245/40r18 In Inches – Tire Size, Rim Fitment & Best Tires

The 245/40R18 tire has an overall diameter of approximately 25.7 inches, a section width of roughly 9.6 inches, and is designed to be mounted on an 18-inch diameter rim. The equivalent tire size in the high flotation system is 25.7×9.6R18.

245 40r18 In Inches

What does 245/40r18 Tire mean?

Tire sizes can be confusing, but understanding them can make all the difference in choosing the right fit for your car. Here is a handy table to demystify this enigmatic tire size – 245/40r18.

Tire NumberIts Explanation
245This refers to the tire’s width in millimeters, measured from sidewall to sidewall. Our friend, the 245/40r18 tire, is 245mm wide.
40This is the aspect ratio, represented as a percentage. It indicates the height of the tire’s sidewall as a percentage of its width. In this case, the sidewall height is 40% of 245mm.
RThis stands for Radial, which is the construction type of the tire. Radial means the tire’s layers run radially across the tire.
18This number tells us the wheel diameter in inches. For the 245/40r18 tire, it’s designed to fit on an 18-inch rim.

What is 245/40r18 Tire in Inches?

You may be wondering, “why do I need to know my tire size in inches?” Knowing your tire size in inches can make it easier to find the right fit, especially when shopping in countries like the US, where tire sizes are often listed in inches.

245/40r18 in Inches and Millimeters

Here is a table converting the measurements of a 245/40r18 tire into both inches and millimeters:

Tire Diameter25.72 inches653mm
Section Width9.65 inches245mm
Rim Height18 inches457.2mm
Sidewall Height3.86 inches98mm
Circumference80.77 inches2051.57mm
Revolutions per Mile784784

A Deeper Dive into the 245/40r18 Tire Specifications

Alright, fellow tire enthusiasts! After our previous crash course on tire specifications, it’s time to rev up your engines and dive deeper into the mysterious land of tire dimensions. Let’s explore the nooks and crannies of our tire-du-jour, the 245/40r18. By the end of this, you’ll be a bona fide tire connoisseur!

Tire Width of 245/40r18

First things first, let’s talk about width. This tire isn’t shy about spreading out. With a whopping width of 245mm or 9.65 inches, the 245/40r18 tire sits pretty wide on the asphalt. This width, coupled with a proper vehicle alignment, translates to better stability, grip, and overall handling. It’s like giving your car a wide pair of feet to stand on – it might not win in a ballet dance-off, but boy, can it hug those corners!

Tire Height of 245/40r18

Next up is the tire height or diameter. With a total diameter of about 25.72 inches (653mm), this tire has a nice balance between height and width. It isn’t too high to cause an uncomfortable ride or too low to sacrifice performance. Think of it as the Goldilocks of tires – it’s just right!

Sidewall Height of 245/40r18

Let’s now cast our gaze upon the tire’s sidewall. With a height of about 3.86 inches (98mm), the 245/40r18 is a low profile tire. This means it delivers excellent performance, especially in terms of steering response and handling. However, with great power comes great responsibility – these tires might make your ride a bit harsher over bumps or potholes. But hey, nothing says “I’m a driving enthusiast” like feeling every crevice of the road, right?

Rim Diameter for 245/40r18

Now, let’s chat about rims. Our hero, the 245/40r18 tire, sits comfortably on 18-inch rims. This rim size is quite popular among modern sedans and sports cars, offering a sleek look without compromising comfort. Remember, choosing the right rim size is crucial – too small, and you’ll have a tire bulging out like a doughnut on a diet; too large, and you’ll have a tire struggling to wrap around it like a belt after Thanksgiving dinner.

Tire Circumference of 245/40r18

Finally, we come to the circumference. The 245/40r18 tire has a circumference of approximately 80.77 inches (or 2051.57mm for the metrically inclined). This translates to about 784 revolutions per mile. If you think about it, that’s quite a workout! It’s like your tire running 784 laps around a 1-inch track for every mile you drive. Talk about burning rubber!

What are the Best 245/40r18 Tires?

Choosing a tire isn’t like playing “Eeny, meeny, miny, moe.” It’s more like speed dating—you need to find a quick match that can last for thousands of miles. So, to help you skip the small talk and get right to the sweet spots, here are our top three picks for the best 245/40r18 tires.

1 – Fullway HP108

The Fullway HP108 is like the Swiss army knife of tires—it does everything pretty well. This all-season tire is designed to offer you an unparalleled balance of comfort and performance. Whether you’re traversing slippery wet roads or embarking on a desert safari, the HP108 is always game.

  • Key Features:
    • Four circumferential grooves for enhanced water evacuation
    • High-performance tread design
    • Siping for improved traction on wet roads
  • Pros:
    • Excellent all-weather performance
    • Great traction and grip
    • Budget-friendly
  • Cons:
    • Might be a bit noisier compared to premium brands
    • Tread life could be better

If you’re looking for a tire that’s a jack-of-all-trades, the Fullway HP108 is a hard option to beat.

2 – Kenda Kaiser KR20A 245/40R18 97W

The Kenda Kaiser KR20A tire is like that reliable friend who always shows up, rain or shine. It’s a high-performance tire that offers outstanding wet and dry traction, thanks to its unique tread design. Plus, its aggressive look will add a sporty touch to your vehicle.

  • Key Features:
    • Directional tread design for better wet grip
    • Rim protector to guard against curb damage
    • High-grip compound
  • Pros:
    • Excellent grip in both dry and wet conditions
    • Reasonably quiet for a high-performance tire
    • Good value for money
  • Cons:
    • Might not perform as well in heavy snow
    • Tread life might not be as long as some competitors

The Kenda Kaiser KR20A is a tire for those who need performance at a reasonable price.

3 – Summit Ultramax HP All-Season Tire – 245/40R18 97W

Last but not least, we have the Summit Ultramax HP. Think of it as the long-distance runner of the tire world. This tire is designed for long tread life and all-season performance. Its wide tread profile improves handling and control for a safer, more comfortable ride.

  • Key Features:
    • Advanced tread compound for long tread life
    • Symmetrical tread design for even wear
    • Large shoulder blocks for improved handling
  • Pros:
    • Offers excellent longevity
    • Performs well in various weather conditions
    • Provides a comfortable and quiet ride
  • Cons:
    • Grip on wet roads could be improved
    • Might not be as sporty as other options

The Summit Ultramax HP is a solid choice for those who prioritize tread life and all-season reliability.

FAQ’s About 245/40r18 Tire

Got questions about the 245/40r18 tire? It’s only natural. After all, tires are to a car what shoes are to us—pretty important for getting anywhere! So, let’s cut to the chase and tackle some of the most frequently asked questions about the 245/40r18 tire.

What Vehicles Use a 245/40r18 Tire?

The 245/40r18 is a versatile tire size that suits a variety of vehicles, ranging from sedans to sporty coupes and luxury vehicles. It’s like the black leather jacket of the tire world—looks good on pretty much anything. You can find this tire size on vehicles such as Audi A4, BMW 3 series, Mercedes-Benz E-Class, Ford Mustang, and more. Always refer to your vehicle’s user manual or consult with a tire expert for precise fitment.

How Many Revolutions Per Mile Does a 245/40r18 Have?

The 245/40r18 tire makes approximately 784 revolutions per mile. That’s a whole lot of spinning! If these tires were at a disco, they’d be the last ones to leave the dance floor.

Price of a 245/40r18 Inches Tire?

The price of a 245/40r18 tire can vary greatly depending on the brand, model, and features. It’s like shopping for a new suit—you can get one off-the-rack or go for a high-end designer piece. On average, prices can range from around $80 for budget brands to over $200 for premium models. Remember, the most expensive option isn’t always the best for your needs. Do your research and find the one that suits your driving style and conditions.

What Kind of Rim Does a 245/40r18 Tire Fit On?

A 245/40r18 tire is designed to fit on an 18-inch rim. The rim width can typically range from 8 to 9.5 inches. It’s like finding the right size belt for your pants—you need to get the fit just right for the best comfort and performance.

How Much Air Should Be in a 245/40r18?

Recommended tire pressure can vary based on the vehicle’s weight and the tire’s load index. However, most 245/40r18 tires will do well with a pressure between 30 to 35 psi. Always refer to your vehicle’s owner manual or the sticker located on the driver’s side door jamb for the recommended tire pressure.

What is a 245/40r18 Equivalent To?

The 245/40r18 tire size can have several equivalents, depending on the dimensions you’re willing to slightly adjust. Some equivalent sizes could include 225/45r18 or 265/35r18. However, tread lightly here! You should always consult a tire professional before deviating from your vehicle’s recommended tire size.

Comparison with Similar Tires

You wouldn’t buy the first pair of shoes you try on, would you? (Well, unless they’re absolutely fabulous.) Likewise, when shopping for tires, it’s essential to consider all your options. So, buckle up, as we navigate through the intriguing world of tire comparisons, setting our 245/40r18 against other close competitors.

245/40r18 vs 245/45r18

Like two siblings with slightly different tastes, the 245/40r18 and 245/45r18 share the same width, but differ in aspect ratio. The 245/45r18 is a bit taller, which could mean a smoother ride but slightly less crisp handling. It’s the sensible elder sibling to the more sporty 245/40r18.

245/40r18 vs 225/40r18

If the 245/40r18 and 225/40r18 were running in a race, they’d cross the finish line at the same height. However, the 245/40r18, being wider, might just edge out in terms of grip. But, if fuel economy is your jam, the slimmer 225/40r18 could help shave off those pesky extra liters.

245/40r18 vs 235/40r18

This comparison is like choosing between a Quarter Pounder and a cheeseburger—they’re quite similar, but the 245/40r18 packs a bit more “beef” in width. That extra width can translate to more contact with the road and potentially better grip, but the 235/40r18 might provide slightly better fuel economy.

245/40r18 vs 255/35r18

In this face-off, the 255/35r18 is wider but shorter, much like a pancake compared to a bagel. The wider 255/35r18 can offer more road contact for improved handling, but the lower profile might mean a less comfortable ride. The 245/40r18, being a bit taller, can offer a bit more cushion for your ride.

245/40r18 vs 235/45r18

This comparison is the tire version of a seesaw. The 235/45r18 is narrower and taller, which might lead to a smoother ride and potentially better fuel economy. The 245/40r18, however, is wider and shorter, potentially offering better handling and road feel.

245/40r18 vs 255/40r18

This is a match-up of two near-twins, but the 255/40r18, being slightly wider, might offer better grip at the cost of potentially increased fuel consumption. The 245/40r18, being a tad narrower, might provide slightly better fuel economy while still offering good performance.

245/40r18 vs 265/35r18

In this pairing, the 265/35r18 is the “muscle car”—wider and shorter, which could translate into superior grip but possibly a rougher ride. The 245/40r18 is a bit more of a “touring sedan”—more balanced, with a slightly taller sidewall for a cushier ride.

245/40r18 vs 235/50r18

This is a bit like choosing between a sports car and an SUV. The 235/50r18 is taller and narrower, potentially offering a smoother ride and better fuel economy. The 245/40r18, being wider and shorter, might give better handling and road feedback.

245/40r18 vs 225/45r18

These two are like different flavors of the same dish. The 225/45r18 is narrower and a bit taller, potentially offering a smoother ride and better fuel efficiency. The 245/40r18, being wider, might provide better grip and handling.

245/40r18 vs 225/50r17

This is like comparing an action-packed movie to a dramatic film. The 225/50r17 is narrower and taller, potentially offering better comfort and fuel efficiency. The 245/40r18, on the other hand, is wider and shorter, possibly providing better handling and stability.


Choosing a tire is a lot like picking out a new pet—it’s a long-term commitment, and you need to ensure it’s the right fit for your lifestyle. The 245/40r18 tire offers a balance of comfort and performance, making it suitable for a wide range of vehicles and driving conditions. However, depending on your specific needs, one of the comparable tire sizes we’ve discussed might serve you better.

As with any big decision, make sure to do your research, consult with professionals, and weigh all your options. At the end of the day, the best tire is the one that makes your driving experience more enjoyable, safer, and efficient. Happy driving, folks!