Steering vibration

[TRCM]

Got a vibration going on, and I'm not sure what it is.

96 sport, 4" lift, 31's, SYE, bilstein shocks, new rear cv DS

Trans started acting up so the truck sat for the 1st half of the year. Now, trans is fixed, abut I picked up a vibration, which can be felt thru the steering as well as yer seat bottom. Almost feels like an egg shaped tire when it happens from the way the steering wheel shakes (not really a visible shake, but it is felt), but it only happenened during the 38-52 mph speed range. Above or below that, no vibes at all.

Rotated the tires to see if it changed, and yes, it did. Now, the same egg shaped tire feeling is still felt in the steering wheel and seat bottom, but the range it happens has narrowed to 48-52 mph, and the shaking feeling in the steering wheel ins't as bad. The general vibration is different but not enough to tell which corner it is coming from.

With the jeep on stands, I put it in 4wd, and the tires have no obvious defects, other than slight side to side waviness in the tread, which I expect on tires with ~15,000 miles on them. No severe out of roundness or bent rims.

Nothing in the steering/track bar appeared to be suspect, ball joints/wheel bearings seem fine, & no play or abnormal movements when it was on the ground or in the air.

Only thing I saw that to me was odd, was the passenger side front tire was harder to spin, like maybe the caliper was sticking slightly, but no overheating smell or anything after a drive @ highway speeds.

I am going to get the wheel balance checked this week, but I see no signs that any weights have been thrown, and I really don't thing they are out that bad.

Any other ideas or thoughts on what to check ??

 

[Tim_MN]

...the steering wheel shakes (not really a visible shake, but it is felt), but it only happenened during the 38-52 mph speed range. Above or below that, no vibes at all.

Assuming all the suspension and steering are fresh and tight, a steering wheel wiggle that appears and disappears at specific speeds is almost always a tire balance or rim issue. Find an independent local tire shop that has a Hunter tire balance machine that will perform a Road Force Balance. The RFB will allow them to offset the heavy spot on the rim and the heavy spot on the tire and reduce or eliminated tire balance issues. Retail tire stores are typically helpless and clueless when asked to fix 4x4's.

 

[CarbonXJ]

Assuming all the suspension and steering are fresh and tight, a steering wheel wiggle that appears and disappears at specific speeds is almost always a tire balance or rim issue.

This was mine - I had new track bar, new steering from the pitman down, new springs, shocks, bearings, everything, and STILL had a vibration/shimmy at that speed you described. I'm also at 4" and 31s, and the shop supposedly balanced my tires when I had my lift installed. Taking it to another shop that deals with my V8 Ranger, they did the Hunter balancing and my shimmy is gone.