King 2.5 springs

Hi everyone! I know this is all late into the work I've been doing and yes I did try to search around and find some kind of stepping stones towards the answer for my question, but couldn't find a pebble to start with.

I know that the springs are interchangeable, but the question I have is will I be okay to swap out my 600lbs springs for 700lbs and call it a day OR would I have to get the CO's revalved, shimmed, and tuned to run adequately in conjunction with the 700lbs spring?

Thanks in advance!
Dara

 

@papasmurf has some experience with this.

 

I do have some experience and honestly just swapping springs will yield a bad riding shock setup. Best option would be to re valve to meet your needs why the increase in spring rate? Not that it’s bad just curious what the isssues and goals are. Fill me in there and I can help guide you a bit.

 

As someone who has experience in this matter, you will be fine and swapping spring will not yield a bad ride, the king 600lb springs wear out pretty quickly. a 700lb spring, with no pre-load would be ideal.

Now if you switch from 600lb to 700lb and leave the pre load the same you will experience a stiff ride

@sdhq_offroad agreed?

 

Well at this point I think I remembered reading about why you switched out yours also, it's mainly because I am starting to feel a bit mushy feel up front. I don't run a winch or a big armor type bumper, just a prerunner style bumper like yours. I was looking to up into the 700lbs spring because I want a more firm an controlled ride when I'm out doing trails (more on the noober highspeed side). I've did some small 1 feet air and went out of bounds with some whoops so thats why I started to feel a weird mush afterwards. Another thing is I'm hoping that the higher spring rate can compensate just a tad bit for each wheel after removing the sway bar.

The build I am doing right now with the truck is more of the MT side. Trying to stay away from LT as it is my only truck and sometimes I tow and most of the time I have a fully loaded bed when going out. Driving type on the terrains are half and half of crawl (not uber crazy crawl) little noob ones, fast trails, and hopefully I can surf some whoops as well. I know it won't be as glamorous as an LT setup, but somewhat near there.

I'd most likely will not be leaving the preload the same hence of the spring rate differences.


Happy Thanksgiving guys!!

Dara

 

On my 4Runner, stock front springs are 500lb/on. I bought Bilstein 5100s with Eibach 620lb/in coils, and hated it. Even after I finally added >250 lbs at or in front of the front wheels (bumper, winch, skids, dual batt, front-mounted hi-lift), I still hated it. Sure, it felt solid in the corners on pavement, but on slow, undulating offroad trails it pivoted and rocked like a hotwheels car. It was actually similar to my wife's TRDP, which is not cushy by any stretch (especially after lifting, since we did not extend the anti-sway bar end links), so I figured that is how it was "supposed" to be. I didn't realize how bad it was until seeing my young kid's head knocking all around in his carseat on a relatively mild trail.

I went back to the 500lb springs, on the highest front perch, and the ride was dramatically smoother. Now, my suspension actually does the work on the trails and my kid naps wonderfully while daddy continues to play (and mommy has a beer at home--win win!). To be clear, there was never any indication of it being under-damped before (i.e. no bouncing under suspension rebound). And, there is no indication of it being over-damped now (the original springs have no issues keeping the tires back down on rough washboard). This leads me to believe there is a decent amount of tolerance for varied spring rates for a given shock valve setup--at least for non-racers.

FWIW, I calculated my front anti-sway bars to add an effective ~530 lb/in of spring rate under off-center loads, so I actually leave that disconnected except for longer highway trips (I hit trails more than interstates lol). This makes a huge difference as well (honestly, to my butt, it basically doubled the effect of going from 620 to 500lb/in springs).

I will happily admit I have notably more body roll in corners (even with the front bars connected, and especially without), and notably more brake dive. Indeed, while my wife's TRDP 4Runner instills a surprising amount of confidence in mountain twisties, my runner feels like an old cadillac.

However, in addition to the more pleasant ride offroad, the softened suspension also actually dramatically improved my climbing capabilities. Not that I was out lifting tires all the time, but the suppler suspension allows the tires to stay more firmly planted on the ground when mildly crossed up, which minimizes diff bias on my open/open truck.


This is all of interest to me as I put together my build list for the Tundra I am about to buy, because I intend to go with coilovers and will likepy at minimum try swapping in softer springs (600s or perhaps even 550s).