Cycling Calculator Watts Cadence Gearing Rider Weight

Cycling Power, Cadence, Gearing & Rider Weight Calculator :root { –primary-color: #004a99; –success-color: #28a745; –background-color: #f8f9fa; –text-color: #333; –border-radius: 8px; –shadow: 0 4px 12px rgba(0,0,0,0.1); } body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: var(–background-color); color: var(–text-color); margin: 0; padding: 0; line-height: 1.6; } .container { max-width: 1000px; margin: 20px auto; padding: 20px; background-color: #ffffff; border-radius: var(–border-radius); box-shadow: var(–shadow); } h1, h2, h3 { color: var(–primary-color); text-align: center; } h1 { margin-bottom: 30px; font-size: 2.5em; } h2 { margin-top: 40px; margin-bottom: 20px; font-size: 1.8em; border-bottom: 2px solid var(–primary-color); padding-bottom: 5px; } h3 { margin-top: 30px; margin-bottom: 15px; font-size: 1.4em; } .calculator-section { background-color: var(–background-color); padding: 30px; border-radius: var(–border-radius); margin-bottom: 40px; } .input-group { margin-bottom: 20px; display: flex; flex-direction: column; gap: 8px; } .input-group label { font-weight: bold; color: var(–primary-color); } .input-group input[type="number"], .input-group input[type="text"], .input-group select { padding: 12px; border: 1px solid #ccc; border-radius: var(–border-radius); font-size: 1em; width: calc(100% – 24px); /* Account for padding */ box-sizing: border-box; } .input-group input[type="number"]:focus, .input-group input[type="text"]:focus, .input-group select:focus { outline: none; border-color: var(–primary-color); box-shadow: 0 0 0 3px rgba(0, 74, 153, 0.2); } .input-group .helper-text { font-size: 0.9em; color: #666; margin-top: 5px; } .input-group .error-message { color: #dc3545; font-size: 0.85em; margin-top: 5px; display: none; /* Hidden by default */ } .input-group .error-message.visible { display: block; } button { background-color: var(–primary-color); color: white; padding: 12px 25px; border: none; border-radius: var(–border-radius); cursor: pointer; font-size: 1.1em; margin-right: 10px; transition: background-color 0.3s ease; } button:hover { background-color: #003366; } button.secondary { background-color: #6c757d; } button.secondary:hover { background-color: #5a6268; } #results { margin-top: 30px; padding: 25px; background-color: var(–primary-color); color: white; border-radius: var(–border-radius); box-shadow: var(–shadow); text-align: center; } #results h3 { color: white; margin-bottom: 15px; } #results .main-result { font-size: 2.5em; font-weight: bold; margin-bottom: 15px; } #results .intermediate-results div { margin-bottom: 8px; font-size: 1.1em; } #results .formula-explanation { font-size: 0.95em; margin-top: 15px; opacity: 0.8; } #results .key-assumptions { font-size: 0.9em; margin-top: 20px; opacity: 0.7; text-align: left; } #results .key-assumptions span { font-weight: bold; } table { width: 100%; border-collapse: collapse; margin-top: 20px; margin-bottom: 30px; box-shadow: var(–shadow); border-radius: var(–border-radius); overflow: hidden; } th, td { padding: 12px 15px; text-align: left; border-bottom: 1px solid #eee; } thead { background-color: var(–primary-color); color: white; } tbody tr:nth-child(even) { background-color: #f2f2f2; } tbody tr:hover { background-color: #e9ecef; } caption { font-size: 1.1em; font-weight: bold; color: var(–primary-color); margin-bottom: 10px; text-align: left; } canvas { display: block; margin: 20px auto; border: 1px solid #ccc; border-radius: var(–border-radius); background-color: #fff; } .article-content { margin-top: 40px; background-color: #ffffff; padding: 30px; border-radius: var(–border-radius); box-shadow: var(–shadow); } .article-content h2 { text-align: left; border-bottom: 2px solid var(–primary-color); padding-bottom: 5px; margin-bottom: 20px; } .article-content h3 { text-align: left; margin-top: 30px; margin-bottom: 15px; font-size: 1.5em; } .article-content p, .article-content ul, .article-content ol { margin-bottom: 20px; color: var(–text-color); } .article-content ul, .article-content ol { padding-left: 30px; } .article-content li { margin-bottom: 10px; } .article-content strong { color: var(–primary-color); } .faq-item { margin-bottom: 15px; padding: 15px; border: 1px solid #ddd; border-radius: var(–border-radius); background-color: #fefefe; } .faq-item strong { display: block; color: var(–primary-color); margin-bottom: 8px; cursor: pointer; } .faq-item p { margin-bottom: 0; color: #555; } .internal-links-section { margin-top: 30px; padding: 25px; background-color: #e9ecef; border-radius: var(–border-radius); } .internal-links-section h3 { text-align: left; margin-top: 0; margin-bottom: 15px; } .internal-links-section ul { list-style: none; padding: 0; } .internal-links-section li { margin-bottom: 12px; } .internal-links-section a { color: var(–primary-color); text-decoration: none; font-weight: bold; } .internal-links-section a:hover { text-decoration: underline; } .internal-links-section p { font-size: 0.9em; color: #666; margin-top: 5px; }

Cycling Power, Cadence, Gearing & Rider Weight Calculator

Cycling Performance Calculator

Input your cycling data to estimate key performance metrics. This calculator helps you understand the interplay between your power output, pedaling efficiency, gear selection, and body weight.

Enter your weight in kilograms (kg).
Your sustainable power output over a period (e.g., 20 minutes).
Pedaling revolutions per minute (RPM).
53T 52T 50T 48T 46T
Number of teeth on your front chainring.
11T 12T 13T 14T 15T 16T 17T 18T 19T 21T 23T 25T 28T 30T 32T 34T
Number of teeth on your rear cassette cog.
Wheel circumference in millimeters (mm). Common road bike size is ~2096mm for 700x25c.

Your Cycling Performance Metrics

Formula Used:
Power-to-Weight Ratio (W/kg) = Average Power (Watts) / Rider Weight (kg)
Gear Ratio = Front Chainring Teeth / Rear Cog Teeth
Speed (kph) = (Cadence (RPM) * Gear Ratio * Wheel Circumference (mm) * 60) / 1,000,000
Key Assumptions: This calculation provides estimates. Factors like drivetrain efficiency (~95-98%), wind resistance, rolling resistance, and terrain are not directly included in the primary formulas but influence real-world performance. Assumes optimal drivetrain.

Power vs. Speed Relationship

Visualizing how power output relates to estimated speed across different gear ratios.

Performance Data Table

Estimated Performance Metrics
Metric Value Unit
Average Power Watts
Rider Weight kg
Power-to-Weight Ratio W/kg
Cadence RPM
Gear Ratio
Estimated Speed kph

Understanding Your Cycling Performance: Watts, Cadence, Gearing, and Rider Weight

Welcome to the comprehensive guide on optimizing your cycling performance. In the world of cycling, whether for competitive racing, endurance events, or recreational fitness, understanding the key metrics that dictate your speed and efficiency is paramount. This article delves into the crucial elements of cycling calculator watts cadence gearing rider weight, explaining how each factor contributes and how you can use tools like our dedicated calculator to quantify and improve your output. We'll break down the science, provide practical examples, and answer your most pressing questions.

What is the Cycling Performance Calculator?

The cycling calculator watts cadence gearing rider weight is a specialized tool designed to help cyclists quantify their performance by analyzing the relationship between several critical variables. It allows users to input their typical power output (measured in watts), pedaling speed (cadence in RPM), selected gear combination (front chainring and rear cog), and their own body weight. In return, the calculator provides key performance indicators such as the Power-to-Weight Ratio (W/kg), Gear Ratio, and estimated speed.

Who should use it?

  • Competitive Cyclists: To benchmark performance, set training targets, and understand race dynamics.
  • Endurance Athletes: To gauge efficiency over long distances and manage energy expenditure.
  • Fitness Enthusiasts: To track progress and set personal goals for improvement.
  • Data-Driven Athletes: To gain deeper insights into their biomechanics and equipment choices.

Common Misconceptions:

  • Myth: Higher wattage is always better. Reality: While high wattage is crucial, efficiency (achieved through optimal cadence and gearing for your power) and power-to-weight ratio are often more decisive, especially on climbs.
  • Myth: There's one "ideal" cadence for everyone. Reality: Cadence preferences vary significantly among individuals. The optimal cadence is often a balance between aerobic efficiency and muscular fatigue, influenced by gear selection and power output.
  • Myth: Gear ratio is solely about speed. Reality: Gear ratio significantly impacts the force required to pedal at a given cadence and power, affecting muscular fatigue and overall efficiency.

Cycling Performance Calculator: Formula and Mathematical Explanation

The core of the cycling calculator watts cadence gearing rider weight lies in its formulas, which translate raw input data into meaningful performance metrics. These calculations are based on fundamental principles of physics and biomechanics.

Power-to-Weight Ratio (W/kg)

This is arguably the most critical metric for cyclists, especially in disciplines involving significant climbing. It directly measures how much power a rider can produce relative to their body mass. A higher W/kg indicates greater efficiency and climbing ability.

Formula:
Power-to-Weight Ratio (W/kg) = Average Power Output (Watts) / Rider Weight (kg)

Gear Ratio

The gear ratio determines how many times the rear wheel rotates for each single revolution of the pedals. A higher gear ratio (e.g., 53/11) means the wheel turns more for each pedal stroke, resulting in higher potential speed but requiring more force. A lower gear ratio (e.g., 46/30) means the wheel turns fewer times, making pedaling easier but resulting in lower potential speed.

Formula:
Gear Ratio = Front Chainring Teeth / Rear Cog Teeth

Estimated Speed

This calculation estimates the speed based on how fast you are pedaling (cadence), how far the bike moves with each pedal revolution (determined by gear ratio and wheel circumference), and the conversion factor for units.

Formula:
Distance per Pedal Revolution (meters) = Gear Ratio * Wheel Circumference (meters)
Distance per Minute (meters) = Distance per Pedal Revolution * Cadence (RPM)
Speed (meters per minute) = Distance per Minute
Speed (kilometers per hour) = (Cadence (RPM) * Gear Ratio * Wheel Circumference (mm) * 60) / 1,000,000
Explanation: Wheel circumference is usually in mm. Multiplying by Gear Ratio and Cadence gives distance covered per minute in mm. Multiplying by 60 converts to mm per hour. Dividing by 1,000,000 converts mm per hour to km per hour.

Variables Table

Key Variables in Cycling Performance Calculation
Variable Meaning Unit Typical Range
Average Power Output Sustainable power a rider can generate over a specific duration. Watts (W) Beginner: 100-150W
Intermediate: 150-250W
Advanced: 250-350W+
Rider Weight The total mass of the cyclist. Kilograms (kg) 45-120 kg
Cadence Number of full pedal revolutions per minute. Revolutions Per Minute (RPM) 70-105 RPM (common ranges)
Front Chainring Teeth Number of teeth on the front chainring. Teeth 34T – 55T (common road bike ranges)
Rear Cog Teeth Number of teeth on the selected rear cassette cog. Teeth 11T – 34T (common road bike ranges)
Wheel Circumference The total distance covered by one rotation of the wheel. Millimeters (mm) ~1900mm (26″) to ~2250mm (700x32c+)
Power-to-Weight Ratio A measure of climbing or acceleration potential. Watts per Kilogram (W/kg) Beginner: 2-3 W/kg
Competitive: 4-5 W/kg+
Gear Ratio Indicates mechanical advantage/disadvantage. Ratio (e.g., 1.81) ~0.8 (climbing) to ~4.8 (high speed)
Estimated Speed The projected speed based on inputs. Kilometers Per Hour (kph) Varies widely based on inputs

Practical Examples (Real-World Use Cases)

Let's explore how the cycling calculator watts cadence gearing rider weight can be applied in realistic scenarios.

Example 1: The Climber's Challenge

Scenario: A cyclist aiming to improve their climbing performance. They weigh 70kg and can sustain 280 watts for a significant duration. On a steep climb, they prefer to maintain a cadence of 80 RPM using a 34T chainring and a 30T rear cog. Their wheel circumference is 2096mm.

Inputs:

  • Rider Weight: 70 kg
  • Average Power Output: 280 Watts
  • Cadence: 80 RPM
  • Front Chainring: 34T
  • Rear Cog: 30T
  • Wheel Circumference: 2096 mm

Calculated Results:

  • Power-to-Weight Ratio: 280W / 70kg = 4.0 W/kg
  • Gear Ratio: 34T / 30T = 1.13
  • Estimated Speed: (80 * 1.13 * 2096 * 60) / 1,000,000 = ~10.8 kph

Interpretation: A 4.0 W/kg power-to-weight ratio is strong and indicates good climbing potential. The gear ratio of 1.13 suggests they are using a relatively low gear suitable for climbing, achieving an estimated speed of just under 11 kph. This data helps them understand their climbing efficiency and compare it to benchmarks or previous performances.

Example 2: The Flatland Sprinter

Scenario: A cyclist focused on flatland speed and sprinting. They weigh 85kg and can produce a massive 500 watts for a short burst. During a sprint, they maintain a high cadence of 100 RPM using their largest chainring (52T) and smallest cog (11T). Their wheel circumference is 2096mm.

Inputs:

  • Rider Weight: 85 kg
  • Average Power Output: 500 Watts
  • Cadence: 100 RPM
  • Front Chainring: 52T
  • Rear Cog: 11T
  • Wheel Circumference: 2096 mm

Calculated Results:

  • Power-to-Weight Ratio: 500W / 85kg = 5.88 W/kg
  • Gear Ratio: 52T / 11T = 4.73
  • Estimated Speed: (100 * 4.73 * 2096 * 60) / 1,000,000 = ~59.4 kph

Interpretation: A power-to-weight ratio of nearly 6.0 W/kg is exceptional, indicating elite-level sprinting power. The very high gear ratio of 4.73 allows for extremely high speeds on flat terrain. The calculated speed of ~59 kph is realistic for a powerful sprint in optimal conditions. This highlights the importance of high power and large gears for flat speed.

How to Use This Cycling Performance Calculator

Using the cycling calculator watts cadence gearing rider weight is straightforward. Follow these steps to get the most out of the tool:

  1. Accurate Inputs are Key:
    • Rider Weight: Weigh yourself accurately, ideally on the same scale at a similar time of day, wearing minimal clothing.
    • Average Power Output: This requires a power meter. Use a recent average power reading from a test (like a 20-minute FTP test) or a typical sustained effort.
    • Cadence: Most bike computers or cycling apps display your current cadence. Aim for your typical sustained cadence or the cadence you hit during a specific effort.
    • Gearing: Note the number of teeth on your front chainring and the rear cog you are currently using.
    • Wheel Circumference: This is crucial for accurate speed calculation. It's often listed on the tire sidewall or can be measured. A common value for a 700x25c tire is around 2096mm.
  2. Enter Your Data: Input the values into the corresponding fields in the calculator. Ensure you use the correct units (kg for weight, Watts for power, RPM for cadence, mm for wheel circumference).
  3. Review the Results: The calculator will instantly update to show:
    • Primary Result (Power-to-Weight Ratio): Your W/kg, a key indicator of climbing and acceleration potential.
    • Intermediate Values: Your calculated Gear Ratio and Estimated Speed for the given inputs.
    • Table and Chart: Visual and tabular representations of your data and its relationship.
  4. Interpret and Decide: Use the results to:
    • Benchmark your current fitness level.
    • Set realistic training goals (e.g., increase power output, improve W/kg).
    • Analyze gear choices for different terrains (e.g., low gears for climbing, high gears for flats).
    • Compare different efforts or training sessions.
  5. Copy and Share: Use the "Copy Results" button to save or share your performance data.
  6. Reset: Use the "Reset" button to clear current inputs and start over with default or new values.

Key Factors That Affect Cycling Performance Results

While the cycling calculator watts cadence gearing rider weight provides a solid framework, several other factors significantly influence real-world cycling performance. Understanding these nuances is vital for accurate interpretation and effective training.

  1. Drivetrain Efficiency: Not all the power you produce reaches the rear wheel. Chain wear, lubrication, bearing friction, and component quality can lead to power losses, typically ranging from 2-5%. Our calculator assumes a relatively efficient drivetrain.
  2. Aerodynamic Drag (CdA): This is often the most significant force a cyclist battles, especially at higher speeds. Rider position, helmet, clothing, bike frame design, and even the presence of other riders (drafting) dramatically affect air resistance. A lower CdA means more of your power translates into speed.
  3. Rolling Resistance: The friction between the tires and the road surface impacts efficiency. Tire pressure, tire width, tread pattern, and the road surface itself (smooth tarmac vs. gravel) all contribute. Lower rolling resistance means less power is needed to maintain speed.
  4. Terrain and Gradient: The calculator's speed estimate is most accurate on flat ground. Hills dramatically change the power required. Climbing requires overcoming gravity, while descending relies on gravity, making power output less critical than weight and aerodynamics.
  5. Wind Conditions: Headwinds increase aerodynamic drag significantly, requiring more power to maintain speed. Tailwinds provide assistance, reducing the power needed. Crosswinds can affect stability and aerodynamics.
  6. Rider Fatigue and Physiology: Your body's ability to produce power fluctuates based on training status, nutrition, hydration, sleep, and even mental state. The "average power" input represents a snapshot in time.
  7. Environmental Factors: Temperature, humidity, and altitude can affect performance. Heat can lead to reduced power output due to thermoregulation demands, while altitude reduces oxygen availability, impacting aerobic capacity.

Frequently Asked Questions (FAQ)

What is the most important metric for climbing?

The Power-to-Weight Ratio (W/kg) is generally considered the most critical metric for climbing performance. It quantifies how much power you can generate relative to your body mass, directly impacting your ability to ascend hills efficiently.

Is a higher cadence always better?

Not necessarily. While higher cadences (e.g., 90-100 RPM) are often associated with better aerobic efficiency and less muscular strain for many riders, the optimal cadence is individual. Some riders perform better at slightly lower cadences (80-90 RPM) depending on their physiology, muscular strength, and the selected gear. Pushing too high a cadence without sufficient power can be inefficient.

How does rider weight affect performance?

Rider weight is a primary factor in the power-to-weight ratio. A lighter rider can achieve a higher W/kg with the same power output compared to a heavier rider. This is why weight management is crucial for climbers, while sprinters might prioritize raw power output.

What is a "good" gear ratio?

A "good" gear ratio is entirely dependent on the terrain and rider's fitness. For steep climbs, a low gear ratio (e.g., 34T front, 30T rear, ratio ~1.13) is desirable for easier pedaling. For flat terrain or descents, a high gear ratio (e.g., 52T front, 11T rear, ratio ~4.73) is needed to achieve high speeds.

Do I need a power meter to use this calculator?

Yes, to get accurate results for Power-to-Weight Ratio and Estimated Speed, you need a power meter to measure your Average Power Output in Watts. Cadence and gear selection can often be observed or recorded without specific sensors, and rider weight is easily measured.

How accurate is the speed calculation?

The speed calculation is an estimate based purely on cadence, gear ratio, and wheel circumference. It does not account for real-world factors like aerodynamic drag, rolling resistance, wind, or gradient, which significantly impact actual speed. Use it as a theoretical benchmark.

What does a 5 W/kg rating mean?

A rating of 5 W/kg is considered very strong. It typically indicates a highly trained amateur or professional cyclist capable of competitive performance, especially in hilly or mountainous terrain. Below 3 W/kg is common for beginners, while 3-4 W/kg is solid for intermediate riders.

Can I use this calculator for mountain biking?

While the core principles apply, the typical ranges for gearing and cadence might differ for mountain biking. However, the formulas for Power-to-Weight Ratio and Gear Ratio remain relevant. You would need to ensure your inputs (especially wheel circumference and gearing) accurately reflect your mountain bike setup. The speed calculation might be less reliable due to varied terrain and lower average speeds.

© 2023 Your Cycling Insights. All rights reserved.
var riderWeightInput = document.getElementById("riderWeight"); var averageWattsInput = document.getElementById("averageWatts"); var cadenceInput = document.getElementById("cadence"); var chainringInput = document.getElementById("chainring"); var rearCogInput = document.getElementById("rearCog"); var wheelCircumferenceInput = document.getElementById("wheelCircumference"); var riderWeightError = document.getElementById("riderWeightError"); var averageWattsError = document.getElementById("averageWattsError"); var cadenceError = document.getElementById("cadenceError"); var chainringError = document.getElementById("chainringError"); var rearCogError = document.getElementById("rearCogError"); var wheelCircumferenceError = document.getElementById("wheelCircumferenceError"); var primaryResultDiv = document.getElementById("primaryResult"); var powerToWeightRatioDiv = document.getElementById("powerToWeightRatio"); var gearRatioDiv = document.getElementById("gearRatio"); var speedKphDiv = document.getElementById("speedKph"); var tableAvgPower = document.getElementById("tableAvgPower"); var tableRiderWeight = document.getElementById("tableRiderWeight"); var tablePwrToWgt = document.getElementById("tablePwrToWgt"); var tableCadence = document.getElementById("tableCadence"); var tableGearRatio = document.getElementById("tableGearRatio"); var tableSpeed = document.getElementById("tableSpeed"); var performanceChart; var chartData = []; function validateInput(inputElement, errorElement, minValue, maxValue) { var value = parseFloat(inputElement.value); var errorMessage = ""; if (isNaN(value) || inputElement.value.trim() === "") { errorMessage = "This field is required."; } else if (value < 0) { errorMessage = "Value cannot be negative."; } else if (minValue !== undefined && value maxValue) { errorMessage = "Value cannot exceed " + maxValue + "."; } if (errorMessage) { errorElement.textContent = errorMessage; errorElement.classList.add("visible"); inputElement.style.borderColor = "#dc3545"; return false; } else { errorElement.textContent = ""; errorElement.classList.remove("visible"); inputElement.style.borderColor = "#ccc"; return true; } } function calculatePerformance() { // Clear previous errors riderWeightError.textContent = ""; riderWeightError.classList.remove("visible"); riderWeightInput.style.borderColor = "#ccc"; averageWattsError.textContent = ""; averageWattsError.classList.remove("visible"); averageWattsInput.style.borderColor = "#ccc"; cadenceError.textContent = ""; cadenceError.classList.remove("visible"); cadenceInput.style.borderColor = "#ccc"; wheelCircumferenceError.textContent = ""; wheelCircumferenceError.classList.remove("visible"); wheelCircumferenceInput.style.borderColor = "#ccc"; var riderWeight = parseFloat(riderWeightInput.value); var averageWatts = parseFloat(averageWattsInput.value); var cadence = parseFloat(cadenceInput.value); var chainring = parseFloat(chainringInput.value); var rearCog = parseFloat(rearCogInput.value); var wheelCircumference = parseFloat(wheelCircumferenceInput.value); var isValid = true; if (!validateInput(riderWeightInput, riderWeightError, 1)) isValid = false; if (!validateInput(averageWattsInput, averageWattsError, 0)) isValid = false; if (!validateInput(cadenceInput, cadenceError, 1)) isValid = false; if (!validateInput(wheelCircumferenceInput, wheelCircumferenceError, 1000, 3000)) isValid = false; // Reasonable range for bike wheels if (!isValid) { primaryResultDiv.textContent = "–"; powerToWeightRatioDiv.innerHTML = "Power-to-Weight Ratio: — W/kg"; gearRatioDiv.innerHTML = "Gear Ratio: –"; speedKphDiv.innerHTML = "Estimated Speed: — kph"; tableAvgPower.textContent = "–"; tableRiderWeight.textContent = "–"; tablePwrToWgt.textContent = "–"; tableCadence.textContent = "–"; tableGearRatio.textContent = "–"; tableSpeed.textContent = "–"; updateChart([], []); return; } var powerToWeightRatio = (averageWatts / riderWeight).toFixed(2); var gearRatio = (chainring / rearCog).toFixed(2); var speedKph = ((cadence * parseFloat(chainring) / parseFloat(rearCog) * wheelCircumference * 60) / 1000000).toFixed(1); primaryResultDiv.textContent = powerToWeightRatio + " W/kg"; powerToWeightRatioDiv.innerHTML = "Power-to-Weight Ratio: " + powerToWeightRatio + " W/kg"; gearRatioDiv.innerHTML = "Gear Ratio: " + gearRatio; speedKphDiv.innerHTML = "Estimated Speed: " + speedKph + " kph"; tableAvgPower.textContent = averageWatts; tableRiderWeight.textContent = riderWeight; tablePwrToWgt.textContent = powerToWeightRatio; tableCadence.textContent = cadence; tableGearRatio.textContent = gearRatio; tableSpeed.textContent = speedKph; // Prepare data for chart var speeds = []; var gearRatiosForChart = []; var gears = []; var availableGears = []; Array.from(chainringInput.options).forEach(function(option) { availableGears.push({ chainring: parseFloat(option.value), name: option.text }); }); Array.from(rearCogInput.options).forEach(function(option) { availableGears.push({ rearCog: parseFloat(option.value), name: option.text }); }); // A simplified approach for demonstration: iterate through common gear combinations var commonChainrings = [52, 46]; // Example chainrings var commonRearCogs = [11, 13, 15, 17, 19, 21, 23, 25, 28, 30, 32, 34]; // Example cogs var chartLabels = []; var chartSpeedData = []; commonChainrings.forEach(function(cr) { commonRearCogs.forEach(function(rc) { var currentGearRatio = (cr / rc).toFixed(2); var currentSpeed = ((cadence * cr / rc * wheelCircumference * 60) / 1000000).toFixed(1); chartLabels.push(cr + "/" + rc + " (" + currentGearRatio + ")"); chartSpeedData.push(currentSpeed); }); }); updateChart(chartLabels, chartSpeedData); } function updateChart(labels, data) { var ctx = document.getElementById("performanceChart").getContext("2d"); if (performanceChart) { performanceChart.destroy(); } performanceChart = new Chart(ctx, { type: 'bar', data: { labels: labels, datasets: [{ label: 'Estimated Speed (kph)', data: data, backgroundColor: 'rgba(0, 74, 153, 0.6)', borderColor: 'rgba(0, 74, 153, 1)', borderWidth: 1 }] }, options: { responsive: true, maintainAspectRatio: true, scales: { y: { beginAtZero: true, title: { display: true, text: 'Speed (kph)' } }, x: { title: { display: true, text: 'Gear Combination (Ratio)' } } }, plugins: { legend: { display: true, position: 'top' }, title: { display: true, text: 'Estimated Speed vs. Gear Selection at Constant Cadence' } } } }); } function resetCalculator() { riderWeightInput.value = "75"; averageWattsInput.value = "200"; cadenceInput.value = "90"; chainringInput.value = "53"; rearCogInput.value = "11"; wheelCircumferenceInput.value = "2096"; calculatePerformance(); } function copyResults() { var resultsText = "— Cycling Performance Results —\n\n"; resultsText += "Power-to-Weight Ratio: " + primaryResultDiv.textContent + "\n"; resultsText += "Gear Ratio: " + gearRatioDiv.textContent.replace('Gear Ratio: ', ") + "\n"; resultsText += "Estimated Speed: " + speedKphDiv.textContent.replace('Estimated Speed: ', ") + "\n\n"; resultsText += "— Key Assumptions —\n"; resultsText += "Assumes ~95-98% drivetrain efficiency. Real-world speed affected by aerodynamics, rolling resistance, wind, and terrain.\n\n"; resultsText += "— Input Values —\n"; resultsText += "Rider Weight: " + riderWeightInput.value + " kg\n"; resultsText += "Average Power: " + averageWattsInput.value + " Watts\n"; resultsText += "Cadence: " + cadenceInput.value + " RPM\n"; resultsText += "Chainring: " + chainringInput.options[chainringInput.selectedIndex].text + "\n"; resultsText += "Rear Cog: " + rearCogInput.options[rearCogInput.selectedIndex].text + "\n"; resultsText += "Wheel Circumference: " + wheelCircumferenceInput.value + " mm\n"; var textarea = document.createElement("textarea"); textarea.value = resultsText; textarea.style.position = "fixed"; textarea.style.left = "-9999px"; document.body.appendChild(textarea); textarea.select(); try { var successful = document.execCommand('copy'); var msg = successful ? 'Results copied to clipboard!' : 'Failed to copy results.'; console.log(msg); // Optionally display a temporary message to the user } catch (err) { console.log('Unable to copy results', err); } document.body.removeChild(textarea); } // Initial calculation on page load window.onload = function() { resetCalculator(); // Sets defaults and performs initial calculation // Fetch default chainring/rear cog text for chart labels if needed var defaultChainringText = chainringInput.options[chainringInput.selectedIndex].text; var defaultRearCogText = rearCogInput.options[rearCogInput.selectedIndex].text; // Initial chart update with placeholder data if desired, or var calculatePerformance handle it. // For now, calculatePerformance will call updateChart after initial values are set. }; // Add event listeners to inputs for real-time updates riderWeightInput.addEventListener("input", calculatePerformance); averageWattsInput.addEventListener("input", calculatePerformance); cadenceInput.addEventListener("input", calculatePerformance); chainringInput.addEventListener("change", calculatePerformance); rearCogInput.addEventListener("change", calculatePerformance); wheelCircumferenceInput.addEventListener("input", calculatePerformance); // Dynamically update chart context when canvas is available document.addEventListener('DOMContentLoaded', function() { // Initial chart setup needs canvas context // updateChart is called by calculatePerformance after initial values load });

Leave a Comment