I remembered i had copied the post and was going to have it done by a local shop with the Hunter 9700 but decided it was not worth it.Here it is so you wont have to go searching for it on the forum.
There seem to be a lot of people posting with tire vibration problems through the steering wheel around 60mph. i was one of them. i've had my FJ for a while now and have gotten it fixed with the help of another member.
The problem seems to be related to a very big and heavy wheel/tire combo, and the suspension not soaking up the small vibrations. The cause of the vibration on the road is not actually the balance, but the Road Force Number (basically if the tire is a little out of round). No tires are perfect but Michelins are historically the most round because of the way they are made. The roadforce number can be reduced.
Also i have noticed that the wheel locks sold by Toyota are 1 Gram off weight compared to the lugs. i noticed a difference on my Fj.
Make sure the tire shop has the Hunter 9700 balancer.
Here's the fix to print and take to your tire shop. if they follow this properly your vibration will be gone!
Please print this out for your tire tech, not many techs know how to do this. This will fix your steering vibration, once & for all, but allow up to 1.5 hours of actual labor & maybe replacing a tire or two. Why some FJ's are sensitive & some aren't, I don't know. I've heard many explanations & I dont know what to believe. Below is our best fix to date.
Start by using a wheel with 15mm or so of offset(on a 8.5" wide wheel), zero offset wheels dont seem to work when using a custom wheel, try to stick to a 275 or skinner tire, we've had some luck with 285's, of course the bigger the badder.
Using the Hunter GSP9700 with the latest software (older 9700 software wont work, uses a different mathmatical formula) with the Smart Weight feature: First, disable the smart weight, very important! Back cone the wheel and use the 6 on 5.5 front finger set up. Road Force & ForceMatch, must Forcematch the wheel & tire combo &/or the set to get each below 15 pounds of road force, the lower the better, even if it Road Forces pretty low, ForceMatch every tire any way, no reason to do it half ass. Also, it MUST only be out in the 1st Harmonic, if any tire/wheel combo is out in the 2nd, 3rd, ot 4th Harmonic, change it out, its not fixable. After this is all done by turning the tire on the wheel &/or swapping tires & rechecking the road force( write this # on each wheel), use the Dynamic balance mode to zero out the balance, then check in static mode, if needed add the 1/4 ounce or so, shouldn't need more than 1/4 ounce if any. If weight was added in static mode respin in Dynamic mode & make sure it still says zero zero (0.00 0.00) if it says OK OK it is still in SmartWeight system & it wont fix the problem! After all this you can put back in the SmartWeight mode and the two tires on the screen should just have a sliver of green on the bottom of the tires, this is good, if it shows more than about 1/10th of the tire in green then it need to be redone or replace the tire or wheel. Now put the lowest road force numbers(hopefull 6 lbs. or less) on the front of your FJ with Hub Centric wheels or with the Hub Rings installed(must be hub centric)!
Road Force Variation is : For every 10 pounds of road force in the assembly = 1/2 ounce of vibration at 50mph or 1/4 ounce vibration at 70mph, so 30 pounds of road force would equate to 1.5 ounces of vibration at 50mph but only .75 ounces at 70mph, this is one reason most vibration problems begin at 55ish and go tend away at 65ish & this can NOT be fixed by balancing!
Let me clarify the Harmonic thing, if an assembly is bad in the 2nd-4th Harmonic then that assembly it is NOT usable, but that doesn't mean the tire or the wheel is bad, just that that paticular marriage is no good , quite possibly the same wheel with different tire is okay or same tire on different wheel is okay.
(9-1-06) One other trick I forgot to post. On sensitive cars we like to raod force hot tires, drive on them for 4 miles or so & do the fronts, drive again & do the rears, it will road force way different hot than a clod tire, more of a real world fix.
Good Luck & Happy Motoring!!