? For the coilover crowd

14s front and rear.

No cutting into the tub or hood required. About 5-6" of up travel. Could have more, but that would just be more ride height.

I tried these rates first, according to a bunch of spring calculators:
16"/12"
250/150 front
200/125 rear
Blue Coil Springs
To squishy for the street, I was into the bump stops all the time. I was also always into the second rate, the 125 and 150 would always be compressed. Triple rate option did not work either, for the ride height I wanted.

Then I made some guesses and ordered the second set of springs.
Now I run, dual rate only.
16"/12"
350/225 front
300/200 rear
Eibach springs
I may have them a bit different, but you get the idea.

Melmo said:

Mine is 14 front and rear with 5.5" up on both ends. No cutting the hood or the tub. 200 - 300 springs on both ends as the weight with the 103 wheelbase is 100 lbs lighter in the rear than the front. Perfect ride and feel for me

Click to expand...

Everyone to post here has their rates backwards.

No offense, its a very common misconception to go with lighter rates in the rear, and is accpetable for PURE crawlers.

For what we do, onroad/offroad, trail riding, hill climbing, technical crawling, etc etc, you want a slightly higher rate in the rear.

Some express it as a ratio compared to the front.

For example, a ratio of 1.2 would look as follows.

Front combined rate of 100 x 1.2 = 120lbs/inch rear rate.

Baja commonly uses a 1.6 ratio.

Pure crawlers use around 0.90

KOH and and other mixed application crowd favor something in the middle around 1.2

So take inlines front rate of 350/225 and calc the combined rate.

350 x 225
350 + 225

136 lbs/inch

Multiply x 1.2 for the rear comes to 164.34

Now you essentially experiment with numbers until your get your desired rate, of a close approximation of it.

Lets try 375/275

I get 158.65 lbs/inch

You can fine tune from there.

Once you have that dialed in, you want to valve your rear shocks slightly lower then your front. Unless you have a perfect 50/50 bias, then you could leave them equal.

The softer valving will help with smother running over mid and high speed terrain, but the higher spring weight will support weight transitions better.

When we climb, hit whoops, accell on corner, so much weight is tranfered to the rear of the vehicle. The additional spring rate back there helps compansate for that weight transfer.

Thats why the Baja run such a high ratio. If they didnt, the back end would sink to hard every time they went into a whoop, and then the front end would lurch forward after. Basically turning the truck into a bucking bronco.

If you make those subtle changes to your set up, you will feel a noticeable difference in handling and performance.

Just as an example, when my good freind competed at KOH, he had a tuning day with King. He runs a 1.2 spring ratio, and equal valving front and rear.

All king did was dial down the rear valving by about 1 setting, and Joey grabbed about 10-15mph more through the same section.

Essentially this is the basics of a good all around setup.

hth

Thanks bnine, that is great info!

Let me make sure I am understanding you correctly using my exact setup as the example. Not all this information will probably matter but since I don't know for sure what will and won't I'll give it all to you.

Wheel Base = 103" = +7" rear and + 3" front
Front weight = 2,400 lbs
Rear weight = 2,280 lbs
FOA 2" x 14" Coilovers valved Light compression, medium rebound
2" Air Bumps
5.5" up travel
8" down travel (limit straps 1/2" short at each corner)
Lower Springs 16-300
Upper Springs 12-200
Front LCA length = 38"
Rear LCA length = 36"
Three Link + Panhard Front
Upper triangulated four link rear

The following is based on the triaged 4 link calculator ver 3.1 and an estimated CG height of 40", with 500 lbs front and 400 lbs rear unsprung weight:

Static anti-squat = 85%
Roll Center = 26"
Roll Axis = 0
Instant Center X-Axis = 69"
Instant Center Y-Axis = 24"

Continued in next post...

Im definately no expert. I have a basic understanding at best, via some trial an error with me and some freinds and a lot of advice from the more informed folks like Blaine.

Spring wise it really depends on the individual user and the rigs application. Pure crawlers love those low rates. 150/250, 140/275 etc etc.

Desert folks favor the higher stuff. 375/425, 250/375, etc etc.

Personally I tune springs like a swaybar. I try for as much rate as possible without sacrificing articulation. Like a swaybar, you crank it up until you lose some travel, and then dial back just a bit.

The numbers of course will change from rig to rig based on weight.

For my rig, I've found that to be in the middle road. Right now I am still a bit soft with 175/250 up front, and 275/200 in the rear. I think I can take everything up about 10-15% and still get away with it. I switched to FOA's last year, and the tuning in my suspensions was severely thrown off from the previous set up. Mostly due to some really soft valving.

Your rig sounds similar to mine Mel. I will probably finish with rates closer to your. If you want to experiment with that rear rate, I would suggest keepimg some variation between the top and bottom rate.