# Roll centre

> What is the roll centre and how does it affect handling?

- Category: Car design › Suspension geometry
- Kind: Standard part
- Basis: Design rules and figures from the cited sources; example geometry by Xem Studio
- Page: https://xemstudio.com/objects/roll-centre/ · JSON: https://xemstudio.com/api/geometry?object=roll-centre · Plain text: https://xemstudio.com/objects/roll-centre/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files Xem Studio Design License (free to use and sell from, not to redistribute as files: https://xemstudio.com/license/)
- 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

- The roll centre is the point about which the body rolls on its suspension; on a double-wishbone layout it is found by extending the arms to their instant centre and drawing lines to the contact patches (Formula1-Dictionary; Suspension Secrets).
- Lower roll centres give more roll; as the suspension compresses the roll centre rises and the roll moment shrinks (Formula1-Dictionary). On a solid axle with a panhard bar, the roll centre is the mid-point of the bar (NC4x4).
- On RC cars, upper shock-tower link holes lower the roll centre and add corner-entry steering; lower holes raise it for high grip (Tekno).
- The file is a reference example built by Xem Studio from the numbers above (Reference 1/10 touring car: wheelbase 260 mm (AARCMCC ISTC 250-270), track 190 mm (EFRA width without body), 50 mm = EFRA rim limit.). Sizes the sources do not fix are illustrative; scale the example to your own vehicle.

## Sizes

| parameter | value or range | source |
|---|---|---|
| Panhard axle roll centre | mid-point of panhard rod | NC4x4 forum |
| Roll axis nose-down | tends to oversteer; nose-up tends to understeer | Formula1-Dictionary |
| RC upper tower holes | lower RC, more entry steering | Tekno setup guide |

## Where the files are

- Formula1-Dictionary: [Roll center](https://formula1-dictionary.net/roll_center.html) — web — Publisher's page; dimensions are facts
- Suspension Secrets: [Suspension geometry explained](https://suspensionsecrets.co.uk/suspension-geometry-explained) — web — Publisher's page; dimensions are facts
- NC4x4 forum: [General 4 Link Suspension Design Information](https://nc4x4.com/forum/threads/general-4-link-suspension-design-information.72892/) — web — Publisher's page; dimensions are facts
- Tekno RC: [Tekno RC Setup Guide](https://teknoforums.com/misc/Tekno-RC-Setup-Guide.pdf) — web — Publisher's page; dimensions are facts
- CompetitionX: [RC Quick Setup Guide](https://www.competitionx.com/?p=129) — web — Publisher's page; dimensions are facts

## Free STEP/STL (1 parts, Xem Studio Design License, Xem Studio)

Index: https://xemstudio.com/files/hardware/roll-centre/index.json · license: https://xemstudio.com/files/hardware/roll-centre/LICENSE.md

- roll-centre-geometry: [STEP](https://xemstudio.com/files/hardware/roll-centre/roll-centre-geometry.step) · [STL](https://xemstudio.com/files/hardware/roll-centre/roll-centre-geometry.stl) — roll centre demo: front axle, track 190 mm, Ø50 tyres, 0° (illustrative layout)

## Questions

**Why raise the roll centre?**

Less roll and quicker response; Tekno uses lower tower holes (higher roll centre) on high-grip tracks.

## Fits with

- [Camber angle](https://xemstudio.com/objects/camber/)
- [Caster angle](https://xemstudio.com/objects/caster/)
- [Front kick-up (RC)](https://xemstudio.com/objects/kick-up/)
- [Front toe (toe-in / toe-out)](https://xemstudio.com/objects/toe-front/)
- [Rear toe-in](https://xemstudio.com/objects/toe-rear/)
- [Ackermann steering geometry](https://xemstudio.com/objects/ackermann/)