# Friction wheels (rolling contact drive), 30 : 60

> How much torque can friction wheels transmit?

- Category: Mechanisms › Belt and friction drives
- Kind: Hardware
- Basis: Xem Studio design following Brown No. 32 (1868)
- Page: https://xemstudio.com/objects/friction-wheels-mechanism/ · JSON: https://xemstudio.com/api/geometry?object=friction-wheels-mechanism · Plain text: https://xemstudio.com/objects/friction-wheels-mechanism/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** True size, with no printing tolerance added.

## Notes

- Two plain wheels pressed together drive each other by friction at the line of contact: ratio = D₂/D₁ (2 : 1 here), opposite directions, and they slip instead of breaking when overloaded.
- Torque at the small wheel ≈ μ·F·R₁: with rubber on steel (μ ≈ 0.6) and 50 N pressing, about 0.45 N·m. Centre distance = (D₁ + D₂)/2 = 45 mm, rims touching.
- Brown's No. 32 (friction wheels with roughened or leather/rubber-covered rims).
- Parts (each has its own page): friction-wheel-30x10, friction-wheel-60x10.
- Brown's movement No. 32 (1868) shows it; this model is a Xem Studio design following his figure, every part at true size.

## Sizes

| parameter | value |
|---|---|
| wheels | Ø30 and Ø60 × 10 |
| centre distance | 45 mm |
| ratio | 2 : 1 |

## Where the files are

- Henry T. Brown (1868, public domain): [Five Hundred and Seven Mechanical Movements — scan on archive.org](https://archive.org/details/fivehundredseven00browiala) — web — Publisher's page; dimensions are facts
- 507movements.com: [Brown's movement No. 32: figure, his text and an animation](https://507movements.com/mm_032.html) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/friction-wheels-mechanism/index.json

- friction-wheels-mechanism-assembly: [STEP](https://xemstudio.com/files/hardware/friction-wheels-mechanism/friction-wheels-mechanism-assembly.step) · [STL](https://xemstudio.com/files/hardware/friction-wheels-mechanism/friction-wheels-mechanism-assembly.stl) — Assembled mechanism, all parts placed at one pose (STEP keeps each part separate)

## Questions

**How much torque can friction wheels transmit?**

Two plain wheels pressed together drive each other by friction at the line of contact: ratio = D₂/D₁ (2 : 1 here), opposite directions, and they slip instead of breaking when overloaded.

## Fits with

- [Friction wheel Ø30 × 10, Ø5 bore](https://xemstudio.com/objects/friction-wheel-30x10/)
- [Friction wheel Ø60 × 10, Ø8 bore](https://xemstudio.com/objects/friction-wheel-60x10/)