Lifts and Front Axles Geometry

[kfs-4runner]

So I have a couple of question perhaps someone out there could answer.

At what lift height do you start getting issue with the front axle geometry?

Is there a viable solution to lowering your differential in remedying this?

The idea of lowering your differential seems counter productive to lifting your vehicle unless larger tires are your only goal. I have actually never owned a 4x4 with independent suspension before, well actually my 82 Bronco did but that was quite different than what on my 4Runner. A suspension lift did not effect the axles on it at all.

In the not to distant future I am planning on installing a 3 inch lift so if that is insufficient to cause any issue I am good but I really do not know anyone have some insight?

 

[UrbanRunner651]

UCAs are recommended with anything 3" & up. You can also do a diff drop kit to level out the CV angle some. Biggest issue without them is just getting the camber in spec and premature wear on the CVs

 

[Jetboy]

To start - what year/make/model of 4Runner do you have?

The diff drops typically are more of a "clocking" that rotates the diff some to help lower the output shaft position. In some generations like the 5th gen, they do very little to help with CV angles.

Generally, on the 5th gen and probably also 4th gen, the primary issue with angle is actually the CV boots. The CV joints aren't wearing out that I'm aware of in any meaningful way at higher angles. It's the boots that fail at high angle. CVs can both bind and also become weaker at extreme angles, but with the OEM control arms, this hasn't been an issue I'm aware of on the later models. The weaker joints in the earlier generations is more of an issue. The later models are very strong.

The diff drops rarely cause issues with differential clearance because the diff is not the lowest point up front. The cross members are lower, so dropping the diff an inch is still, in most cases, higher than the cross members and with most skid plates, it's still not interfering with the skid plate. So it doesn't hurt the ground clearance.

The ride quality degrades as you go higher. Your best ride quality will be stock height. And IMO having run my 5th gen at every height from 0-3", the best balance is around 1.5" of lift for overall highway ride quality. 1.5" up front and about 1" rear lift with 34" tires works really well for almost everywhere I go in my 4Runner other than the harder rock gardens. I do re-adjust my setup to 3" lift front and rear for the Rubithon trip. Not ideal - but it takes about an hour or so to crank up the front coilovers, swap rear springs, and re-adjust the alignment close enough for the trip. I just reset when I get back.

 

[rdruss]

I like your term "clocking" the front diff because that is really all you do when you lower one point only. An Australian firm, Phatt, makes a real diff drop, it replaces the arms too so you really do get a "drop", not sure what years/models they have available.