I have a 2010 FJ. It was stock 3 weeks ago and drove perfect. Recently installed factory 17" steelies and 255 80 17 BFG KM2 tires and now have the shimmy. This is not secluded just to the TRD wheels apparently.
YES EXACTLY! MINE ALSO HAS THIS FEEL!Also something to note. I know the 2010+ FJ have a tighter turning radius. Not sure what they changed, but I notice a difference in the steering wheel feel between my 2007 and 2010 when they both had big tires. The 2007 turned silky smooth, the 2010 has a feel in the steering wheel, kind of like a force feedback steering wheel found in arcade games...the ones where you had to hold the wheel still or the game would spin it any which way.
I checked the 2011 FSM and yes there is a preload on the steering gear. However if your truck ever drove ok, then I would doubt this value was incorrect. Let him try it if it works then sweet, maybe we have another fix option:bigthumb:An old tech who works at the shop across the street from my office claims that this whole shimmy problem is due to a misadjusted rack & pinion. He told me to get the specs on the "adjustment" and that he promised that the problem would go away after re-adjusting it.
I think he's talking about something like the preload adjustment on standard, old-style steering boxes. Do our rack & pinions even have any such adjuster?
You know, he might have a point. The fact that the steering wheel shimmies left to right rather than the usual balancing-related up'n down has got to mean something.