need advice on bad shimmy in truck since going to 38 inch tires. truck does need front shocks could this be the cause?  

the first thing i would do is balance the tires  

I WOULDNT EVEN BOTHER BALANCING THEM, TOO BIG OF TIRE YOU'LL END UP WITH 5lbs. OF WEIGHT ON EACH RIM.  FIRST THING IS I NEED TO KNOW WHAT KIND OF TRUCK U HAVE , WITH MOST STRAIGHT AXLE TRUCKS ESPECIALLY DODGES YOU GET A SHIMEY OR A PULL FROM BOUND UP FRT AXLE JOINTS

part of it is shocks,maybe a new steering stabilizer, possibly ball joints, and tie rod ends, and maybe get a front end alignment. check the ball joints first, my 79' bronco did the same thing when i first went with 36's, it was the ball joints, and trac bar bushing. hope this helps. also check tire balance

Like it was already mentioned it this post, balancing 38's is takes a tonne of weight added to the rim. Tire tuning is almost a lost art, but works great on big tires. This involves trimming the tread to achieve proper balance. Lots of folks used to think that cutting off good rubber was a waste, but in the long run you get better tread life out of a properly balanced/tuned tire.

I would check axleshaft u-joints (worn/chewed/missing needles will cause a shimmy), diveshaft u joints, and driveshaft balance. Dirveshafts can go out of balance alot easier than most people suspect. My buddy had an ugly shimmy in the rear of his 88 k1500, u joints were good, 35" boggers just dont balance, so we took the driveshaft to the local shop, the tech there spun it on the machine and welded on 3 washers for $15. Smooth as silk after.

not to dispute your word, and i agree with you on the tire tuning, but my 36" tsl's balanced just fine and the most weight i got on one of them is about 6oz. you just got to find some one who knows what they are doing, also saw this argument in a back issue of peterson's. good point on the driveshaft though, i didn't think about that. this shows that when you get enough people together, you can get a lot of ideas on how to fix your problems.

Some sets of tires seem to balance and others dont. Your TSL's taking only 6oz is pretty impressive. Like you say, tire balacing is all in the person running the machine. Radials tend to balance better than Bias-ply too (not sure if yours are radial).

Balancing that set of 35x14.50 boggers I mentioned was a no go. The rims were true, and the tires rode Ok after. I also had no problems at all balancing a 35x14.5 Mickey T's.

....now i'm stuck on 235/85/16......8(

I agree with everybody when comes to the shocks and everything one thing you can do like I did was go to a good tire shop and tell them to balance them with Equal its a sand that makes your tire true it might work it might but I did mine 5 years ago and still good. Then they can try to balance them with weights. Hope that helps too.  

i had a little mexican guy balance my tires. they are bias ply, and yes, i agree, radials do balance better because they are made to run on the street. boggers just have so much meat and such a crazy tread pattern, i would say they probably are a nightmare to try and balance. you know, come to think of it, i don't believe the guy that started this post even said what kind of shoes he was running.  

Nope, he didn't say. what tires he was running.

Now I know why my tires wouldnt balance, up here in Canada we have shortage of little mexican guys....8)

y would anyone ballance an offroad tire.

every time u go wheelin u loose a chunk of rubber somewhere on the tires, somtimes only wheighing a fraction of an ounce, other times more, ur tires are never gonna be completely ballanced after wheeling so dont waste money.

uneven or low tire preasure may cause a shimmy. if u air down try to get back to recomended preasure when done wheeling or as soon as u can.

My 2 cents ($1.87 CND)  

you can use "sand bag packs" for semi truck tires. they work well on those huge tires.
low tire presure plays a role, but on the 38's you wind up with about 25psi to keep them from wandering all over.
the steering stabilizer is a good place to start, I use duals on my chevy to control it.  

Steering stabilzer is definately a way to go (any thing over 35's recomened a dual stabilizer. As for balancing 38's and higher sand works well, but might give balancemasters.com a try  

definatly go with the multi steering stabilizer and try the sand discs/equal. they look kinda like pizza pans, but do wonders for the balance. also, a good tire shop might be able to get the balance on by adjusting the torque on each lug nut. i had a guy do this on my big truck...thought he was crazy, but it worked. they raise the wheel, while on the vehicle and spin it and have something like a timing light blinking off a florecent dot on the side of the tire, then they'll make the adjustments....don't know the machanics of it all, but it worked.  

one of the advantages of equal or magnum powder balance is it balances the tire with tire wear. Boggers wear fast and balancing of tire changes fast and the equal will go to wear its needed. Used to use bb's but makes funny noises when you stop and people will look at you. Powder still has some issues but better than nothing or fixed balance weights.