TM-1 Web

Idle
LOOSER TIGHTER
—Hz
—kgf
Tip: rest a finger on the spoke it crosses to damp it, then pluck this one.
Tune Mode — points you at the worst spoke
Spoke
1 / 32

Wheel Map

Good Uneven Critical
Mean
—
Min
—
Max
—
Spread
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Readings

SpokeHzTensionDev.
No readings logged yet

Wheel & Spoke Setup

Measure the exposed spoke, not the full length: from where it enters the nipple to the point it crosses its neighbor (or to the hub flange for radial spokes).
Rough starting points only — check your rim/spoke maker's spec if you have one. Leave blank and it'll use the average of your own logged spokes instead.
Advanced (mic tuning) — most people won't need this
Auto: the listen range is worked out from your spoke's gauge and length, so you don't have to guess a frequency window.

How this works

Pluck a spoke like a guitar string. The mic captures the "ping," the app finds its fundamental frequency, and converts it to tension using the standard vibrating-string formula:

T = 4·μ·L²·f²

μ = mass per unit length of the spoke · L = free (speaking) length · f = pluck frequency.

This is a ballpark estimate, not a lab instrument — same idea as a mechanical deflection meter, just with a mic instead of a spring. Don't treat the absolute kgf number as gospel. What it's genuinely good at is telling you which spokes are way off from the others — the relative pattern across your wheel is much more trustworthy than any single exact reading, because errors in your spoke's mass/length estimate shift every spoke's number by roughly the same amount.

Two things that matter more than anything else for accuracy: hold the phone mic close to the spoke, and rest a finger on the neighboring spoke it crosses so it doesn't ring along and confuse the reading. Free length also has to be measured carefully — see the hint under that field in Settings.

Tap Start Microphone, then Listen for Pluck right before each pluck — it only listens for about 2 seconds after you tap, so it won't fire on background shop noise the rest of the time. When a clear tone is detected it fills in automatically — tap Log Reading to save it and step to the next spoke. Don't know your spoke's mass per length or a target tension? Settings has quick "Road/MTB ballpark" buttons and works out a sensible listening frequency automatically — you don't need to know any of the physics to get started.

The wheel map and gauge update live and color each spoke by how far it deviates from your target (or the running average of whatever you've logged so far — the gauge is dim/inactive until you've set a target or logged at least one spoke) — that's the real point of this tool: it doesn't just give you one number, it shows you which spokes are the problem.

If a wheel is badly uneven, turn on Tune Mode (below the mic button). It walks you through any unmeasured spokes first, then always points you at the single worst spoke left — telling you to tighten or loosen it — and re-ranks after every reading. Adjust the nipple, re-measure that same spoke, and repeat until it says everything's within tolerance. A rough guide: a quarter-turn on a nipple is a meaningful change in tension, but exactly how much varies by spoke and thread — always re-measure after each adjustment rather than counting turns. And remember tensioning shifts trueness too, so check the rim in a truing stand as you go, not just at the end.

Needs HTTPS (or localhost) — phones block microphone access on plain http.

Build 2026-07-31.4