Front Suspension Droop Limit with King 3.0s

Hi everyone,

I recently installed some King 3.0s with clickers, along with MCM upper control arms on the front of my 2017, the rest of the front end is stock.

They are currently adjusted as low as possible for lift height, and set to the middle range on the clickers.

Initially, I didn't re-install the front sway bar and found that when the suspension rapidly drooped out, I could hear/feel what I believe was the coil over topping out while driving.

When I was installing the suspension, and before the first test drive, I allowed each side of the front suspension to droop out and checked for binding at the UCA, steering, and CV axles with the sway bar removed, and didn't find any. It would also seem that my coil over was not topping out during these garage tests, but now I'm second guessing that. I'm also wondering if I didn't look close enough at the LCA ball joint to see if it was binding.

I decided to install the front sway bar before a multi day trip I just completed, and can't seem to recall that same topping out feeling or noise during the entirety of this trip, which included plenty of time in the dirt, and suspension cycling that I feel would have induced the same noise.

My garage testing would tell me that the front sway bar DID NOT limit suspension or droop, but more dynamic testing would seem that it might.

Does anyone else have any experience with what component(s) limit the front suspension droop or down travel?

 

Sounds like you need limit straps.

 

OEM replacement coilovers are always going to be the limiting factor on droop for IFS, they specifically design them that way so you can bolt them up and go. Just like OEM suspension, the coilover is the limiting factor on droop.

What you're feeling is almost certainly topping out. The reason you don't feel it with a swaybar is because that'll drastically slow down how long it takes the opposing corner to hit full extension, that's just how swaybars work by linking the two sides together. The best fix would be to add limit straps so those are the limiting factor and absorb the droop, but it's not really needed per say because there's nothing wrong with letting the coilovers be the limiting factor.

 

Seems like your testing was wrong, since you seem to conclude that nothing was the droop limit. It's almost always the coilover topping out, though some trucks I've seen the uniball cup can tap the spring at full droop. I am surprised you'd experience that onroad really ever though.

 

Doubt you were hearing coilover top out unless the wheels left the ground. “Low as possible” is the coil spring loose at full droop?, that’s usually a nice top out kinda noise. Did you check the nitrogen in the shocks?, not uncommon for them to be low, can also make noise.

 

Thanks for the replies everyone! For the time being, the front sway bar will likely stay on the truck until I come up with a good solution.

@Vizsla

The coil spring is not loose at full droop, or wasn't when I garage tested. I have not checked Nitrogen, but I will be doing that. It's very possible the wheels were leaving the ground, or coming very close. Without having someone outside of the truck, or getting out and checking my tracks it's hard to say.

@snivilous

Thinking back on it now, none of the components mentioned were binding, so it must have been the CO's that were stopping any further droop. There was no contact with the uniball cup on the coil that I noted. The topping out feeling wasn't experienced on roads, it was experienced in the dirt while trying to learn how to tune the rear bypasses (which I need to learn more about) over some faster bumps/whoops.

@EatSleepTacos

This makes sense, the noise I heard was very similar to other setups I've run on other trucks with other setups (Icon's on my last two toyotas) so it that was why I guessed it was them topping out. Even knowing that they are designed to be the limiting factor, it still doesn't sit right with me. However, the engineers at King are way smarter than me, it's safe to assume that them being the limiting factor is within their design parameters.

@Cruzer

Limit straps, or possibly a "lighter" sway bar are on the radar. I'm contemplating ordering up a currie anti rock bar in the 36 inch width (it "might'' be the only width that could work) and seeing if I could re work the arms to play nice with the tundra front suspension, I've used them in the past and really liked how they performed. It might be a good middle ground between a too tight factory sway bar and nothing at all. It also might be worth pulling the front sway bar and then adjusting/re-valving the kings until I find the sweet spot. Projects, and decisions I suppose. Thanks for the good deal on the deavers, they work great with the ADS bypasses on the rear of the truck.

Mike

 

I’m not sure how familiar you are with shocks/nitrogen/etc but don’t just put a normal air pressure checker on the schrader valve. The volume of nitrogen is so low that just by checking, you’ll release some and throw it all off. You need a special no-loss chuck to correctly check it. Honestly I wouldn’t even bother though, I’m extremely confident you just heard them topping out.

 

@EatSleepTacos

thanks for the heads up, I actually have a decent no loss nitrogen system I put together a few years back.

 

Glad they worked out!

 

How much weight do you have upfront. Maybe you need the upgraded spring. Kings only come with 600lb springs

also, is the front sway bar hitting the bottom of the coil over? They sell a slacker kit that’s like 60 bucks that fixes that.

Did you notice much difference in the ride with the front sway bar off?

 

@Greywind Tundra

Only additional weight up front is a RCI skid plate, I don't feel as though the spring rate is an issue. As of right now it rides great, and with the coil overs set as low as they will go, I still ended up with a bit more lift than I wanted. I imagine the 700 pound springs would pick the front end up even more.

The front sway bar was aggressively chopped at the ends(as much as I felt was possible without compromising material around the bolt holes) and does not hit the lower coil cups.

I did notice a difference with the bar off. I prefer the ride with bar off on everything other than certain street scenarios; windy mountain roads, back and forth sweeping turns, and certain highway maneuvers. Off road, and on poor condition paved roads the ride without the sway bar really lets the suspension be independent and work much better which keeps the truck more planted. With the sway bar back on, and uneven bumps (think the opposite of speed bumps) the truck has a slight tendency to oscillate back and forth a bit since the sway bar is actively trying to combat suspension motion from one side of the truck to the other. I'm pretty sensitive to this kind of stuff, so I think I feel it more than the average person would. Overall, with the bar on and off, I'm quite impressed with how nice this truck rides, particularly in the dirt, and I haven't even started tuning the bypasses on the rear.