# DC motors: 775, N20 gearmotor, TT gearmotor

> What are the 775 motor dimensions and mounting holes?

- Category: Hardware › Motion
- Kind: Hardware
- Basis: Common supplier drawings for the 775 brushed motor, N20 micro gearmotor and the yellow TT gearmotor; values typical, verify on your unit
- Page: https://xemstudio.com/objects/dc-motors-775-n20-tt/ · JSON: https://xemstudio.com/api/geometry?object=dc-motors-775-n20-tt · Plain text: https://xemstudio.com/objects/dc-motors-775-n20-tt/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

## Notes

- 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.

## Sizes

| 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) |

## Where the files are

- Pololu: [Micro metal gearmotor dimension diagram](https://www.pololu.com/category/60/micro-metal-gearmotors) — PDF, STEP — Pololu site terms (verify at link)
- DFRobot: [TT geared motor drawing](https://www.dfrobot.com/product-100.html) — web — DFRobot site terms (verify at link)
- Wikipedia: [DC motor](https://en.wikipedia.org/wiki/DC_motor) — web — CC BY-SA 4.0 (text)

## Free STEP/STL (3 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/dc-motors-775-n20-tt/index.json

- motor-775: [STEP](https://xemstudio.com/files/hardware/dc-motors-775-n20-tt/motor-775.step) · [STL](https://xemstudio.com/files/hardware/dc-motors-775-n20-tt/motor-775.stl) — 775 brushed DC: Ø42 × 66.7, 2 × M4 on 29 mm, Ø5 shaft × 17
- motor-n20-9mm-gearbox: [STEP](https://xemstudio.com/files/hardware/dc-motors-775-n20-tt/motor-n20-9mm-gearbox.step) · [STL](https://xemstudio.com/files/hardware/dc-motors-775-n20-tt/motor-n20-9mm-gearbox.stl) — N20 micro gearmotor: 12 × 10 × 15 motor + 9 mm gearbox, Ø3 D-shaft × 10
- motor-tt-dual-shaft: [STEP](https://xemstudio.com/files/hardware/dc-motors-775-n20-tt/motor-tt-dual-shaft.step) · [STL](https://xemstudio.com/files/hardware/dc-motors-775-n20-tt/motor-tt-dual-shaft.stl) — TT yellow gearmotor envelope: 70 × 22.5 × 18.5, 5.5 mm double-D shafts

## Questions

**What are 775 motor dimensions?**

Ø42 mm × 66.7 mm body, Ø5 mm shaft 17 mm long, two M4 holes 29 mm apart. Runs 12–24 V; needs a Ø42.3 mm printed cradle or the face holes.

**What is the N20 motor shaft size?**

3 mm D-shaft, about 9–10 mm long; Pololu-style brackets clamp the 12 × 10 mm body.

**What are TT motor mounting dimensions?**

Two Ø3.2 holes 17.6 mm apart on the gearbox side; body 70 × 22.5 × 18.5 mm; 5.5 mm double-D shaft for the standard 65 mm yellow wheels.

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