how to center the rear axle

[Pete M]

it has to.  in fact any suspension link will move in an arc because it has one firm point of attachment.    but in regards to the track bar, the left-to-right movement is fairly minimal in a stock suspension.  the flatter the track bar (as defined be drawing a line between the two attachment points), the less the axle will move laterally.

[omega_rugal]

soo, whenever the front axle hits a bump, the truck moves to one side slighty

[Pete M]

is your truck still stock height?  check the track bar bracket bolts for any sign of movement.  side to side movement should not happen when everything is acting as it should.   

 

check the wheel bearings and ball joints too.  if something is loose, a bump can easily tweak the direction of a tire which would cause the truck to move sideways. 

[AZJeff]

1 hour ago, omega_rugal said:

soo, whenever the front axle hits a bump, the truck moves to one side slighty

Sort of.  The BODY of the truck will move sideways (relative to the front axle).   Now if the MJ is at normal (factory) ride height, the bumpsteer should be virtually zero, so the steering wheel won't really move, even if the body does.

 

Note:   the amount of movement sideways, on a Jeep with close to factory ride height, will be EXTREMELY SMALL.  I have never bothered to calculate the maximum theoretical movement, but I would guess it's 1 to 2 millimeters

[omega_rugal]

On 2/4/2021 at 5:13 PM, AZJeff said:

1 to 2 millimeters

 

 is more than that, i need to make an animation

[Pete M]

can you push the truck body sideways?

[AZJeff]

1 hour ago, omega_rugal said:

 

 is more than that, i need to make an animation

No need, just do the trigonometry for the arc the track bar traverses from normal ride height to the bump stop.

 

Be sure to use a stock track bar and a stock mount at stock ride height.  All the crap we do to modifying MJ’s and XJ’s to change ride height and suspension geometry is outside the original design intent of the system.

[omega_rugal]

 

 

direct comparison

[AZJeff]

14 hours ago, omega_rugal said:

 

 

direct comparison

There is no doubt that a watts linkage minimizes lateral movement compared to a track bar (panhard rod).  The only question is how much that improves the handling of an oxcart....er, I mean an MJ🤪

[omega_rugal]

On 2/18/2021 at 1:01 PM, AZJeff said:

The only question is how much that improves the handling of an oxcart....er, I mean an MJ

 

i want to find that out

[Tex06]

On 2/18/2021 at 1:01 PM, AZJeff said:

There is no doubt that a watts linkage minimizes lateral movement compared to a track bar (panhard rod).  The only question is how much that improves the handling of an oxcart....er, I mean an MJ🤪

 

MJs actually would benefit from it quite a bit, the unibody construction made for a very stiff setup (good thing) and they were fairly successful as racers back in their day. If my old body on frame nova benefits from it, the unibody MJ/XJ would definitely see some improvement.

Not many folks running a lowered MJ (and 2WD obviously) which would necessitate/justify the running of a Watts Link.  For a 4WD, lifted vehicle this would be terrible as you would get rid of most any "flex" in the suspension for clearing obstacles.

[thecodemonk]

Many years ago, Full Traction Suspension had something similar...the "CRC link".  They no longer offer it through, I suspect because it either didn't sell well or there were some issues (such as limits on travel, like Tex06 said above).