 670R15 ---- compares to the

670-15 bias plys.   The whitewall width on this tire, made by American Classic,  is 2 3/4 inches.  It is maybe an inch

wider tread than my old bias tire that was made in 1961 (yeah, my spare was ancient---an old Goodyear Double

Eagle purchased back in the 1970s).    Cost of this new style radial was around $250 before tax.......it was purchased

at Carlisle last fall from Universal Tire Co. and brought home by a friend.  I use a tube in it as well.    

I don't know if this kind of long winded item will help as it just reflects my preferences.  

 

The first picture shows my ancient spare on the wheel compated to the new narrow radial just purchased.

Very close in both tread width and height to the oldie......the white wall is a little wider.  The second pic is old/new comparison, third is the B F Goodrich brand tires on my car.

 

      New style radial tire upper......old 1961 model tire lower.  Close in tread width.

Edited June 2, 2017 by BobT-47P15

[Bob Riding]

On 6/1/2017 at 1:17 PM, BobT-47P15 said:

I would imagine that when new, that DeSoto had the old tire sizing such as  225x15......the old bias ply

skinny tire size.   I have run 215x 15s on my 47 Plymouth.     ..     Nowadays, if you want to use modern

radials instead of bias ply (they offer better drivability, don't follow the ruts in the road, etc) .  There are numerous

tire sizes and styles in both non radial and radial, offered by several vendors such as Coker Tire, Universal Tire, Diamond Back and others.  

If you want a wide whitewall,  you can find various widths of white also.  It is my opinion, based on certain observations, that you need to buy a tire that is just a bit more expensive than the cheapest WWW offered.  About a year ago, I purchased

from Coker Tire a set of four "B F Goodrich Silvertown"  radials, size P215/75R15, with a whitewall width of 2 1/2 inches.....

at a cost of around $250 each (plus tax and shipping if you have them sent to you).  I saved shipping and hauled them

home myself from the Carlisle, PA swap meet.  These tires are a wider tread design, like modern cars.  They can be

used tubeless, but I use tubes because they are mounted on old Chrysler wire wheels.  

However......for my spare tire, I bought one of the new "bias ply look" radials...........so it would fit into my spare tire

well as it is more narrow tread like the old model tires.   The size I'm using is listed as 670R15 ---- compares to the

670-15 bias plys.   The whitewall width on this tire, made by American Classic,  is 2 3/4 inches.  It is maybe an inch

wider tread than my old bias tire that was made in 1961 (yeah, my spare was ancient---an old Goodyear Double

Eagle purchased back in the 1970s).    Cost of this new style radial was around $250 before tax.......it was purchased

at Carlisle last fall from Universal Tire Co. and brought home by a friend.  I use a tube in it as well.    

I don't know if this kind of long winded item will help as it just reflects my preferences.  

 

The first picture shows my ancient spare on the wheel compated to the new narrow radial just purchased.

Very close in both tread width and height to the oldie......the white wall is a little wider.  The second pic is old/new comparison, third is the B F Goodrich brand tires on my car.

 

      New style radial tire upper......old 1961 model tire lower.  Close in tread width.

Great info - Not long-winded, good winded! I have the Coker Classics 6.00-6s. Bought used but never mounted, for $200 per.

The ww is 2 3/4" and the tread is 5"across.I wonder if it would corner better, maybe lean less with a wider tire? 

 

[BobT-47P15]

Hi Bob.  Here is a thought on perhaps how to try some wider radial tires on one of your vehicles before

investing the bigger money in vintage look wide white radials.  I presume your vehicle has 16 inch tires.

Do you have a late model car that also uses 16 inch tires that might fit on your oldie?  Are you going to

replace them with new tires any time soon?  Do you have an extra set of vintage 16 inch rims to mount

them on.  Or find some USED late model radials to put on old rims for test purposes.  Just a thought.......

I kept the 16 inch tires that were worn but not totally used up from my 2013 Dodge Caravan........and

may mount them on the original 16" wheels from the convert just for fun......painting my rims yellow to

match the car and then using the late model black sidewalls with original hub caps for a different look.

As I said............just a thought.     ..

Edited June 3, 2017 by BobT-47P15

[Bob Riding]

I hadn't thought of that...I think I may have some on a parts car-great suggestion!

[rcb]

Regarding effect on lean, I've found on other vehicles it helped some. Using a high load tire helps as well. Of course you have more traction with a narrower tire.