PDA

View Full Version : Wait for New Double A-Arm Front-end OR Go with Reverse Kingpin front setup???


Felix2010
2010.09.26, 03:13 PM
The question of the day: What disadvantages would keep you from buying the PN Reverse-Kingpin Front Suspension kit for your MR03? I love the smoothness it is capable of. But I am unsure about the Kingpin weight becoming part of the moving suspension. I'm not a math or setup genius so I don't know much about consequences of sprung/unsprung weight, but isn't it better to have less unsprung weight?

The PN Reverse Kingpin system looks very interesting. Just I don't want to invest in a full Front-end suspension only to have the latest and greatest (Dbl A-Arm) come along and prove superior in every way. You know what I mean? Any tech guys out there who can chime in on this please? Thanks in advance, and great job PN with all your new stuff BTW:cool:.
-Lawrence

EMU
2010.09.26, 03:41 PM
You can use the stock front end, and reverse the kingpin... Works just as well. Just put the ball in the lower arm, and the ball part of the kingpin in the upper arm. Clip the tip off the kingpin, and shave it down a little. A no cost way to get super smooth suspension travel. I have this on a couple cars that the Reflex coil over kingpin setup doesnt fit under.

I learned this trick from Kromie101

color01
2010.09.26, 05:14 PM
Smoothness is always going to trump improvements in unsprung weight for Mini-Z, IMO. The bigger deciding factor for me between reverse-kingpin and coilover configs is the ease of maintenance and tuning. The reverse-kingpin setup is a PITA to change roll center on since you have to shim both the tower bar and the springs, and you can't take out the tower bar without taking the steering knuckles with you (otherwise everything falls apart).

The double-A-arm setup should actually have about the same unsprung weight as the reverse kingpin setup given that there are two short arms replacing one longer arm, per front corner. I haven't investigated the double-A-arm enough to know whether or not the roll center is adjustable, but if not then that's actually one advantage the reverse-kingpin setup has.

EMU
2010.09.26, 05:18 PM
Reverse kingpin should also have less bump steer. Smoother tracks, the A-arm may work a little better, bumpier tracks the reverse kingpin should would a little better...

Felix2010
2010.09.26, 08:12 PM
Thanks for the input guys. I might have to try the Rev Kingpin then...:cool:

benmlee
2010.09.27, 03:33 PM
EMU: The MR03 A-Arm should have no bump steer because tie rod is on the bottom on MR03. Same with the MA010 double a-arm.

You can reverse the stock pin to get smooth travel. However, you get more advantage if you use the PN reverse pin along with the lower tower bar.
The ball on the PN pin is narrower than stock. The tower bar is also slightly raised over stock. The two together gives you more ground clearance since the revese pin sticks out the bottom.

The reverse pin also have an e-clip at the bottom to control suspension bottoming. Some people like to limit bottoming so the car can have quick turn in, but once in the corner, bottoming the front suspension limits front traction to prevent spin out and roll overs.

EMU
2010.09.27, 06:41 PM
Thanks for the additional info Ben :)

Bodom
2010.09.28, 04:14 AM
You can use the stock front end, and reverse the kingpin... Works just as well. Just put the ball in the lower arm, and the ball part of the kingpin in the upper arm. Clip the tip off the kingpin, and shave it down a little. A no cost way to get super smooth suspension travel. I have this on a couple cars that the Reflex coil over kingpin setup doesnt fit under.

I learned this trick from Kromie101

Do you have pictures of this setup ?
I tried this on my 03 and it is definitely smoother. But the tip of the kingpin sits very low and when compressed - it hits the floor. So it really needs shaving, but I am curious how much.. I would cut the whole head of the pin (the area where the C-clip sits) :)

hrdrvr
2010.09.28, 08:25 AM
Bodom - Thats exactly what these guys are doing, just snipping the head off (at the c-clip groove), and sanding it smooth.


For a small bit more invested, you can get the PN or RR delrin balls to replace the lowers, and smoothness will be pretty much ideal. The PN balls are thinner, so they would net you the least amount of friction.