Bike Cadence and Speed Calculator
Our cycling calculator computes bike cadence speed instantly. Get accurate stats with historical comparisons and benchmarks.
Formula
Speed (km/h) = (Cadence x Gear Ratio x Wheel Circumference x 60) / 1000
Speed is calculated by multiplying the pedaling cadence (RPM) by the gear ratio (chainring teeth / cog teeth) to get wheel RPM, then multiplying by the wheel circumference to get distance per minute, and converting to km/h. The wheel circumference accounts for both the rim diameter and tire width to give the total rolling diameter.
Worked Examples
Example 1: Road Cycling Speed Calculation
Problem: A road cyclist pedals at 90 RPM with a 50-tooth chainring and 17-tooth rear cog on a 700c wheel with 25mm tires. What is the speed?
Solution: Gear Ratio = 50/17 = 2.941\nWheel diameter = 700 + (25 x 2) = 750mm = 0.75m\nCircumference = 3.14159 x 0.75 = 2.356m\nDistance per pedal rev = 2.356 x 2.941 = 6.929m\nDistance per minute = 6.929 x 90 = 623.6m\nSpeed = 623.6 x 60 / 1000 = 37.4 km/h\nSpeed = 37.4 x 0.621 = 23.2 mph
Result: Speed: 37.4 km/h (23.2 mph) | Gear Ratio: 2.94 | Development: 6.93m
Example 2: Climbing Gear Analysis
Problem: A cyclist climbs at 75 RPM with a 34-tooth chainring and 28-tooth rear cog on a 700c wheel with 28mm tires. Calculate the climbing speed.
Solution: Gear Ratio = 34/28 = 1.214\nWheel diameter = 700 + (28 x 2) = 756mm = 0.756m\nCircumference = 3.14159 x 0.756 = 2.375m\nDistance per pedal rev = 2.375 x 1.214 = 2.884m\nDistance per minute = 2.884 x 75 = 216.3m\nSpeed = 216.3 x 60 / 1000 = 13.0 km/h\nGear inches = 1.214 x (756/25.4) = 36.1
Result: Speed: 13.0 km/h (8.1 mph) | Gear Ratio: 1.21 | Development: 2.88m | Gear Inches: 36.1
Frequently Asked Questions
What is cycling cadence and why does it matter?
Cycling cadence is the number of complete pedal revolutions per minute (RPM) that a cyclist makes. It is one of the most fundamental metrics in cycling because it directly affects speed, power output, energy efficiency, and muscle fatigue. Professional road cyclists typically maintain cadences between 80-100 RPM, with sprinters sometimes exceeding 120 RPM in maximal efforts. Cadence matters because pedaling too slowly (grinding) in a hard gear puts excessive strain on the knees and quadriceps, while pedaling too fast (spinning) in an easy gear wastes cardiovascular energy through rapid leg movement. Finding the optimal cadence for your body type, fitness level, and riding style is key to efficient and injury-free cycling.
How does gear ratio affect cycling speed?
Gear ratio is the relationship between the number of teeth on the front chainring and the rear cog, determining how many times the rear wheel rotates for each pedal revolution. A higher gear ratio (like 53/11 = 4.82) means the wheel turns more per pedal stroke, producing higher speeds but requiring more force. A lower ratio (like 34/28 = 1.21) turns the wheel less per pedal stroke, producing lower speeds but requiring less force, ideal for climbing. For flat terrain riding, gear ratios between 2.5 and 3.5 are common. For climbing, ratios between 1.0 and 2.0 are typical. The interaction between gear ratio and cadence determines the actual speed, so the same speed can be achieved with a high gear at low cadence or a low gear at high cadence.
What is the optimal cadence for different types of cycling?
Optimal cadence varies significantly depending on the type of cycling and individual physiology. For road cycling, research consistently shows that cadences between 85-95 RPM are most efficient for trained cyclists, with Chris Froome famously using cadences around 100 RPM on climbs. For time trialing, cadences of 90-100 RPM are common due to the sustained power output required. Mountain biking typically involves lower cadences of 70-85 RPM because of variable terrain. Track sprinting uses extremely high cadences of 120-160 RPM during maximal efforts. Recreational cyclists often pedal at 60-75 RPM, which is generally too low and contributes to knee problems. Training to increase comfortable cadence is one of the most effective ways to improve cycling efficiency.
How does cadence relate to power output and efficiency?
The relationship between cadence and power output follows a complex curve influenced by muscle physiology. Power output equals torque (force on the pedals) multiplied by angular velocity (cadence). At very low cadences, high torque is needed, recruiting predominantly fast-twitch muscle fibers that fatigue quickly. At very high cadences, the metabolic cost of rapid leg movement increases cardiovascular demand. Research by Lucia et al. found that trained cyclists produce maximum sustained power at cadences between 80-100 RPM, with the most efficient cadence (lowest oxygen consumption for a given power) typically around 60-80 RPM. However, freely chosen cadence tends to be higher at 85-95 RPM because this distributes the workload between muscular and cardiovascular systems more evenly for sustained efforts.
How can cyclists use speed and cadence data to improve performance?
Cyclists can leverage speed and cadence data in several ways to enhance performance. First, cadence drills help develop neuromuscular efficiency by practicing riding at specific RPMs, typically alternating between high cadence (100-120 RPM) and low cadence (50-60 RPM) intervals. Second, understanding the relationship between cadence and speed for each gear combination helps with race strategy, allowing cyclists to select optimal gears for different terrain and wind conditions. Third, tracking cadence during training reveals drift patterns where fatigue causes cadence to drop, indicating when to shift to an easier gear. Fourth, comparing cadence across similar efforts over time shows improvements in pedaling efficiency. Many cycling coaches prescribe specific cadence targets for different training zones.
How do professional cyclists approach cadence strategy in races?
Professional cyclists employ sophisticated cadence strategies that vary by race situation and individual ability. Time trialists like Filippo Ganna maintain steady cadences around 100-105 RPM in their aerodynamic position, optimizing power output per metabolic cost. Climbers like Tadej Pogacar often increase cadence to 90-100 RPM on steep ascents, reducing muscular force per stroke to delay fatigue. Sprinters like Mark Cavendish reach cadences of 120-140 RPM in final sprints, maximizing power through rapid pedaling in large gears. Team directors monitor real-time cadence data via race radios to advise riders on gear selection and pacing. Modern bikes with electronic shifting (Shimano Di2, SRAM eTap) can be programmed to shift automatically based on cadence targets, helping riders maintain optimal RPMs without conscious effort.