[Surfah]

Tried this..

Stand on the rear side of your truck bed by the 4x4 decal
shake the truck side to side... oscilate it, get with the rythym and really shake the bugger.

Notice the flex? yikes! /ubbthreads/images/graemlins/eek.gif

Then go and do the same thing to a brand new F-150... /ubbthreads/images/graemlins/zombie.gif
almost no flex....

Are there any mods or fixes at all to stiffen the frames on our
older bodystyle trucks ? /ubbthreads/images/graemlins/shrug.gif

Thanks

Chris

 

[DZLJIM]

Box the frame and cross members.
/ubbthreads/images/graemlins/eek.gif

 

[95_stroker]

Try it with a CC/LB/4WD /ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/eek.gif /ubbthreads/images/graemlins/eek.gif

But I figured if it wasnt supposed to flex Ford would have stiffened it up a bit more from the factory. /ubbthreads/images/graemlins/shrug.gif

 

[helixhippie]

Funny this comes up today....I've been thinking about it the last few days. I have a big, stout, enclosed service box behind my ex-cab. Been there since the truck had 300 miles. It's U-bolted in 6 spots & I have pretty much no frame flex back there. I wonder if that contributes to my fairly rough ride. Anyhow,
I'm starting to see cracking in the cab body at the top & bottom of the door openings. It's at the roof line & floor line at the rearmost area of the door openings. I guessing that the front section of frame under the cab is getting more than it's share of flex?
Any thoghts?

 

[bigbore]

One explanation I heard from a spring company in SoCal is that the CC trucks were desighned to flex since the suspension did not have a lot of articulation. This company told me if you box the frame the truck will be more rigid and ride smoother since the suspension will be soaking up the bumps, not the flexing frame. I have been seriously considering doing this.

 

[bignissan]

I disagree, the suspension on our trucks is designed to handle loads, if the susp. was soft, for a smooth ride, any load would make it sag. The frame needs to flex to contribute to a better ride. "Forcing" the suspension to do more work wouldn't help much I don't think, it won't change the spring rate of the springs. Take the 80's chevy's for example, my old half ton rode great, farely soft springs....and probably the most flexy frame any manufacturer has ever designed, under articulation, the bed would touch the cab and keep going if there was room. If you box the frame, you'd better do the whole thing, otherwise, you are going to localize stress and start cracking real soon. As far as stiffening it up though, it may be better to NOT box it, and to add flat plate to the top and bottom. That would make it stiffer and you wouldn't have to worry about stuff mounted in the frame rails.

 

[Suns_PSD]

[ QUOTE ]
I disagree, the suspension on our trucks is designed to handle loads, if the susp. was soft, for a smooth ride, any load would make it sag. The frame needs to flex to contribute to a better ride. "Forcing" the suspension to do more work wouldn't help much I don't think, it won't change the spring rate of the springs. Take the 80's chevy's for example, my old half ton rode great, farely soft springs....and probably the most flexy frame any manufacturer has ever designed, under articulation, the bed would touch the cab and keep going if there was room. If you box the frame, you'd better do the whole thing, otherwise, you are going to localize stress and start cracking real soon. As far as stiffening it up though, it may be better to NOT box it, and to add flat plate to the top and bottom. That would make it stiffer and you wouldn't have to worry about stuff mounted in the frame rails.

[/ QUOTE ]

I assure you that our trucks ride MUCH better w/ no flex. Frame flex can really cause that teeth rattling shake that you might get on occasion over repaeted stutter type bumps.

I base this on the fact that I have been selling big trucks for a few years and I've speced many, many trucks w/ different flex characteristics. In fact off the top of my head I can count about 16 different frame thicknesses combined w/ or w/o liners and such and I have seen more than one truck that rode just horrble because the salesman or customer speced it too light.

 

[mike100]

watch a long wheelbase mid 90's 1/2 ton F-150 4x4 flex off road. with it's lighter crossmembers and flexy suspension, you will really get the cab and bed to move off center from each other. disturbingly far apart...