· Hugo · Maintenance · 3 min read
What Is a 700c Bicycle?
700c is the standard wheel size for road, hybrid, and many gravel bikes. Learn what it means, how it relates to 29" and 28", and which tires fit.
“700c” appears on road bikes, hybrids, and gravel bikes. It’s a wheel size standard—but the name is historical and can be confusing.
The short answer: 700c refers to a wheel with a 622 mm bead seat diameter (ETRTO). It’s the same rim size as 29” and 28”—the difference is tire width and naming tradition. 700c wheels are used on road bikes, hybrids, gravel bikes, and some touring bikes. Tire widths typically range from about 23 mm to 50+ mm, depending on the rim and frame.
Here’s a clearer explanation.
What Does 700c Mean?
The “700” comes from an old French system—the approximate outer diameter of the tire in millimeters. The “c” was a width code (narrower than “a” or “b”). The name stuck even though modern tires vary in width.
What actually matters: The bead seat diameter—where the tire bead sits on the rim. For 700c, that’s 622 mm (ETRTO standard). So 700c = 622 mm = the same rim as 29” and 28”.
700c vs 29” vs 28”
| Name | Bead seat diameter | Typical use |
|---|---|---|
| 700c | 622 mm | Road, hybrid, gravel |
| 29” | 622 mm | Mountain bikes |
| 28” | 622 mm | Older European road/touring |
Same rim, different names. The rim is identical; the tire width and tradition differ. A 700c road tire might be 25 mm wide; a 29” MTB tire might be 2.2” (56 mm). Both fit 622 mm rims.
Which Bikes Use 700c?
- Road bikes — Almost all use 700c
- Hybrids — Most use 700c
- Gravel bikes — Most use 700c (wider tires, e.g. 38–50 mm)
- Touring bikes — Often 700c
- Some cyclocross — 700c or 650b
Tire Width Compatibility
700c rims can fit a range of tire widths. Rim width limits the safe range:
- Narrow rims (e.g. 15–19 mm internal) — Typically 23–32 mm tires
- Wider rims (e.g. 19–25 mm internal) — 28–50+ mm tires
- Gravel rims — Often 40–50+ mm
Check the rim manufacturer’s recommended range. Too narrow a tire on a wide rim (or vice versa) can affect handling and increase pinch-flat risk.
700c vs 650b
650b (also called 27.5”) has a 584 mm bead seat diameter. Smaller than 700c. Some frames are designed for 700c or 650b—switching may require different tire sizes and can affect geometry. Not all frames can swap between them; check frame clearance and brake reach.
What Is a 700c Bicycle FAQs
Is 700c the same as 29 inch?
Yes, in terms of rim size. Both use a 622 mm bead seat diameter (ETRTO). The names come from different traditions—700c for road, 29" for mountain. The rim is the same; tire width differs.
What does the 'c' in 700c mean?
Historically, 'c' was a width code in the French tire sizing system. The '700' referred to approximate outer diameter in mm. The name stuck even though modern 700c tires vary widely in width.
What tire widths fit 700c rims?
Depends on rim width. Narrow rims often suit 23–32 mm; wider rims can take 28–50+ mm. Check the rim manufacturer's recommended range. Road tires are often 23–32 mm; gravel 38–50 mm.
Can I put 650b wheels on a 700c frame?
Sometimes. It depends on frame clearance and brake reach. Smaller 650b wheels with wider tires can fit some 700c frames, but geometry and brake compatibility must be checked. Not all frames support the swap.
Summary
700c means a wheel with a 622 mm bead seat diameter—the same as 29” and 28”. It’s the standard for road, hybrid, and many gravel bikes. Tire width varies (roughly 23–50+ mm) based on rim and frame. The name is historical; the important number is 622 mm. For measuring all wheel sizes, see How to Measure Bicycle Wheel Size.