Find your tire size

Use the ETRTO number first

Look for a two-part marking such as 37-622 on the sidewall. In this example, 37 is the nominal tire width in millimetres and 622 is the tire's inner diameter. That diameter must match the rim. Labels such as 26-inch or 28-inch can describe more than one rim diameter, so the familiar wheel-size name alone is not enough.

Check width and clearance separately

A matching diameter does not make every width suitable. Compare the proposed tire with the rim maker's permitted widths and the bicycle maker's clearance guidance. Actual inflated width can differ from the sidewall number. Check the frame, fork and fenders; a tire that is only slightly wider on paper may leave too little room in use.

Match the wheel's construction

Tube-type, tubeless-ready and hookless requirements are different buying decisions. For a hookless wheel, check the exact tire model and width against the wheel maker's requirements, including pressure limits. Schwalbe specifies TLE/TLR tires for hookless rims. A tubeless label is not a blanket approval for every wheel, and adding a tube does not remove the wheel's requirements.

Choose the tube and valve together

For a setup using a tube, its listed size range must include your tire's diameter and width. Compare the valve type with your existing rim and pump, and choose a valve length suitable for the rim depth. A tube's broad size range is normal; it does not mean that a tire with a different inner diameter will fit.

Your shopping checklist

Keep a photo of the sidewall and wheel markings beside your shortlist. Choose tread and puncture protection only after the dimensional checks are settled. If a marking is unreadable or you are changing width, have the proposed combination confirmed before ordering.

• Exact ETRTO size and intended front or rear wheel.
• Rim model, permitted tire widths and frame clearance.
• Tube or tubeless requirements, valve type and length.
• Manufacturer pressure, load and intended-use limits.