There's concern about the fitment of Fat Cat/5XR bump stops on MX-5 applications where the "cup" that holds the OEM bump stops to the top of the shock assembly doesn't hold our bump stops like the OEM versions. There are two separate bump stop cups used on the NC - one that grabs our bump stops perfectly (that's for the rear) and a wider bump stop cup on the front that doesn't hold our 50mm wide bump stops. Our bump stops are at bit smaller in diameter than the OEM fronts at 50mm OD at the widest point. Our bump stop will still FIT inside the cup, but is not RETAINED inside the cup like the OEM's. Some people worry about that, but it's not an issue. The bump stop simply rests at the bottom of the shock shaft, next to the shock body, as is the case with many / most applications. Therefore there's no reason not to use the FCM/5X stops on an NC.
Here's a video to help visualize the fitment: https://youtu.be/j7sF9SnVCuY
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