Good year Power Streak II

Brakes, Suspension, Rims and Tires

  1. jbooth35

    jbooth35 Member

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    Are these old wheel/tires worth putting on the shelf and keeping? I’m getting ready to get new wheels and tires and one option would be to just put new rubber on these 14s. I figured there may be some collector value as these seem to pop up for sale occasionally. Anyhow I have 5 of these H78-14 with the spare and just figured I’d be getting 5 new wheels/tires in a 15 to 17 inch size for regular use. Do folks actually drive on these old tires just for shows?

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  2. Davea Lux

    Davea Lux Old Man with a Hat FCBO Gold Member

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    They have an original appearing style white wall and Goodyear Tires did appear on some Mopars. If they have good tread and the casings are free from cracks, they probably are a display tire for a car show. I probably would not recommend trying to drive the car with those tires as they are very old. Can't tell from the photo is these were belted or not. The early Polyglass tires were famous for throwing chunks even when new. Upside H-78-14 tires are mostly not being reproduced, so you have a tire size that was probably original to the car if that was how it came from the factory. The biggest modern radials that are readily available at your local tire store are going to be P215-R14, which is small for a C-Body and you will get a lot of wheel flex which tends to throw hub caps on the factory 14 inch wheels.

    Dave
     
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  3. jbooth35

    jbooth35 Member

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    image.jpg Thanks Dave. I guess I’ll just put these on the shelf for now.
     
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  4. CBODY67

    CBODY67 Senior Member

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    As good as those tires might have been when new, they were not OEM-level tires. Chrysler and Goodyear obviously had a strong relationship for decades, just as GM had with UniRoyal and Ford with Firestone.

    Due to the age of the tires (verifiable by the codes cast into the inner sidewall, they are probably well past their useable life. They would probably be good to use to roll cars around on, but NOT for street driving. It used to be that as long as the tire would reliably hold air, with some amount of tread on it, it was still "good". Or good enough to put on farm grain "drills", etc.

    Of course, they would make good display items and reference items to compare to modern tires which might replace them.

    14" wheel flex is real, evidenced by the two nubs on the outer edge of the 14" wheels, either side of the falve stem. With corresponding tangs on the wheel covers . . . which did NOT prevent the wheel covers from rotating on the wheel on our '66 Newport. Luckily, the valve stems didn't break, just flexed. I ended up removing the valve stem extensions and installing the wheel cover with the valve stem hole away from the valve stem itself. No similar problems with the 14x6.5" station wagon wheels I put on the '67 Newport or the 15x6" wheels on the '72 Newport Royal.

    Enjoy!
    CBODY67
     
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  5. jbooth35

    jbooth35 Member

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    I may as well use this thread to figure out the new tire/wheel size needed. I've scoured the wheel threads and 65 polara/monaco threads, but haven't found any exact specs that will fit for certain on the car. I've seen plenty of pictures of 15x7 wheels with 235-70 tires but the offset spec is what I need before ordering tomorrow.

    I believe a 15x7 with 3.75 backspace (-6 offset) will work, but was hoping for confirmation or suggestions. the -6 offset seems pretty standard for a 15x7 wheel, but would a 4 or 4.25, 4.5 backspace be a better fit? Anyhow I'm looking at all 4 tires the same.

    I do see that a 235-70-15 puts me at 1" height more than stock which should mean that 65 mph is actually 67.4. I also have 1" higher than stock rear springs.

    Thanks for the input everyone.
     
  6. CBODY67

    CBODY67 Senior Member

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    I've got P245/70-14 Advantage T/As on the 14x6.5" "station wagon wheels" on my '67 Newport. They physically match the diameter of the prior H76-14s we had on it before that. Whetner in the Golden Sonic brand or the BRG Silvertown belteds. The car originally had Goodyear Custom Power Cushion 8.55x14s on it, which is what the spare is.

    www.miata.net had a tire size comparator section on it. Old vs. new, percent of odometer error and such. There are some other websites that have similar apps, too.

    As for revs/mile, from the AMA Specs which Chrysler filed with the Automobile Manufacturers Assn., for the '69 and '70 C-body Plymouths and Chryslers . . . 8.25x15 revs/mile = 752, 8.55x15 = 735, 8.85x15 = 721, and 9.15x15 = 719. As a point of reference, the P225/70R-15 BFG Radial T/As are right at 760 revs/mile. 8.25 = "G", 8.55 = "H", 8.85 = "J", 9.15 = "L". My prior calculations indicate that an 8.55-14 and 8.25-15 are the same diameter. All of the above are for the "normal" aspect ratios or the later '78" aspect ratio. Just as the later P235/70x15 is the same diameter as the P225/78x15 tire. In the '78-aspect ratio tires, use the "mm" conversion factor to go from the numeric size (8.55-15) to the metric equivalent width (217.17mm), which would be the P225/75R-15 size or P215/75R-15 size. In this case, the revs/mile spec should be what's used, I believe. As the P225.75R-15 size seems to be going the way of the old H78-14 size, i.e., (not around much any more), then some allowances might need to be made. Either a bit more inflation pressure of "the next size up".

    I've seen some 15x7 4.0" Bksp VN501s on a B-body and they look like they work on the rear, just glancing at them. The spec to find is the 15x7 Magnum GT or 15x7 "cop car" wheels' backspacing. On the front, you have the outer tie rod ends to worry about how close they are to the tire's inner sidewall, especially with 14" tires. On the rear, on the inside it's the outer edge of the leaf spring and on the outside, it's the inner quarter panel wheel house/fender skirts.

    Just some thoughts,
    CBODY67
     
  7. FK3 Sport Fury

    FK3 Sport Fury Hoser in a toque

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    I use old bias ply tires like that for winter storage to keep the good tires from getting flat spots and will use them for the odd trip I'll take around town to keep things lubed and moving freely.I wouldn't take them up to highway speeds or go very far with them.
    I also like the vintage vibe they give when they're on the car.
     
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