Good afternoon group,
One more question about tires for the 65 F100. What are the rolling and static diameters for the stock 670x15 or G78x15 tires. I want to get tires that are as close as possible to the originals, so my speedo will be very near accurate. Thanks to all that responded to the rim question. That will be very helpful in my search for tires and rims for this truck. Have a great day!

Grover Atwood
McNary61
65 F100 Style side short bed

 

I am not sure about the stock tires on yours. The stock tire for My F100 was a 700X15. The overall tire diamater for this tire is 29 in according to the Bridgestone web site. I do know that Bridgestone makes an tire called the vsteel that is a radial in this size. If you go with the modern raidial they have a larger footprint and make the non powerstearing trucks harder to turn. I am currently runing bias ply tires due to the price 78-90 vs 120-150 and I wanted to keep the original size.

I suspect that if you found 78X15 on it they were put on by someone else in the 70's

 

Radial tires on single I beam front ends is a bad idea for many reasons, overall effects Ackerman principle during turns being the most severe reason. Another drawback is the
need for having gas shocks with radial tires, which may not be available for single I beam systems.

I believe the speedometer gearing is calculated with correctly inflated tires running in a dynamic, or rolling state, so static diameter variable and is not relevant.

I also know that with mechanical drive/driven speedometers ( gears & encased cable set up turning a motor in speedo head) accuracy does not exist, as say compared to pulse sensed digital speed sensors & read outs used today. Speedometers based in old analog and/or mechanical technology are averaged with error included, they may be close enough to get an idea of speed & distance, but I doubt they're precise enough or
dead on exact enough to be called accurate. I know their procduct will not stand up as being accurate in court.

Jusy my $.02. . . .
FBp

 

OK You got me I had to go look up the Ackerman Principle. I agree with you on most raidials. I do not think it would hurt with the Vsteel or any other raidal in 700 X15 as they are desigined with the stronger sidewall mostly for this type of application. They do not bulge and roll like the lets say a LT235x75x15. They run with a very similar footprint to the bias in the same size. If I am off base please let me know. I was planning on switching to the Vsteel or something simmilar once I run my bias tires out. That could take a couple of years at this rate as they are new.

 

Good morning group,
The 65 F100 in question has the twin I beam front suspension, I am currently running
295x50xR15 tires on einke 10x15 rims. I have a 13 inch steering wheel and john armstrong steering and brakes. All I want to do is return it to stock wheels and tires. I thank you for the input on tire size, but I am more interested in the rolling diameter for the 700x15 tires. Is there any place that I can fine the revs per mile for the 65 F100 with a 3:50 rear end gear? Thanks Fbp and frty7ford. Have a great day!

Grover Atwood
McNary61

 

I would like to suggest you read cdherman's post in this topic regarding speedometer calibration located here. An accurate way to get as close as possible without the guesswork.

 

Good afternoon group,
Thanks RaleighDad66 for the info about cdherman's post on speedos. The post
about tire and gear calculations was very helpful. I bookmarked the webpage about tire sizes and diameters that is very helpful. The info about the rev/mile of 744 was what I was looking for. I realize that it is for a specific tire size, but that has me on the track. I would like to thank frty7ford and Fordboypete for their coments as well. Now that I am armed with info, I can make a decision as to what size tires I want to go with. Once again thanks to all you fine folks. Have a great evening!

Grover Atwood
McNary61

 

Following #'s may be interesting to you:

7.25 - 15 4 ply, 785 rev
7.75 - 15 8 ply, 785 rev

8.15 - 15 4 ply, 772 rev
8.15 -15 8 ply, 772 rev

These come right out of the back of my 65 owners manual. My father thought that he had 6.75 - 15 for quite a while too, but he likes low trucks. That size was NOT listed in the manual at all.

If you are interested in original rims, the following site will be of interest to you as well.

http://www.hermannsonline.com/f100/rims/index.htm

I am honored as well that Raleighdad remembered my rather erudite post about speedo calculations. PLEASE NOTE: The 744 Rotations per mile of my tires would seem to be less than the above tires, indicating a "larger than stock" tire. However, I cen tell you that 205/75R15 radial tires sit quite a bit lower than stock, AND for todays highway driving, they are not at all optimal with a 3.50:1 rear diff. (I had 3.5 and swapped to 3.25)

later...

cdherman aka David Hermanns

 

One more fact/question from me -- the Bridgestone Vsteel seems to be available only in 16" rim sizes? Anyone know if this is true?

 

so what is the STOCK size in todays tires? and I shouldnt use RADIALS?

 

I'm not sure you could say there is a stock size. In the OE market we build each tire to the speck of the manufacturer (Ford,GM,Chrysler,etc.) They request a certain characteristic for each tire to match the suspension of whatever car or truck their building. All I can say for sure is they're getting bigger. I've been in the tire making business a long time and I've seen my plant go from 13" to 18" with plans to go bigger still

 

JCS1966,

If you have twin I beam, or other IFS rather than a live, single front axle you can run radials just fine.

To enhance radial performance & eliminate radial "rebound chatter" in your steering system you must use radial tuned, gas pressurized, shocks. This set up dampens road and rebound vibrations which result in the "chatter" generated at road speeds.

Without radial tuned shocks vibration is telegraphed/ transmitted via steering linkage & strg gear to steering wheel. Not only is that annoying, constant vibrations are hard on steering components over time. IMHO radial tuned shocks are a minimal, mandatory, addition when putting radial tires on a vehicle that did not come with them OEM.

To truly maximize radial tire performance & life, I suggest using a set of radial tuned, progressive, shocks to go with radials instead of just radial tuned, gas filled, shocks. I prefer Monroe Sensa-Tracs but there are probably others available.

Essence of Progressive shocks is they increase resistance as loads on them increase, as in panic stops, entering corners a tad too fast, or forcing corrective lane change at speeds and so forth.

I run these in front & rear, along with front & rear anti sway bars using Poly Graphite bushings & insulators. I corner great on LTX Michelins at any speed, in most weather except flooded road ways.

FBp

 

Again THANK YOU FBF

 

I know that when I was looking for tires about a year ago I had to talk to the dealer at home and he could still get them. I just checked their website and they are listing this tire Bridgestone R230 in a 7.00 X 15. I know Yokahoma used to list a radial in this size. Cooper tires has a bias traction tire that works great also

 

JCS a R235X75X15 has the same height as the stoc 700X15