Steps


1
Look at the letter/number combination on the tire. Most tire sizes begin with a letter or letters that identify the type of vehicle and/or type of service for which they were designed. The common indicators are as follows:
P225/50R16 91S
P = When a tire size begins with a "P," it signifies the tire is a "P-metric" size that was designed to be fitted on vehicles that are primarily used as passenger vehicles. This includes cars, minivans, sport utility vehicles and light duty pickup trucks (typically 1/4- and 1/2-ton load capacity). The use of P-metric sizes began in the late 1970s and they are the most frequently used type of tire size today.
/50R16 92S = If there isn't a letter preceding the three-digit numeric portion of a tire size, it signifies the tire is a "Metric" size (also called "Euro-metric" because these sizes originated in Europe). While Metric tire sizes are primarily used on European cars, they are also used on vans and sport utility vehicles. Euro-metric sizes are dimensionally equivalent to P-metric sizes, but typically differ subtly in load carrying capabilities.
T125/90D16 98M
T = If a tire size begins with a "T," it signifies the tire is a "Temporary Spare" ("space saver" or "mini spare that was designed to be used temporarily only until a flat tire can be repaired or replaced.
LT245/75R16 108/104S
LT = If a tire size begins with "LT," it signifies the tire is a "Light Truck-metric" size that was designed to be used on vehicles that are capable of carrying heavy cargo or towing large trailers. This includes medium and heavy-duty (typically 3/4- and 1-ton load capacity) pickup trucks, sport utility vehicles and full-size vans. Tires branded with the "LT" designation are the "little brothers" of 18-wheel tractor-trailer tires and are designed to provide substantial reserve capacity to accept the additional stresses of carrying heavy cargo.
50R16LT 112/107Q, 8.75R16.5LT 104/100Q or 31x10.50R15LT 109Q
LT = If a tire ends with "LT," it signifies the tire is either an earlier "Numeric", "Wide Base" or "Flotation" Light Truck size designed to be used on vehicles that are capable of carrying heavy cargo and towing trailers (Numeric sizes), use 16.5-inch diameter rims (Wide Base sizes) or are wider, oversized tires designed to help the vehicle drive on top of loose dirt or sandy surfaces (Flotation sizes). This includes light, medium and heavy-duty (typically 1/2-, 3/4 and 1-ton load capacity) pickup trucks and sport utility vehicles. Tires branded with the "LT" at the end of their size designation are also the "little brothers" of 18-wheel tractor-trailer tires and are designed to provide substantial reserve capacity to accept the additional stresses of carrying heavy cargo.
/70R15C 104/102R
C = If a Euro-metric sized tire ends with a "C," it signifies the tire is a "Commercial" tire intended to be used on vans or delivery trucks that are capable of carrying heavy loads. In addition to being branded with the "C" in their size, these tires are also branded with their appropriate Service Description and "Load Range" (Load Range B, Load Range C or Load Range D).
ST225/75R15
ST = If a tire size begins with "ST," it signifies the tire is a "Special Trailer Service" size that was designed to only be used on boat, car or utility trailers. ST-sized tires should never be used on cars, vans or light trucks.

2
Look at the three-digit numeric portion. This identifies the tire's Section Width (cross section) in millimeters.
P225/50R16 91S. The 225 indicates this tire is 225 millimeters across from the widest point of its outer sidewall to the widest point of its inner sidewall when mounted and measured on a specified width wheel. This measurement is also referred to as the tire's section width. Because many people think of measurements in inches, the 225mm can be converted to inches by dividing the section width in millimeters by 25.4 (the number of millimeters per inch). mm / 25.4 = 8.86"

3
Look at the two-digit number following the Section Width number. This is the Sidewall Aspect Ratio.
P225/50R16 91S. The 50 indicates that this tire size's sidewall height (from rim to tread) is 50% of its section width. The measurement is the tire's section height, and also referred to as the tire's series, profile or aspect ratio. The higher the number, the taller the sidewall; the lower the number, the lower the sidewall. We know that this tire size's section width is 225mm and that its section height is 50% of 225mm. By converting the 225mm to inches (225 / 25.4 = 8.86" and multiplying it by 50% (.50) we confirm that this tire size results in a tire section height of 4.43". If this tire were a P225/70R16 size, our calculation would confirm that the size would result in a section height of 6.20", approximately a 1.8-inch taller sidewall.

4
Look at the letter following the numbers -- it identifies the tire's internal construction.
P225/50R16, P225/50ZR16. The R in the P225/50R16 91S size identifies that the tire has a Radial construction in which the tire's body plies "radiate" out from the imaginary center of the wheel. Radial tires are by far the most popular type of tire today representing over 98% of all tires sold.
If the R in the size was replaced with a D (225/50D16), it would identify that the internal tire body plies crisscross on a Diagonal and that the tire has a "bias ply" construction. Tires using this construction are for light truck and spare tire applications.
If the R in the size was replaced with a B (225/50B16), it would identify that the tire body plies not only crisscross the tire on a diagonal as before, but that they are reinforced with belts under the tread area. This type of tire construction is called "Belted." Tires using this construction are practically extinct.

5
Look for the Speed Rating. Today, the only tires that continue to include the speed rating "in" the tire size (P225/50ZR16) are Z-speed rated tires. In this case, following the two digits used to identify the aspect ratio are the letters ZR to identify the tire's speed rating (Z) and its internal construction (R). Since 1991, all other speed ratings are identified in the tire's Service Description

6
Consider the Tire and Wheel Diameter.
P225/50R16 91S. The 16 indicates the tire and wheel diameter designed to be matched together.
Tires that have a rim diameter expressed in inches (P225/50R16, as well as 8, 10, 12, 13, 14, 15, 17, 18, 19, 20, 22, 23, 24, 26 and 28) are called "inch rim" sizes, are the most common type of tire size and are used on most cars, minivans, vans, sport utility vehicles and light duty light trucks. While not as common, two additional "unique" types of tire/wheel diameters are still in use today.
Tires and wheels that have a rim diameter expressed in "half" inches (8.00R16.5LT, as well as, 14.5, 15.5, 17.5 and 19.5) are used on some heavy-duty trailers, heavy-duty light trucks and box vans.
Tires and wheels that have a rim diameter expressed in millimeters (190/65R390, as well as, 365 and 415) are called millimetric sizes. Michelin initiated millimetric sizes for their TRX tires that saw limited use on many different car models in the late 1970s and 1980s.
Michelin PAX System run flat tires have been introduced as an integrated wheel/tire system on a very limited basis as Original Equipment (O.E.) in North America. An example PAX System size of 235/710R460A 104T expresses tire and wheel dimensions in millimeters (235 mm Section Width, tire Overall Diameter of 710 mm and a 460A mm rim diameter, with the "A" in 460A signifying these tires feature "asymmetric" beads in which the outside bead (450 mm) and inside bead (470 mm) are actually different diameters.
All of these "unique" tire/wheel diameters were developed specifically because the tire and wheel design or intended vehicle use required them to be different than conventional tires and wheels. All of these tires and wheels feature bead profiles that have a different shape than traditional "inch rim" sizes.

http://m.wikihow.com/Tell-the-Size-Difference-on-a-Car-Tire

This plenty storybook wey I no fit read na just to identify tyre

Me: Drives to the market, oga Andy abeg see my motor I wan buy new tyre for am.

Seller: Ok this Venza? I get am na 19 rims.

Me: You be correct. See as you use eye gauge run am
Oya change the back tyres, carry the two for front go back then put the new ones for front.

Deal done, counts money and zooms off
Shikena

@ colossus2 quite hilarious

When buying a car to Jiji, the seller told me that. Thank you for the article useful

colossus2:
This plenty storybook wey I no fit read na just to identify tyre

Me: Drives to the market, oga Andy abeg see my motor I wan buy new tyre for am.

Seller: Ok this Venza? I get am na 19 rims.

Me: You be correct. See as you use eye gauge run am
Oya change the back tyres, carry the two for front go back then put the new ones for front.

Deal done, counts money and zooms off
Shikena

very simple.. Those dealers already know the car tyres size once they sight the car.. Op jst they blow grammar;P

Nice one op

Nice thread though, my head to heavy to dey carry tyre codes, Kazeem go do that one jare.............

Isn't an expert knowledge needed in this instance? I think we should leave those things we cannot do to experienced experts.


Neteller here: .com.ng

Nice one OP but one can always check by the frame of the body of the car na,
It's always written by the driver's side by the door.

Nice information

only tyre get all this textbook story.
useful though.

colossus2:
This plenty storybook wey I no fit read na just to identify tyre

Me: Drives to the market, oga Andy abeg see my motor I wan buy new tyre for am.

Seller: Ok this Venza? I get am na 19 rims.

Me: You be correct. See as you use eye gauge run am
Oya change the back tyres, carry the two for front go back then put the new ones for front.

Deal done, counts money and zooms off
Shikena

Or simply crack open the owners manual.

We Dat don't have a car yet nko....well I can get d tyre down now...who knows d future...I might be MISS NAIRALAND 2017...Will just use d cash price to get a car

Ion Have A Car Yet, But Soon, Lemme Jes Calm Down And Learn

Please refer to the Manufacturers Manual and not the process. This is how NOT to know your tyre size.

fkj950ax:
Please refer to the Manufacturers Manual and not the process. This is how NOT to know your tyre size.

I never knew Manuals come with tyres ooooo, maybe I don't ask! Be truthful at least to yourself, when last did you read a Manual, as in any Manual at all? Let us appreciate him, that little piece of info is live saving. You now know what to buy before getting a Manual not getting a Manual after buying "wrongly".

I'll be back

.....do all tyres come with that first letter?....

colossus2:
This plenty storybook wey I no fit read na just to identify tyre

Me: Drives to the market, oga Andy abeg see my motor I wan buy new tyre for am.

Seller: Ok this Venza? I get am na 19 rims.

Me: You be correct. See as you use eye gauge run am
Oya change the back tyres, carry the two for front go back then put the new ones for front.

Deal done, counts money and zooms off
Shikena

Correct Muan!.......

The most important thing for me is the tyre size..... eg 265/70 R18....or 205/65 R15......etc

Is it necessary the size of tyres you use? I actually like big tyres on small cars

Is it necessary the size of tyres you use? I actually like big tyres on small cars

MrBully:
Is it necessary the size of tyres you use? I actually like big tyres on small cars

When you put big tyres in small cars, ensure the front tyres ain't partially touching the metal body when you wheel to the right/left [that would surely shorten the lifespan]

Onyenna:


When you put big tyres in small cars, ensure the front tyres ain't partially touching the metal body when you wheel to the right/left [that would surely shorten the lifespan]

That's true. After changing my tyres, I had to raise the shocks a little bit so that it doesn't touch the metal.

aw many pple dey look for all these?? nice info tho

Youngetskilz23:
very simple.. Those dealers already know the car tyres size once they sight the car.. Op jst they blow grammar;P

Why would some of U just come here to display ignorance? Have you thought for a 2nd you could upgrade your tyres from 15 inch to 16in
How about if the previous owner did this?