How Tall Are 315 70R17 Tires? | Exact Height Math

A tire in this size is about 34.4 inches tall, or 872.8 mm, before load, tread wear, and air pressure change the real-world measurement.

When people ask about the height of a 315/70R17 tire, they usually want more than a raw number. They want to know whether it is close to a true 35, whether it will clear the fenders, how much it will change gearing, and whether the speedometer will drift enough to notice. That makes sense, because this size shows up on lifted trucks, trail builds, and daily drivers that need one tire to do a lot of jobs.

The headline number is simple: a 315/70R17 measures about 34.36 inches in overall diameter on paper. Round it the way most owners do, and you get 34.4 inches tall. That puts it just under a true 35-inch tire. The gap is small, but it still matters when you are checking garage clearance, spare-tire fit, axle gearing, or body rub at full lock.

There is one catch. The catalog number is a calculated size, not a promise that every tire from every brand will stand at the exact same height once mounted and aired up. Tread design, carcass shape, measuring rim width, and inflation all nudge the final number a bit. So the smart way to think about this size is 34.4 inches on paper, then a touch above or below that in real use.

How Tall Are 315 70R17 Tires On Paper And On The Truck

If you want the clean math, the sidewall tells the whole story. As Goodyear’s sidewall breakdown shows, the first number is the tire width in millimeters, the second number is the sidewall height as a share of that width, and the last number is wheel diameter in inches.

What Each Number Means

In 315/70R17, the 315 is the section width. That means the tire is 315 millimeters wide from sidewall to sidewall at its measuring width. The 70 is the aspect ratio, so the sidewall height is 70 percent of 315 millimeters. The 17 is the wheel diameter, which tells you the tire fits a 17-inch wheel.

Once you split the code that way, the height stops being mysterious. You are just adding two sidewalls to the wheel diameter.

The Exact Formula

Here is the math step by step:

• Section width: 315 mm
• Sidewall height: 315 × 0.70 = 220.5 mm
• Two sidewalls: 220.5 × 2 = 441 mm
• Wheel diameter: 17 × 25.4 = 431.8 mm
• Overall diameter: 441 + 431.8 = 872.8 mm
• Overall diameter in inches: 872.8 ÷ 25.4 = 34.36 inches

That is why this size gets called a “34.4” by plenty of truck owners. It is also why people shopping for 35s often land here. You get most of the visual punch and ground clearance of a 35-inch tire without stepping all the way into a taller flotation size.

Why A Tape Measure Can Show A Different Number

Mounted height can drift from the paper spec for a few reasons. A tire measured on the shop floor is not carrying vehicle weight, a tire on the truck is. Fresh tread also adds height that shrinks as miles pile on. Then rim width, inflation pressure, and brand-to-brand construction can stretch or squash the casing a bit.

That is why one 315/70R17 all-terrain may stand a little taller than another mud-terrain in the same labeled size. If you are right on the edge for rubbing, it is better to check the maker’s spec sheet for the exact model you plan to run than to trust the size code alone.

Measurement	Metric Value	Imperial Value
Section width	315 mm	12.40 in
Aspect ratio	70%	0.70 of width
Single sidewall height	220.5 mm	8.68 in
Two sidewalls	441 mm	17.36 in
Wheel diameter	431.8 mm	17.00 in
Calculated overall diameter	872.8 mm	34.36 in
Calculated circumference	2,742 mm	107.95 in
Revolutions per mile	About 365 per km	About 587 per mile

What A 34.4-Inch Tire Changes On Your Vehicle

A tire this tall does more than fill the wheel wells. It changes the way the truck feels in small, easy-to-miss ways. Some owners love those changes. Others notice them the first time they pull away from a stoplight or back into a tight parking spot.

The main shifts usually land in these areas:

• Ground clearance: You gain about half the diameter change at the axle. So if you move from a tire that is 32.7 inches tall to 34.4, axle clearance goes up by about 0.85 inch.
• Speedometer reading: A taller tire covers more ground per turn, so the vehicle may be moving a bit faster than the dash says.
• Effective gearing: The truck feels like it has taller gears. That can soften launch feel and add more work on climbs.
• Clearance at full lock: The extra width and height can bring the tire closer to body mounts, liners, mud flaps, and control arms.
• Brake and steering feel: More rotating mass can make the truck feel a touch lazier when changing direction or coming to a stop.

There is also the fitment side of the job. A 315/70R17 is not just tall; it is wide. On many trucks, width causes rubbing before height does. Wheel offset, suspension lift, caster setting, and tread shoulder shape all enter the picture. A rounded all-terrain can clear where a blocky mud-terrain in the same labeled size kisses the liner or body mount.

Before you mix sizes, read your placard and the owner’s manual. Bridgestone’s tire replacement manual says road tires should match size, type, and speed rating on an axle unless the vehicle maker says otherwise. That matters on modern 4x4s, where traction aids, ABS, and gearing do not love a random mismatch.

315/70R17 Tire Height Compared With Nearby Sizes

People rarely shop this size in isolation. They cross-shop it against 285/70R17, 295/70R17, and 35×12.50R17 because those sizes land in the same broad band of truck fitments. The actual gap is easy to underestimate until you line up the numbers.

If you are jumping from 285/70R17 to 315/70R17, you are adding width and about 0.66 inch of diameter. That does not sound huge, yet it can be the difference between no trimming and a little trimming. Against a labeled 35×12.50R17, the 315/70R17 usually sits a shade shorter.

Tire Size	Approx. Height	What You Notice
285/70R17	33.7 in	Easier fit on stock-ish trucks, less width to manage
295/70R17	33.3 in	Wide stance, still shorter than many expect
315/70R17	34.4 in	Near-35 look with metric sizing
35×12.50R17	34.8 to 35.0 in	Usually taller, often heavier, may need more trimming

When This Size Makes Sense

A 315/70R17 fits the driver who wants a near-35 stance, extra axle clearance, and a broad footprint without jumping straight to a flotation tire on every build. It is a sweet spot for many half-ton and three-quarter-ton trucks with the right wheel and enough room around the body mount and liner.

It also makes sense for owners who want to stay in metric sizing because there is often a strong spread of all-terrain and mud-terrain choices in this size. You can shop by load range, tread style, and winter rating without getting boxed into only a few patterns.

Questions To Ask Before You Buy

1. What is the real measured diameter of the exact tire model I want?
2. What wheel width and offset will I run?
3. Does my truck need trimming, a level, or a lift for this width?
4. Will I regear or recalibrate the speedometer?
5. Is the spare-tire location large enough for a mounted 315/70R17?

If you can answer those five points with confidence, this size is easy to judge. If not, the size can still work, but the tape measure and the spec sheet need a little more of your time before you order.

The Number Most Owners Want

A 315/70R17 tire is 34.36 inches tall by calculation, which most people round to 34.4 inches. That makes it a near-35 tire, not a full true 35. If your truck has enough room for the width and your gearing can live with the added diameter, it is a strong size for a fuller stance and more clearance without taking the next jump up.