How To Calculate Tire Size
When changing tires, its important to calculate tire size to ensure they will fit the vehicle and wheels, have the correct stance, and ensure the speedometer reading will be accurate.
The important components of a tire designation that indicate the tires size are the width, aspect ratio, and rim diameter. Using these three values, you can calculate a tires height , circumference, sidewall, and revolutions per mile .
You can use some simple formulas to calculate tire size given the width, aspect ratio, and rim diameter.
Strength To Seek Adventuredurability To See It Through
You never know where the road will take you. So we prepared for everything. When you roll on our latest tire, youre driving on plenty of on-road performance with light off-road capabilities. Because if you wait for perfect weather or perfect road conditions, youll wait forever. The Trail-Terrain T/A® is engineered to ensure you can live life on your terms, regardless of the adventures you chase.
Where To Find The Tire Size
At this point you might be wondering where to find the tire size for your vehicle. You can find it it two places.
1: Each tire will have the size code printed or embossed in the sidewall of the tire. Note that while this is the actual tire installed on the vehicle, it might have been replaced in the past and its not guaranteed to be the suggested size for the vehicle.
2: A yellow or white tire and loading information sticker should be visible on the inside of the drivers side door frame. This is the tire size and pressures suggested by the manufacturer for the vehicle, but as stated above, it might not match the tires that are currently installed.
Recommended Reading: Va Tire And Auto South Riding
How To Calculate Tire Height
You can find the tire height using the sidewall dimension from the previous step. The formula to calculate diameter is:
diameter = + rim diameter
Thus, the tire diameter is equal to the sidewall times two, plus the rim diameter.
For example, lets find the diameter of a 245/40R18 tire. Recall that the sidewall for this tire is 98mm.
Start by converting the sidewall to inches. 98mm is equal to 3.86 inches.
diameter = + 18diameter = 25.72
Noteworthy Original Equipment Assignments
Along with positive user ratings, the KO2s original equipment assignments should inspire confidence. Not every OE tire performs well, but where legitimately extreme vehicle performance is expected by customers, engineers have to make sure that the OE tires will deliver.
The All-Terrain T/A KO2 has been fitted to various 4x4s where robust off-road performance is a user expectation and demand, perhaps most notably as the OE tire for the latest generation Ford F-150 Raptor, as well as the Jeep Wrangler Rubicon.
The BFGoodrich All-Terrain T/A KO2 is BFGoodrichs toughest & best all-terrain tire to date. Its an undoubted class leader, and arguably the modern all-terrain standard. For more details, check out the .
Thinking the All-Terrain T/A KO2 is the right fit for your 4×4, or want to discuss all-terrain tire options? Give us a call at 866-961-8668.
Read Also: How Long Do Tire Patches Last
The Origin Of Speed Ratings
We can thank Germanys famous Autobahn for tire speed ratings. Tire speed ratings range from A to Y . But the chart is not completely in alphabetical order. For example, H is between U and V, with the common perception that H stood for high performance at one time. As manufacturers continue to add speed to their vehicles, tire speed ratings evolve to match the speeds. For example, Z was the highest rated speed at 149+ until W & Y were used to match the higher speeds of exotic sports cars.
How To Read Tire Size
If youre in the market for new tires, the first step is to check the size of your current tires. Simply check the sidewalls of your tires for a series of numbers and symbols that should look like this: P215/60 R17. The wheel diameter will be the last number in the series. In this example, the vehicle’s rim diameter is 17″.
The other numbers and symbols refer to the tire type, tire width measured in millimeters from sidewall to sidewall, aspect ratio, and tire construction type. The rim size is the most important number to pay attention to when youre shopping for tires that will fit your vehicle properly.
Again, if you dont have existing tires to refer to, you can find your vehicle’s recommended tire size by checking the vehicle’s tire information placard on the inside of the driver’s side door or your owners manual.
You May Like: Mount Spare Tire Under Trailer
Speed Ratings Refer To More Than Just Speed
Contrary to the name, speed ratings arent just about speed. Theyre also about ride comfort, wear and cornering ability. Typically, the higher the speed rating, the better the grip and stopping power, but the lower the tread life. You can always increase the speed rating of the tires on your vehicle for improved performance, but can never decrease it without reducing the vehicle top speed to that of the lower speed rating selected.
Highly Rated By Users
The All-Terrain T/A KO2 has fared well in the real world according to TireBuyer.com users, achieving a 4.6/5 rating with almost 300 reviews registered. Notably, the KO2 is a remarkably well-rounded performing tire, with no real weaknesses.
These positive KO2 user ratings are reflected just about everywhere, including overseas by European users. Sales of the BFGoodrich All-Terrain T/A KO2 surpassed 5 million in 2016.
You May Like: Tesla Model 3 Performance Tires
Larger Tires Affect Speedometer & Odometer
Larger tires will decrease the speedometer reading by about 3-4 mph . For example, if the speedometer reads 55 mph, our true speed is 58-59 mph. We have to keep that in mind to avoid speeding tickets!
It also impacts the odometer, so some things like the oil change warning might be off.
Ford dealers cant fix that, and theres no unofficial fix that we know of. Edit: there might be ways to do it: Speedometer calibration on FordTransitUSAforum.com
Bfgoodrich Radial T/a Tire Pressure Chart Has A Total Of 23 Tire Sizes With A Maximum Tire Inflation Range Of 35 To 35 Psi And A Maximum Tire Load Capacity Range Of 1074 To 2205 Pounds
Select BFGoodrich Radial T/A tire size to locate its greatest tire load limit at its predetermined tire inflation. Tire load limit and tire inflation settings may differ based on tire load range or ply rating. Check BFGoodrich Radial T/A tire sidewall for more information. Remember that psi esteem imprinted on the tire sidewall is the maximum tire pressure that BFGoodrich Radial T/A tire can be inflated to at its related maximum weight limit, and not really the suggested tire pressure for your vehicle. Never over-burden or over-inflate BFGoodrich Radial T/A tires past the maximum tire load limit and maximum tire inflation values demonstrated on the tire sidewall.
Recommended Reading: 29.5 X10x12 Atv Tires
Increased Mileage And Treadlife Warranty
To assess the KO2s treadlife and mileage potential, BFGoodrich commissioned both internal and external testing.
As compared to the original KO, the KO2 doubles up on its gravel endurance/mileage potential. Asphalt wear is also much improved with a 15% gain.
Select specification All-Terrain T/A KO2 tires are offered with a 50,000 .
All Obstacles All Possibilities
Our passions often lie outside the roads painted lines. We engineered our latest tire for both on-road performance and light off-road situations.So, take on the world as you see fit.
Years of experience and testing in some of the toughest conditions on Earth have resulted in a tire that thoroughly and consistently defies expectations. Here’s why.
We chew up dirt. We grind through snow. We happily weather the abuse of standard city roads. And still — through all of that — we offer a 60,000 mile standard warranty to prove our dependability.
The 3-Peak Mountain Snow Rating denotes the severe snow driving capability of the Trail-Terrain T/A®, which exhibits powerful traction long after the mercury drops.
Trail-Terrain T/A® features full-depth 3D sipes that create plenty of grip in any condition without compromising road noise.
Our signature shoulder design gives the tire a powerful look, and serrated shoulder blocks enhance traction in soft-soil situations
Read Also: Inflate Bike Tire With Co2
How To Calculate Sidewall Height
The sidewall height is determined by the section width and the aspect ratio. The formula to find the sidewall is:
sidewall = section width ×aspect ratio / 100
To find the sidewall, simply enter the section width and aspect ratio into the formula and solve. The result will be the sidewall measurement in millimeters use a conversion calculator to convert to inches.
For example, lets find the sidewall of a 245/40R18 tire.
sidewall = 245mm ×40 / 100sidewall = 98mm
How To Calculate Tire Circumference
The circumference of a tire is required to calculate speedometer error. You can find the tires circumference using the diameter and a simple formula:
circumference = diameter ×
The circumference is equal to the diameter times pi. Pi is equal to roughly 3.14.
For example, lets find the circumference of the 245/40R18 tire using the 25.72 diameter that we calculated above.
circumference = 25.72× 3.14circumference = 80.8
You May Like: 205 75r14 All Terrain Tires
Ten Things To Know About The Bfgoodrich All
the quality of BFGoodrich tires makes itself felt on a wide range of surfaces, including earth, sand, rock and asphalt, proof of the incredible versatility of BFGoodrich products. – BFGoodrich.co.uk
Pay a weekend visit to an off-road park or 4×4 trailhead, and inevitably you’ll encounter BFGoodrich tires.
The BFGoodrich reputation has been forged with off-road performance, including numerous wins at world-renowned events like the Paris-Dakar Rally and Baja 1000. Legitimate all-terrain, off-road performance is at the very core of the BFGoodrich identity.
And so when BFGoodrich assigns adjectives like best and toughest to one of its 4×4 products, best take note
According to BFGoodrich, the All-Terrain T/A KO2 is the brands best all-terrain tire to date. If youre on the hunt for a class-leading all-terrain tire, then the KO2 has to be considered.
This fourth generation BFGoodrich all-terrain draws from progress made over the past 40+ years. BFGoodrich launched its first all-terrain tire, the Radial All-Terrain T/A, back in 1976. The All-Terrain T/A KO2 is the first update since 1999.
Here are ten things to know about BFGoodrichs latest flagship all-terrain tire:
Engineered For Up To 50% Off
The All-Terrain T/A KO2 is intended for 4×4 drivers who split their time on- and off-road. BFGoodrich suggests that its the right tire for trucks and SUVs that travel off-road up to 50% of the time.
The takeaway: In consistently challenging, mixed-use conditions where Truck/SUV all season tires are unlikely to endure and hold up, the KO2 thrives.
As compared to the outgoing All-Terrain KO , the KO2 offers measurable traction and durability improvements. According to BFGoodrich, the KO2 is:
+ 10% improved in mud traction.
+ 19% improved in snow traction.
+ 20% in sidewall strength.
You May Like: What Is The Best Tire Brand
How To Calculate Revolutions Per Mile
Once you have the tire circumference, its possible to find the revolutions per mile using this formula:
rev/mile = 63,360 ÷ circumference
The revolutions per mile are equal to the number of inches in a mile divided by the circumference in inches.
For example, lets find the revolutions per mile of the 245/40R18 tire. Remember that the circumference is 80.8.
rev/mile = 63,360 ÷ 80.8rev/mile = 784.16
Ford Transit/ko2 Compatible Tire Sizes
We cant possibly go through all the different brands/models on the market, so well stick to what we know for now:
|Tire Size, Load Index & Speed Rating
|Rim Width Range
1LT225/75R16/E 115 S: Take note of the 115 load index this is much lower than the factory tires. We DID run these tires at first for a few years without issues, but because the load index is so low, we wouldnt recommend them.
2 The pinch weld has to be trimmed. Check out Moreys in Transit instructions.
3 Fit in the spare tire carrier of the Ford Transit 148 Extended-Length only. You can still fit it in the non-extended length by following Moreys in Transit instructions.
Read Also: What Size Are My Tires
Ford Transit Factory Tires
Our 2016 and 2021 Ford Transit came equipped with Continental 235/65/R16 121C.
They are 28 diameter.
Dont be fooled by the Four Seasons or All Seasons appellation. Theyre simply not made for snow! For example, driving with these in Quebec during winter is illegal! They are also useless in mud or on wet grass
Note the 121 load index.