FD Bump Steer Correction without Rack Interfaces (for OEM Mazda subframes)

Guess what? The FD has a surprising amount of factory bump steer.

We were pretty amazed when Ronin proved this in testing. Check out the video if you haven't seen it yet. It really debunks the notion of any "magic" in the FD's steering rack placement. But it also got us thinking: where do folks actually want to set their kits? Do they prefer a racecar-perfect setup, or do they enjoy the lively, if less stable, handling that Mazda originally designed?

It's such a personal preference that, for now, we've decided to give you full control, even when using the OEM Mazda subframe.  Our kit is designed adjustable Speedway Motors spindles. 

But here's the twist. One issue with adjusting bump steer by lowering the ball joint (using rod end sphericals) is that it can stress the spindles. And those Speedway spindles are pretty long. Many RX7 owners end up cutting them down, but some have still managed to bend them, especially during spirited driving.

To address this, we're throwing in a little something extra: a Ronin exclusive support piece. This nifty contraption slides over the spindle hex and is tightened just snug—don't overdo it! It provides a wider base of support for the bending load as it enters the steering knuckle. Just be careful not to pinch the rod end against the spindle support nut!  

And if your rod end is already high enough on the spindle that the support doesn't fit, don't worry too much. The added bending force is likely small enough that you won't need it anyway.

Our bump steer kit for the OEM subframe includes:

• 2x Mazda tie rods to rod end adapter pieces (precision machined from high-strength stainless steel)
• 2x FK rod ends (because we only use top-quality bearings)
• 2x Speedway Motors “pinto” steering rack spindles (complete with nut and lock nut to locate the rod end)
• 2x Ronin spindle supports with 2x locking jam nuts.

So, how do you go about adjusting bump steer? You could get fancy with a dial indicator, or keep it simple with a DIY version using a laser pointer. Here's a handy video to show you how.