# TT yellow gearmotor 70 × 22.5 × 18.5 mm, Ø5.5 double-D shafts

> What are TT motor mounting dimensions?

- Category: Hardware › Motion
- Kind: Hardware
- Basis: Common supplier drawings for the yellow TT (1:48) gearmotor; clones vary by about ±0.5 mm
- Page: https://xemstudio.com/objects/tt-gearmotor/ · JSON: https://xemstudio.com/api/geometry?object=tt-gearmotor · Plain text: https://xemstudio.com/objects/tt-gearmotor/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses

**Exact dimensions.** Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part.

## Notes

- The TT envelope is a 37 × 22.5 × 18.5 mm gearbox plus a Ø18.5 × 33 motor: 70 × 22.5 × 18.5 overall.
- The output is a Ø5.5 double-D shaft, 3.7 mm across the flats, sticking out 9.5 mm on both sides (41.5 across).
- Two Ø3.2 holes run through the gearbox's 22.5 mm width, 17.6 mm apart along its length and 17.5 mm apart in height.
- Many clones vary by about ±0.5 mm.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| TT shaft | Ø5.5 double-D, 3.7 across the flats | wheel hub | press | motor-tt-* |
| mounting holes | Ø3.2 × 2, 17.6 apart | M3 screws through the gearbox | designed | motor-tt-* |

## Sizes

| feature | size_mm |
|---|---|
| overall | 70 × 22.5 × 18.5 |
| gearbox | 37 × 22.5 × 18.5 |
| shaft | Ø5.5 double-D, 3.7 across flats |
| shaft span | 41.5 |
| holes | 2 × Ø3.2 |

## 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 (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/tt-gearmotor/index.json

- 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 gearmotor envelope: 70 long (37 gearbox + 33 motor), 22.5 tall × 18.8 thick, Ø5.5 double-D output shaft (3.7 across the flats) 37 tip to tip, 25.8 from the motor end of the gearbox; two Ø3.2 mounting holes through the 18.8 thickness, 5 from the motor end, 17.6 apart one above the other (0.85 mm of wall to the top and bottom faces)

## How it fits

### Connects to
- [18650 lithium cell](https://xemstudio.com/objects/18650-cell/): a common supply for TT robot chassis

### Alternatives
- [N20 micro gearmotor 12 × 10 mm, Ø3 D-shaft](https://xemstudio.com/objects/n20-gearmotor/): smaller metal-gear motor

## Questions

**What are TT motor dimensions?**

70 × 22.5 × 18.5 mm overall with a Ø5.5 double-D shaft (3.7 across the flats) on both sides.

**What wheel fits a TT motor?**

Any hub with the Ø5.5 double-D, 3.7 mm across the flats; the standard yellow wheels are 65 mm.

## Fits with

- [N20 micro gearmotor 12 × 10 mm, Ø3 D-shaft](https://xemstudio.com/objects/n20-gearmotor/)
- [775 brushed DC motor Ø42 × 66.7 mm, Ø5 shaft](https://xemstudio.com/objects/775-dc-motor/)
- [18650 lithium cell](https://xemstudio.com/objects/18650-cell/)