Stepping down to 650# from 700# coils?

trying to figure out if I should drop down in coils...

Right now I have 700# coils on extended Kings. Here’s what I have weight wise-

-35” e rated tires
-Dakar mediums in the rear
-ARB bumper with Warn steel cable winch
-homemade skids close to RCI in weight maybe slightly heavier
-three threads preload on driver, one or two on passenger Kings

Shock top plate to bolt measures 21” which should be halfway through the stroke for the extended kings so I’m not topping or bottoming out

Will be adding Brute Force HC, sliders, and making a swing out as soon as they get here.

all this weight adds up to around 675# which accutune’s website states would be fine for 700# coils. My thing is, all my front weight has been pretty much added and it’s harsh on the small stuff. I feel every piece of gravel and crack in the road. Not much different than when I had 5100’s and 886s. On dips in the road, I tend to bounce a couple times before settling.

I’m not sure how much weight in the back is going to help much with the front at this point. The 35” e rated tires don’t help. Shocks are off the shelf valving- which doesn’t help. Would stepping down to 650# coils be the answer or is the rest of the weight to the rear and middle going to help out enough?

 

Your load range E tires are the biggest contributor to harsh ride. If you can't/won't change to load range C, drop the pressure down to 25-28 psi.

The other big contributor to harsh ride are all the rubber bushings and isolator pads that have been replaced with metal heim joints and billet spring perches. Not much you can do about that. Race-derived components = race-derived harshness.

Going to 650 # coils won't help.

 

Didn’t think about the lack of rubber bushings now, that’s a good point. I wonder if any isolator pad could work in the perch? I’m at 36 psi right now, but could probably step down a hair and still be good on tire life. Didn’t see many options for 35” c rated. Plus I just bought five so I’m stuck for a while...

Edit- was around 32 cold. Dropped front to 28, rear to 30.

 

The ride quality issues you mentioned would be from the valving in the shocks, not the springs. Going from a 14" x 700lb spring to a 14" x 650lb spring wont do much at all.

 

@AccuTune Offroad I regret not purchasing these through you guys and having you tune them. Live and learn. I feel like I bought an expensive suit off the rack and didn’t get it tailored to fit. Can you shoot me a quote for getting these tuned? King OEM replacements with adjusters, extended all four corners.

 

Sent!

 

Its pretty well documented on most of the suspension stickies that spring rate for regular coilovers determine ride-height only. Also, I'm not sure what your tire weight would really change for spring rate as your tires are supported by the road, not your coilovers.

 

Preload determines ride height in conjunction with coils from what I understand. Heavy tires make for more unsprung mass- probably more relative to tuning than coil size/rating. But I’m no expert.