Hi, been thinking about lowered minis and ball joints. Whenever people tend to ask about lowered car there's a general consensus that it's a Terrible idea and ball joints will snap...
Now I under stand that lowering has its pros and cons but that's not my question! My question is how are the ball joints affected by lowering the ride height? The travel isn't changed provided the bump stops are retained and I can't believe the ball joints would be pushed beyond their travel by the suspension arm hitting the stop?
So therefore why are there so many comments warning people not to lower cars with horror stories of ball joints failing?
I did some measurements on this to establish exactly what the ball joints will do and how far they articulate. This was done with a set of Original Ball Joints, some of the replacements may not do this. It also used Stock Upper, Lower Arms and Caster Bars.
For the purpose of these tests, I did a 'worst case, where I removed the Bump and Rebound Stops, as there's a chance these can break off in 'normal' use (yes, they should be replaced, but you just never know when and how these situations may occur).
In Terms of Full Compression (or lowered all the way past the Bump Stop) as far as the Ball Joints go, there's no issue with either Top or Bottom binding and that includes all steering angles too. The Joints were just making contact between the Pins and the Cups at this point. Your Drive Shafts will contact the Window in the Subframe before you reach this point.
In Rebound was where where there was an issue. While the Wheels were in a straight ahead position, this was OK, but with Steering inputs, the lower joint did bind and got worse with more steering input.
If you have any Negative Camber dialed in, on Rebound, the Lower Ball Joint will lock and breakage is a very real possibility. The Factory in fact recommended packing up the Rebound Stop by 1/8" (3 mm) if any Neg Camber is to be used.