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ADS Coilover Spherical Bearings (resolved)

Replacing spherical bearings on the front coilover. Note that the (left) FKSSX10T-F1 bearings from the lower eye show almost no rust (since they are stainless steel) after replacement, while the (right) upper bearing FKS10T-F1 (hardened steel) shows significant rust.

TL;DR - I'm convinced that switching to extra tight stainless steel spherical bearings is the way to go, and I have numbers to prove it.

I've replaced my spherical bearings several times (I put a lot of miles on the truck) and there have been no shortage of posts covering the topic. Now, more than 120,000 miles after putting the first set on the Tacoma, I have what I feel is a conclusion: it is extremely important to use FK branded bearings, and they must have the F1 fit. F1 is the FK designation for an extra-tight fit (details).

For the curious, here's the overall timeline for spherical bearings in my lower front shock eye - the bearing that is subject to the most grit and grime of any bearing on the truck.

  • The first set (from the ADS factory, I have no idea what brand they were) lasted 22K miles
  • Second set of (as far as I know, unbranded, purchased from ADS) COM10T: 9K
  • Third set of (as far as I know, unbranded, purchased from ADS) COM10T: 7K
  • Fourth set of (as far as I know, unbranded, purchased from ADS) COM10T:10K
  • Fifth set of (as far as I know, unbranded, purchased from ADS) COM10T:9K
  • Sixth set of FKSSX10T-F1: 40K
  • Seventh set of FKSSX10T-F1: 15K so far, still "like new"

Over that time, I haven't had to replace the upper front or rear spherical bearings until the sixth set of bearings went into the lower front (97K miles).

There are two benefits of the FKSSX10T-F1. First is the stainless steel, which (obviously) does not rust. As such, there isn't rust eating away the Teflon. Second (and maybe more importantly) is the -F1 fit. That is a tighter bearing and as such, allows much less grit and grime from the trail into the bearing.

Personally, the lower eye on my front coilovers sees *way* more grime than the front uppers or rears (both lower and upper), so I'm now continuing to use the stainless steel in the front lowers. For all the rest, I'm using FKS10T-F1 (this is a hardened steel version vs. the COM10T which is just mild steel) and of course, with the -F1 fit. This saves money on 3 of the 4 spherical bearings. Frankly though, since I've only had to replace them after 97K miles, it probably doesn't matter what I use on those.


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