Why 700c Wheels Are Popular

700c Wheels: What That Actually Means

Wheel sizing terminology has gotten complicated with all the different standards flying around. As someone who got confused by the guy at the shop saying “700c” when I bought my first road bike, I learned everything there is to know about what that number actually means.

I nodded like I understood. Took me longer than I’d admit to figure out what was actually going on.

The Sizing Explained

Probably should have led with this section, honestly. 700c refers to the wheel’s bead seat diameter – specifically 622mm. That’s the measurement that matters for tire compatibility. The “700” was an old French sizing convention, and the “c” designated width category. The other categories (700a, 700b) mostly disappeared.

What’s confusing: 700c wheels aren’t actually 700mm in diameter. The outer diameter depends on the tire width. A 700x23c tire sits differently than a 700x32c. The 622mm BSD is the constant.

Why 700c Became Standard

Road bikes, gravel bikes, cyclocross bikes, and most hybrids use 700c wheels. The size offers a good balance of speed, rollover ability, and tire selection. It won the standardization war decades ago.

For comparison: 27-inch wheels (630mm BSD) were common on older bikes but aren’t the same as 700c despite being close. Don’t mix them up when buying tires.

Tire Width Options

The range is huge now. Road racers might run 25mm. Gravel riders often use 38-45mm. Some frames clear up to 50mm on 700c wheels.

Wider generally means more comfort and grip. Narrower means lower weight and sometimes less rolling resistance (though the science on that has evolved). Most recreational riders would be happier on 28-32mm than the 23mm tires that were standard years ago.

Tire Pressure Considerations

Pressure depends on tire width and rider weight. Narrower tires need higher pressure. Wider tires run lower. The old advice of pumping road tires to 120 PSI is mostly outdated – 80-95 PSI is more common now for 25-28mm tires, even lower for wider rubber.

Your tire’s sidewall shows the recommended range. Start there and adjust based on feel. Lower pressure is usually more comfortable, higher pressure reduces pinch flat risk but can feel harsh.

Tubes vs. Tubeless

Traditional setup uses inner tubes inside clincher tires. Works fine, easy to fix roadside. Tubeless ditches the tube and uses sealant to prevent flats. Lower pressures, better feel, self-sealing for small punctures.

Tubeless requires compatible rims and tires, plus more initial setup work. Worth it for many riders, but tubes aren’t obsolete. I run tubeless on my gravel bike, tubes on my road bike. Both work.

Wheel Materials

Aluminum rims are affordable, durable, and brake well in wet conditions. Most riders don’t need anything else.

Carbon rims save weight and can improve aerodynamics. The cost jump is significant. Nice to have, but not necessary for recreational riding. I’ve seen plenty of fast riders on aluminum wheels.

Spoke Count

Race wheels might have 20 spokes. Touring wheels might have 36. More spokes mean stronger wheels that carry weight better. Fewer spokes mean lighter, potentially more aerodynamic wheels.

For most riders: 28-32 spokes is the sweet spot. Strong enough for everyday use, light enough that you won’t notice.

Compatibility Notes

If you’re buying wheels, make sure the hub spacing matches your frame (road bikes are typically 130mm rear, disc bikes are 142mm). Also verify your brake type – rim brake wheels won’t work with disc brakes and vice versa.

Cassette compatibility matters too. Shimano and SRAM use the same freehub body. Campagnolo doesn’t. Check before buying.

Bottom Line

That’s what makes understanding wheel sizing endearing to us cyclists who’ve figured it out. 700c is just a wheel size – the standard for road-type bikes. Once you understand that the 622mm bead seat diameter is what defines it, tire shopping gets less confusing. Match the BSD, pick a width that fits your frame and riding style, and you’re set.