My calculator says about 3.4% taller.


285 x .70 = 199.50
199.5 x 2 = 399
399 / 25.3 = 15.77"
15.77" + 17" = 32.77"


285 x .75 = 213.75
213.75 x 2 = 427.50
427.50 / 25.3 = 16.90"
16.90 + 17 = 33.90"

33.9 / 32.77 x 100 = 103.44%.

 

Exactly. Thanks for stating.

 

When comparing tires most people don't carry a calculator, so you can use the rough math that a tire with a 75% profile is 5% taller than a 70% profile.

Is it exact? No, but generally neither is doing the math on most tires. Its nothing to get wraped up around 3.4 or 5%.

 

Yup, just saying that it isn't what it seems. Remember that 5% is doubled too... It's 75% of the width..... but for tire height you add above the rim and below the rim. You'd think the tire would be 10% higher!

 

I have been using 315/70/17 bfg tko's on stock wheels since I bought my truck in 2005. The first set I got around 65k miles out of them and still had tread left but figured I was pushing it so I bought a new set. The key to having them last is to run 50 psi in the front and 40 psi in the rear unless towing heavy to keep from wearing the centers out of the rear tires. The other key is to have them rotated every 5k miles which is easy to do when you buy them at a place like discount that rotates and balances for free.

The only down side to these tires are that they are D rated. So if you tow a lot and tow heavy I wouldn't advise getting the 315's. But if your like me and tow a boat around on the weekends and only occasionally tow heavy they work really well.

Hope this helps. Look in my gallery and you can see what they look like.

 

I put the 315/70/17 BFG KO's on my stock rims and have really liked them. The only rub I get is at full turn and you drive over something like a curb. And to be honest I have only heard them hit a handful of times in the past 63k that I have had them on. I always run 50 in the front and 38-40 in the back. If I am pulling a light trailer I just leave the back alone. If I am hooking up to a heavy gooseneck I will run 45 in the back. I have a 6'er so I really didn't notice a power difference.