Why do they sell lift kits with just the upper A arms and not the lower?

Why everytime i check out a lift kit they always sell the upper control arms but not the lowers?

 

Because you don't need to change the lower A arms for most "normal geometry" lifts.

Folks change the upper control arms to restore factory caster, which is typically reduced to something less than one degree on a 3" lift when using factory control arms.

The only reason to change lower control arms is

1. increased strength and armor for very heavy duty application. Most folks don't need this. The intermediate ground is LCA armor like from BAMF.

2. Increased length for "long travel" lift. That's a much bigger project than a standard lift, and again, most folks don't do that.

Hope this helps.