Tire size help

[Steven Bowers]

Okay, I presently have 225/75-14” tires on my stock 14”x6” steel rims….this size tire is no longer available….this size tire is 271/2” tall….fills my wheel wells up great….unfortunately there’s only around 6” of rubber on the road….can any of you guys honestly tell what tire size will come close to matching this height…..can go taller….I’d like to gain some tire width also….any and all comments leading me to a solution to my dilemma will be greatly appreciated….

 

[R413]

225/70R14. Wider, a bit shorter

 

[Steven Bowers]

225/70R14. Wider, a bit shorter

How much wider……

 

[Mark Barnes]

How much wider……

This will help-
https://tiresize.com/comparison/

 

[Steven Bowers]

This will help-
https://tiresize.com/comparison/

This works fantastic…..thanks so much….

 

[MoparLeo]

40 years in the tire industry.
Just a tire size caveat: Each tire manufacturer has slightly different spec sizing.
The only thing regulated is the tires load capacity. All manufacturers have to meet a standard for safety. The above calculator is not exact. Each mfg is slightly different. Go to a tire store and check for yourself.
So for example all 225/75-14 load range "B" tire would have to carry the same load at the same air pressure. 32 PSI.
But you could stand 4 different tires of the same size from 4 different manufacturers side by side and they will all have different diameters and contact(tread) width.
Like buying different brands of pants or shirts. They will all have a different cut even though the tag says the waist and inseam are the same.
Unfortunately tire sizing does not give the actual tread measurement. It is a formula in millimeters and ratio percentages.
The reason for large diameter 14" tires in those was to give a softer ride on the current bias ply construction tires. A tall tire with a smaller diameter rim had more flex in the sidewall to absorb bumps in the road better. Radial tires eliminated that as all radial tires had very flexible side walls.
Current tire sizing gives you first, the section width which is the widest point through the sidewall, (not tread) in MM.
so 225 is section width in MM.
Second is the aspect ratio. Like 1/2 is 1 divided by 2 or half, 225/75 , is 225 MM Divided by 75 (%). The tire is 75% as tall as it is wide through the section. Still with me ? Therefore a 225/70 is shorter (70%) and a 60 is even shorter (60%) and so on . This mean the lower the number, the shorter the tire is. Less flex in the side wall = Con: hard, stiffer ride. Pro: Quicker steering wheel response, better cornering.
Last number, 14" or 15" is just the rim diameter.
So which tire has the "widest tread " ? You have to physically measure it. The size won't tell you.
Back in the 50-60's the tire sizing formula did tell you that. A 9.00 - 15 would be a 15" rim with a 9.0 " tread width tire. As you can see a lot of other information was left out back in those days.
Go with a 15" rim. Much easier to get tall tires. 14" are just ancient history. 15" is still a truck/SUV size so tires are still available and aftermarket repros are made in 15" sizing as well. 14" not so much.
I will post an illustration:

 

[68BabyBlue]

I currently run Coker Firestone GR70-14's on my '68 GTX, radials with bias ply style tread pattern. Tires on the vintage picture were G70-14 fiberglass belted bias plies on 14x6 magnums.

 

[Gsmopar]

225/75-14
225 mm wide
75 Side wall is 75% of the width
14in Wheel

225 x.75x2 (top and bottom side wall) = 337.5mm
337.5mm = 13.28 inches
13.28 + 14 (wheel) = 27.28 inches high

...or you can just use the link above.

 

[MoparLeo]

225 mm is the section width not tread width.
/75 is 75% of the section height from the rim to the top of the tire, not the width.