Cadence and Speed Chart: How Fast Is 90 rpm? Guides by Gear and the Formula

Speed = gear ratio × tire circumference × cadence

One pedal revolution moves the chain by the number of teeth on the front gear (chainring), which turns the rear gear (cassette sprocket) that number divided by its own teeth. The rear wheel turns with the rear gear, so the number of tire revolutions per pedal revolution is the gear ratio, and the distance traveled is the development. Multiply development by cadence for the distance per minute, and by 60 for the distance per hour.

• Gear ratio = front teeth ÷ rear teeth
• Development (m) = gear ratio × tire circumference (m)
• Speed (km/h) = development (m) × cadence (rpm) × 60 ÷ 1000
• Required cadence (rpm) = speed (km/h) × 1000 ÷ 60 ÷ development (m)

1. 1

   Find the gear ratio

   With 50T front and 17T rear, 50 ÷ 17 ≈ 2.94. The rear wheel turns 2.94 times per pedal revolution.

2. 2

   Find the development

   A 700×28C tire has a circumference of about 2.130 m, so 2.94 × 2.130 ≈ 6.26 m. You travel 6.26 m per pedal revolution.

3. 3

   Find the speed

   At a cadence of 90 rpm, 6.26 × 90 × 60 ÷ 1000 ≈ 33.8 km/h.

Chart of speed by gear and cadence

These speeds are calculated for 700×28C (circumference 2130 mm), and list common combinations of a 50-34 compact crank with an 11–34T cassette. For 25C, take about 0.9% off the table values; for 32C, add about 1.2%.

The table shows that just 10 rpm more cadence raises speed by over 10%. With 50×17, for example, 80 rpm gives 30.1 km/h and 90 rpm gives 33.8 km/h. For the same speed, spinning a light gear quickly takes less force per pedal stroke than pushing a heavy gear slowly.

Which gears hold 20–40 km/h?

For long rides, the easy gears are those you can spin at about 80–95 rpm. With 50-34 at the front and a 12-speed 11-34 at the rear (700×28C), these combinations give the target speed at 80–95 rpm. The figures in parentheses are the cadence needed for that speed.

For 30 km/h, 50×19 on the big ring at 89 rpm is just right, and the small ring's 34×12 or 34×13 can do it too. But the small ring with the smallest sprockets is close to cross-chaining, with the chain running at an angle, which adds noise and wear, so on the flat the big ring is the normal choice for cruising. Cross-chain ranges are also explained in the article on choosing cranks, Compact vs. Semi-Compact Cranks.

What cadence should you aim for?

There's no correct cadence, but about 80–95 rpm when cruising on the flat is generally said to balance the load on leg muscles and on heart and lungs. New riders tend to push heavy gears at about 60–70 rpm, and often find their thighs tire first.

What matters is whether you have a gear that gives that speed at a cadence you can spin comfortably. If you drop below 60 rpm on climbs, there's room to fit larger low sprockets or a smaller chainring. Guidance on the teeth needed for climbs is calculated by gradient and power in How to Choose a Cassette: Teeth Needed for Hill Climbs.

How to measure cadence without a sensor

Even without a cadence sensor, a watch is enough to measure your own cadence. Just count how many times one foot (the right, say) reaches the bottom.

1. 1

   Choose a flat stretch without signals

   Somewhere you can ride at a steady pace for at least 30 seconds, and get up to your usual speed.

2. 2

   Count how many times your right foot reaches the bottom in 15 seconds

   Count while watching the seconds on your bike computer or wristwatch. Counting 1, 2, 3… in your head is enough.

3. 3

   Multiply by 4

   22 times in 15 seconds means 22 × 4 = 88 rpm. For 10 seconds multiply by 6, and for 20 seconds by 3.

Another method is to work back from gear and speed. With 50×17 and 700×28C at 30 km/h, 30 × 1000 ÷ 60 ÷ 6.26 ≈ 80 rpm. This assumes an accurate speed sensor, so set your tire circumference by checking Tire Circumference for Bike Computers.

Tips for raising your cadence

• Go 1–2 gears lighter: holding the same speed naturally raises your cadence. First get used to 5–10 rpm above your usual
• Raise it 5 rpm at a time: aiming straight for 90 rpm makes you bounce in the saddle. Go 75→80→85 over several weeks
• Short intervals: on the flat, spin at 100–110 rpm for just 1 minute, rest for 2, and repeat several times
• Think of steadying your ankles more than of pulling up: when your ankle flexes on the downstroke, power leaks away. Thinking of moving quickly through the bottom of the stroke tends to work better than drawing circles
• Check your saddle height: too high and your pelvis rocks at the bottom of the stroke; too low and your knees get cramped, holding your cadence back

The goal when raising cadence is not more power but more revolutions at the same power with a lighter gear. If your heart rate jumps sharply, that's a sign you've gone too light.

Development, gear inches and gain ratio: the differences

Several measures compare how heavy a gear is. All are based on gear ratio, and they differ in how far they account for tires and cranks.

Gain ratio compares how far the tire's outer edge moves with the circle the pedal draws, and the longer the crank, the smaller (that is, lighter) it gets. The same 50×17 gives 6.04 with a 165 mm crank and 5.70 with 175 mm. It's handy when changing crank length, or comparing bikes with very different tire sizes.

FAQ

How fast do I go at a cadence of 90?

It depends on gear and tire. On 700×28C, 50×17 gives about 33.8 km/h, 50×21 about 27.4 km/h, 50×13 about 44.2 km/h, and 34×28 about 14.0 km/h. Speed = gear ratio × tire circumference (m) × cadence × 60 ÷ 1000.

What cadence do I need to ride at 30 km/h?

On 700×28C, about 89 rpm with 50×19, about 80 rpm with 50×17, and about 70 rpm with 50×15. Required cadence is speed × 1000 ÷ 60 ÷ development (m).

What's a good cadence on a road bike?

About 80–95 rpm is the general guide for cruising on the flat. New riders can start from 70–80 rpm, and on climbs, choosing a gear that keeps 70–85 rpm helps your legs last.

Can I measure cadence without a sensor?

Yes. Count how many times your right foot reaches the bottom in 15 seconds and multiply by 4 for your cadence at that moment. If you know your gear and speed, you can also work back with speed × 1000 ÷ 60 ÷ development.

Does a higher cadence make you faster?

In the same gear, higher revolutions mean more speed, but what sets your speed is power output. The reason to raise cadence is to reduce the force per pedal stroke so your leg muscles tire less. The basic approach is to pick a gear that gives your target speed at a cadence you can spin comfortably.