[clg82]

Hey everyone took the jeep out of town this weekend, and when hitting the 55mph -60mph speeds i get bad vibrations......but below 55 and above 60 there is no vibrations...could this be driveline related? or tires need balancing? thanks for any help....~Chris

[Robert J. yates]

Could be anything... what have you changed recently?

[clg82]

lower front control arms with savvy JJ adjustable control arms..

[Jerry Bransford]

Speed sensitive shimmies/vibrations felt through the steering wheel are nearly always tire or sometimes wheel related. Out of balance, out of round, bent wheel, etc. A bad alignment can cause tire problems that can cause a shimmy or vibration but by itself, a bad alignment will not cause a speed-sensitive shimmy or vibration.

Vibrations felt up through the seat of your pants are nearly always drivetrain related and often caused by a bad u-joint or bad pinion angle.

[clg82]

Originally Posted by Jerry Bransford

Speed sensitive shimmies/vibrations felt through the steering wheel are nearly always tire or sometimes wheel related. Out of balance, out of round, bent wheel, etc. A bad alignment can cause tire problems that can cause a shimmy or vibration but by itself, a bad alignment will not cause a speed-sensitive shimmy or vibration.

Vibrations felt up through the seat of your pants are nearly always drivetrain related and often caused by a bad u-joint or bad pinion angle.

I did feel it more in the seat of my pants than the steering wheel....would those certain speeds be because of drivetrail as well?

[Jerry Bransford]

Yes some vibes like from a bad u-joint can be speed sensitive. Pinion angle related vibrations are often noticed most when either accelerating or deaccelerating. Too high of a rear pinion angle will cause more vibrations when accelerating, too low of a rear pinion angle will cause more vibes when deaccelerating.

[clg82]

Originally Posted by Jerry Bransford

Yes some vibes like from a bad u-joint can be speed sensitive. Pinion angle related vibrations are often noticed most when either accelerating or deaccelerating. Too high of a rear pinion angle will cause more vibrations when accelerating, too low of a rear pinion angle will cause more vibes when deaccelerating.

I have all new ujoints in the rear driveshaft, and new ones in the tom woods up front......maybe a tire rotation is in order?!

[Jerry Bransford]

At this point, if you are sure your rear pinion angle is good, I'd try a different tire balancer or take it back and tell them to balance them again. The bigger the tire, the more critical it is that the tires be perfectly balanced. Many tire balance jocks only balance tires to what they feel is "good enough" which isn't usually good enough for a TJ. My local Discount Tire shop normally does a good job balancing my tires for me but I have had to come back twice in one day several times to have them balance the tires again when the first job left speed-sensitive shimmies.

[Robert J. yates]

Originally Posted by clg82

I have all new ujoints in the rear driveshaft, and new ones in the tom woods up front......maybe a tire rotation is in order?!

Are you sure you got the front pinion angle dialed in correctly with those new arms? Pinion angle takes precedence over caster on the front end.

Originally Posted by clg82

lower front control arms with savvy JJ adjustable control arms..

[clg82]

Originally Posted by Robert J. yates

Are you sure you got the front pinion angle dialed in correctly with those new arms? Pinion angle takes precedence over caster on the front end.

How is the front pinion angle supposed to look in relationship to the yoke?

[Hughes6]

Same thing happened to my jeep and at the same speed as you said. I got my tires balanced and it was fine after that.

[Robert J. yates]

Originally Posted by clg82

How is the front pinion angle supposed to look in relationship to the yoke?

You set it up the same way as the rear..... rotate the front pinion until it is pointed at the t-case yoke. I'd shoot you a picture of mine but its a high pinion 30 and the way the driveshaft is set up, it looks a bit different. Maybe someone else here can post one up for you.

[clg82]

Originally Posted by Robert J. yates

You set it up the same way as the rear..... rotate the front pinion until it is pointed at the t-case yoke. I'd shoot you a picture of mine but its a high pinion 30 and the way the driveshaft is set up, it looks a bit different. Maybe someone else here can post one up for you.

I should be able to figure it out...... might try and get the tires balanced first and see if that fixes things..

[toolbate]

My tj did that after i went mudding one time. It was just caked on mud inside the tires and rims

[clg82]

Originally Posted by toolbate

My tj did that after i went mudding one time. It was just caked on mud inside the tires and rims

no mud anywhere on my jeep.....