I'm thinking about refreshing my bushings with new hardened rubber ones. Over the 8 or so years I've owned this car (5 with a lot of track and autocross, and the most recent 3ish years mostly just autocross 5-6 times a year), I've replaced all the engine, transmission, and diff mounts, and many of them were badly torn. So I wouldn't be surprised if the suspension bushings are in similarly bad shape, but I haven't felt any obvious issues. Aside from the UCA bushings though, which I switched to offset ones when I was trying to fit 10.5s for SST, they're all the original rubber as far as I know.

I'm guessing the front compliance bushings (ie. the rear bushings on the front LCAs) are likely in need of replacement. What I'm trying to decide is, should I just do those, or should I order the full kit from Hardrace and just replace everything (aside from the UCA ones I already did). Like, if there are no visible cracks that you can see without disassembling, and no obvious slop in the suspension, can you just assume the other bushings are fine? Or after 8 years of hard use would they all likely benefit from a refresh?

I don't want to just waste money replacing things that are perfectly fine, but since I'll be ordering parts and getting some work done anyway, figure now would be the most efficient time if they are going to need to be done.

 

Replace them all if you're already pulling the arms off. If you've been driving hard track & auto-x for 8yrs, they're likely all toast - especially if you've been running 18x10.5s with 200TW or stickier tires.

I would recommend going spherical for your compliance bushing - that one gets beat up quite a bit. I've gone through 3 comp-bushings now - wish I did spherical the last time I got it replaced - unplanned replacement and had the shop do it while they were doing other work for me.

 

I only ran the 10.5s briefly, but yeah, it's seen a lot of autocross. I'm fairly sure replacing rubber with spherical isn't legal for STC.

 

Ah, yeah, stick with the hardened rubber from hardrace then.

Regarding the 10.5s Classing reasons? or performance/technical related?

I just made the switch to 10.5 with 265s. Got one track day on it, and blew up my differential - didn't really get to test and feel it out properly. Bigger test coming up in 2-weeks to see how I like it and the new differential.

 

Yes, this is the Street Touring rule for bushings:

So you can use aftermarket rubber or poly (though I have no interest in the latter), but can't change from rubber to spherical.

 

Got it.

Follow up question on the 18x10.5s - stopped running them for rules/classing reasons as well? Or something else?

 

Yes, S2000 got moved from SST back to STR and then STC, so can't use them for autocross anymore. And since I bought a GT4 in 2022, I mostly use that for time attack and lapping, so the S2k is mostly just an autocross car for me now. 265s on 10.5 are definitely faster than 255 on 9 though. (Albeit difficult to fit. Best setup I could get, even with the offset UCA bushings, they'll rub on the UCA before full lock.)