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Setting the wheel diameter on an SW900, EN06 or KD718 display

SW900 / EN06 / 810LED / KD718 generic displays

P06 on the SW900 (inches, decimal), plus P07 for the number of speed pulses. The KD718 names it 'Wheel' in its menu.

Step by step

  1. Switch the display on. Within 10 seconds, press and hold ▲ and ▼ (or + and −) together for about 2 seconds until P01 appears. Most SW900 have no password; if a code is requested, the published defaults are 1919 or 8018.
  2. Press power to P06. Set the diameter in inches: 20.0, 24.0, 26.0, 27.5, 28.0, 29.0 (fat 20 × 4: 25.0).
  3. Press power to P07: 1 for a spoke magnet; motor pole-pair count (often 20–23) if the hub's Hall signal is used. Leave the factory value if in doubt.
  4. Power (short press) moves to the next parameter; ▲ / ▼ change the value; hold ▲ and ▼ together to save and exit.
  5. KD718: menu → Wheel → choose 16–29 / 700C → Exit.
  6. Verify against GPS.
Tip: Circumference reference (ETRTO tyre on a normal rim): 20" ≈ 1590 mm, 24" ≈ 1910 mm, 26" ≈ 2075 mm, 27.5" (650B) ≈ 2150 mm, 28" (700C) ≈ 2200 mm, 29" ≈ 2300 mm. Fat or plus tyres add 60–120 mm; a roll-out measurement (mark the tyre, roll one full turn, measure) beats any table.

Can't find it?

Speed a clean multiple wrong (2×, 20×): P07. Speed a few percent wrong: P06. Speed frozen at 0: sensor/magnet, see error 21/E21 here.

Frequently asked

KD718 wheel list stops at 28?

Use 28 for 29" and accept 4 % under-reading, or set P18 speed ratio if present.

Does wheel size change the speed limit?

Indirectly: a too-small wheel makes the bike cut assist early, a too-big one late (and illegal).

SW900 P06 max?

Usually 30.0.

Other SW900 / EN06 / 810LED / KD718 generic displays guides

SW900 / EN06 / KD718: switch km/h to mphSW900 / EN06 / KD718: assist levels (P05)SW900 / EN06 / KD718: speed limit (P08)SW900 / EN06 / KD718: passwordSW900 / EN06 / KD718: battery voltage (P03)SW900 / EN06 / KD718: walk assistSW900 / EN06 / KD718: throttle (P10, P09)
Still stuck? Take a photo of the display and show it to a local e-bike workshop. Bring the bike's system name (e.g. Bosch Performance Line CX) and the exact code; that saves diagnostic time and money.