DC motors: 775, N20 gearmotor, TT gearmotor — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/dc-motors-775-n20-tt/  (CC BY 4.0)
Basis: Common supplier drawings for the 775 brushed motor, N20 micro gearmotor and the yellow TT gearmotor; values typical, verify on your unit
Catalog version: 2026-10-20

Sizes: see table below
- 775: Ø42 mm can, 66.7 mm long, two M4 mounting holes on 29 mm centres in the face, Ø17.5 × 2 mm boss, Ø5 mm shaft 17 mm long.
- N20: 12 × 10 mm section, 15 mm motor + gearbox 9–12 mm depending on ratio; Ø3 mm D-shaft 9–10 mm long; two M1.6 face holes 9 mm apart.
- TT (yellow, 1:48): 70 × 22.5 × 18.5 mm overall with the motor, 5.5 mm double-D shaft both sides, two Ø3.2 mounting holes 17.6 mm apart on the gearbox; many clones vary by ±0.5 mm.

motor  section_mm  length_mm  shaft  mounting
775  Ø42  66.7  Ø5 × 17  2 × M4 @ 29 mm
N20  12 × 10  24–27 with gearbox  Ø3 D × 10  2 × M1.6 @ 9 mm
TT  22.5 × 18.5  70  5.5 double-D  2 × Ø3.2 @ 17.6 mm (gearbox)

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Pololu: Micro metal gearmotor dimension diagram — PDF, STEP — Pololu site terms [verify license at link] — https://www.pololu.com/category/60/micro-metal-gearmotors
- DFRobot: TT geared motor drawing — web — DFRobot site terms [verify license at link] — https://www.dfrobot.com/product-100.html
- Wikipedia: DC motor — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/DC_motor

Free files (CC BY 4.0, Xem Studio; STEP + STL, 3 parts): https://xemstudio.com/files/hardware/dc-motors-775-n20-tt/index.json
API: https://xemstudio.com/api/geometry?object=dc-motors-775-n20-tt