Caleb MorganBy Caleb Morgan

Updated November 2026

A bike tire rim size chart tells you which tire sizes fit a given rim, so you can buy tires that seat properly, hold air, and stay safe at speed. To use one, you need to read your rim’s diameter and internal width, then match them to a tire marked for that rim. This guide shows you how to do that in a few minutes.

Start by Reading Your Rim Markings

Most rims are stamped on the sidewall or the inside of the rim bed. Look for two numbers: the diameter and the internal width. In the European ETRTO system, you will see something like 622 x 19, where 622 is the bead seat diameter in millimeters and 19 is the internal width. In inch-based systems, you may see 700c or 26″, which describes the wheel diameter but not the exact bead size.

Shopping for one? See our guide: 5 Best Road Bike Shoe Size Charts (2026): Expert Picks.

If the markings are worn off, measure the rim yourself. Use a caliper to measure the internal width between the bead hooks, and check the diameter against a size chart. A quick overview of how these numbers relate is in Bike Rim Size Chart: How to Match Rim Diameter, Width and Tires.

Match the Tire Diameter to the Rim

The tire diameter must match the rim diameter exactly. A 622 mm rim takes a 622 mm bead tire, whether that tire is labeled 700c, 28″, or 700 x 25C. Inch labels are often confusing because the same wheel can carry several names, so use the ETRTO number when you can.

Common label ETRTO bead size Typical use
700c / 28″ 622 Road, gravel, hybrid
650b / 27.5″ 584 Touring, some mountain
26″ 559 Mountain, older hybrids
20″ 406 Kids, folding bikes

Check the Tire Width Against the Rim Width

Tire width is the second match. Manufacturers list a recommended width range for each rim, often in millimeters. A tire that is too narrow for the rim can roll off the bead, while one that is too wide may rub the frame or fork. As a general rule, a tire mounted on a rim with an internal width near the middle of its recommended range performs most predictably. For more detail on width ranges, see Road Bike Rim Width Tire Size Chart: Match Tires to Your Rims.

Confirm Clearance and Final Fit

Once diameter and width match, check clearance. Mount the tire, inflate it to the pressure shown on the sidewall, and spin the wheel in the frame. Look for even gaps around the tire at the seat stays, chainstays and fork crown. Tires that look like they fit on paper can still rub when the bike is loaded or the suspension compresses.

Bike Tire Rim Size Chart Checklist

  1. Find the ETRTO number and internal width on the rim.
  2. Match the tire bead size to the rim diameter.
  3. Confirm the tire width falls within the rim’s recommended range.
  4. Check the frame and fork clearance with the tire inflated.
  5. Verify the tire pressure limit on the sidewall before inflating.

Common Mistakes

  • Trusting inch labels alone. Two “700c” tires can have different widths, so check the ETRTO width.
  • Ignoring the maximum pressure. Exceeding it can cause a blowout or a bead to pop off.
  • Assuming a wider tire always rides better. Oversized tires on narrow rims can squirm and wear unevenly.
  • Skipping clearance checks after upgrading to a wider tire.

A digital caliper makes measuring internal rim width quick and accurate, which is useful when markings are faded. View on Amazon

A quality tire pressure gauge helps you stay within the sidewall limits of your new tires. View on Amazon

FAQ

Can I put a 25 mm tire on a 19 mm internal rim?

Often yes, because 25 mm is usually within the recommended range for a 19 mm internal rim. Always confirm against the rim manufacturer’s stated range before buying.

Are 700c and 28″ the same size?

They refer to the same 622 mm bead diameter, though tire brands may use either label. The ETRTO number is the most reliable way to confirm.

Where do I find the maximum tire pressure?

It is printed on the tire sidewall. Do not exceed it, and check your rim’s own pressure limit as well.

Conclusion

A bike tire rim size chart works best when you match diameter first, then width, then clearance. Use the ETRTO numbers whenever possible and confirm the fit with the tire mounted. If you are unsure about a specific wheel, a bike shop can check the rim markings for you.

Ready to choose one?

Caleb Morgan

About Caleb Morgan

Caleb Morgan is part of our editorial team and reviews and edits our cycling for beginners guides, checking product details against manufacturer specifications and owner feedback.