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Rear End Bounce

rharr

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Falcon may be good but wow their info on them SUCKS! Give me a straight answer on what each adjust does already.... @TeraFlex Suspensions @TeraFlex


This is a guess since I can't find any info in their docs but it looks like the adjust knob on the piggy back is their compression adjuster?? big lever knob would be low speed compression and the little inner knob high speed compression? (that is what is standard in every piggy back dirt bike shock and really all you can control at that location, rebound happens at the piston)

The 3.3 also have a quirky turn the shock shaft 360 degrees thingy which seems to be a half baked way to giving some adjustability to rebound.

https://teraflex.com/amfile/file/download/file/576/product/22493/


Based on what you say sounds like you don't have enough rebound dampening. Start there. Un bolt the eye of the shocks and turn them 360 degrees to engage " performance mode" aka more rebound damping and set your compression adjuster knobs in the middle of their adjustment range.

Go for a drive. Did any thing change?

Those high heaves you are hitting trigger the high speed compression circuit (aka high speed is not related to vehicle travel speed, it is how fast the shock compresses on an impact) square edge hits in a road at speed will cause a high speed compression action. By adjusting the high speed circuit of the shock to harder you are basically adding more resistant/damping to the upward stroke and slowing down that upward movement.

If the adjusting of the rebound (360 degree turn) doesn't help start playing with just the high speed compression adjustment. Turn it one click harder (CW) from your middle adjustment go for a drive, did it help? if not turn it back to middle (aka base setting) and then turn it one click toward soft (CCW). did that help? If a little go one more click toward soft (CCW) and see what that does, keep repeating this, going back to base setting and then adding 1 more hard or soft click. Work through the full range until you can develop a feel for what each adjustment direction does and how it feels. You will start to get a feel for which direction to go in the adjustment based on how the truck feels.

My guess is you need more rebound and a touch more High speed compression to dampen the upward stroke on those square edge hits.
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OVRLND_G8R

OVRLND_G8R

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Falcon may be good but wow their info on them SUCKS! Give me a straight answer on what each adjust does already.... @TeraFlex Suspensions @TeraFlex


This is a guess since I can't find any info in their docs but it looks like the adjust knob on the piggy back is their compression adjuster?? big lever knob would be low speed compression and the little inner knob high speed compression? (that is what is standard in every piggy back dirt bike shock and really all you can control at that location, rebound happens at the piston)

The 3.3 also have a quirky turn the shock shaft 360 degrees thingy which seems to be a half baked way to giving some adjustability to rebound.

https://teraflex.com/amfile/file/download/file/576/product/22493/


Based on what you say sounds like you don't have enough rebound dampening. Start there. Un bolt the eye of the shocks and turn them 360 degrees to engage " performance mode" aka more rebound damping and set your compression adjuster knobs in the middle of their adjustment range.

Go for a drive. Did any thing change?

Those high heaves you are hitting trigger the high speed compression circuit (aka high speed is not related to vehicle travel speed, it is how fast the shock compresses on an impact) square edge hits in a road at speed will cause a high speed compression action. By adjusting the high speed circuit of the shock to harder you are basically adding more resistant/damping to the upward stroke and slowing down that upward movement.

If the adjusting of the rebound (360 degree turn) doesn't help start playing with just the high speed compression adjustment. Turn it one click harder (CW) from your middle adjustment go for a drive, did it help? if not turn it back to middle (aka base setting) and then turn it one click toward soft (CCW). did that help? If a little go one more click toward soft (CCW) and see what that does, keep repeating this, going back to base setting and then adding 1 more hard or soft click. Work through the full range until you can develop a feel for what each adjustment direction does and how it feels. You will start to get a feel for which direction to go in the adjustment based on how the truck feels.

My guess is you need more rebound and a touch more High speed compression to dampen the upward stroke on those square edge hits.

Take your rear shocks and turn them if you have the mode adjust falcon's. you most likely are exceeding the dampening available from the shocks and need to swap to the higher dampening rate...

If your nearing bottom out then the shocks will push to extend quickly due to the nitrogen charge. Typically adjustment on most shocks are for compression only. I believe the SP2 Mode adjust changes both.
thank you both. I have another weekend project now lol

When I had the shocks out I noticed the mode adjust instructions and thought I put them in performance mode but will be sure to check that. They had a tag saying do not over rotate and I couldn’t feel any difference when rotating CCW or CW 360 degrees and also wondered what mode they were in out of the box. Maybe I have one shock in one mode and one in another. I will be sure to report back 👍🏼
 

rharr

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here is a video of the mode adjust and what it does.



the vid is pretty good at showing how the shock works and what the stuff does. It has some sales'y stuff, but at the end of the day both shocks work the same way, the manufacturers just took different approaches and where to save money.
 
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OVRLND_G8R

OVRLND_G8R

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After watching the video and a few others, I am almost convinced the SP2 mode adjust is not correct on my truck. I will still take videos and go through all the comments on this. Will report back. Thank you all for the help
 

steve68

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Good shock info,
I noticed that with my 37", pressure at 31psi, bed full of luggage, bike rack, 2 bikes, truck full, 4 adults, of course stuff in the truck, OK, my 2 daughters, backpacks, pillows, blankets, they are adults, My recent drive to NC, I noticed I would get the rear end bounce, Stock Rubicon suspension, has the rake, nose dives when hard on the brakes, nose down ass up, I cant wait to do a lift and good shocks, level, no rake,

Side note, 12' JKU, best riding suspension I had on it was Terra Flex Leveling kit, and Rancho 5000, handled great flat in the turns, I actually wish I would have left it like that,
 

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hickman785

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Hey all,

I’ve searched the forums, but can’t seem to find anything providing the solution to some rear end bouncing.

so far starters…. The mods
2020 Jeep Gladiator Rubicon
- 2.5” Clayton overland plus lift kit (comes with the triple rate springs)
- falcon 3.3 shocks
- 35x12.5 Goodyear duratrc at 28 psi
- smartcap, 270 awning, iKamper 2.0, fridge/freezer ( so a decent amount of weight which will only grow when fully loaded for camping trips)

What’s happening is when hitting bumps, mainly the segmented concrete highway, I get a bad bounce that is only up and down. No sway during this. It is repetitive and constant until the segmented Highway section ends and the truck smooths out almost instantly. I do notice the same feeling on side streets where it provides a similar situation.

I have adjusted the shocks settings messing with them to see if adjustments would solve the issue. No luck.
I’ve removed the weight from the truck, and it seemed to get a little better but did not solve it.

i redesigned the mounting of the iKamper to lower it closer to roofline to see if reducing the amount of air getting under the RTT would help, which it did but the bouncing is still present

are other people experiencing this and I am just being to critical on the truck?

Any advice, things to check, etc would be greatly appreciated

thank you
I have the exact same issue with mine. I built it with around 600 pounds on the rear end, no suspension changes and after about 6 months the bouncing suddenly started. Everywhere I go at 35 mph it starts, then on concrete highways it becomes so bad I have to get off the road. I added Falcoln 3.3 shocks, new KO2 tires, new wheels, and finally a Clayton ride right kit and nothing helped at all. Strange thing is that higher tire pressures make it bounce less.
Went to the dealership, they put it on a lift by the frame, suspension fully drooped, and they could still feel it bouncing. I could actually see the driver side rear tire wobbling. They told me its definitely not suspension or weight related, they replaced the drive shaft and rear axles and nothing changed.

Next they called in a Jeep engineer who very quickly blamed the weight while completely disregarding the testing that we had already done. He demanded that I remove all of the weight before he would come look at it again.

I took my RTT off, nothing changed, I removed about 200 pounds of gear from the bed, that helped a little but it still bounced, then I removed my Alu Cab canopy and nothing changed. It still bounces everywhere I go, just not as bad.
The dealership brought in another Jeep "engineer" who apparently doesn't know his ass from last Tuesday, and he drove it and said it isn't bouncing at all, even though it bounced all the way to the dealer and then all the way back home. At this point I know its a driveline issue, but I have no clue how to fix it. I've called around 15 overland shops around the country and none of them have a clue what it could be or how to fix it.
 

hickman785

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interesting. I will have to try this and report back. I will perform the test on the firmest setting and the softest setting and see what the results are. I hope these falcon shocks are adjustable enough to work. I see plenty of people running heavy loads with these shocks and haven’t seen them post anything similar to my situation.

Or like you said, it’s just specific to that interval that I luckily drive almost everyday lol
I have the 3.3s and I'm experiencing the same issue. The 3.3s are absolute garbage.
 
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OVRLND_G8R

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I added Falcoln 3.3 shocks, new KO2 tires, new wheels, and finally a Clayton ride right kit and nothing helped at all.
Are you saying you had rear end bounce, then added the shocks and still have it?

did you try what was mentioned above yet? Making sure the SP2 mode is correct? I had a busy couple days and was unable to get to working on the truck yet.
 

Lynn_F

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I found that adding a rear track bar relocation bracket helped. The rear suspension, if lifted, causes the rear track bar angle to increase and creates "bump steer" on the back of the truck. This would be a relatively cheap step to take and see if it works. I added the Teraflex to my 2020 gasser and it made a world of difference in ride quality. I have the Evo one on my '22 Ecodiesel.

20211115_050839.jpg
 

j.o.y.ride

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Honestly, the Falcon shocks and the Clayton springs are both known to be on the stiffest side. Unless you're running on soft setting I suspect the issue is not lack of damping. I suspect the opposite... that it's too stiff.

Not stiff like you're riding on rocks, but stiff like there is no actual damping of the bump, no slowing and control of it, and it bounces back off.

Sounds like you're hitting a frequency of bumps that when the first isn't fully able to be dampened, the next exacerbates the issue. I know the feeling.

I have those springs, I am strongly considering trying some Teraflex instead, though the issue was somewhat mitigated by the Accutune Fox 2.0 external bypass shocks.
 

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hickman785

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Are you saying you had rear end bounce, then added the shocks and still have it?

did you try what was mentioned above yet? Making sure the SP2 mode is correct? I had a busy couple days and was unable to get to working on the truck yet.
Yes it started with all factory suspension....then I added Rubicon shocks, which didn't help...then I added the 3.3s...no help either...I have confirmed the sp2 is in the soft setting (the firmer setting was unbearable)...I've adjusted them in every configuration possible and nothing has made any difference...I've been dealing with this bounce issue for well over a year and no one has a clue what it could be...I've also wasted over $6000 trying to fix it...
 

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I have a fully stock 2020 Overland that does the same on a section of segmented highway that we have here. The faster I'm going, the worse the up and down bounce is. I have a RSI Smartcap with a roof rack, and a bunch of stuff in the bed and back seat (at least 400 pounds all together). I also run the tires at 40psi cold. I did buy a set of Rubicon Fox Shock take-offs, but have not installed them yet. I haven't done anything to try and fix it, so far, I just try to drive slower over that one section of road.
 

NewGladdyOWNR

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I have a Overland with the Clayton 2.5" overland plus, with FOX shocks. My truck does the same thing in my brothers subdivision, but no where else. It's 100% the road.
 

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I have a 2020 Sport Max tow, Clayton 2.5 premium lift, 35 inch Nitto terra ridge grapplers 32 PSI and Falcon 3.3 shocks. I have adjust them all over the place. It seems like Iam floating down the and swaying with he road. Sway from side to side ,Steering is tight. no matter what setting I have it on there is very little change. Any ideas?
 

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Anyone ever find a solution or at least isolate the issue?

I'm here after doing a 2k mile trip from FL to CO and it seemed to only start around West Kansas.

I thought it was just that particular section of road but it seems to be doing it on many roads now (though not all).
I think I remember hitting a pothole a little while before it started but can't say for sure if that would cause anything to change.

I kinda thought maybe a wheel weight fell off but don't see anything obvious.

I'm on new 37" Baja Boss AT's setup on KMC Beadlocks.
Balanced just before I left on this trip and while not perfect.. seem smooth as long as the road is smooth.

Only other factor I can think of is my rear driveshaft hasn't been perfect since I banged it up on some rocks.. It vibrates a bit but not enough to cause the oscillation I'm feeling (I don't think at least) and that was 20k miles ago...

Wondering if there's an issue with the axel housing or shafts.

I'm gonna start isolating when I can.. but of course this happens in the middle of a 5k mi trip...

Things I'm thinking to check:

-Wheel Balance
-Rear Driveshaft
-Axel Housing
-Alignment
-Track Bar

I'll let y'all know what I find!
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