I am working on a 56 Mercury and to the point I need to buy tires. That said, I am a ways off from wanting to buy expensive tires and just wondering what size radial is the “right” size. 15” rim
I'm not sure how much room you have but on my 50 Merc, I'm running 205 /70 /15 Diamond Back radials on the front. I think they are too small but it is the tallest tire that I can run. I want to run 215s Below is a kool size chart from Diamond Backs web site. It is very helpful. Click the Link below. https://dbtires.com/conversion-chart/
^^^^^^ Everything about that car is just plain RIGHT!!! ^^^^^^ Sorry, didn't mean to derail the thread.
If the car is drivable at this point and you can determine that the speedo is accurate with the old tires on there now....... that is a good indicator of what the height of the new tires should be. Then it's just a matter of how wide of a tire you can go without rubbing. On the 40s/50s and up, full fender cars, I personally try for a tidy, tailored, fender gap fit on the outer face of the wheel/tire combo. Getting the maximum width tire possible in the fender is a secondary consideration for me.
The 75 series tires fit the midsize cars (Ford, Chevy, Merc) as the original 6.00/6.50 X 16 did in darker days... '70' series gets wide proportionally, looks too 'fat' and sometimes too low in profile, giving away its 'Radialness'.