Moto Gear Ratio Calculator

Moto Gear is a set of 16 calculators for people who actually work on motorcycles — riders chasing the right gearing, track-day regulars, racers, tuners and mechanics. Every tool reads from one shared bike, so change a sprocket in one place and the chain length, speedometer error and top speed update everywhere. Every result exports as a PDF with your inputs, the numbers and the drawings, ready to print or send to a customer. GEARING & SPROCKETS Gearing Analyzer (free): speed in every gear at any RPM, tachometer and speedometer gauges, shift-point graph, speed table, compare ratio sets and sprocket combinations. Save your bikes. Sprocket Matrix: a front × rear grid showing final ratio, percentage change, top speed at redline or RPM at cruising speed — find the combination that does what you want, then tap it. RPM at Speed: engine speed in every gear at a road speed, or road speed at an RPM, for your current and planned setups. Ratios from Teeth: enter tooth counts and get primary and gearbox ratios, the RPM drop at every shift, and push them straight into the analyzer. CHAIN Chain Length: how many links the new sprockets need, whether your current chain still fits and how far the rear axle moves — in millimetres and against your adjuster range. Exact geometry, not a rule of thumb. Chain Wear Pattern: hunting-tooth analysis showing how evenly links and teeth share the load, and which link counts wear best. Chain Stretch: elongation from a pin-to-pin measurement against the manufacturer's limit, plus a slack check. TIRES & SPEEDOMETER Tire Size Compare: metric, inch and alpha sizes (190/55 ZR17, 4.00-18, MT90B16), diameter, circumference, ride height, speedometer effect and the equivalent sprocket change. Speedometer Error: indicated versus true speed after sprocket or tire changes, with the sensor location taken into account, a correction factor for speedo healers and an odometer check. SUSPENSION Suspension Sag: free and rider sag from L1/L2/L3 measurements, targets for street and track, how much preload to add or remove, and whether your spring rate suits you. ENGINE Engine Builder: displacement, compression ratio from chamber, gasket, deck and piston volumes, bore/stroke and rod ratios, mean and peak piston speed, and what it takes to reach a target compression. Degree Wheel: durations, lobe centrelines, lobe separation and overlap from your cam card, a piston-stop TDC finder, and a printable full-scale degree wheel with a check bar. TOOLS Pulley & Belt, Power to Weight (with quarter-mile estimates), Fuel Range and a mechanic's unit converter (torque, pressure, spring rate, fuel economy, chain pitch). BUILT FOR THE WORKSHOP Metric or imperial everywhere, switchable at any time. Diagrams drawn to scale: chain runs with the axle movement, tire overlays, sag bars, dual-needle speedo, tooth-contact rings. PDF reports for every calculator. Formulas checked against manufacturer manuals and engineering references, and documented in each report. Works offline. No account, no tracking. FREE AND PRO The Gearing Analyzer is free, with no limits. Every other calculator gives you three free calculations to try it on your own bike. Moto Gear Pro unlocks all 16 calculators and PDF export, as a monthly or yearly subscription or a one-time lifetime purchase. If you bought the original paid app, everything stays unlocked — forever. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period and can be managed in your App Store account settings. Privacy policy: https://zhsystems.me/privacy-policy-moto-gear-ratio-calculator-rpm/ Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/