Longer ball joints ?

#1
What are the benefits of installing longer upper balljoints in stock upper control arms ?
I bought new Mevotech ball joints from Summit but the taper is wrong , the nut only goes halfway down,no way I can install the cotter pin.
The Mevotechs might work as longer ones but I sure like to have the cotterpins in place !
 

TexasT

Texas, Where are you from
#5
the taller joints fit into the stock arms but the whole idea is to create the geometry so the tire stays flat with max tread on the surface. With the stock arms and the taller joints the geometry isn't at its best.
 
#6
Speedway Motors sells non rebuildable tall ball joints. They work with stock arms.

If you install taller lowers, you need a bump steer correction kit.
 

scot w.

GNSperformance.com
#7
OR Call us at GNS Performance and we can go over your budget and come up with the proper solution for an upgraded suspension.
 

IrvJr

Well-Known Member
#8
Speedway Motors sells non rebuildable tall ball joints. They work with stock arms.

If you install taller lowers, you need a bump steer correction kit.
I thought taller lowers helped eliminate some of the bump steer and reduced the need for a correction kit.
 
#9
I thought taller lowers helped eliminate some of the bump steer and reduced the need for a correction kit.
Think about the way the front suspension is put together. A taller lower ball joint moves the spindle upwards away from the lower control arm. It also moves the steering knuckle, since it's attached to the spindle. That moves the tie rod end upward, and then it's no longer parallel with the lower control arm.

That's what creates bumpsteer. When the tie rod doesn't move in the same arc as the LCA, you get toe change as the suspension moves.

The upper ball joint doesn't disturb the relationship between the LCA and the tie rod, so you can change it without affecting bumpsteer. But the lower? You want to add bumpsteer correction if you lengthen the lower ball joint.
 

IrvJr

Well-Known Member
#10
From what ive read/remember the tie rod is not parallel with the lower control arm now and thats why we have bumpsteer now and raising the spindle helps eliminate that and the bumpsteer kit was for stock height ball joints. But im just telling you what i thought, not that you are wrong.
 
#11
From what ive read/remember the tie rod is not parallel with the lower control arm now and thats why we have bumpsteer now and raising the spindle helps eliminate that and the bumpsteer kit was for stock height ball joints. But im just telling you what i thought, not that you are wrong.
The stock steering geometry isn't bad. The OEMs don't like bumpsteer, never have. Sure, the camber curve is crap and the roll centers are in terrible places, but a car with a jumpy steering wheel that can't track straight on a gravel road won't sell because it's scary to drive.

Just glancing at the front suspension from the front, it might appear the arms aren't parallel with the tie rods, but that's because the arms are bent for clearance and to make the lower spring pocket horizontal. Draw a straight line from the LCA pivot to the ball joint (which defines the actual radius of the arm's range of motion), and that line will be parallel to the tie rod on a stock car with a front end in good shape.
 

Ttype6

Well-Known Member
#14
From what ive read/remember the tie rod is not parallel with the lower control arm now and thats why we have bumpsteer now and raising the spindle helps eliminate that and the bumpsteer kit was for stock height ball joints. But im just telling you what i thought, not that you are wrong.
Using a .5" taller lower ball joint greatly diminishes the bump steer that the factory geometry creates. To get it perfect,you will need to add a bump steer correction kit. I don't think it is worth the cost. The negative camber curve is the more important thing to correct and you can get it much better with lower and/or upper extended length ball joints. If you don't want to lower the car and you want to get rid of bump steer,you need to use a stock length lower ball joint and a bump steer kit.
 

Ttype6

Well-Known Member
#15
the taller joints fit into the stock arms but the whole idea is to create the geometry so the tire stays flat with max tread on the surface. With the stock arms and the taller joints the geometry isn't at its best.
Using taller upper and/or lower ball joints with the stock upper control arms improves the camber curve. The problem that you encounter,when doing this with the stock arms,is getting the camber to zero degrees so the tire is straight up and down/plumb. The factory upper control arms travel down hill from the pivot point to the ball joint. As we raise the spindle with a taller lower ball joint,the upper control arm rotates upward. If we also add an upper ball joint with a taller stud,the upper control arm is rotated even farther upward. Since the upper control arm,in its stock configuration,travels down hill from the pivot point to the ball joint, the upper ball joint is moved farther and farther away from the control arms pivot point as we rotate the upper control arm upward with taller upper and/or lower ball joints. This moves the top of the tire away from the engine which is positive camber. To move the upper ball joint toward the engine,to get the camber angle to zero/so that the tire is straight up and down/plumb,with the stock upper control arm,requires a lot of alignment shims which moves the bushings closer and closer to the downpipe. To reduce or eliminate all of those shims,we need to use an upper control arm with a shorter distance from the pivot point to the center line of the ball joint. This is the reason that we need to use an aftermarket upper control arm when we use taller upper and,or lower ball joints. We need an upper control arm with a shorter distance from its pivot point to its ball joint center line. A shorter control arm.