Bullbar vibration

[Schickies]

Hi all,

I have a genuine Nissan steel winch bar on my 2008 and noticed it has a vibration when driving. It's vibrates so much that the top half of my UHF aerial snapped off.
Does anyone have any suggestions?

 

[qqc d22]

Buy a different car mine does it to ironman bar. Spotlight vibrate like crap

 

[bods]

yep, i have a 2010 with an xrox bar and it's pretty scary the amount it moves around. most people recommend getting an aerial with a spring base to help absorb some of the vibrations

 

[qqc d22]

If mine wasnt so new id drill out the captive nuts and bolt right through the front chassis tube and if that didnt work id drag the welder out

 

[nakedape]

I've an alloy bar - it shakes about like it's made from jelly!

 

[qqc d22]

I think it because there bolted to that swiss chese crush zone

 

[qqc d22]

Makez you wonder whats going on there if your using a winch

 

[shan_b]

just two days ago I checked the bolts on my ironman bar on 2010 D22 because of this issue! it seems to move around a fair bit, but every bolt was tight!

 

[FatBoy89]

It's the flex between the chassis and the body. That's all.

 

[qqc d22]

Nah its not just the body moving on the mounts. The actual bullbars do move around and vibrate. I at first thought it was just cab movement but its not

 

[qqc d22]

A set of brush rails might stiffen it up tho

 

[FatBoy89]

Nah its not just the body moving on the mounts. The actual bullbars do move around and vibrate. I at first thought it was just cab movement but its not

How did you come to the conclusion?

 

[qqc d22]

Because you can just tell plus go pro camera and with the spotlight shake also makes it more obvious.
I know what you mean by the body moving differently to the chassis. It would be doing that aswell making it look worse than it is. My old rodeo use to look like the bullbar was moving heaps but it was just the body moving on the chassis like you said

 

[ben85]

i've done a bit of winching off my steel bar, on a fair angle too. no dramas yet, vibrates over bumps etc but doesnt seem to cause any probs for me.

 

[scooba_285]

its called bullbar "flutter", nothing you can do to stop it, i did drill right through the chassis because i stripped all the captive nuts and it still does it

 

[terryc]

When you are using the winch, the chassis will be under tension, i.e being stretched, which is the opposite to what happens when you collide with stuff front on.

The reason the bull bar vibrates is that it is effectively cantilevered off a chassis made of "thin" panels. Think wobble board (Rolf Harris's muscical instrument for the ancient). This is what gives its "crushability" for the safety rating. If you don't want it to wobble, you would need to go back to a vehicle with a solid chassis.

For most people, who spend their 99% of driving on the black stuff, end of story. Use mounting springs (and mass blocks) for stuff mounted on it. Or change the suspensions and/or drive slower.

Our 6/9db aerial with one or two loading coils in the shaft changes vibration modes depending on the shaking off the bull bar(speed and conditions).

Now, if you are hammering 100kms of corrugations too and from work each day and think it is getting really bad after 5 years, then have a look at the chassis at the various points where it attaches and see if it is cracked, or permanently deformed, or even just shedding or crazing of the coating. Anything you do to beef it up, like running a welding bead, will compromise any safety rating. My 2c is that you would see "damage/signs" at the shock absorber mounting points first. And you'll probably need a new seat.