How to Read Tyre Size: UAE Guide to Sidewall Markings

Reading 225/45 R17 94W piece by piece

The first number, 225, is the section width in millimetres, measured from sidewall to sidewall at the widest point. The second, 45, is the aspect ratio: the sidewall height as a percentage of the width, so this tyre has a sidewall of about 101 mm. Lower numbers like 35 or 40 mean a short, stiff sidewall typical of sports models; 60 to 70 means a tall sidewall typical of SUVs and pickups.

The letter R means radial construction, which covers almost every car tyre sold in the UAE today. The number after it, 17, is the rim diameter in inches, and it must match the wheel exactly. Put together, 225/45 R17 has an overall diameter of about 634 mm.

The service description 94W comes last. 94 is the load index, the maximum weight one tyre can carry at the correct pressure, here 670 kg. W is the speed symbol, the maximum sustained speed the tyre is built for, here 270 km/h. These two figures are the ones people most often ignore when buying cheaper tyres, and they are the ones that matter most on long, fast UAE highways.

P-metric, LT and flotation sizes on 4x4s

A P before the size, as in P265/70 R16, marks a US passenger tyre; no prefix means a European metric tyre, and the two use slightly different load tables at the same index. LT, as in LT265/75 R16 123/120Q, marks a light-truck tyre with a stronger carcass, higher pressures and two load figures, one for single and one for dual rear wheels. LT tyres suit heavily used Hilux, Land Cruiser pickups and work vans, but they ride harder and need the higher pressure printed for their load range.

Many off-road tyres in the UAE use flotation sizing in inches, such as 31x10.50R15: about 31 inches tall, 10.5 inches wide, on a 15-inch rim. Metric 265/70 R16 is about 30.6 inches tall, so the two are close in height but not interchangeable, because the rims differ. When moving between the systems, compare overall diameter and width, not the numbers on the label.

Load index and speed rating explained

The load index is a code, not a weight: 91 means 615 kg per tyre and 94 means 670 kg, so a small change in the number is a meaningful change in capacity. Multiply by four for the most the set can carry, which must exceed the vehicle's gross weight with a margin. The table below lists common indexes. The speed symbol is a letter for the maximum sustained speed, tested under load. In UAE summer heat a tyre runs hotter than in the test lab, so the factory rating is a minimum, not a target to undercut.

ZR inside the size, as in 245/40 ZR18, is an older marking for tyres rated above 240 km/h. Modern ZR tyres still show a service description such as 97Y, and if the letter is in brackets, (Y), the tyre is rated above 300 km/h.

• Q = 160 km/h: some LT mud-terrain and commercial tyres
• R = 170 km/h and S = 180 km/h: all-terrain and light-truck tyres
• T = 190 km/h: economy sedans and many SUV highway tyres
• H = 210 km/h: most family sedans and SUVs such as Camry, Prado, X-Trail
• V = 240 km/h: sporty sedans and premium SUVs
• W = 270 km/h and Y = 300 km/h: BMW, Mercedes, Porsche, Range Rover and performance trims

DOT code and tyre age in the UAE

The last four digits of the DOT code give the manufacturing date: 2324 means week 23 of 2024. The full code starts with DOT, then a two-character plant code identifying the factory, a size code, an optional manufacturer code, and finally the date digits, often in a raised oval. The full code with the date is sometimes moulded on one side only, so check both sidewalls before deciding it is missing.

Heat and UV age rubber quickly in the UAE. As a working rule, do not accept new tyres more than about two years past their manufacture date, and replace tyres around five years old even if the tread looks deep, because the rubber hardens and develops fine cracks between the tread blocks and on the sidewall. A tyre that has sat in a hot warehouse or on a trailer in the sun ages faster than one in a cool store. Ask for the DOT dates when you get a quote, and check them before the old tyres come off.

XL, run-flat, M+S and UTQG markings

XL or Extra Load, sometimes shown as Reinforced, means a stronger tyre that carries more at a higher pressure; a 225/45 R17 is 91 in standard load and 94 in XL. If your car came with XL tyres, replace them with XL. Do not confuse a Reinforced RF marking with run-flat: run-flat tyres use brand codes such as RFT (Bridgestone), ROF (Goodyear and Dunlop), ZP (Michelin), SSR (Continental) and Run Flat or r-f (Pirelli). BMW also adds a star symbol for its approved fitments, and Mercedes uses MO or MOE.

M+S (mud and snow) and the three-peak mountain snowflake (3PMSF) symbol relate to cold and snowy conditions and add nothing on UAE roads. M+S appears on many all-terrain SUV tyres and is harmless. A true winter tyre with 3PMSF and a soft compound will wear very fast in 45°C heat, so avoid them unless you are shipping the car somewhere cold.

UTQG ratings are on most tyres sold for the US market. Treadwear, for example 400, compares wear only within one brand. Traction runs AA, A, B, C for wet braking. Temperature runs A, B, C for resistance to heat build-up at speed, and A is the grade to look for in the UAE.

Where to find your tyre size and how staggered fitments work

The quickest place to find your size is the sidewall of the tyre already on the car. The driver's door placard and the owner's manual show the factory size, which matters if a previous owner fitted something different. Many cars list two or three approved sizes depending on trim, such as 215/55 R17 and 235/45 R18 on a Camry. Sending a clear photo of the sidewall on WhatsApp is the fastest way to get an exact quote.

A staggered fitment uses wider tyres at the rear than the front, common on BMW, Mercedes AMG, Porsche and Ford Mustang, for example 225/40 R19 front and 255/35 R19 rear. Read both axles, because the sizes and sometimes the load indexes differ. Staggered tyres cannot be rotated front to rear, and the rears typically wear out first, so budget for rear pairs more often than fronts.

Plus-sizing: bigger wheels without the problems

Plus-sizing means fitting a larger rim with a lower-profile tyre while keeping the overall diameter within about ±3% of the original. A Corolla on 205/55 R16 (about 632 mm) can move to 225/45 R17 (634 mm) or 225/40 R18 (637 mm) and stay well inside that limit. Going outside it confuses the speedometer, ABS and stability control, and can cause rubbing on suspension or arches at full lock.

A larger overall diameter makes the speedometer read lower than your true speed, which matters with fixed radars on every major road; a smaller one makes it read higher. The load index must be equal to or higher than the original, which on lower profiles often means an XL tyre. The speed rating must also be equal or higher.

There are real costs. A lower sidewall rides harder, transmits more road noise and gives less protection against kerbs, potholes and the steep speed bumps in communities like JVC, Al Barsha and Mirdif, so bent rims and sidewall bulges become more common. Tyre prices rise too: a mid-range 205/55 R16 costs about AED 300–420 each, while a mid-range 225/45 R18 runs about AED 420–600. Also tell your insurer, as non-standard wheels can affect a claim.

• Keep overall diameter within about ±3% of the factory size.
• Match or exceed the original load index; use XL where needed.
• Match or exceed the original speed rating.
• Check offset and width so the wheel clears brakes, struts and arches.