Rayons vs Wheelwright

Rayons (spokes in French) accurately calculates the proper spoke length given a set of measurements that you provide. Hub and rim manufacturers may provide the measurements or you can measure them yourself. Detailed instructions are provided in the app. The app uses simple and accurate controls to input your measurements. The spoke length for your wheel set is displayed in real-time. You can save the calculation in the app as a wheel set by typing in a text field and giving it a name. Formula The spoke length formula used by the Rayons app has a set of limitations based on the mathematics and the nature of the drawings. The formula was designed for use on conventionally laced wheels with j-bend spokes. These types of wheels are most commonly custom made by hand. The limitations outlined here may not be all inclusive. A wheel has: An even number of spokes The same number of spokes on each side of the wheel Equal spacing between spoke holes, on the rim or the hub Spokes that are crossed in pairs on each side of the wheel which dictates a spoke count divisible by four App Minimum and Maximum Dimensions The Rayons app can be used to calculate spoke lengths for a variety of component types. This covers the majority of Road, Track, Mountain Bike, Touring, Tandem, Fat Bike, Downhill, Generator and Internally Geared wheels. At this time, the app is not recommended for use with E-Bike components. Check your component dimensions and compare them with this chart. Be sure the component dimensions are supported by the app. Read the Terms of Service for more information. All of the values are in millimeters. Front Hub Flange Diameter Minimum: 28 Front Hub Flange Diameter Maximum: 150 Front Hub Offset Minimum: 15 Front Hub Offset Maximum: 48 Rear Hub Flange Diameter Minimum: 35 Rear Hub Flange Diameter Maximum: 150 Rear Hub Left Offset Minimum: 20 Rear Hub Left Offset Maximum: 60 Rear Hub Right Offset Minimum: 10 Rear Hub Right Offset Maximum: 52 Hub Spoke Hole Diameter Minimum: 1.5 Hub Spoke Hole Diameter Maximum: 3.0 Effective Rim Diameter (ERD) Minimum: 300 Effective Rim Diameter (ERD) Maximum: 700 Rim Spoke Offset Minimum: 0.0 Rim Spoke Offset Maximum: 5.0 Fat Bike Rim Spoke Offset Minimum: 0.0 Fat Bike Rim Spoke Offset Maximum: 20.0 Counts Minimum Number of Spokes: 12 Maximum Number of Spokes: 48 Minimum Number of Crosses: 0 Maximum Number of Crosses: 4

Parts ordered, spokes not yet cut. The ERD printed on the rim box and the ERD Marcus just measured with two spare spokes disagree by 2 mm - and a 2 mm spoke error is stripped nipples or poke-through. Down in the basement with one bar of signal, the web calculator won't load. Marcus needs a tool that lives where the work happens. Wheelwright is the wheelbuilder's bench tool: exact spoke lengths, geometry-derived tension targets on your own meter's curve, and a permanent record for every wheel - fully offline, no account, nothing to log into. WHAT IT DOES - Spoke length engine: per-side inputs (ERD, flange PCD, center-to-flange, hole count, cross, spoke-hole diameter, rim offset, adjustments). Results to 0.1 mm with stocked-size rounding and a borderline flag when the raw length sits on a size boundary - so you verify the ERD before you cut. Bracing angles and the drive/non-drive tension ratio come out alongside. - Every number shows its work: tap any result for the exact formula and inputs. - Measurement helpers: guided two-spoke ERD and chord-method PCD flows do the arithmetic and draw the diagram. Your measured value overrides any saved or entered value and wears a "measured" badge. - Tension sessions: enter readings spoke-by-spoke on big bench-friendly steppers, watch the radar chart tighten over each round, and save a snapshot from round one to final. Per-side mean, spread, and balance are computed for you. - Your tensiometer, your curve: transcribe your own meter's reading-to-kgf card once. Wheelwright interpolates - and refuses to guess beyond the range you calibrated. Any analog or digital tool; direct-kgf entry for digital meters. FREE, AND USEFUL FOREVER Unlimited manual-entry calculations with full formula transparency, both measurement helpers, 2 builds, 1 tool profile, and 1 tension snapshot per build. A careful hobbyist can build wheel after wheel here. PRO - Component library - save your own hubs and rims from a caliper measurement or a manufacturer spec, with measured-override, and reuse them across builds so you never re-type a hub's geometry. - Unlimited builds - a permanent, frozen record of every wheel, each with a searchable customer tag (free keeps 2). - Tension history and compare - keep every session snapshot and overlay before/after to prove the balance (free keeps 1 per build). - Build sheet PDF - a customer spec card with components, lengths, pattern, and the final tension radar. - Multiple tool profiles - a calibration curve for every tensiometer on the bench (free keeps 1). - Home Screen widgets - last-build quick-open and wheels built this year. HONESTY, BY DESIGN We built Wheelwright to agree with the workshop rule that the caliper outranks the catalog. It bundles no component database - the hubs and rims are the ones you save, and your measurement always wins. Borderline lengths are always flagged, radial lacing on a disc or drive flange always warns. It is a reference tool: verify critical dimensions by measurement before cutting spokes. No wheel-strength, safety, or warranty is certified. Your builds live on this iPhone, in your hands. No account to make. Designed exclusively for iPhone. PRICING Lifetime: $49.99 one-time - own it. Annual: $19.99/year with a 30-day free trial. Monthly: $2.99/month. One purchase unlocks every Pro feature. Restore is always available. Privacy Policy: https://app-legal-pages.vercel.app/wheelwright/privacy Terms of Service: https://app-legal-pages.vercel.app/wheelwright/terms