Mouse Notes 08

Scroll Wheel + Small Parts

Parts covered: scroll encoder, scroll wheel, middle click, side buttons, flex cables, onboard memory, USB-C, DPI button, LEDs, frame + screws.

1. The scroll wheel system

wheel (rubber or plastic) encoder = counts the steps middle click switch (under)
each notch of the wheel = one step counted by the encoder
  • Encoder: counts each 'step' (notch) of the wheel and tells the mouse's chip which way you scrolled.
  • Middle click: a small switch under the wheel - press the wheel down to click.

2. Encoder types

Mechanical metal contacts Optical light beam Magnetic magnet ratchet + free-spin
three ways an encoder counts wheel steps
  • Mechanical: metal contacts. Cheap + replaceable, but this is the part that wears out + gets dusty.
  • Optical: light counts the steps, nothing touches, so it's immune to contact wear. Found in many newer esports mice.
  • Magnetic (Logitech MagSpeed): in the MX Master line - below a speed it clicks step by step; spin harder and a magnet releases it into free-spin (up to 1000 lines/sec claimed). No grinding part to wear out.

!! Conflicting info: one source says the Logitech Superlight uses a TTC mechanical encoder, another says the Superlight 2 uses optical - could be different models, so ask the seller which encoder your exact model uses before you buy.

3. Encoder brands + feel

Kailh Red - lightest TTC Red - light TTC Gold - medium ALPS - heavy

(TTC Red's placement is rough - listed as low scrolling force)

  • TTC, Alps, Kailh: build most mechanical encoders.
  • Kailh Red: lightest + smoothest, rated 50 million.
  • TTC Red: low scrolling force, rated 5 million.
  • TTC Gold: medium - the in-between pick, rated 50 million.
  • ALPS (Japan): heavier, well-defined steps. Reported as the loudest, but most stable + long-lived.

e.g. Razer Viper V2 Pro: 12mm Kailh encoder. Logitech G Pro X Superlight: 8mm TTC encoder.

e.g. Endgame Gear XM2 8k: TTC Silver encoder. XM2 8k v2: upgraded dustproof Kailh. WLMouse Strider: 'Dust Proof Silver' encoder.

  • Encoder height: replacements must match the height (commonly 9-14mm) - measured from the base plate to the wheel holder.

4. Scroll problems + fixes

dust, hair, fabric fibres, crumbs fall into the wheel slot like a funnel -> encoder skips / jumps backwards
dust in the slot is the most common cause of a jumpy wheel
  • Symptoms: scroll skips, double-scrolls, or jumps the WRONG direction.
  • Main causes: dust in the slot + a worn mechanical encoder (the most common reason wheels start jumping).

Fix it step by step:

  1. Test - run an online scroll test.
  2. Clean - use compressed air while scrolling.
  3. Retest - still jumping?
  4. Replace - fit a new encoder.
  • Replacing an encoder = desolder a few pins + solder a matching TTC / Alps / Kailh one. One of the easier mouse repairs.
  • Why it matters: in CS2 / Valorant, a weapon switch on the wheel + one phantom reverse step can mean your knife comes out mid-clutch.

5. Scroll features

  • Free-spin: wheel spins freely for long pages.

    e.g. Logitech G502 X: hyper-fast free spin + ratchet mode.

  • Tilt: push the wheel left / right for 2 extra buttons.

    e.g. Logitech G502 X tilt, Razer Basilisk HyperScroll Tilt Wheel.

  • Defined steps: clear notches you can count - best for weapon switching.

    e.g. Ninjutso HyperScroll: marketed for defined steps that stay consistent. Logitech Superstrike: tighter wheel than before (fewer accidental weapon switches).

6. Side buttons + extra buttons

front (buttons) back forward + back buttons check: position, size, click feel, wobble, easy to press by accident?
check the side buttons the way you'd check any other switch
  • Normal gaming mice: 2 side buttons (forward + back).
  • MMO mice: lots of side buttons for skills + macros (Razer Naga / Logitech G600 style) - heavier + bigger.
  • Accidental presses: ultralight + fingertip-grip mice can have side buttons you hit by mistake.
  • Side button switches: often on their own small PCB, linked with a flex cable.

    e.g. WLMouse Beast X: OM Blue Dots switches for side buttons.

7. Software + onboard memory

G HUB → Logitech
Synapse → Razer
iCUE → Corsair
SteelSeries GG → SteelSeries
CORE → Glorious
  • Brand apps: install on your PC to change DPI, polling, buttons, lighting.
  • Web driver trend: configure in the browser - no install needed.

    e.g. Zowie EC1-DW web driver, ASUS ROG Gear Link, Keychron Launcher web app.

  • Onboard memory: saves DPI + settings inside the mouse, so you can take it to a friend's PC / a LAN and the settings stay.

8. The other small parts

  • Flex cables: thin ribbon wires linking side / top boards to the main PCB. Like nerves.
  • DPI button: top or bottom. Bottom = no accidental presses mid-game.

    e.g. Endgame Gear OP1 8k: CPI button on the bottom.

  • USB-C port: for charging / wired use. Check whether you can play while it's charging.
  • LEDs / RGB: status light or decoration - adds weight + battery use.

    e.g. Logitech G502 LIGHTSYNC RGB. Many ultralight mice skip RGB.

Frame + screws (the skeleton):

carbon rod / inner skeleton = thin + light shell that still doesn't flex dots = screws, usually hidden under skates
a frame inside the shell keeps an ultralight mouse stiff

e.g. G-Wolves Warg / VUK Medium: carbon rod reinforcement. Ninjutso Sora V3: endoskeleton at 40g.

9. Scroll + Small Parts Dictionary

  • Encoder: from 'encode' - turns movement into a signal the mouse's chip understands.
  • Detent / notch: each little 'click' step you feel while scrolling.
  • Steps per rotation: how many notches in one full wheel turn.
  • Free-spin: wheel spins without notches.
  • MagSpeed: Logitech's magnetic scroll wheel (MAGnet + SPEED).
  • Ratchet: the part that makes notches - like a bike's freewheel click.
  • Tilt wheel: wheel you can push sideways for extra buttons.
  • Encoder height: size of the encoder (9-14mm) - must match to replace.
  • Dustproof encoder: sealed design that keeps dirt out longer.
  • MMO mouse: Massively Multiplayer Online games mouse - lots of side buttons.
  • Web driver: mouse settings page that runs in a browser.
  • Onboard memory: storage inside the mouse for your settings.
  • Flex cable: flexible ribbon wire between boards.
  • Endoskeleton: 'endo' = inside - a frame inside the shell (like our bones).

10. Test before you buy

  1. Online scroll test: any skips or reverse steps?
  2. Step feel: light / medium / heavy, clear notches?
  3. Scroll noise: quiet or loud?
  4. Wheel wobble side-to-side?
  5. Middle click: too hard? does it scroll by accident while clicking?
  6. Side buttons: reach, feel, accidental presses?
  7. Software: app or web driver? does it save to onboard memory?
  8. DPI button position + frame flex (squeeze test)?
  9. Check again in the first 2-4 weeks (dust / wear)?
Mouse Notes 08 - What the scroll wheel, side buttons and other small parts... ← Back to blog

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