Help Needed: Bouncy Ride - 5100’s and Rear Spacers
 

Hi, just installed bilstein 5100’s set at 2.5 in the front and a 2” spacer in the back on my 2021 Limited. I kept the stock springs, and installed Toyo AT3’s 275/60R20 on the stock wheels. Now the car feels considerably bouncy both front to back and side to side. This isn’t a stiff bounce… it’s a soft rocking bounce. When I pull down on the roof rack to one side, it seems to rock side to side at least two times (two times noticeably plus some minor residual bounce). A couple of notes:
1. My caster in the front is low ~1.4 - scheduled for an alignment with a shop that knows an alignment is more than just getting the toe right (don’t ask).
2. My tire pressure was around 37 psi when I checked this AM. I’m guessing this is high for the larger tires, but again, the bounce feels soft, not stiff.
3. I have not yet installed extended rear sway bar links and poly bushings or the front sway bar relocation kit - still waiting on those. Still on factory sway bar end links/bushings in the rear.
4. Maybe this is normal - never lifted a vehicle before. Forgive my ignorance here.

Any thoughts on what the issue is? Sway bar, track bar, springs, something else? Most of what I read seems to indicate a stiffer ride after a lift.

I’ve noticed a couple of times the front end seems to sink a bit low if I’m going downhill and turning into a parking lot and hit a dip or bump as I turn in. One time I heard an unnerving clunk.

Any help is appreciated.

Edit: I’ll add that I have around 200 lbs of gear in the back, and an added battery under the hood on the passenger side along with a bunch of cabling. Although I never noticed this added weight with the stock tires/suspension.

I can't be of much help to troubleshoot, but I can say that I had 5100's on. my Gen4 set at 2.5" and the results were the opposite of yours. Much stiffer and stable, less sway, less roll. Just all around better. So I would expect your results should be at least somewhat close on a 5th Gen.

so you got rid of the x-reas, what did you replace the rear shocks with?

Bilstein 5100’s in the rear (and front) with stock springs.

Brand new shocks shouldn't be bouncy or allow more than 1 rebound movement before staying still if moving the vehicle by body weight. Were these 5100s new? Did you compress/extend them before installation? They should be very difficult to compress and the nitrogen charge should cause them to extend on their own after being compressed.

They were new… or at least they appeared to be when I opened the packaging. I ordered them from Shocks Surplus. I compressed the rears by hand slightly to get them installed. Based on the video I saw on Bilsteins website, they didn’t seem to compress any more easily than what I saw in the installation video. And they did extend back on their own. I will say, when I hit quick short bumps in the road, the shocks seem to absorb quite well. It’s when I hit slower more significant dips that I notice the rocking.

I'm just going out on a limb here.

Has anyone else noticed the rocking when sitting in your car. Getting rid of x-reas means you have less sway control with what the OEM specs provided (smaller sway bar than non -xreas models) and you are still using OEM springs, which means your suspension might be mismatched.

Unfortunately, there isn't alot of people still around on this forum with that experience anymore. Maybe post up on FB groups too.

My wife is the only person that’s ever sat in my car, and she’s only been in it once since I lifted it. The only thing she noticed is it sits higher. I wonder if I need stiffer rear springs, as most of the rocking seems to be in the back. I’m also thinking/hoping extended rear sway bar links and poly bushings will help.

it probably is a good idea to go with stiffer springs, or ideally, match those ALL your springs to your new shocks all around, that will fix your bounciness. Not sure what toyota specs are on those springs. Extended rear sway bar links won't fix your issue, its to fix geometry issues. Poly bushings is just to extend the life of maintenance items.

Getting a bigger sway bar or a OEM non limited sway bar will help with your side to side movement.

I wonder if you can install regular OEM sway bars from other trim..i think thats the direction you should be going.

@mrblah , thanks for the suggestion. I was able to find part numbers for the non-limited, non-kdss front sway bar, bushings and brackets. Didn’t realize it was a different size. Is the limited rear sway bar different from the other non kdss trims? Im struggling to find the part number if it’s different.

My TRD Off Road with KDSS isn't really a perfect analog, but when my 5100s were installed, I found that the ride was similar to the stock ride... just lifted. At the time, I also installed SPC ucas and had 5 degrees of caster and the steering tracks very well... better than stock. I would think that 1.4 degrees of caster would make the steering fidgety. That combined with x-reas no longer dampening roll may mean that your stock sway bars are a little overwhelmed. Just a thought.

thats pretty much the same conclusion im arriving at also. Replacing Xreas, means literally replacing the entire suspension. Shocks, springs, and sway bars to standard spec, and then upgrading the usual stuff (UCA) to get better alignment specs when lifted.

OP will have a pretty slick setup when all said n done.

I have an alignment scheduled with a proper shop to see what they can do with my caster… hoping to hold off on the UCA’s until the spring.

Right now, I just want to get my ride as comfortable as possible.

I am wondering… is it just the front sway bar that’s different with the Limited? I can’t seem to find a part number for a non-KDSS, non-limited rear sway bar.

i wish my knowledge base is more extensive but its not....

I can tell you what i would do if i was in your shoes, i would:

1. get good aftermarket springs to match your weight, you might get away with not having to mess with sway bars.

2. try to get an alignment and see if you can move your caster..you might not have to get UCA.

3. try to fit OEM non-kdss, non-limited roll bars if the suspension isn't to your liking yet. I would do this as last resort. Just know, you will probably never replicate XREAS no matter how hard you try (that firm/planted feeling), with the standard 4runner suspension setup (everything is going to be not as firm or as controlled as xreas).

So, I’ll do my alignment tomorrow and see what they can do.

I already had Icon 52700 queued up in my cart to replace my rear OEM springs and 2” spacers. I’ll go ahead and order those. Still struggling with the front springs… mostly because I had a tough time getting my spring compressors into my driver side stock coil. The lifted coils appear to have narrower spacing between each coil, so unsure how to compress those. Open to suggestions there.

My wife and daughter are out of town in mid-January, so I’ll plan on replacing the front sway bar, bushings and brackets with non-limited OEM parts. Since I scrapped the XREAS it only seems appropriate.

Hopefully someone can chime in on the rear sway bar for the limited vs non limited. Are the rear sway bars the same between the sport and standard suspensions? If anyone can confirm, I’d certainly appreciate it.