Hey y'all... Spent my last couple evenings working on the subframe listings and realized we haven't talked through the details on Ronin’s plan to address bump steer correction so I wanted to give a folks a preview of that.
As we noted in testing, the factory FD exhibits a great deal of bump steer from the factory. Evidence from testing linked here:
https://youtu.be/tN4JNP2yN6c in case you missed it. It certainly proves that Sikky's claims about the magic of the FD steering rack placement are pretty much crap. However, it also left us scratching our heads a bit about where exactly folks might want to dial in their kits to. Would folks want it closer to racecar theoretically perfect, or do folks actually like some lively but less stable handling like that Mazda used?
It's such a call on preference that at least to launch with we decided to give folks full adjust-ability. We're giving you both the ability to shim the steering rack since you'll want this close to your oil pan--1/8 to 3/16" clear is a good target--and including adjustable Speedway Motors spindles.
It generally installs like this (pic from Speedway’s website, we’re using a female rod end)
One twist though... One of the few complaints about adjusting bump steer by shifting the ball joint lower (rod end sphericals in this case) is that it puts more load into the spindles. See how much cantilever is possible in the pics above? For rx7 applications most folks will cut these down but still… A few folks have managed to bend spindles--both Samberg and Speedway--in off track adventures. As such, in addition to the pieces of a bump steer kit folks are used to we're also including a Ronin exclusive support piece. This effectively slides over the spindle hex and is tightened only snug tight. We don't want to unload the taper but it gives a nice wide base supporting the bending load as it enters in the steering knuckle.
We'll get pictures of the real deal when it comes off the CNC next week but this is the idea.
If your rod end is choked up high enough on the spindle that the support doesn’t fit vs where the tie rod wants to be, then the added bending is small enough that you don’t need the support. Make sense?
So the full bump steer kit will include:
-2x steering rack interface pieces
-8x steering rack spacers (1/8” each, so up to ½” rack motion possible)
-2x Mazda tie rods to rod end adapterr pieces (custom machined)
-2x Aurora rod ends (only brand name, quality bearings for us)
-2x Speedway Motors “pinto” steering rack spindles (w/ nut and lock nut to locate the rod end)
-2x Ronin spindle supports w/ 2x locking jam nuts.
Rack interface:
Rack spacer:
Tie Rod to Rod End Adaptors:
Like I said, apologies that we don’t have final pics yet, however our test parts were much rougher so the CAD is closer to the end product all things considered.
So how do you adjust bump steer? You can track down a gauge and measure via a dial indicator. You can also do a simple DIY version with a laser pointer.
Given all that, anything else we can do to help you all in dialing in bump steer? I’ve even debated including an inexpensive laser pointer but it seems there are so many ways to approach this that it might be simpler to leave it open for you guys to dial in via your method of choice.
Thoughts?
-Joel Payne
(for RSW)
