CBI Rear Bumper 'Standard' Full Swing Arm "Death Wobble" - Chime In

[JWaldz]

I've been in contact with CBI regarding the lack of upper support on their 'standard' full length swing arm. This issue may or may not involve triangulated swing arms. It does involve those who have a full size swing arm. Plated or hybrid bumper should not matter. Those who have noticed a large amount of bounce/wobble (off or on road) please chime in. We are trying to isolate the problem.

Main Issue: While on some steadily bouncy roads, the swing arm will begin to bounce/wobble (up to or more than 1/2" of movement) causing rear end of vehicle to bounce as well. Some movement is allowed, however, excessive movement like this should not be occuring.

It is possible to make wobble reoccur demonstrated in video. Remember this is only by hand where as on or off road manners are likely worse.


<iframe width="560" height="315" src="//www.youtube.com/embed/ulsWc3kDXy4" frameborder="0" allowfullscreen></iframe>


If possible, please inspect and verify the following:

1. Rear body mounts tight and intact.
2. Bumper mounts/bolts/nuts tight and intact.
3. No cracks or failure in metal of swing arm.
4. All above correct and problems still persists? (Y/N)

Also, please list your options:

1. Body Lift (Y-?" or N)
2. Size Spare Tire
3. Hybrid or Plated Bumper
4. Latch Type
5. Jerry Can (0,1, or 2)
6. Hi-Lift Jack (Y-?" or N)

[MENTION=44220]BigFishAllDay[/MENTION] [MENTION=88391]NateMob[/MENTION]

 

[Skidmarcx]

Get the rear body mounts that Sonoran Steel makes

Rear 4Runner Polyurethane Body Mounts (Pair) - $75.00 : Sonoran Steel, Sonoran Steel Custom Metal Fabrication L.L.C. Custom Toyota Truck Parts

 

[hrt4me]

Get the rear body mounts that Sonoran Steel makes

Rear 4Runner Polyurethane Body Mounts (Pair) - $75.00 : Sonoran Steel, Sonoran Steel Custom Metal Fabrication L.L.C. Custom Toyota Truck Parts

do those actually lift the body or retain the stock height/gap?

 

[Skidmarcx]

do those actually lift the body or retain the stock height/gap?

I believe it replaces the existing mount with a sturdy version for added support... I ordered mine today, so when my Savage bumper shows up I'm good to go... Sonoran Steel seems to know their shit, so I'm assuming this rectifies the problem... Maybe somebody with the mounts can confirm?

 

[txbonds]

take this with a grain of salt as mine is new, with no wheeling yet, and has taken no off road hits so I'm not sure it really helps but here you go:



If possible, please inspect and verify the following:

1. Rear body mounts tight and intact. will have to check
2. Bumper mounts/bolts/nuts tight and intact. tight. Check.
3. No cracks or failure in metal of swing arm. none. In good shape.
4. All above correct and problems still persists? (Y/N). some movement if I push on it but nothing like yours.

Also, please list your options:

1. Body Lift (Y-?" or N). none
2. Size Spare Tire. 285/75/16 mtr
3. Hybrid or Plated Bumper. hybrid
4. Latch Type. screw pin style
5. Jerry Can (0,1, or 2). 2, but no cans in it

 

[NateMob]

Mine vibrates quite a bit just driving down the road, very visible in the rear view mirror and by anyone following behind me.

Rear body mounts tight and intact. CHECK
Bumper mounts/bolts/nuts tight and intact.CHECK
No cracks or failure in metal of swing arm. CHECK
All above correct and problems still persists? (Y/N) YES

Also, please list your options:
Body Lift (Y-?" or N) Happened before and after 1/2" body lift, no change in severity.
Size Spare Tire Same issues with 32" and 34" tire.
Hybrid or Plated Bumper Hybrid
Latch Type Screw Type
Jerry Can (0,1, or 2) 0


I honestly think it is just too much leverage hanging out away from the bumper and carrier attachment points.

 

[Skidmarcx]

How is this off topic? Did you read the description on the link? It specifically involves quelling increased oscillation from added weight such as tire carriers

 

[Skidmarcx]

Do you have a CBI Rear Bumper with Carrier? If not, then you arent aware of the issue or problem that we are talking about.

Not trying to be a dick but this is a thread for CBI to gather facts and rectify an issue, not a thread for someone to suggest spending money on body mounts to fix an unsupported spare tire carrier.

10 4 I don't have the CBI bumper... Just an idea for anyone willing to explore the option...

 

[NateMob]

10 4 I don't have the CBI bumper... Just an idea for anyone willing to explore the option...

ray2: sorry for sounding aggressive. Your contribution is appreciated, i just dont see it helping based on previous discussions of those mounts and the reasons stated above. cheers.

 

[Dous]

Mine moves a lot, and so does the bumper itself surprisingly. I can get the whole bumper to deflect 1/2-3/4". You can see where it has smashed into the body from hard hits offroad.

Every bolt is installed and torqued, so it is odd to me


Rear body mounts tight and intact. YES
Bumper mounts/bolts/nuts tight and intact. YES
No cracks or failure in metal of swing arm. NO
All above correct and problems still persists? (Y/N) YES

Also, please list your options:
Body Lift (Y-?" or N) NO
Size Spare Tire 35" Spare, but wiggled just the same with 33"
Hybrid or Plated Bumper Full Plate
Latch Type Standard Auger Type
Jerry Can (0,1, or 2) NONE

 

[Gerdo]

Get the rear body mounts that Sonoran Steel makes

Rear 4Runner Polyurethane Body Mounts (Pair) - $75.00 : Sonoran Steel, Sonoran Steel Custom Metal Fabrication L.L.C. Custom Toyota Truck Parts

Awesome find. My bumper moves some but it is all frame flex. The bumper, even with almost an inch gap, does make contact with the body.

Now the big question. With a more positive mounting of the body to the frame, are we asking for the some body torquing?
That energy needs to go somewhere.

 

[TCMach]

If possible, please inspect and verify the following:
Rear body mounts tight and intact. Yes
Bumper mounts/bolts/nuts tight and intact. Yes
No cracks or failure in metal of swing arm. None
All above correct and problems still persists? (Y/N) yes

Also, please list your options:
Body Lift (Y-?" or N) No
Size Spare Tire 33 on steelies
Hybrid or Plated Bumper. Hybrid
Latch Type. Standard auger
Jerry Can (0,1, or 2). 0
High Lift. Yes, 48"

Mine doesnt seem to be quite as bad as yours. I barely notice it unless its pretty rough. However there has been a couple times when my bumper harmonics match the highway's :lookout:. I also carry a high lift on mine so I added that to the list. I've been debating a side hoop setup for a while now and was debating adding another attachment point on the latch side due to how I want the hoops. Should help if I go through with it.

 

[gs300tt]

Rear body mounts tight and intact. Yes
Bumper mounts/bolts/nuts tight and intact. Yes
No cracks or failure in metal of swing arm. None that I have found
All above correct and problems still persists? (Y/N) Yes

Also, please list your options:

Body Lift (Y-?" or N) None
Size Spare Tire First 285/75/16 on stock rim Now 35/12.50/17 4"BS
Hybrid or Plated Bumper Plate
Latch Type Screw
Jerry Can (0,1, or 2) No can or holder


I have had a problem with both tires and tried different heights on the tire mount. I can make it start and stop by varying speeds. It is the worst on concrete roads with expansion joints evenly spaced. I do not see it much on black top roads.

I was hesitant to start a thread I am glad someone did.

Ben

 

[Dirtyfingers]

I had a wobble for a little while with my tire carrier part, then I got some red MILSPEC locktite, and some self locking nuts along with the bolts and man. That thing hasn't moved.

 

[smallfry]

I'll keep and eye on mine. Haven't seen/had any problems yet.

 

[hrt4me]

Awesome find. My bumper moves some but it is all frame flex. The bumper, even with almost an inch gap, does make contact with the body.

Now the big question. With a more positive mounting of the body to the frame, are we asking for the some body torquing?
That energy needs to go somewhere.

I'm looking forward to Skidmarcx's review once he receives and installs his... then I may add those to my 4Runner as well...

 

[sn0wrunner]

fftopic:
Not what this thread is asking for or even about. Keep the chit chat else where. They have nothing to do with the tire mount shaking. If anything they will make the problem worse by transmitting more vibration through the frame near the bumper mounts.

I'm going to disagree... I think he's spot on with the body mounts. At least that's what i need for mine. I know my tire carrier (no not a CBI) has some wobble. But the tire carrier and it's connection with the bumper itself is solid. When the tire carrier is moving the entire bumper moves with it. Either because the body mounts are not tight enough, or because the mounts themselves are too soft. It's hard to see if the bumper is also moving in the video, but if it is, the Sonoran body mounts would likely help quite a bit since they are stiffer.

 

[NateMob]

I'm going to disagree... I think he's spot on with the body mounts. At least that's what i need for mine. I know my tire carrier (no not a CBI) has some wobble. But the tire carrier and it's connection with the bumper itself is solid. When the tire carrier is moving the entire bumper moves with it. Either because the body mounts are not tight enough, or because the mounts themselves are too soft. It's hard to see if the bumper is also moving in the video, but if it is, the Sonoran body mounts would likely help quite a bit since they are stiffer.

I don't see how much the body is floating on the factory rear mounts is tied to the tire shaking and vibrating on its mount.

I'm not an engineer and I don't claim to understand everything. I do know that Sonoran developed his mounts to be a solid body mount instead of the floating factory style, to reduce bounce and jarring of the body itself.

How will stiffer body mounts stop the bumper and tire from shaking from undulations in the road?

 

[JWaldz]

Doesn't matter if it's relevant or not, all input regarding possible solutions are welcomed. Do I think just replacing the body mounts will fix the problem, not likely. But, it would probably help with bumper movement some.

I plan on doing a full look over of mine this weekend. After that I will report back with CBI and direct them to this thread as well.


Let me note that I have no problem with CBI products. All their stuff is top notch. Things like this are hard to foresee when fabricating. So, it's up to the us customers to speak up to make any issues known. I'm thankful for CBI's customer support and willingness to take care of the issue. Steve, their main fabricator, called me yesterday. So they are definitely aware of everything.

[MENTION=82211]TCMach[/MENTION] Forgot about the Hi-Lift.. Added to original post. Thanks

 

[sschaefer3]

fftopic:
Not what this thread is asking for or even about. Keep the chit chat else where. They have nothing to do with the tire mount shaking. If anything they will make the problem worse by transmitting more vibration through the frame near the bumper mounts.

They will not transmit more vibration.

This is the year 2001. 13 years ago, the tire did the same thing on my tire carrier. Only not as much.

So to correct the mis-information in the thread, the mounts are an exact stock replacement and they DO NOT increase any vibration.

This is EXACTLY why I would never make a tire carrier bumper for a 3rd Gen. Exactly why !!!