opensus
opensus compared with other suspension design software
opensus is a free, browser-based suspension kinematics tool: nothing to install, and design and analysis are free. Established desktop tools such as OptimumK, SusProg3D and Lotus's suspension analysis software are more mature and have been used on many more cars; opensus's advantages are cost, access from any computer, and analysis that goes past kinematics into compliance and link loads.
Details of other products below are general and based on their public descriptions as of November 2026. Check each vendor's site for current features, platforms and pricing.
At a glance
| opensus | Established desktop kinematics tools | CAD sketch | |
|---|---|---|---|
| Cost | Free to design and analyse; Pro for file exports | Paid licences; some offer student or team pricing | Part of your CAD licence |
| Install | None: runs in the browser | Desktop install, typically Windows | Your CAD package |
| Suspension types | Double wishbone (pushrod/rocker), MacPherson, five-link, semi-trailing, or any linkage built from links and joints | Broad libraries of types, refined over many years | Anything you can sketch |
| Kinematic curves | Camber, toe, caster, KPI, scrub, trail, roll center, anti geometry, motion ratio, track and wheelbase change, Ackermann | Comprehensive | Manual: you measure each position |
| Whole-car behaviour | Steady-state cornering and braking, plus transient bumps and manoeuvres | Varies by product | No |
| Compliance and link loads | Geometric compliance and design load cases built in | Varies; some focus on kinematics only | No |
| Track record | New | Long, widely used by Formula Student and professional teams | Long |
When to use something else
- You need validated, industry-standard results for a professional programme: an established tool with a long track record, and the support contract that comes with it, is the safer choice.
- You need bushing compliance, flexible bodies or full multibody dynamics: opensus's links are rigid and its compliance uses one reference stiffness. Dedicated multibody packages, or tools that link to them, do this properly.
- You're packaging parts around the suspension: you will end up in CAD anyway. opensus exports points, DXF sketches and STEP layout models to start from.
When opensus fits
- Learning suspension design, or a Formula Student team on a small budget: free, with docs that teach the engineering behind each number.
- Early concept work, comparing layouts quickly before committing to detailed design.
- Any computer: a borrowed laptop, a Mac, a Chromebook, or a workshop PC with no admin rights.
- Going past kinematics early: check compliance steer and worst-case link loads on the same model, before the CAD is drawn.
See the methodology for exactly what opensus models, and the validation page for how accurate it is.