How to read a tyre size

Using 195/65 R15 as an example: how to read the size marking, the load index and speed symbol, and the production week and year, and what to check before you buy.

First, copy down the markings on your current tyres' sidewalls, letters and all.

Try the numbers

Change rim width, offset or tyre size and see the difference in millimetres and on the diagram.

Try the numbers

Showing the new wheel.

Drag the car to rotate it; double-tap to reset the view.

Current wheel

Rim width (J)

Offset (ET)

New wheel

Rim width (J)

Offset (ET)

Tyre size and clearances (optional)

Tyre size Gap to the fendermm Gap to the suspensionmm

A rim 1 inch wider makes the same tyre about 10 mm wider.

Outer edge
Inner edge
Wheel centre
Track (per axle)

Show the formula

Static calculation. Clearance shrinks when you steer or the suspension compresses.

205/55 R16 → 225/45 R17

Original size

Width205 mm

Aspect55%

Rim16″

New size

Width225 mm

Aspect45%

Rim17″

Pick from a list

Original size

WidthAspectRim

New size

WidthAspectRim

Vehicle production date Jan 2007 or later Dec 2006 or earlier

Original diameter: 631.9 mm
New diameter: 634.3 mm
Difference: +2.4 mm (+0.38%)

Speedometer	40	60	80	100
Actual speed	40.2	60.2	80.3	100.4
Actual speed

Japanese inspection rule (speedometer at 40 km/h)

Actual ≈40.2 km/h: within the rule by calculation (31.0–42.5 km/h).

Assumes the original speedometer is exact; real speedometers are built to read slightly high.

Almost the same diameter (+0.38%). At 40 km/h indicated you drive ≈40.2 km/h.

Based on nominal sizes. Real diameter varies with tyre model, wear and pressure. The inspection measures actual speed at 40 km/h indicated.

The 3D car is a generic model; the numbers use the same formulas as the calculator.

3D model: Pooya_dh (Sketchfab), CC BY 4.0; wheels, logos, paint and stickers changed3D model: Ciasny (Sketchfab), CC BY 4.0; wheels, logos and paint changed

This is a calculated guide, not a guarantee that parts fit your car. Before buying, tell us the model code, first registration date and your current tyre and wheel sizes.

Reading the size marking

Let's read "195/65R15" one number at a time.

Illustration: the mascot beside a wheel explains how to read the tyre size

The tyre size is marked on the side of the tyre (the sidewall). A marking such as "195/65 R15 91H" reads from left to right:

Example

1195 265 3R 415 591 6H

Size 1–4Indexes 5–6

Use the arrow keys to switch.

Press a number to see what that part means.

1Size

195 — tyre width

What it means: Nominal tyre width (section width) in millimetres.
In this example: Width: 195 mm

2Size

65 — aspect ratio

What it means: Aspect ratio: sidewall height as a percentage of width, also called the "65 series".
In this example: Sidewall height: 195 × 0.65 = 126.75 mm

3Size

R — radial construction

What it means: Radial construction.
Good to know: Markings vary by tyre type and maker; some read like "235/45ZR17", with "ZR" before the rim diameter. Tyres with "ZR" in the size are radial tyres with a maximum speed above 240 km/h.

4Size

15 — rim diameter

What it means: Rim diameter in inches; it matches the diameter of the wheel the tyre fits.
In this example: Rim diameter: 15 in = 15 × 25.4 = 381 mm
Good to know: The number after R is not the tyre's outside diameter. Outside diameter = sidewall height × 2 + rim diameter. For 195/65 R15 that is 126.75 × 2 + 381 = 634.5 mm. This is calculated from nominal dimensions; check the actual outside diameter in the tyre maker's catalogue.

5Indexes

91 — load index

What it means: The maximum load one tyre can carry under specified conditions.
In this example: 91: 615 kg per tyre
Good to know: When replacing tyres, choose an LI equal to or higher than the original.

6Indexes

H — speed symbol

What it means: The maximum speed at which the tyre can run under specified conditions while carrying the load its LI indicates.
In this example: H: 210 km/h
Good to know: Some tyres show a ply rating (PR) for strength instead of a load index and speed symbol.

1 / 6

1225 245 3R 417 594 6W

Size 1–4Indexes 5–6

Use the arrow keys to switch.

Press a number to see what that part means.

1Size

225 — tyre width

What it means: Nominal tyre width (section width) in millimetres.
In this example: Width: 225 mm

2Size

45 — aspect ratio

What it means: Aspect ratio: sidewall height as a percentage of width, also called the "45 series".
In this example: Sidewall height: 225 × 0.45 = 101.25 mm

3Size

R — radial construction

What it means: Radial construction.
Good to know: Markings vary by tyre type and maker; some read like "235/45ZR17", with "ZR" before the rim diameter. Tyres with "ZR" in the size are radial tyres with a maximum speed above 240 km/h.

4Size

17 — rim diameter

What it means: Rim diameter in inches; it matches the diameter of the wheel the tyre fits.
In this example: Rim diameter: 17 in = 17 × 25.4 = 431.8 mm
Good to know: The number after R is not the tyre's outside diameter. Outside diameter = sidewall height × 2 + rim diameter.

5Indexes

94 — load index

What it means: The maximum load one tyre can carry under specified conditions.
In this example: 94: 670 kg per tyre
Good to know: When replacing tyres, choose an LI equal to or higher than the original.

6Indexes

W — speed symbol

What it means: The maximum speed at which the tyre can run under specified conditions while carrying the load its LI indicates.
In this example: W: 270 km/h
Good to know: Some tyres show a ply rating (PR) for strength instead of a load index and speed symbol.

1 / 6

195 — nominal tyre width (section width) in millimetres.
65 — aspect ratio: sidewall height as a percentage of width, also called the "65 series".
R — radial construction.
15 — rim diameter in inches; it matches the diameter of the wheel the tyre fits.
91H — load index and speed symbol (see "Load index and speed symbol").

The number after R is not the tyre's outside diameter. Outside diameter = sidewall height × 2 + rim diameter. For 195/65 R15 the sidewall height is 195 × 0.65 = 126.75 mm and the rim diameter is 15 × 25.4 = 381 mm, so the outside diameter is 126.75 × 2 + 381 = 634.5 mm. This is calculated from nominal dimensions; check the actual outside diameter in the tyre maker's catalogue.

Markings vary by tyre type and maker; some read like "235/45ZR17", with "ZR" before the rim diameter. The diagram's "225/45 R17 94W" reads the same way; its sidewall height is 225 × 0.45 = 101.25 mm.

Example: 195/65 R15

Width: 195 mm
Sidewall height: 195 × 0.65 = 126.75 mm
Rim diameter: 15 in = 15 × 25.4 = 381 mm
Outside diameter (calculated): 126.75 × 2 + 381 = 634.5 mm

Parts of 195/65 R15 91H6 rows

Parts of 195/65 R15 91H
Mark	Meaning	Unit / this example
195	Nominal tyre width	mm
65	Aspect ratio: height as a percentage of width	% (height 126.75 mm)
R	Radial construction	—
15	Rim diameter	inches (381 mm)
91	Load index	615 kg per tyre
H	Speed symbol	210 km/h

Source: Bridgestone: reading tyre sizes (Japanese)

Why keep the outer diameter

Beyond the size

Even with the same size, check the load and speed markings too.

Matching "195/65 R15" is not enough on its own. Also check:

Load index (LI)
Where to find itNumber after the size
What to checkEqual to or higher than the original
Speed symbol
Where to find itLetter after the LI
What to checkMeets your vehicle's specification
XL (extra load)
Where to find itTyre standard
What to checkPressure set for that standard
Approved rim width
Where to find itTyre maker's catalogue
What to checkYour rim width is within the range
Vehicle-specified pressure
Where to find itLabel near the driver's door or fuel filler
What to checkReference for the original size; with a different LI or standard, pressure for the same load

Load index (LI): when replacing tyres, choose an LI equal to or higher than the original tyres. A lower LI than the original can lead to tyre damage and, in turn, an accident.
Speed symbol: check that it meets your vehicle's specification.
Inflation pressure: the vehicle-specified pressure is set by the car maker for each model and applies to tyres of the original size. If a tyre has a different LI or standard (such as XL), the pressure it needs to carry the same load can differ. Ask a tyre specialist for the pressure that gives the same load capacity as the pressure on the label. The load capacity of XL (extra load) tyres depends on pressure, so they need the correct pressure setting and closer pressure management.
Approved rim width: tyre makers set a range of rim widths for each tyre width. Check that your wheel's rim width is within it.
Vehicle-specified pressure: shown on the pressure label near the driver's door or the fuel filler.
Vehicle-specified size: the tyres currently fitted may not be the specified size, so compare them with the vehicle's specification.

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If the listing does not show the load index or speed symbol, ask us for the sidewall markings.

Load index and inflation pressure

Different front and rear sizes

If your car uses different front and rear sizes, check both.

Illustration: the mascot shows two wheels, for the front and rear axles

Some vehicles use different tyre sizes on the front and rear axles. In that case, check the size, load index and speed symbol for each axle. When buying a set, also confirm how many tyres you need for each axle.

1Front axle 2Rear axle 3How many tyres

Use the arrow keys to switch.

Press a number to see what to check.

1Axle

Front axle

What to check: Front: size, LI and speed symbol

2Axle

Rear axle

What to check: Rear: size, LI and speed symbol

3When buying

How many tyres

What to check: How many tyres for each axle

1 / 3

Try “Different front and rear” in the calculator

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Catalogue filters show candidates that match your conditions. They do not certify that a tyre fits your vehicle.

Load index and speed symbol

In "91H", 91 is the load index and H the speed symbol. Compare them with your vehicle's specification.

Try it

Decode a marking like “91H”

The number is the load index, the letter the speed symbol.

Marking after the size

Examples

Values are read from this section’s tables (excerpt). When replacing, choose an LI equal to or higher than the original tyre.

In a marking such as "91H" after the size, the number is the load index (LI) and the letter is the speed symbol.

The load index shows the maximum load one tyre can carry under specified conditions. 91 means 615 kg per tyre; 94 in the diagram means 670 kg. When replacing tyres, choose an LI equal to or higher than the original. This load capacity is also the reference for adjusting inflation pressure, for example when changing size.

The speed symbol shows the maximum speed at which the tyre can run under specified conditions while carrying the load its LI indicates. H means 210 km/h; W in the diagram means 270 km/h. Tyres with "ZR" in the size are radial tyres with a maximum speed above 240 km/h.

Some tyres show a ply rating (PR) for strength instead of a load index and speed symbol.

Example: 91H and 94W

91H: 615 kg per tyre, up to 210 km/h
94W: 670 kg per tyre, up to 270 km/h
If the original is 91, choose 91 or higher

Load index and load capacity (excerpt)21 rows

Load index and load capacity (excerpt)
LI	Load per tyre
80	450 kg
81	462 kg
82	475 kg
83	487 kg
84	500 kg
85	515 kg
86	530 kg
87	545 kg
88	560 kg
89	580 kg
90	600 kg
91	615 kg
92	630 kg
93	650 kg
94	670 kg
95	690 kg
96	710 kg
97	730 kg
98	750 kg
99	775 kg
100	800 kg

The full table for LI 62–121 is in the source.

Source: Bridgestone: reading tyre sizes (Japanese)

Speed symbol and maximum speed11 rows

Speed symbol and maximum speed
Symbol	Maximum speed
L	120 km/h
N	140 km/h
Q	160 km/h
R	170 km/h
S	180 km/h
T	190 km/h
H	210 km/h
V	240 km/h
W	270 km/h
Y	300 km/h
ZR	over 240 km/h

ZR is a speed category shown on radial tyres with a maximum speed above 240 km/h.

Source: Bridgestone: reading tyre sizes (Japanese)

Hub Garage store guide

In "91H", 91 is the load index and H the speed symbol. Compare them with your vehicle's specification.

Production week and year

The production week and year are the last four digits of the sidewall code.

Try it

When was the tyre made: the sidewall code

Enter the last 4 digits of the sidewall code: the first two are the week, the last two the year.

Last digits of the code

Examples

JATMA recommends replacing a tyre 10 years after production. It is a guideline, not an expiry date.

The production week and year are the last four digits of the serial code on the sidewall: the first two are the week and the last two the year. For example, "1220" means week 12 of 2020.

Tyres made in 1999 or earlier use the last three digits: "159" means week 15 of 1999.

How to judge age and condition is covered in "How to read photos of used tyres and wheels".

Example: 1220

12: week (12th)
20: year (2020)
→ made in week 12 of 2020

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Hub Garage items

Compare it with the production year shown in the listing.

Tyre age: guidelines

Before you buy: checklist

A photo of your current tyres' markings makes it easier to compare with the listing.

What to note down — example

Size: 195/65 R15
LI and speed symbol: 91H
Production week and year: 1220
Front and rear sizes: same / different

Check for yourself

Size of your current tyres (e.g. 195/65 R15)
Load index and speed symbol (e.g. 91H)
Your vehicle's specified size and the pressure label
Whether front and rear sizes differ
If you are also changing wheels: whether the rim width is within the tyre's approved range
Season (summer or winter) and how many tyres you need

Checked 0 of 6

Checking these points before you buy makes it easier to avoid choosing the wrong size. A photo of your current tyres' markings makes comparing easier.

Choosing at Hub Garage

If a marking is missing or anything concerns you, contact us with the item number.

Illustration: the mascot welcomes questions

We wash and clean tyres on arrival and visually inspect scratches, dirt, wear, cracks and other visible damage.

Cracks and puncture repairs that we identify are stated in the item description. Internal damage and small air leaks cannot always be detected by visual inspection alone, and the absence of a note does not guarantee that there has been no repair or defect.

Catalogue filters show candidates that match your conditions; they do not certify that a tyre fits your vehicle. If the listing does not show the load index or speed symbol, or anything concerns you, please ask before purchase.

When you contact us, please give the item number, vehicle make and model, year, chassis code and trim.

What to tell us

Item number
Vehicle make and model, year, chassis code and trim
Current tyre size, load index and speed symbol (if known)

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Purchase terms

Report defects in regular items within 7 days of receipt. C/D items have separate terms.

Summer tyres Winter tyres Cleaning and inspection Condition grades

Hub Garage store guide

If a marking is missing or anything concerns you, contact us with the item number.

Back to the catalogue

How to read a tyre size

Try the numbers

Reading the size marking

195 — tyre width

65 — aspect ratio

R — radial construction

15 — rim diameter

91 — load index

H — speed symbol

225 — tyre width

45 — aspect ratio

R — radial construction

17 — rim diameter

94 — load index

W — speed symbol

Beyond the size

Load index (LI)

Speed symbol

XL (extra load)

Approved rim width

Vehicle-specified pressure

Different front and rear sizes

Front axle

Rear axle

How many tyres

Load index and speed symbol

Production week and year

Before you buy: checklist

Choosing at Hub Garage

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