While control arms might be considered the horizontal members of the front end, spindles would be the vertical member that ties the control arms together. Both upper and lower control arms attach themselves through ball joints to the spindle. This is a cast iron part where the machined “axle” or steering knuckle is located. The wheel bearings and brake rotors are mounted to the axle, and the spindle also locates the brake caliper and tie rod end (steering). Steering knuckles are found on some late model trucks. They do exactly the same thing as a traditional spindle only there is no axle mounted in them. A hub center which has wheel bearings and wheel
mounting hubs integrated together just bolts into the knuckle. This allows the OEMs to use the same casting (knuckle) for both 2WD and 4WD. Drop spindles do a pretty good job of lowering especially the older axle type. If you just want a couple of inches drop for your 98 and older Chevy, spindles are hard to beat. But you still have the chronic spindle problems - wheel clearance! In some cases you need to grind away material from the factory lower control arm to use drop spindles, in other cases you must buy at least 18” wheels or bigger just to mount the wheels and you still will grind the exposed stud off the lower ball joint. Unfortunately this means you cannot use your factory spare on the front, could be very inconvenient. Plus after accepting these shortcomings you still only get two inches of drop. One solution is to add a dropped coil spring to the mix. While this works okay, it causes more problems. You lose suspension travel (which reduces ride quality), lowered coils have a higher spring rate, (which reduces ride quality) and you usually need to replace your shock absorber with a shorter one (this could reduce ride quality). Plus you have to pay for it. Now I can feel some of you starting to puff up and say "buzz off". I mean no offense, I know there are alot of
very nice lowered trucks running around with spindles and springs,
hell for a long time that was the best way to lower your truck. Like
I said its a good way, but especially on the newer truck using control arms is just a better way to lower for a lower cost. Spindles can’t help you with correcting alignment issues (see alignment page), they tend to make your front end a little wider, (wheel clearance thing) and because the tooling costs are so high it is very difficult to make improvements in design. You may get stuck with a 20-year-old design in a part that you bought just yesterday. Role your cursor over the graphic at the top of this column to see how a spindle lowers your truck.