Linkage (current version Linkage X3, developed by Racooz Software and hosted at bikechecker.com) is the most widely used suspension simulation and design tool for mountain bikes. Engineers, frame builders, and enthusiasts use it to model how a bike’s suspension behaves under real-world conditions, calculating leverage ratio, anti-squat, pedal kickback, and axle path across the full range of travel. If you’ve ever wondered why two bikes with the same travel feel completely different, Linkage X3 is the tool that explains it.
This guide covers what Linkage X3 does, where to download it safely, the difference between the free and paid versions, how to get started, and the best alternatives. For geometry-minded riders, Linkage bridges the gap between static frame measurements (which we cover in our geometry explained guide) and the dynamic behavior of the suspension system.
Where to Download Linkage X3 (Safely)
The only official source is the developer’s site, bikechecker.com, with the Professional license sold through Racooz Software on Gumroad. Avoid third-party “download” mirrors and “crack” sites (software.informer, freedownloadmanager, and similar); they bundle unwanted software and rarely carry the current, safe build. Always download Linkage X3 from the official site.
Free vs Paid: Which Version Do You Need?
- Demo (free): lets you open and explore pre-modeled bikes and see how the simulation works, with export and custom-design features limited. Ideal if you just want to compare existing bikes or learn how kinematics work.
- Linkage Personal: unlocks the full online bike library and the core analysis tools, aimed at riders, home mechanics, and bike customers.
- Linkage Professional: the complete feature set (custom linkage design, advanced modeling, and full export) used by brands, engineers, and designers.
Current pricing for the Personal and Professional licenses is listed on the official purchasing page at bikechecker.com, and upgrades from older versions (v2012 or v2.5) are available there too.
What Linkage Does
At its core, Linkage models the kinematics of a bike’s suspension linkage — the physical pivot points, links, and levers that connect the rear wheel to the frame. By defining these points in 2D space, the software calculates how the rear axle moves through its travel and how the leverage ratio changes at every point. This matters because leverage ratio determines how the shock is compressed at different points in the travel, which directly affects small-bump sensitivity, mid-stroke support, and bottom-out resistance.
The software also calculates anti-squat (how much the suspension resists compression under pedaling forces), pedal kickback (how much the pedals move when the suspension compresses), and the rear axle path (the arc the rear wheel follows as the suspension cycles). These kinematic properties interact with geometry — a bike with progressive leverage and high anti-squat will feel completely different from one with linear leverage and low anti-squat, even if their geometry charts look identical.
The Bike Library
One of Linkage’s most useful features is its extensive library of pre-modeled bikes, with over 2,000 mountain bike models available and their suspension pivot points already mapped. You can pull up a bike, run the simulation, and compare it against any other model instantly. This makes it possible to compare the suspension kinematics of a Specialized Stumpjumper against a Trek Fuel EX not just on geometry numbers but on how their suspensions actually work through the stroke.
How to Get Started With Linkage X3
- Download the version you need from bikechecker.com.
- Install it on Windows (see the Mac note in the FAQ below).
- Open a pre-modeled bike from the library to see leverage ratio, anti-squat, and axle path plotted instantly.
- Load a second bike and overlay the curves to compare how two suspensions behave through the stroke.
- Adjust pivot points to see how small changes alter the ride, the fastest way to build intuition for suspension design.
Linkage X3 Alternatives
- syn | Linkage Designer (syn.bike): a newer, browser-based suspension design tool. No Windows install, runs anywhere. Worth a look if you want an online option.
- Manufacturer leverage-curve charts: many brands publish leverage curves for their bikes, useful if you only need one model and don’t want software.
- Bikometry’s geometry tools: Linkage models the dynamic suspension behavior, while our geometry calculator covers the static geometry side. Use both together for the complete picture of how a bike will ride.
Why Suspension Kinematics Matter for Geometry
Static geometry — the numbers on a geometry chart — describes a bike at one specific point: fully extended, unweighted, with the rider off the bike. The moment you sit on the bike, the suspension compresses into its sag point and the geometry changes. Head angle steepens, BB height drops, wheelbase shortens, and reach decreases. How much these numbers change depends on the suspension kinematics.
A bike with a progressive leverage curve will resist deep travel and maintain geometry closer to its static numbers through most of the riding. A bike with a linear or degressive curve will sag deeper, changing its effective geometry more dramatically. This is why two bikes with identical static geometry can feel different on the trail — their suspensions alter the dynamic geometry in different ways.
If you’re comparing bikes on our geometry pages and two models look nearly identical on paper, their suspension kinematics may be what separates them in practice. Tools like Linkage help visualize that hidden dimension.
Key Metrics in Linkage
Leverage Ratio Curve: Shows how the mechanical advantage between the wheel and the shock changes through the travel. A progressive curve (leverage decreasing through travel) resists bottoming out; a linear curve provides consistent resistance throughout.
Anti-Squat: Expressed as a percentage, anti-squat describes how much the chain tension counteracts suspension compression under pedaling. Values above 100% mean the suspension actually extends under pedaling force. Most modern trail bikes target 100-130% anti-squat at sag.
Axle Path: The arc traced by the rear axle as the suspension moves through its travel. A rearward axle path helps the wheel move backward over square-edge hits, improving traction and comfort.
Pedal Kickback: How much the cranks rotate as the suspension compresses. Lower pedal kickback generally means a more comfortable pedaling feel on rough terrain.
If you’re more interested in understanding geometry than suspension design, start with our mountain bike geometry guide and learn how to read geometry charts. For riders who want to go deeper into the engineering behind how bikes handle, Linkage X3 is an invaluable tool for connecting the dots between frame geometry and suspension performance.
Frequently Asked Questions
Is Linkage X3 free?
There is a free Demo version with limited functionality. The Personal and Professional licenses are paid and unlock the complete bike library, advanced metrics, and custom design tools.
Where do I download Linkage X3?
Download it from the official site, bikechecker.com, with the Professional license available through Racooz Software on Gumroad. Avoid third-party mirror and “crack” sites, which are not the current, safe build.
Is there a Linkage X3 tutorial?
Yes. Start by opening a bike from the built-in library and overlaying two models to compare their leverage and anti-squat curves (see the getting-started steps above). The developer also hosts basic-use videos on the bikechecker.com site.
Does Linkage work on Mac?
Linkage is a Windows application. Mac users can run it through Boot Camp, Parallels, or other Windows virtualization solutions.
Is there an online version of Linkage?
Not officially, but syn | Linkage Designer (syn.bike) is a browser-based alternative that runs without a Windows install.