The rear suspension of the Roadster provides another opportunity to customize and update the car. But unlike other choices that can be easily upgraded after the build (like the seats), the rear suspension should be locked in up front, as changes after the build would require significant work to complete.
FFR offers several different options for rear suspension setups – 3-link, 4-link, and Independent Rear Suspension (IRS)…I’ve been racking my brain as to which is the right choice, much like the engine options. 4-link setups are generally designed for more straight-line performance, so that is out, which leaves the decision between the 3-link & IRS.
3 Link Pros & Cons
PROS: The 3-link is a more simplified, solid axle rear suspension. Being “old tech”, its a tried and tested design that is rock solid and streetable. An added benefit is that it is the most cost-effective option of the two.
CONS: Both rear wheels are connected to one another via a solid axle. The solid axle is also heavier. Combined these together and the spring rates need to be a bit harder which potentially results in a harsher ride. Installing a 3-link can also harm resale values.
IRS Pros & Cons
PROS: The IRS is derived from the suspension of the 2015 Ford Mustang GT. It is a very popular and well rounded piece of equipment. Additionally FFR did extensive testing before launch to tune the setup in their vehicles. Today, the IRS offers not only the most compliant ride (relatively speaking), but it also performs better during “spirited” driving compared to the 3-link.
CONS: Installation is more complex, and requires the lug nuts to be pressed out of the hubs, and new ones installed. Cost is also a concern as the IRS suspension commands a roughly $2,000 premium over the 3-link setup