[tomtom]

I understand the lowest one should go on the 335i suspension is 1" around.
what is the technical reason for this?
Does it have to do with suspension travel? I know you need stiffer springs to support the lowered car?

[VTECaddict]

too low is when you scrape on flat roads.

[BimmerJack]

It really depends where you live.
I live in Hong Kong, and I've been into an indoor parking that I would get scratched if I didn't go diagonally on ramp, AND I'M RUNNING ON STOCK SPORT SUSPENSION, which there are like 4 fingers wheel gap at the front.

[leftcoastman]

Originally Posted by tomtom

I understand the lowest one should go on the 335i suspension is 1" around.
what is the technical reason for this?
Does it have to do with suspension travel? I know you need stiffer springs to support the lowered car?

If you lower the car too much, you will DEGRADE handling. People selling you the suspension will focus on center of gravity when selling you a lowering kit, but they don't talk about roll center.

When you lower a car, the drastic change in roll center will make a car MORE likely to lean in corners, unless you compensate by stiffening the springs.

Additionally, the geometry of the suspension goes to hell when you over-lower a car. I run a D/A Tc Kline kit with camber plates and I set it purely for track performance. I have it set to the highest possible ride height, to maintain optimum suspension geometry.