tire size
Elder User
Joined: Jul 2006
Posts: 664
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From: Rural Southern Colorado
I have a pair of H78-15's on the back of mine, that one and the L78-15 are both outsize bias-ply tires. The 205-75/R15 is a radial tire and it's close to the correct size for the truck, from what I understand. I would imagine it handles strangely with that assortment of rubber.
Fleet Mechanic
Joined: Mar 2005
Posts: 1,511
Likes: 1
From: peyton, colorado
About a month ago in another thread someone said that original equip was a 670-15, which sounds about right. That became a 7.75-15 in the early sixties, a F78-15 in the late sixties, and a P205/75-15 around 1980. Measuring a 670-15, the 205/75 seemed a hair short, so I'd go with a P215/75r15. It seems small compared to what we run today, but that's pretty darn close to what was on it stock. Most of the trucks that were still driven in the last few years were swapped over to a P235/75r15 (the old L78-15) because that was the standard, 15" 1/2 ton truck tire.
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Elder User
Joined: Jul 2004
Posts: 825
Likes: 3
From: Michigan
Originally Posted by cruzin55f100
how do i determine the correct size, does any body know the overall diameter of the stock 15" tires.
Fred
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Elder User
Joined: Jul 2004
Posts: 825
Likes: 3
From: Michigan
Originally Posted by fking1
The 55 F100 Dealer Brochure only shows 6.00-15 & 6.50-15. The Brochure for F250's and up says a large variety of tire sizes are available, so I'm sure one could get 7.00-15's by special order.
Fred
Fred
Fred
Tuned
Joined: Jun 2005
Posts: 372
Likes: 1
From: Walnut Creek, CA
The original tire size is a 6.70-15. There are multiple choices for replacement with current day radials. Coker recommends a 205/75/15. If you go to their web site you can look at the tires and they will show you the diameter which if significantly different from the original tire will make your speedometer incorrect. If you choose a larger tire keep that in mind as well as the fact that if it is much wider and you don't have power steering it will make it harder to steer at low speeds. There was a similar thread a few weeks ago and Rusty will give personal advice through PM's if you email him. I am looking for the stock look and am choosing between 205/75/15's and 215/75/15's.