Adj. Trackbars or High steer kit?(Steering shimmy)
So, I have some steering shimmy in my front end(NOT DW) just a constant small shaking. I'm getting mixed reviews when searching this topic. I've read that centering the axles will help eleminate the problem and there is no true high steer kit for a JK. Is this true? I've also read that using aftermarket CA's to adj the caster will fix the issue as well?
Is steering shimmy solved by a high steer kit? Or is just a fancy setup?
Is my problem coming from running stock tracbars and control arms?
I am slowly putting together the rest of my suspension together so I am getting currie TB's and CA's when money permits. (Probably taxes)
Thanks in advance
Covering a lot of ground here, but your "shimmy" problem can be quite a few things. To pin it down, check your front wheels for balance, bent rims, etc. If that's ok you likely have something loose. On a JK the front ball joints are junk. They wear out very quickly and if you add larger tires, lift, etc., and wheel it a bit they'll go even faster. Best replacements for the money are the Poly Performance units. Dynatrac makes some that are indestructible, but very expensive.
As for high steer, the reason to install one is to eliminate bump steer caused by excessive lift-created angles on the drag link & front track bar. I'm not sure what you're running, but generally anything 3" or more will benefit from a high steer conversion, and most good kits either include one or offer it as an option. Again, I'm not sure who told you there is no true high steer for JK, but I would disagree. The kits will include some kind of track bar mount adapter that either raises the mounting point on the axle, or, drops it on the frame side, both usually around 3". The kit will then include a replacement drag link that installs on top of the passemger side steering knuckle, usually requiring you to either use a reamer to cut a new taper in the knuckle, or drill out the stock hole and install a steel sleeve. To correct the bump steer problem you have to do both a track bar relocation and a drag link flip. You can't just do one or you'll create more problems than you already have. Good kits are available from Synergy (Poly performance), AEV, Teraflex and Rock Crawler. Would add that a couple kits use a dropped pitman arm and leave everything else stock. Time has proven this to not be a good solution due to the weak JK steering box. The pitman arm drop will eventually lead to sector shaft breakage.
Centering the axles under the rig is essential to proper alignment. To achieve it on more than about 2" of lift you'll need track bar relocation brackets front & rear as mentioned above, and perhaps adjustable track bars. Depends upon your setup. In my experince the axles need to be within 1/8" side to side. I've seen them on budget boosts or small spring lifts where the axles are off center 1/2" or more and the rig is all over the road.
My shimmy wasn't balljoint or tire induced, so here's some more data points to offer.
My shimmy was corrected by proper toe-in and adjustable LCAs to get the caster back in spec. The autoshop I took it to for a 'professional' alignment post lift install left me with 0 degree toe-in, and I was at about 2 degrees caster. I set my toe at about 3/32" (+/-), and bought some adjustable LCAs to bring the caster up to about 5.5 (I'm running a 4" lift on stock 32s at the moment). The LCAs were the leading contributor to clearing up the shimmy (and the toe-in check/set is free).
I don't have a highsteer kit yet (on the wishlist), and I do get bump steer that can can ocassionally cause a shimmy, but the LCA investment was clearly the better choice for me. Already had the adjustable trackbar on, I'd agree with SoK's suggestions there.