yonson

When I was at Evasive a couple weeks ago getting my alignment etc... done they didn't have any in stock or I would have gotten them then...

jimtway1

I ran 13k & 11k springs and it was plenty stiff with R-Comps. The "west coasters" do have an erroneous love for stiffer spring rates. Its even embedded in their rule set where stiffer springs draw higher point penalties.

VitaRenovatio

Just to be clear, if you are not lowered, then you should not be using a roll center adjuster. For the front, the ball joint is the camber-adding part, and the plate is the roll center adjusting part. The rear is purely for roll center adjustment. I would recommend that next time you're getting an alignment, you remove the RCA plate in the front.

VitaRenovatio

Please do tell, what is so erroneous about stiff spring rates?

takchi

Am I getting this wrong, but isn't the damper more important than spring rates at this point? HKS is valved to be super aggressive, but has softer springs.

Either way, just want to know if rear RCA is really necessary because I am very close to installing my coilovers soon.

VitaRenovatio

Depends on your definition of necessary. I am hoping they improve traction over bumpy surfaces ... by how much, I'll have to try it out to see.

Maxrev likes them: http://www.maxrev.net/site/index.php...sion&Itemid=58

sweetdill

I have a set of BNIB Hardrace roll center adjusters, front and rear, I'll sell them for what I paid.
I'm wishing I'd gone with the J's.

Bullwings

Why is that? Did you order the wrong part and get 6622, which is roll center only and not offset camber? Part 6621 is identical to the J's S1/S2 piece - or somewhere in between that. I'm not sure what the max camber i can get with stock suspension is.


Also, thanks. I know the whole point of the RCA is to return suspension geometry back to "normal" after lowering, so essentially, I've put my suspension geometry out of whack, right? Yeah, next alignment I'll have them switch it up...

takchi

I guess that's a green light for "JUST DO IT!".

jimtway1

To clarify, it is erroneous to assume that a stiffer rate spring is faster on track than a softer spring. The rule set decrees this as true by charging more point penalties for stiffer springs. This community has seemed to take that at face value and thinks that 16-20K springs are fastest and anything in the 10K-12K rate must be slow on track.

Here's a quote from Carroll Smith's Tune to Win, "I wish that there were hard and fast rules for the determination of optimum (spring) rates. To my knowledge, there are none. Optimum rates vary with gross vehicle weight, power to weight ratio, aerodynamic downforce generation, tire width, track characteristics, driver preference and technique and, quite probably, the phase of the moon. My basic system is to run the softest rear springs that will keep the car off the track - and maintain some semblance of camber control - at the ride height that I want to run. I then balance the understeer/oversteer with the front springs - and equal rate front and rear bars. I try to do this in long, medium speed corners so as to simulate steady state conditions at low enough road speeds so that aerodynamic downforce doesn't confuse the issue (say 60 mph).....This gives the basic front and rear ride (spring) rates."

We could go on and on, but this is already off topic. More pictures and video please!