serious roof flex issue

Setup: 2 15" type r's, custom ported box tuned to 30 hz. 4" aeroports, audiopipe ap30001d amp, dual batteries, 250 amp alt. 1995 ford ranger extended cab. The roof will not stop flexing. It flexes around 35-50 hz. I have tried 3 layers of peel n seal, doesnt change at all. I have put expanding foam between all the braces and the sheet metal of the roof. I dont want to do anything to the exterior of the truck to fix the problem. Liuke no holes for braces, or welds, cuz they will burn the paint. Any other suggestions? And the cheaper the better too, lol.

-------------
Disturbin' Tha Peace

I am pretty sure the only way you will get the roof to quit flexing is to turn the volume down.  Sorry but I think that there is going to be no economical way to stop it.

x2. Or get an older vehicle.

Proper bracing is usually the only way - eg, welded or glued ribs (pressure ribs tend to distort panel) or sandwich ribs - sometimes an external band or rib may work or help.


If stripping roof lining for this, or repainting etc, make sure the welds & glue hold - ie, must be better than spot arc welding - big 1-100Hz vibrations fatigue boundaries quickly.

make a false roof out of 1" mdf or a convertable

How about a piece of 3/8" plywood with expanding foam? Im thinking if I have the sheet metal then the foam then the plywood it will make.it strong enough it wont flex.much if any and my headlined can still go back in. think it will work?
Also what kind of glue would hold up if I were to put some wood or metal braces? The roof flexes.a good inch or so.

-------------
Disturbin' Tha Peace

A few years back, I had a customer with this problem.  He stood on his roof, dented it way in, then reshaped it on the outside with duraglass body filler!  He said it took a gallon and a half!  It had to be 2 to 3 inches thick in some places,  He repainted it and it looked sort of ok.  Kind of a ghetto solution, but it didnt flex any more!

Maybe if you take the headliner out, and your peel and stick stuff off, scratch the INSIDE of the roof panel with some 36 grit.  Smear a healthy layer of body filler all over it.  You could accomplish the same results without having to damage and repaint your roof  .  

damn you must have some serious knock in your ranger to make the roof flex that much. i have a 01 ranger ex-cab with a single 18 in the back and my back wall flexes way more than my roof. as for a solution, you could try to mount some 1/8th thick strips of metal to the frame work on the roof and anchor it to the side walls where ever possible.think of it like a roll cage but with flat iron instead of pipes. make sure you mount them in a way that actually puts tension to the roof like if you were on the inside pushing up on the roof. if you just screw metal to it without any tension then it wont solve your problem.

wood can also work but its bulky and will probably make it to where your headliner wont go back on.

the only other way i can think of is pretty extreme but this is the way true competitors do it, run a pipe from floor to ceiling and bolt it down to the bracing thats already on the roof.

-------------