I have been running the stock blue spring that came with my HPI center shock. Many guys seem to be running the yellow spring. Or should I say flouresent yellow. Does anyone know the rate of the stock blue spring. And what rate/part number for the yellow spring. I have a list but it has a few yellow springs listed. Not sure which one I need to order. Any help would be appreciated.

I have 2 of the HPI springs that I run. Yellow p/n 6843 and Orange p/n 6841. Chart says Orange 12.1 lbs/inch and Yellow 12.7 lbs/inch. I think the blue is too stiff.
Hope that helps.

Thanks that helps.

Brando
This may help you in your spring selection
The Blue you are running is 14.8 lb/in

Rear Center Springs:

Associated Macro Shock
Black 3.20 lbs/inch
Green 3.50 lbs/inch
Silver 3.85 lbs/inch
Blue 4.20 lbs/inch

Silva Concepts
Gold 5.0 lbs/inch
Silver 6.0 lbs/inch
Copper 7.0 lbs/inch
Black 8.0 lbs/inch

Integy (these are not published rates, I did some testing on a niftech spring guage to get these rates, so dont quote me on them, but they should be super close)
Light Green/Yellow 5.00lbs/inch
Red 5.27lb/inch
Dark Green 6.25lb/inch
Purple 8lb/inch
Blue 11lb/inch

HPI
6824 Copper 8.2 lbs/inch
6825 Silver 8.6 lbs/inch
6826 Gold 11.2 lbs/inch
6841 Orange 12.1 lbs/inch
6843 Yellow 12.7 lbs/inch
6844 Red 13.3 lbs/inch
6846 Green 13.8 lbs/inch
6847 Blue 14.8 lbs/inch
6849 Pink 15.2 lbs/inch
6833 White, Prog. 16.7 lbs/inch
6834 Yellow 16.9 lbs/inch
6851 Navy 17.9 lbs/inch
6852 Grey 19.0 lbs/inch
6751 Orange 19.3 lbs/inch
6834 Yellow, Prog. 19.7 lbs/inch
6753 Yellow 22.0 lbs/inch
6835 Red, Prog. 22.1 lbs/inch
6754 Red 24.2 lbs/inch
6756 Green 26.9 lbs/inch
6836 Black, Prog. 27.0 lbs/inch
6757 Blue 27.6 lbs/inch
6759 Pink 30.2 lbs/inch
6837 Green, Prog. 32.3 lbs/inch
6838 Blue, Prog. 34.3 lbs/inch
6839 Purple, Prog. 37.5 lbs/inch

Thanks Erock1331 :thumbsup: you just saved me hours of searching for spring rates.

You are the man Erock! Thanks!

There's a nice setup sheet with the spring rates at

http://www.classichobbiesraceway.com/modules.php?name=SetupSheet

If I do say so myself. :)