The Official TIRE SIZE THREAD

 

1973 Gran Torino Sport

16 x 7 Ford Crown Vic police steel rim

Goodyear Eagle 225/60/16 radial*

 

*Note- these tires are both too short of a side wall for my liking.

What are the largest tires that will fit our cars out back, when plus-sizing?

I am looking for a 17" tire, but I want something in the range of a 275 series, around a 30" tall. I want to say there is a 275/60r17 on General's site in the grabber UHP series.

I also saw a 255 tire...but at 27" tall, too short for my taste for back tires.

 

I looked at the typical Mustang type 275/40r17, and forget it, I don't want a donut 25" tall tire. I need some sidewall!

 

 

On that car, i would think the tire size should be around a 225/75 or a 235/75 series size tire.

205 and 215 seem entirely too small for the weight of a Wagon, let alone a 4 door or coupe.

You can still run a bit of a tire on a 14" rim, but the sizes are getting increasingly a pain to find.

I forget, but I would image a 225/60 will fit a 7" wide rim?

Or, at the wheels you have a 14x6?

 

From what I gather, you should stick at least a 225/75/R14 tire on your car.

If I was you, I would upgrade to Ford 15"x7" steel wheels, and go to a 235/75/r15 for a larger stock Torino sized tire that a lot of cars had. Every Elite I have owned were factory 15" wheel cars.

The Gran Torino Sports I have owned have all had 14x8 wheels, I have some 14x8 factory steel rims That I have held onto a few as spares with original bias Goodyear or Firestone tires because I like the look of the old tires.

 

Remember, you have a wagon. That car has some serious heft to it.

If you want to stick a whitewall on there, stick with a good brand...you are going to spend twice for white walls versus a blackwall or raised white letter, judging by the Coker Classic line of wide white walls, but BFG would be another good choice.

I figure you will have $900 for 4 tires, $1,125 for 4 plus the spare, and that's not including the shipping.

I would tell you to check out a local you-pull it for a 80's crown vic, those wheels should still accept the Torino center cap if the rim's center has the bumps for retaining the cap.

 

If you wanted to get fancy, I have a set of the Elite specific slotted stainless steel hubcaps, but you would need a 15" rim.

  

 

This bit came off here:

http://www.imperialclub.com/Repair/Wheels/size.htm 

 

The first number is the width of the tire in millimeters, measured from sidewall to sidewall. To convert to inches, divide by 25.4 In the example above, the width is 185mm or 7.28".

The second number is the aspect ratio. This is a ratio of sidewall height (also referred to as "section height" in the diagram) to width. In the example above, the tire is 7.28" wide, multiply that by the aspect ratio to find the height of one sidewall. In this case, 185x0.60=111mm or 7.28"x0.60=4.36".

The last number is the diameter of the wheel in inches.

To figure the outside diameter of a tire, take the sidewall height and multiply by 2, (remember that the diameter is made up of 2 sidewalls, the one above the wheel, and the one below the wheel) and add the diameter of the wheel to get your answer.

Example...185/60R14 85H or 185/60HR14

185mm x .60=111mm x 2=222mm + 355.6mm(14")= 577.6mm or 22.74"

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Tips from Dick on How To Calculate Your Tire Size:

Here is how you figure out the dimensions on a tire and what will work for your car. The first number is the width in Millimeters "255" is 255 mm, or about 10". I don't know what year your car is, but chances are these tires will be at least 1" and maybe almost 2" wider. You'll have to look to see if you have clearance, between the fender skirt and the rear wheel, and between the frame and the inside of the front tire in a sharp turn. Remember when you hit a bump in a turn, the tire will move a little closer to the frame.

The second number is the percentage relation between the height from the rim to the road as compared to the width. "70" means the tire is 70% as high as it is wide, or 7 inches from rim to tread (with no load on the tire). This will be a short, fat looking tire for your car, when the original was a tall thin dude. Some like this new look, some don't. You pick it.

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Tips from Chris on Tire Measurement:

The measurement of the sidewall height on tires is always done as a function (or percentage) of the section width, and it's called the "aspect ratio."

In the 1950s and early 1960s, the standard aspect ratio was 82-84%, meaning the distance from the top edge of the rim to the top of the tire tread was that percentage of the width of the tire (which is measured about mid-carcass, not at the tread). Tire sizes were usually given as simply the section width and rim size, like 9.15-15 (9.15 inches wide, 15-inch rim).

Around 1970, bias-ply tires moved to a 78% aspect ratio, this the term "H78-15. H was a load rating, 78 was the aspect ratio, 15 the rim size. All tires using the same load rating (for example, G70-15, G60-15, etc.) were the same diameter. Because the diameter was the same and the aspect ratio was lower, a 60-series tire was wider than a 78-series.

As radials became the norm, these designations stayed in use, but an R (for radial, of course) was added: HR78-15. In the 1970s, US tire manufacturers adopted the European system of metric sizing (though the rim diameter is still in inches). Example: 235/75R15. R still stands for Radial, 235mm is the section width, 75 the aspect ratio, 15 the rim diameter. What's different in this system is that the section width is an absolute number, so a 235/75 is just as wide as a 235/60. The 60-series tire is therefore smaller in diameter.

During this time period, the "standard" aspect ratio dropped to 75% (today, 65%, 60% and even down to 35% on some exotic sports cars, are all common).

So, if you wanted to put a set of radial tires on an old car and approximate the original sidewall height, you'd have to go with an enormously wide tire, which is undesirable for many reasons, including more difficult steering and some odd handling response (for these cars, which were not designed to have such a big contact patch between rubber and road).

As such, we compromise with a balance of width and height that comes closest overall... an old 9.15-15 might become a slightly wider but shorter HR78-15, which then becomes an even shorter 235/75R15.

Finding correct-size 14-inch tires today is harder still, because few tire manufacturers make little 14's strong enough and wide enough to manage the load of a 5,000-lb car. Choose carefully, note the load rating (remember, some 65% of your car's weight is on the front wheels) and the temperature grade (B is OK, A is better, C is not good enough), and maintain proper tire pressure (about 4 lbs below max is what I use). We've all seen what happens when under-inflated tires overheat in a heavy vehicle like, oh, I dunno... a Ford Explorer?