Alright, I have tried EVERYTHING, and I still have a shimmy in my truck. It's from 50-60ish. Shakes like hell some days, hardly at all on other days.

A little backround. I bought my truck with an R Title. It had frame damage. and two bent rear axles. Put a new rear end in, complete, from a 94 22R-E, eliminated most of my shimmy. I had my right lower ball joint replaced, which helped yet again. I had a bent rim, so I replaced all 4 with straight and true rims. Helped a little more.

Then, I got my frame straightened, and I felt almost no difference at all. After having the frame straightened, I knew it had to be aligned. I had it aligned and put on new shocks all around and new rear leafs, as I was told this would help. No difference in the ride. Handles a hell of a lot better though...

Before the leafs, there was a 1/4" difference in the wheelbase, but the X dimensions from frame caddy corners proved the frame was true. The frame is straight...

ANY ideas guys and girls? There is no way I can sell this truck to get a 5 speed with an R Title and a shimmy like that, no one would ever buy it. BTW, my frame was really out of square, my rear wheels tracked the front ones by almost 2-3 inches to the left. now they track perfect. NO funny tire wear either...

PLEASE Yotatech, Help!!!

 

Have you checked your steering componants? This is somthing I would hope the guys at the alignment shop would do, but you never know.

Are you sure your wheels are balanced?

You say it comes and goes, in what conditions does it do said shimmy in? Does that even apply?

 

forgot to mention tires have been balanced TWICE since I got it back at the beginning of December...

certain roads make it shake worse than others, but the intensity of the shakes on the same stretch of road varies from day to day.

as far as steering components go, thats where I am thinking the problem lies, but what about drive train as well? motor mounts, u-joints, anything? If I know what to look for, I will do so.

Thanks guys, for looking!

I owe ya, you can send electrical questions my way, thats my specialty!

 

shimmies are caused by poor balance, out of round tires/wheels, or force variations in the tires themselves. some tires are just prone to shaking, especially big ones.

play in the steering components can amplify the vibration as can poor alignment settings, but ultimately the cause is the rotating assemblies themselves.

 

any idea what sort of accident it was in? it might help to know what forces were applied in which directions to what components to help narrow down your search. it sounds like you've done a lot of work on it and taken a lot of steps forward with the project. good work! how much work (besides the the lower ball joint) have you done on the ifs? does the shimmy seem to come through the seat of your pants (i.e. the rear end) or the steering wheel (i.e. the front end)? any difference if you rotate your tires front to rear? is the wheelbase still off the 1/4 inch?

on another line of thought...when they straighten a frame do you know if they check to see if one frame rail is higher/lower than the other. i know they do the X measurement to make sure it is square that way, but if a car got a little upward force on the side that it hit it might push it up a bit? seems like your frame crossmembers would tell you a little bit about that. a good plumb bob and a framing square on a frame crossmember might help? i dunno though (thinking out loud)...the suspension might absorb any actual difference in height of the two frame rails, so a measurement from the top of the spring pack to the bottom of the frame (on the rear, of course) might tell you something as well (so would the relative angles of the shackles...if they are the dead same, then there they will have the same spring compression side to side).

one more thought (again, thinking out loud)...does it still shimmy when you've got weight in the bed? might try some extra weight to see it helps?

 

Have you checked your idler arm? That was a huge cause of wheel shake on my truck. But like I said, before they align the truck, the whole front end should be inspected, I know because I had to take my truck back twice before I could get it aligned.

 

what kind of tires you running?

 

Lots of good thoughts here!
I've done so much work on this truck that I am really ready to dump it and start new... One thing after another, but for now its solid.

No difference with weight in/out of the bed. Frame was done at Penn Tech for free, didn't cost me anything, but yes, all, and I mean all, dimensions were true. Up and down. Truck was struck in the right rear. I'll scan the initial measurements of my frame, and you will be able to see it was bent three ways. Its fixed now though. Shake is most noticeable from the front end. I have an after market cruise control on the truck that has a mounting stem on the steering column. The column shakes like hell at the mentioned speeds.

And Jay, I am unsure of what all was checked on the front suspension, but considering the source of the shimmy, I'd like to believe its up front...

 

straight tread street radials, had them on an SUV before, one of the best riding tires that are of the LT likes that I've ever ridden on... 31x10.50

Forgot to mention that I have not measured the wheel base since I got the new springs on, but the impression that I've gotten from many people is that 1/4" shouldn't make a big difference in the ride at all...

 

Drive line angles?

 

what do you mean, exactly? If you mean do I have lift or anything? no, completely stock as far as suspension goes. No BL either.

 

Check your wheel bearings
Check the idler arm

Go from there Checking stuff is free

 

No lift forget about DL angles, have you checked drive shaft for damage, knocked out of balance; ie dents or dings.

You did say tires are balanced, right.

 

I was just going to suggest the same thing; many times an unbalance driveshaft or UNIVERSAL JOINT GOING BAD will cause a vibration that is mistaken for tires/suspension.

 

ya my drive line made my runner shake like hell.... I would stick with the IFS theory . check your caster angle. that would account for the wheelbase thing and the shimmy. better yet go out and buy a new steering stabilizer. I would say for sure its up front.

 

is it 50-60 mph coasting or with throttle or always?

 

always.

Thanks a lot for the replies! I will be checking this stuff!
If you got more ideas, I'm keen to them as well!

And Caster is simply the relationship between the front wheels and the back wheels when compared side to side, correct?

 

oh, and if it makes any difference, I am unsure, but there is a slight, and I mean ever so SLIGHT difference between hubs locked and unlocked. I don't think its related...

 

every shimmy ive ever had was bad tires.


but, to check it all.
raise the front end. and spin the tires/ while touching the spring.
if the spring is vibrating, its suspension.

if the wheel itself moves. its the hub.

i just think its the tires. rubber gets old and hard in its age. thats why i prefer soft rubber tires that wear out every 2 years. (*not 80,000miles).

a set of michelins got me here, they were high mileage tires, and the car was not a d.d. so years later, the tires just became really hard and slippery.

 

try this one thing for me... go get a new steering stabilizer and throw it on... any large body one (procomp, ome,etc) will do. anything but the stock one...