Topic: 39 wheel and tire size


danny boy    -- 12-11-2021 @ 5:11 PM
  Converted my 39 tudor sedan to 40 model 5x5.5 hubs. Will 15x6 wheels with 3.75 backspacing fit under all 4 corners ? If so what is the best tire size to feel up the fenders with out any rubbing issues. Still has original axles and suspension front and rear.


trjford8    -- 12-12-2021 @ 11:54 AM
  The 15X6 wheel should work fine on the rear. I have used the 15X5 on the front, but I normally run a smaller tire on the front with a dropped axle.


danny boy    -- 12-12-2021 @ 12:45 PM
  Ok. Thanks for the info. Like alot of other parts, wheels are on backorder for months depending on what size your looking for.


wmsteed    -- 12-18-2021 @ 12:00 PM
  If it is your intent to use '40 Ford style 16" 5 on 5.5 wheels on your car, the correct size tire would be 600x 16.. You can use wheels from '40 '48 with their stock hubcaps, or you can use Ford F100 '57-66 15" 5.55 which will also accept the earlier hubcaps.
You will have to make sure the wheels are Ford, they will be stamped with the Ford logo, Dodge and Jeep used similar wheels, however the Ford caps won't fit. Watch the width of the rim, the earlier wheels can be a narrow as 4.4", whereas the later rims can be up to 5.5" wide.

Bill
36 5 win delx cpe


danny boy    -- 12-19-2021 @ 7:10 AM
  Thanks for reply. Ended up with a set of 15x6 with 3.75 backspace smoothies and 215/75/15 tires. Basically because any other size was on backorder until atleast April.


wmsteed    -- 12-20-2021 @ 10:17 AM
  The 215/75R15 tires you are buying are too small for your car.. According to the tire books, the average size of a 215/75 R15 is 27.1" where-as the original 600 x 16 is 28.3", an inch difference in tire size will make a huge difference in your gear ratio, under gearing it and there-bye raising the rpm's.
A 235/75R15 would have been a better selection, a 235 is 28.8, on the average, just slightly taller than a 600 x 16 at 28.3.
Tire and wheel fitment, and sizes, are probably one of the least understood items that tire salesman and the average motorists are aware off.
Reviewing the pix you posted I noted the tires you have on your car. I just put a similar narrow white side wall on my 53 Olds 88, 235/75R15 to replace 710-15's.
You should have your alignment corrected to allow for the radials, you should also put a hydraulic steering dampener on the tie rod to minimize steering issues.
I have used hydraulic steering dampeners, (looks like a shock absorber) on all of the solid I beam axle vehicles I have had for the past 30 years.

Bill
36 5 win delx cpe

This message was edited by wmsteed on 12-20-21 @ 10:33 AM


danny boy    -- 12-20-2021 @ 3:06 PM
  Thanks for the information. Was concernerd with getting too wide of a tire on rear and having rubbing issues. Ill give the 235 a look before I put this on the road.


juergen    -- 12-21-2021 @ 6:16 AM
  Let's calculate the huge difference in mileage/speed/rpm,. The difference in diameter is 1.2 inches which is proportional to distance traveled or in this case about 4.4%. So at 60mph your speed is off about 2.5 mph. And if your cruising rpm is usually 2500, now you will need 4.4% more or about 110 rpm.


wmsteed    -- 12-21-2021 @ 8:33 AM
  I would doubt very much that a stock '39 Ford would have a cruising RPM of 2,500 at 60 mph with a standard gear ratio of 4.11.

Bill
36 5 win delx cpe


JayChicago    -- 12-21-2021 @ 8:56 AM
  Just academic brainstorming here:

Radials have a more flexible side wall. Under the weight of the car, you can see it in the tell-tale bulge at the bottom of a radial tire. So does that make the effective diameter of a radial tire slightly (1/4”?, 1/2”?) less than its nominal diameter?


Kens 36    -- 12-21-2021 @ 9:17 AM
  No.


JoseGuidry    -- 11-04-2022 @ 1:40 AM
  If you're looking to fit 15x6 wheels on your 39 Ford Tudor sedan, you'll need to make sure you have the right tire size and wheel backspacing. You'll also need to ensure that your suspension is able to handle the larger wheels. Otherwise, you may end up rubbing when you turn. With the right setup, however, 15x6 wheels can give your Ford an aggressive new look. More interesting information here https://wheel.tips/


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