This link has some good tire and wheel size info for the Mustang based cars

http://www.mustangii.org/tech/tipsntricks/wheels-101.shtml

If you can't get to it on their site, I copied it onto the Annex HERE

Wheel swap on International based Glassics

September, 2006 - Dennis Crozier swapped rims and tires on his car # 189

I found these on E-Bay doing a search for 4 lug, 4.5 inch 15 inch wheels. Well I came up with a few hundred so I narrowed it to Mustangs. Came up with a bunch as well but none with the 4.5 inch bolt pattern. I then remembered a set of VW wheels that would fit multiple patterns. Ah, maybe dual bolt pattern, so I put in universal 4 bolt wheel. BINGO! Just a couple came up and one said:

"15X7 4 lug Mustang +other American Racing chrome wheels"   

  I e-mailed the seller right away with questions like: Please measure across the wheel, center lug to center lug and the inside diameter from the back of the wheel and the depth from the center where it hits the drum to the outside of the rim. All vital info since I needed first to make sure the bolt pattern would work and that it wouldn’t hit anything on the inside. (tie rod ends, body, etc) So anyhow, he sent the info I requested and I knew they would work. You have about a ¼ inch gap between the tie rod end and the inside of the stock wheel. Measuring at 4 inched depth and 13 ½ across the inside I knew I needed at least a ¼ inch gap with whatever I put on. Let me compare the old to the new….

Old                                            New

14” wheel                                  15” wheel

Inside diameter 13 ½                  inside diameter 14 ½

Stand off 4”                                stand off 4 1/2 “ (backspacing)

Bolt pattern 4x4.5                      bolt pattern dual 4x4.25 and 4x4.5
(Note from the Annexmaster - my 1978 bolt pattern is 4 x 4 1/4")

Like I say, the key is to maintain at least the ¼” gap between the tie rod end. I paid $76.00 for the wheels and about $65 shipping. (8/2006)

Car 189 15 inch wheels

Executive Summary:

78 V-8 phaeton with P205 75R 14 tires, suggested 26 psi front and 30 psi rear (or less).

To:   weegan@goodyear.com

Subject:  Tire pressure calculation needed.


Hi --
I found your name relating to tire pressures for electric vehicles, or something, and thought you might be willing to help. I would appreciate a "guesstimate" for a tire pressure for a Glassic replica car -- no manual,no door sticker, and not many other cars around either.  Here are the specs, and thanks in advance if you are willing to take a shot at this for me.

P205 75R 14 95S tires which state: 35 psi max

Front GVWR 1500
Rear              1900

This is a fiberglass replica with 78 Mustang II 302 V-8 and auto trans. The tires have about 30 psi now, and the car has NO softness to the ride. Of course the shocks look original, so the tires may be inflated correctly.
Any thoughts?

   Don

Weegan responded 7/1/01

(I (Don) took some liberties formatting the chart data for clarity)

Don:

WHEN THE CAR WAS LIGHTENED THE AFFECT ON THE TIRES WAS NOT TAKEN INTO ACCOUNT. THE REAR IS OK AT 30 TO 32 PSI, BUT THE FRONT IS UNDER LOADED. I AM SURPRISED THAT YOU DO NOT NOTE THE UNDERSTEER CHARACTERISTICS. TRY 26 IN THE FRONT AND SEE WHAT THAT DOES. AS FOR THE RIDE, IT IS LIKELY THAT THEY DID NOT TAKE THAT INTO ACCOUNT
EITHER AND USED THE SAME SPRING RATES AND SHOCK. THIS WOULD MAKE IT RIDE BAD. I WOULD PUT A GOOD SET OF GAS SHOCKS ON IT AND PLAY WITH THE INFLATION PRESSURES. DO NOT GO BELOW 26 PSI.