Bicycle Tire and Rim Width Compatibility Chart: From Sidewall Numbers to Safe Fit

Short answer: A bicycle tire fits a rim when two numbers match. The tire's bead seat diameter must equal the rim's bead seat diameter exactly. The tire's section width must also fall within the range the rim and tire makers approve for that internal rim width. Both numbers are in the ETRTO size printed on the sidewall, such as 28-622. That means a 28 mm wide tire for a 622 mm bead seat diameter rim. For a rim with a 17 mm internal width, many published charts list tires from roughly 25 mm to about 47 mm. The approved range for your specific rim and tire always takes priority over a general chart.

What do the numbers on a bicycle tire sidewall mean?

A bicycle tire sidewall usually shows the same size in two or three systems. Some numbers describe the tire's dimensions. Others are pressure limits or construction and performance ratings, which are not sizes at all. The ETRTO number is the most reliable size marking because it uses millimetres and states the bead seat diameter directly.

ETRTO tire size: width and bead seat diameter

The ETRTO (European Tyre and Rim Technical Organisation) tire size, also used in ISO 5775, is written as width-diameter in millimetres, for example 37-622 or 57-584.

• First number, the tire section width (mm): the nominal width of the inflated tire. It is measured on a reference rim width. On your rim it may measure a little wider or narrower.
• Second number, the bead seat diameter or BSD (mm): the diameter of the rim surface where the tire bead sits. This number must match the rim exactly. A tire with a different BSD will not mount safely.

Traditional and inch markings

Older naming systems describe roughly the same tire in less precise terms. Use them only to identify a tire, then confirm the size with the ETRTO number.

• French sizing (for example 700x28C): 700 is a nominal outer diameter in millimetres, and 28 is the width. In this system the letter C once marked a diameter class. It does not mean the tire is for a hooked rim. A 700C tire has a 622 mm BSD.
• Decimal inch sizing (for example 29 x 2.25): 29 is a nominal wheel size, and 2.25 is the width in inches. 2.25 inches is about 57 mm, so this tire is typically 57-622.
• Fractional inch sizing (for example 26 x 1 3/8): fractional and decimal inch sizes that look alike can have different bead seat diameters. A 26 x 1 3/8 tire is usually 37-590. A 26 x 1.375 tire is usually 35-559. The two are not interchangeable.

Common wheel sizes and their bead seat diameters

Common name	Bead seat diameter (BSD)	Example ETRTO size
700C / 28-inch / 29er	622 mm	28-622 (700x28C), 57-622 (29 x 2.25)
650B / 27.5-inch	584 mm	47-584 (650B x 47), 61-584 (27.5 x 2.4)
650C	571 mm	23-571
26-inch mountain bike (decimal sizes)	559 mm	54-559 (26 x 2.1)
26 x 1 3/8 (older roadster/touring)	590 mm	37-590

The 29er and the 700C road wheel share the 622 mm BSD. They differ only in tire width.

Pressure limits and performance ratings

These markings describe how the tire may be used, not how big it is.

• Pressure range (bar / psi): for example "min 3.5 – max 6 bar (50–87 psi)". These are the tire maker's limits. A hookless rim may impose a lower maximum.
• TPI (threads per inch): the density of the casing fabric. A higher TPI usually means a more supple casing. It says nothing about size or rim compatibility.
• Tubeless markings: labels such as TLR, TL-Ready or Tubeless Ready mean the tire is designed for tubeless setups. A tire's suitability for hookless rims is a separate approval from the tire maker.
• E-bike ratings: labels such as "E-25" or "E-50" indicate testing for e-bikes up to the stated speed in km/h. This is a load and speed rating, not a size.
• Direction arrows: these show the intended direction of rotation and have no effect on size.

Internal rim width vs tire size: what is the relationship?

Internal rim width is the distance between the inner walls of the rim, measured where the tire beads sit, in millimetres. It controls how far apart the beads are held. That spacing determines the tire's shape, its measured width and how stable it is under load.

Rims often show an ETRTO rim size written as BSD x internal width plus a letter code, for example 622x17C. This means a 622 mm bead seat diameter and a 17 mm internal width. On rims, C indicates a hooked (crotchet) profile. TSS (tubeless straight side) indicates a hookless profile. If the rim has no marking, measure the internal width across the inside of the rim walls with a caliper.

The internal width is the number that matters for tire compatibility. The external width is the outside measurement across the rim walls. It is useful for frame and brake clearance, but it does not set the tire range.

• Tire too narrow for the rim: the sidewalls are pulled outward and lose support. The tire is more exposed to rim strikes and damage. On hookless rims the bead may not stay securely seated.
• Tire too wide for the rim: the beads are squeezed together, so the tire can squirm and roll under cornering loads. Tubeless setups are more likely to "burp" air at low pressure.
• Tire within the approved range: the tire takes its intended profile and behaves as the tire maker designed.

Bicycle tire and rim width compatibility chart

The chart below shows typical pairings of internal rim width and tire width seen across road, gravel and mountain bikes. It is a general orientation guide, not an official standard. The approved tire widths published by your rim maker, and the rim widths approved by your tire maker, override it. This is especially important for hookless rims, which usually have stricter limits.

Internal rim width	Typical use	Tire widths commonly paired
13–15 mm	Older narrow road rims	About 23–28 mm
17 mm	Older road, touring, hybrid and early mountain bike rims	About 25–47 mm in many published charts; check the maker's range for wider tires
19–21 mm	Modern road and endurance rims	About 25–40 mm
23–25 mm	Gravel and wide road rims	About 28–50 mm
25–30 mm	Cross-country and trail mountain bike rims	About 2.1–2.5 in (roughly 54–64 mm)
30–35 mm	Trail and enduro mountain bike rims	About 2.3–2.6 in (roughly 58–66 mm)
35–45 mm	Plus-size rims	About 2.6–3.0 in (roughly 66–76 mm)
50 mm and wider	Fat bike rims	About 3.8 in (roughly 97 mm) and wider

What is the maximum tire width for a 17 mm rim?

For a 17 mm internal width rim, many published compatibility charts give an upper limit of about 47 mm. That is roughly 1.85 inches. The commonly listed lower limit is about 25 mm.

Some older mountain bikes ran 2.0–2.1 inch (about 50–54 mm) tires on rims of similar width. Such wider pairings may work, but expect a more rounded, less stable profile at low pressure. Only exceed the published chart range if the rim or tire maker approves it.

The practical maximum tire size for a 17 mm rim also depends on:

• The rim type: a hooked 17 mm rim is the usual case. Narrow hookless rims are rare, and each has its own maker-specified range.
• The intended pressure and riding: wide tires on a narrow rim need enough pressure to stay stable. Low-pressure off-road riding exposes their weaknesses most.
• Frame, fork and brake clearance: a 17 mm rim may accept a tire your frame cannot fit.

Can you put a different tire width on the same rim?

Yes. One rim can take a range of tire widths, provided the bead seat diameter matches and each width falls within the rim's approved range. For example, a 622x19C rim can take both a 28-622 and a 35-622 tire if both widths are approved for that internal rim width.

Changing width on the same rim changes these things:

• Measured width: the printed width refers to a reference rim. A wider rim generally spreads the tire so it measures wider than printed, and a narrower rim makes it measure narrower. Measure the inflated tire on your own rim for an accurate figure.
• Tire height and overall diameter: a wider tire is also taller, so the wheel grows in diameter. This is covered in the next section.
• Suitable pressure: wider tires generally run at lower pressure. Stay within both the tire's and the rim's limits.
• Clearance: extra width and height must still clear the frame, fork, brakes and any mudguards.

How tire width changes height, diameter and circumference

Bicycle tires do not carry an aspect ratio marking the way car tires do. A car tire marked 205/55 R16 states its sidewall height as 55% of its width. A bicycle tire is not labelled this way because its inflated cross-section is close to round. As a working approximation, its height above the rim is roughly equal to its section width.

Any change in width therefore changes the tire height and the overall wheel size.

Simple calculation method

1. Read the ETRTO size, for example 28-622.
2. Take the tire height as approximately equal to the width: 28 mm.
3. Calculate overall diameter = BSD + 2 × height = 622 + 2 × 28 = 678 mm.
4. Calculate circumference = π × overall diameter = 3.1416 × 678 ≈ 2,130 mm.
5. Repeat for the other tire and compare. The change in outer radius is half the change in diameter, and it shows how much closer the tire comes to the frame or fork crown.

Worked examples

ETRTO size	Common name	Approx. overall diameter	Approx. circumference
28-622	700x28C	622 + 56 = 678 mm	≈ 2,130 mm
32-622	700x32C	622 + 64 = 686 mm	≈ 2,155 mm
61-622	29 x 2.4	622 + 122 = 744 mm	≈ 2,337 mm
71-584	27.5 x 2.8	584 + 142 = 726 mm	≈ 2,281 mm
54-559	26 x 2.1	559 + 108 = 667 mm	≈ 2,095 mm

On the same 622 mm rim, going from 28 mm to 32 mm adds about 8 mm to the overall diameter. That brings the outer edge of the tire about 4 mm closer to the frame or fork. It also adds about 25 mm of circumference, or roughly 1.2%, which changes the distance a bike computer records per wheel revolution by the same proportion.

The last two rows show how rim diameter interacts with width. A 27.5 x 2.8 tire on a smaller 584 mm rim reaches an overall diameter close to a 29er. Its extra height makes up much of the 38 mm difference in BSD.

Calculated geometry vs real tire dimensions

These calculations are estimates. The real inflated size depends on the casing, tread depth, inflation pressure and internal rim width. Many tires are slightly less tall than they are wide, and knobby tread adds height. For a bike computer, measure the actual rollout: mark the tire, roll the wheel one full turn under the rider's weight, and measure the distance. For frame clearance, measure the inflated tire on the rim you will use.

Hooked vs hookless rims: how compatibility changes

Hooked rims have a small lip on each rim wall that grips the tire bead. They work with inner tubes and, when the rim is tubeless-ready, with tubeless tires. Hookless rims have straight inner walls and rely on a tight bead-to-rim fit. They follow stricter rules:

• Tire approval: use only tubeless-compatible tires that the tire maker approves for hookless rims.
• Minimum tire width: each internal rim width has a minimum tire width. Hookless rims typically have a narrower approved range than hooked rims of the same internal width.
• Maximum pressure: hookless road and gravel rims are commonly limited to 5 bar (about 72.5 psi). The rim maker's stated limit applies even if the tire's own maximum is higher.

How to check tire and rim width compatibility step by step

1. Read the rim size: find the bead seat diameter and internal rim width, for example 622x21C, or measure the internal width.
2. Read the tire's ETRTO size: confirm the BSD matches the rim exactly, for example 622 with 622.
3. Check the rim maker's approved tire widths for that internal width and rim type (hooked or hookless).
4. Check the tire maker's guidance: confirm the tire is approved for your rim width and, if relevant, for hookless or tubeless use.
5. Estimate the size change: calculate the new overall diameter, then confirm the frame maker's stated maximum tire size and the real clearance at the frame, fork, brakes and mudguards.
6. Set pressure within both limits: use the lower of the tire's and the rim's maximum pressures.

What dimensional differences mean, and their limits

Sidewall numbers let you compare tires and estimate changes in width, height, diameter and circumference. They do not guarantee fit on a particular bike.

The bead seat diameter is a strict match requirement. The section width is a nominal value that changes with the rim. A compatibility chart shows a typical safe range, not a promise for every rim and tire.

Confirm the fit by checking the rim and tire makers' published ranges and the frame maker's maximum tire size, then measure the inflated tire on your own wheel.