SADfab bronze retrofit STR Legal
 

Hello all

just recently got a NA8 Miata that I want to set up to run in STR. Due to lack of service done by PO Is going to replace bushings. I originally decided on ES poly bushings but I am quickly seeing some shortcomings. That leads to the question at hand.

Is the SADfab bronze bearing retrofit legal to run in STR? I’m specifically wondering about the section of the rules that state “In a replacement bushing, the amount of metal relative to the amount of non-metallic material may not be increased.” I am wondering if having the bronze bearing & sleeve increases this ratio and thus makes it illegal.

let me know if I am overthinking things.

You would need to remove the metal center section of the original rubber bushing and then measure it and compare.

In the sadfab retrofit instructions it requires you to bore out some of the poly bushings to 7/8" inner diameter, which is larger than the normal metal sleeve supplied in the ES kit, but I have no idea how either of those compare to the OEM sized sleeve in the rubber bushing.

Oof

You see, the way STR is currently set up is...

If you're just having fun locally, do the bushings REQUIRE service? You sure?
If you're trying to build a competitive NA for STR, well, godspeed.

Oof indeed... now I see now my brainfart in that post. What I meant was STS. Thanks for calling me out on that.

On the subject of bushings..
1-I know my RUCA-O bushings are shot
2-The cam bolts are the "old" style which I have read is prone to yielding and not providing the necessary clamping force to hold an alignment
3-The previous owner did very little service and admitted to never having the car aligned in 10 years of ownership(Tires are wearing unevenly too). I am afraid those cam bolts will be sized into the sleeves due to lack of attention. Im not in the rust belt but we get our fair share of road salt where im at.
4-On point 3 if I have to do any drilling/cutting/Torching/etc to get a bolt out and ended up damaging a bushing I wanted to have replacements handy.

So it isn't that my bushings are needing service but more like since I already need the alignment & Cam Bolts... why not just go ahead and change them out to what I want long term? Assuming that it would be legal in my class