Hi all,

In my seemingly never ending quest to find an axle to replace the timken rear end in my F3, I've found a 59 F250 dana 60. It appears that this is still going to be wider than the stock rear though. How much clearance is there between the rear guards and the tyres? If the wheels come outwards by 1 to 1.5" each side will they foul the guards? I'll be using stock 16" F2 wheels and 8.25x16 tires.

 

The Dana 60 axle should be exactly the same width as your Timken 51524 axle. The only issue in my view is the additional width you'll get from your wider rear tires.

The below charts should support my view on the axles. The first chart of the F-3 from the 1951 Saleman's Handbook shows rear track width of 62". The secord chart from the 1957 Body Builder's Layout Book (should be the same as '59) shows Dana 60 rear axle track width of 62.02". The spring perch measurements should also both be the 40.25" measurement since both frames are SAE standard 34" wide.

To the point about your tires, the secord chart shows the section width (D measurement) of the various sized tires available on the stock F-250. The widest shown in the chart is of the 8-17.5" tubeless at 7.73" section width. Because your 8.25" x 16" tires have a different sidewall profile than the 17.5s, they will be wider. My 1979 Tire and Rim Association Yearbook shows that an 8.25" tire will have a section width of 9.30". Whether a more current tire will have the same section width I can't say, but I bet it will. So it comes down to you checking your tires (assuming you have them mounted already) to see what their section width is. At worst you should find that you have 1.5" or so of additional tire width on each side, half on the inside and half on the outside of each wheel. So I'd guess you'll have .75" of additional overall width which should be no problem with fender/guard clearance. Stu

 

Stu, your knowledge amazes me as always. I asked the question over on the 57-60 forum and someone was kind enough to measure their 59 for me, 64.5" was the result. I measured my 49 at 61.5", hence this question. I'm hoping that I can go and see this 59 in Aus and it will be 62" but I'm getting desperate enough to think I might just have to live with the wider track if it isn't.

As for the tyres, I haven't actually bought them yet but was planning to use that size to get as close as possible to the diameter of the original 7.50x17. Also I want this truck to be highway friendly so a large rolling diameter seems sensible.

 

That same Tire and Rim Association Yearbook has a page that is entitled "Maximum Dimensions For Grown Tires In Service For Use By Vehicle Manufacturers In Designing For Tire Clearances". Centrifugal forces will cause tire dimensions to increase while in service. Using the chart I referenced in my first post, your stock 7.50 x 17" will have a section width of 8.45" and 33.82" outside diameter. The above "Grown" chart shows that 7.50 x 17" tires grow to 9.21" wide and 35.17" tall. Compare this to your 8.25" x 16" tires that grow to 10.55" wide and 35.58" tall. Should give you the added road speed you're looking for. Stu