Pics & Review of My Bilstein PSS10 Lowered Red Turbo by cannga

3 minute(s) of a 612 minute read

6-30-2013

Ok, I could feel the anticipation exploding. Following is what I think is the answer; any expert feel free to correct as needed. Although it is common knowledge that negative camber is beneficial for cornering, my problem is I kept asking why. Why is it so? I looked for this information for a long time and finally found it in this book Stock Car Driving Techniques, Don Alexander .

First an important basic concept: when you make say a left turn, the left wheel (inside wheel) lifts and loses traction as this side of car lifts up, and the right wheel (outside wheel) gains traction as this side of car is compressed. This is a result of centripetal force causing left to right weight transfer. Traction of the outside wheel (right wheel in this case) is therefore of paramount importance in a turn. It's the one doing a lot of the steering as it is the one with the best contact patch.

And here is the key to the answer, in most front suspension systems, the wheel gains positive camber as it undergoes compression travel. In other words, as you turn, the outside wheel is compressed AND, because of the positive camber gain, starts to tilt outwards. As it tilts outwards, it is no longer parallel to road surface, and therefore loses contact patch area, and therefore loses traction. To counteract this, you pre-set the wheel with negative camber, so that during a turn, the preset negative camber cancels out the positive camber gain of the outside wheel to keep it parallel to road surface, and maintain full road contact and traction. I hope I am making some sense here LOL.
Of course, as in ALL suspension matters, there is a trade-off. Excessive preset negative camber is bad for straightline traction and braking. So for the track, high negative camber is beneficial, while for straightline racing, such as drag racing and racing for best 60-130 times, less negative camber (and less toe-in or toe-out, you want the wheel *straight*) is desirable.

7-1-2013

Wow I love this data - thanks. Very interesting comparison to GMG:

GMG Front Sway: 3 settings: soft, medium, stiff. The front settings are 15%, 25%, and 35% stiffer than stock. 

GMG Rear Sway: 3 settings: soft, medium, stiff. The rear settings are 30%, 45%, 60% stiffer than stock.

From previous postings, I believe most GMG users use the 15% and 25% for front, and the 45% or 60% for rear (in other words, soft front/medium rear AND medium front/stiff rear). In theory, this would make Eibach bar quite a bit stiffer; in reality, I have no idea how it compares since not many people have used it and give a detailred report on it.

I'll respond to your other question later regarding which component decreases the rear shake the most, it is an interesting choice to make.