Free · no account needed
Free bike calculators: tire pressure, gear ratio and tubeless sealant.
Three calculators that run the same math as the Drais app. They work on any device, no account needed.
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Tire pressure calculator
Front and rear pressure from your weight, tire width, rim and surface — with a chart per bike type, in bar and psi.
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Gear ratio calculator
Compare bike gearing, cassettes and chainrings. See low gears, total range and speed at your cadence for road, gravel and MTB. Free, no account needed.
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Sealant calculator
Work out how much tubeless sealant you need per tire for road, gravel and MTB: first fill, top-up and how much to buy. Free, no account needed.
Save the setup for every bike.
Drais keeps your bikes, parts, maintenance and rides together in your digital garage.