ya know, we used to drive at all kinds of speeds and such on bias ply tires. They'd last 20-40K miles if you kept the inflation pressures high enough (more toward 30psi than 24psi), usually lasting the longest on Chrysler products, by observations. Many bias ply tires traversed the great American Southwest at speeds of 90mph in the heat of summer with few problems. BUT the difference was in the quality of the tires, even the less expensive ones, AND the general knowledge of the service station people of what those pressures needed to be. By the middle '80s, it seemed the D-metric bias ply tires were NOT of the same quality of construction and materials as what the mainstream major brand bias ply tires were 20 years prior, to me. If you wanted better tires, equivalent to the major brand bias ply tires of the '60s, you got the newer belted-bias ply tires. Later? Radials.
Bias-belted were a hybrid of sorts, which worked better. Radials were still too expensive for the general public . . . until fuel economy/emissions concerns made them more popular and tire manufacturers found ways to make them lighter and less expensive.
The last non-P-metric radial I bought had much thicker sidewalls than what replaced it. When we had a Federal Excise Tax on tires (10 cents/pound) the normal 8.55x14 or H78x14 tire had a sales tax of $2.80-$3.00 tire (28-30 pounds/tire). Check the tire weights in TireRack specs sheets and you'll see there have been about 5 pounds of weight that's not there any more in similar-size tires. That's a lot of rubber! Especially in the sidewalls. I've got some of the old BFG Silvertown Belted H78-14 whitewalls that were on my '66 Newport (1972 production) that graphically indicate how thick the older sidewalls were. BTAIM
We learned about 15 years ago that BFG would not warranty any tire over 6 years old, even if it had spent that time in one of their warehouses. In the middle '70s, Exxon wanted all of the tires on their company vehicles replaced at 30K miles, as I understand it. But then back then, many tires were getting worn out by that time. One of their safety regulations, it seems.
The issue I might have with the radial-look tires is just how wide the radial belt might be on those "narrow-tread width" tires? Yet they still also have the earlier tread designs that might not be as good as the later ones, considering wet weather traction and such. For me, "the jury's still out" on them, unless they are the wider-tread performance tires. Personally, I like to maintain "the correct look" of the car and match modern tires to that, when possible, whether in the correct whitesidewall width or physical dimensions.
Enjoy as the "car driving season" progresses!
CBODY67
