Calculators
Bike fit and geometry
- Bike Frame Size CalculatorEstimate road, gravel or MTB frame size in centimetres from inseam and height. Inseam sets the size; height only nudges the rounding.
- Stack and Reach Ratio CalculatorDivide frame stack by reach. Below 1.35 is race, from 1.35 up to 1.45 is fast endurance, from 1.45 up to 1.55 is endurance, and 1.55 or higher is upright.
- Optimal Saddle Height CalculatorLeMond saddle height is 0.883 times inseam, measured from the centre of the bottom bracket to the top of the saddle.
- Handlebar Width CalculatorMatch road bar width to shoulder width. Add 20 mm for gravel flare and 40 mm for flat MTB bars.
- Crank Length CalculatorMap inseam to 165, 167.5, 170, 172.5, 175 or 177.5 mm cranks, plus a shorter modern alternative.
- Stem Length and Angle CalculatorSee how stem length and angle add horizontal reach and vertical drop on top of frame reach.
- Cleat Fore-Aft CalculatorEstimate foot length from an EU shoe size and place the cleat centre near the ball of the foot.
Drivetrain and gearing
- Bicycle Gear Ratio CalculatorGear ratio is chainring teeth divided by cassette cog teeth. Compare the easiest and hardest gears for real chainring and cassette pairs.
- Gear Inches and Roll-out CalculatorConvert a chainring and cog plus wheel size into gear inches and metres travelled per pedal revolution.
- Optimal Chain Length CalculatorEstimate chain links from chainstay length, the largest chainring and the largest cassette cog. Rounded up to an even link count.
- Derailleur Capacity CalculatorTotal capacity is the chainring difference plus the cassette difference. See whether a short, medium or long cage is enough.
- Cadence to Speed CalculatorTurn cadence, chainring, cog and wheel size into speed. Roll-out per revolution times cadence gives km/h.
- Cassette Range CalculatorCassette range is the largest cog divided by the smallest, times 100. A 10–52 is 520%.
- Fixie Skid Patch CalculatorSkid patches are cog teeth divided by the greatest common divisor with the chainring. Odd counts double if you skid with both feet.
Wheels and tires
- Tire Pressure CalculatorStarting tyre pressure from system weight, tyre width and surface. Front and rear are split, and hookless rims cap at 72.5 psi.
- Spoke Length CalculatorSpoke length from rim ERD, flange diameter, offset, spoke count and cross pattern. One side per calculation.
- Tubeless Sealant CalculatorEstimate tubeless sealant in millilitres from tyre width and bead-seat diameter. Wider tyres and 29-inch wheels take more fluid.
- Rim and Tire ETRTO CheckerCheck a tyre width against an inner rim width using simplified ETRTO bands. A yes means the width sits inside the nearest band.
- Wheel Circumference CalculatorWheel circumference in millimetres from bead-seat diameter and tyre width. Use it to calibrate a speed sensor.
Suspension and MTB setup
- Fork Sag and PSI CalculatorSag in millimetres from travel and a target percent, plus a starting air pressure from rider weight.
- Rear Shock Spring Rate CalculatorEstimate a coil spring rate in lb/in from rider weight, leverage ratio, stroke and target sag.
- Brake Rotor Size CalculatorPick a front and rear rotor diameter from rider weight and discipline: road, gravel, trail, enduro or downhill.
- Flip-Chip Geometry CalculatorSee a typical flip-chip change: 0.5° slacker head angle and 6 mm lower bottom bracket in the low position.
Performance and e-bikes
- E-Bike Battery Range CalculatorEstimate e-bike range from battery watt-hours, assist level and average gradient. Uses 90% of the pack.
- Power-to-Weight CalculatorDivide functional threshold or peak watts by body weight in kilograms. The result is W/kg.
- Climbing VAM CalculatorVAM is elevation gained per hour. With body weight it also estimates the steady climbing watts required.
- Speed to Watts CalculatorEstimate steady-state watts from speed, drag area (CdA), weight, rolling resistance and gradient.
- Calories and Carbs CalculatorEstimate kilocalories from average watts and duration, and a carbohydrate target in grams per hour.
- Cost per Gram CalculatorDivide the price difference by the grams saved. At $5 per gram or less the flag says the upgrade is in a sane range.
- Bicycle Torque GuideCommon bicycle bolt torques in newton-metres for stems, seatposts, rotors, cranks, pedals and thru-axles.