I'm trying to choose from Cusco Zero-2 and Zero-2R.
Apparently (or AFAIK), the only diff is that 2R's are inverted design.
What is it and what's good about it?

 

i might be wrong, but i think one of the reason they have inverted design its because that way less heat from brake system will effect the oil in the coilover.

 

It has more structural strength because of the extra thick rod.

 

i believe it also means that since its inverted, the heavy part of the strut is closer to the body rather than closer to whell. this nicely reduces the unsprung weight as there is less weight moving up and down with the wheels.

i once saw a nice animation of the process at a website like 3-4 years ago i'll do a search and see if its still out there.
-Lou

edit: heres what sport compact car had to say about inverted struts:

"Inverted dampers are good for several reasons, but the primary advantage is that their design, which places the body upside down above the strut housing, is far more resistant to side loads than a conventional strut design. The shock body is located by large-diameter bushings, which more evenly distribute side loads, making the entire assembly more durable. And since side loads are what rally cars like the WRX generate when driven hard, inverted struts are good things to have. Plus, with the shock body above the shaft, the shock cools better than one which is surrounded by a strut housing as well."

hope that helps.

ahah! i knew i was right! check out what a respected rally tuner, Road race engineering, had to say about one of their products that happen to be inverted struts:

"The 1G front struts are an inverted "upside down" design. This makes it look as if the shock piston is huge. What you are seeing is actually the shock body. This makes for less unsprung weight and a much stronger strut."

i keep looking for that animation. it was really cool, that picture really told you 1000 words worth of info!

 

Most highend suspensions are inverted. Most of the advantages of the inverted design have been covered, I'll through out one that most people don't think about- inverted struts have their damping adjustment at the bottom of the strut. If you have a sedan this means you can get to your damping w/o removing the rear seats.

Big Sky

 

I heard inverted struts have to be serviced really often. Is that true? Thinkin of mayve pickin up some. But dont want the extra service cost all the time.