Cadence is how fast you turn the pedals, in revolutions per minute (rpm). Speed is how fast the bike moves over the ground, in km/h or mph. They’re linked by your gear: the same 90 rpm can mean 14 km/h on a steep climb or 33 km/h on the flat. Speed can come from GPS or a wheel sensor, but cadence needs a sensor on the crank, a power meter or a smart trainer, because GPS has no way to know what your legs are doing.
What’s the difference between cadence and speed? #
| Metric | What it measures | Unit | Measured by | Can GPS provide it? |
|---|---|---|---|---|
| Cadence | Crank revolutions per minute | rpm | Crank-arm sensor, power meter, some smart trainers | No |
| Speed | How fast the bike is moving | km/h or mph | Wheel sensor or GPS | Yes |
| Distance | Total ground covered | km or miles | Wheel sensor or GPS | Yes |
How gearing links the two #
Speed equals cadence times your gear ratio times the wheel’s circumference. Two examples with a 2,105 mm road wheel:
- 90 rpm in a 50×17 gear: each pedal turn moves the bike about 6.2 meters, so you’re doing roughly 33 km/h.
- 90 rpm in a 34×28 gear: each pedal turn moves the bike about 2.6 meters, so you’re doing roughly 14 km/h.
Same legs, same rhythm, less than half the speed. That’s why cadence tells you about how you’re pedaling, and speed tells you about the result once wind, gradient and gearing have had their say.
What is cadence useful for? #
Cadence is a rider metric. It helps you pedal in a way you can sustain.
- Choosing gears. If your cadence drops sharply on a climb, you’re probably in too big a gear. Shifting down to spin a little faster is often easier to sustain over a long hill.
- Finding your comfortable rhythm. Many road riders settle somewhere around 80 to 95 rpm on the flat and lower on steep climbs, but comfortable cadence varies a lot from rider to rider. Watching the number helps you find yours.
- Structured training. Indoor workouts often prescribe cadence targets, and a sensor or smart trainer is the only way to hold them.
Cadence says nothing about how fast you’re going or how hard you’re working. For effort, riders use heart rate or a power meter.
What is speed useful for? #
Speed is a result metric. It tells you how the ride is going.
- Pacing a route and estimating when you’ll arrive.
- Comparing rides on the same course, ideally using average speed while moving so stops don’t skew it.
- Staying within a limit on a shared path or a busy descent.
- Spotting problems. If your usual speed drops at your usual effort, check the tire pressure, brakes and wind before blaming your legs.
Because wind, gradient and drafting all change speed, a slower number isn’t necessarily a worse effort. Pairing speed with cadence, heart rate or power gives the full picture. For the accuracy side of speed readings, see bike speed sensor vs GPS.
Which sensor do you need? #
- You just want speed and distance. A GPS app on the handlebars or a wheel speed sensor does it. No cadence sensor needed.
- You want to work on your pedaling. Add a cadence sensor. Most current ones strap to the crank arm, use an accelerometer instead of a magnet, and connect over Bluetooth or ANT+ to a bike computer, watch or training app.
- You want both from one device. Combined speed-and-cadence sensors exist, and most power meters report cadence alongside power.
- You ride indoors. Many smart trainers report cadence or estimate it, so check yours before buying a separate sensor.
Can a phone measure cycling cadence without a sensor? #
Not through GPS. Satellites can see where the bike goes, not how often the cranks turn. A phone mounted on the handlebars doesn’t feel your pedal strokes either, so reliable cycling cadence needs a sensor on the crank or a power meter.
Where a GPS speedometer fits #
Speedometer GPS is a GPS speedometer, not a cadence tool. On a bike it gives you a large live speed readout on an auto-ranging dial, distance, top speed, average speed while moving and moving time, and it saves each ride with its route and a speed chart that you can export as GPX. It doesn’t measure cadence and doesn’t pair with Bluetooth or ANT+ sensors. Its trip distance also reads short below about 18 km/h (11 mph), because it ignores steps under 5 metres between one-second fixes, so on slow climbs multiply average speed by moving time or trust a wheel sensor for distance. If cadence matters to you, use a sensor with a bike computer or training app that supports it; the phone app works well alongside it as a big, simple speed readout or as a record of where and how fast you rode.
Whatever you use, mount the phone or computer firmly and set up the screens before you ride, so you’re glancing at numbers, not tapping at them. And if your speed and distance totals disagree between devices, our guide to bike computer vs GPS distance explains why.
Frequently asked questions #
Can GPS measure cycling cadence? #
No. GPS measures where the bike is and how fast it’s moving, not how often the pedals turn. Cadence needs a crank-arm sensor, a power meter or a smart trainer that reports it.
What is a good cadence for cycling? #
There’s no single right number. Many road riders settle around 80 to 95 rpm on flat roads and pedal more slowly on steep climbs, but comfortable cadence varies between riders and with fitness. The useful habit is choosing gears that let you keep a rhythm you can sustain.
Do I need a cadence sensor or a speed sensor? #
If you want speed and distance, GPS or a speed sensor covers it. A cadence sensor is only worth adding if you want to track how you pedal, follow structured workouts, or train indoors. Combined sensors do both.
Does a higher cadence make you faster? #
Not by itself. Speed depends on the power you put out, your gear and conditions like wind and gradient. A higher cadence in a lighter gear can feel easier to sustain, but the same cadence in a small gear is slower than in a big one.