Sissy wabble cracked my fender - suggestions on how to stabilize?

[mikewerx]

So my sissy bar is somewhat high, 1/2" stainless goes about 4' above the fender, and it vibrates when riding of course. There is one point of connection for the top of the seat, which has a fiberglass pan, so not a heavy steel seat pan to stabilize even more. After a couple months of riding chatter, the fender where the sissy attaches has grown a nice tension crack. There is no rush, and it's a pretty new lowbow ribbed fender. which is now almost completely ripped out.

Can anyone suggest some good ways, after I weld this back up, ways to stabilize the sissy so it doesn't happen again? Would another connection point half way up the seat help? I'm just using rivet nuts into the fiberglass seat back to connect the seat back to the sissy bar.

Thanks fellas!

[Jessechop]

Is the left bolt tight? It looks like the threads bottomed out on the left and the bar isnt tight?

[tjgonz]

Dont have a good answer but that setup is tits!
pretty close to what i run..mines hella shorter but the vibes over bumps flex my fender & its pretty thick.
Could/would you chop it down?

[CoLoNpEe]

Two strips of flat stock under the fender below each bolt should take care of that. Run them the length of the fender to the lower mounting point.

[Dragstews]

Two strips of flat stock under the fender below each bolt should take care of that. Run them the length of the fender to the lower mounting point.

Or tie the two bars together on top of the fender..
Arrest the harmonic vibrations..

[mikewerx]

1. Yeah, it's tight, but it WAS loose for a week or so, wonder if this happened then...?
2. Thanks, but NOT going to chop down...seriously?
3. Totally going to try this... 1/8" flat bar should be good enough?
4. Don't think this would help, but thanks!

[andri]

Also I think the bung being welded on top of the fender gives the swing arm more leverege to tear the fender apart.

My solution would be to drill a hole in the fender to put bolt through for the sissy instead of the welded on bung. That I think will put way less strain on the area surrounding the hole.
Also the standard way of a brace under the fender is a proven way to mount, especially with someone sitting on it as well..