" The tires used on the Sprint hardtop model are 6.5” x 13”. "
Does that indicate the tread width and wheel diameter?
What is the sidewall height of that size tire?
Thanks, Dennis.
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" The tires used on the Sprint hardtop model are 6.5” x 13”. "
Does that indicate the tread width and wheel diameter?
What is the sidewall height of that size tire?
Thanks, Dennis.
Couldn't have said it better myself :
http://www.barrystiretech.com/tiresizing.html
Thanks, Jeff.
6.5-13 overall diameter highway tread = 24.58"
Hmmm. I am trying to figure out the source of my speedometer inaccuracy.
I am running 175/80 tires (tread width mm / height aspect %) with a tread width of 6.875” and a sidewall height = 0.8*175 = 140 mm = 5.5 inches. With 13” wheels and 175/80 tires that gives an overall diameter of wheel (13) + tire (11) = 24". So, what I have is a little smaller than what was originally specified (24.58").
But, my speedometer reads 3 mph slower than my actual speed. My actual speed was calculated from a 24" wheel size and tachometer rpm plus observations of road side radar signs that say "Your speed is ..... " that were 3 mph higher than my speedometer. It is a puzzle that with a smaller tire/wheel diameter that my speedometer should be reading slower than actual speed. It should read higher.
PS: I really like the white roof on your wagon. My first car was 1963 four door Falcon wagon with a 170 and I still think that Falcons were the most nicely sized, styled, and designed station wagons that have ever been made. I love the roll down back window and the way the back seat flips around to make a flat surface and that the car has no blind spots. They are pure automotive perfection.
Thanks for the kind comment on the color. The White Roof was original color and the Blue (Ming Green actually) is fairly close - the intent was an exact match to original but there was some communication issues with the painter. It could have been worse I guess.
I think you can easily solve your speedo problem by increasing your tire pressure to approximately 75psi :ROTFLMAO: Don't forget your kidney belt.
Have you tried changing the driven gear on the speedo cable? I adjusted my speedo vs. reality that way and actually found the gear I needed at the Ford dealer.
Here's info on what I did.
http://www.redfalken.com/pages/drivengear.html
Hello, Kenny.
I compared the circumferences of the original 6" x 13" and 6.5" x 13" tires and concluded that the sizes were similar enough that that there would only be a 1/2 mph difference up or down between them and the 175/80 13 tires that I am using.
The speedometer gear must have been changed in the past with a gear that was slightly larger than the original (giving a slightly lower indicated speed).
Here are pictures of the gear that I took while my Ford-O-Matic was being rebuilt:
Attachment 3271
Attachment 3272