I recently made two changes at the same time to my highly modified 2007 JKUR... new heavy duty AEV 4.5" springs and new Falken Wildpeak M/T 37" tires. The new springs replaced my older and overloaded AEV springs (I was running a 3.5" spring up front and a 4.5" spring in the rear) and lifted the Jeep more than an inch over it's previous height. The new tires replaced my crappy Milestar Patagonias of the same size.

Ever since those changes I've noticed a noise and slight vibration that starts at 75 MPH. At first I thought it could be the front u-joint so I disconnected the driveshaft which made no difference. Next, I rotated the tires, which also made no difference. The noise is a low pitch rumbling. There's a vibration but it's very slight.

I'm kind of at a loss to figure this out. The only thing I can think of is that it could be airflow related due to the higher front end and possible change in pitch. I have an aftermarket front bumper, flat fenders and no fender liners.

I'd love to hear some feedback from anyone with an idea what this could be.

Thanks!

 

Did you have your alignment checked after replacing the springs?

 

There's not much to align. I recentered the axle by adjusting the trackbar length and adjusted the caster by lengthening the lower control arms (both aftermarket adjustable parts of course). Even if out of adjustment I can't see how either would produce a noise like that.

 

Noise may just be the tires? I’ve never used those tires so I can’t say anything. I was thinking that if you lost caster and didn’t adjust it back in then your steering return to center would be reduced and may cause a high speed vibe. I’m no expert on this but it sounds like that’s not a cause of you added it back in.