How much frame flex is "too much"?
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From: Pittsburgh
How much frame flex is "too much"?
Did a couple shots today while I was wheeling. The ones here I did because I was with some guys that said they'd never seen a truck flex like mine when it came to crossing things like creeks and ravines, they kept saying my frame was moving more than the rest of the suspension. Decided a couple log shots would illustrate this well:
https://www.ford-trucks.com/user_gal...=70653&width=2
https://www.ford-trucks.com/user_gal...=70654&width=2
https://www.ford-trucks.com/user_gal...=70655&width=2
The guy in the third picture is about 5'8", put him there for reference. So I got my drivers front tire about 24" off the ground, other three are firmly planted with no signs of lifting. My front suspension is yet to start flexing and the rear shackles have barely started to move.
Do other people's trucks act like this and these other guys are just used to jeeps and newer trucks, or am I twisting a bit "too much"?
Justin
https://www.ford-trucks.com/user_gal...=70653&width=2
https://www.ford-trucks.com/user_gal...=70654&width=2
https://www.ford-trucks.com/user_gal...=70655&width=2
The guy in the third picture is about 5'8", put him there for reference. So I got my drivers front tire about 24" off the ground, other three are firmly planted with no signs of lifting. My front suspension is yet to start flexing and the rear shackles have barely started to move.
Do other people's trucks act like this and these other guys are just used to jeeps and newer trucks, or am I twisting a bit "too much"?
Justin
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From: Senoia, GA
when you start breaking mounts and cracking your frame! lol, mine does the same thing except a bit worse. i dunno if there is an algorthim used to determine the max amount of flex a frame can handle before snapping or not but i do know it ain't always good. i gotta try and soften up my springs a good bit.
-cutts-
-cutts-
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From: Pittsburgh
I've already toasted 3 body mounts and split my exhaust system. Don't ::think:: i've bent the frame in the middle. When it first hits the ground it drives kinda cockeyed, but flattens out after about a quarter mile.
Justin
Justin
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From: Atlanta GA
I had my 1997 Ranger twisted so much going down an ATV trail it looked like a X from the back. Cab one way, bed the other, each following an axle.
If you take a BII off road with a body lift you will find the frame can flex so much that the driver's side floor pan readily rips, front to back, along the welded seam. Especially if it is rusty from salt. Does on the pass. side sometime and right under the rear seat. When I buy a used one, I always look for that damage.
I call extreme twist when your rear slider pops out or your windshield cracks
One strong point about a CJ-7 is the W/S is mounted separately from the body so it is hard to crack it from twisting.
I took a semi-tractor "slightly" off-road and found you can flex even a double framed (1" total thickness) tractor if it has enough weight hanging off the frame (tandem axles). Never drove one that far up hill again
If you take a BII off road with a body lift you will find the frame can flex so much that the driver's side floor pan readily rips, front to back, along the welded seam. Especially if it is rusty from salt. Does on the pass. side sometime and right under the rear seat. When I buy a used one, I always look for that damage.
I call extreme twist when your rear slider pops out or your windshield cracks
One strong point about a CJ-7 is the W/S is mounted separately from the body so it is hard to crack it from twisting.
I took a semi-tractor "slightly" off-road and found you can flex even a double framed (1" total thickness) tractor if it has enough weight hanging off the frame (tandem axles). Never drove one that far up hill again
Last edited by rebocardo; Feb 27, 2005 at 09:20 PM.
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From: Coutts Canada
I've noticed too that our years of trucks the frame flexes a lot (espically the trucks with the swiss chees frames, like mine, which got bent in a really rough pit), One of the few ways to prevent this would be to box the frame where you can get at it (mainly by where the cab and box meet, and i've seen the frame crack up by the radius arm frame mounts as well).
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From: Spokane, WA
You got plenty of flex left in that thing Justin. My heavy 3/4 ton frame has been flexed far more than that. Watching WhiteKnights videos there was one or 2 Fords that had some insane flex. I've got to say though that I have never seen a Chevy flex its frame as much as the Ford trucks do. I don't know if it's something to do with the crossmembers or that . . . kind of interesting though.
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Might just head out and try to find something taller to climb then, I wanna see how bad this thing can really get. Guess I should start looking for angled retaining walls about 3-4' tall. Possibly more pics to come. . .
Justin
Justin
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12 point rollcage mounted to solid mounts on the hooked to the frame stps that. I can put mine on something to the point 2 opposite corner tires are not touchng and the cab to box body lines will still be lined up
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I'm getting ready to start some caging of the bed area, I killed my second bed and am tired of scrounging "new" ones. gonna do a roll bar at the rear of the cab and then tube in the back of the bed. Not keeping any outer skins, just inner of some sort. Thinking about going for the angled side dumptruck type look. . .
Justin
Justin
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So here's the update: My frame doesn't flex anymore than it does in that picture. Once the frame gets to that point is when the springs start to take over. I imagine if I were to flex it out completely, the frame would twist a bit more before lifting a tire. Issue at this point is finding something tall enough to unload the suspension completely. Today I had the drivers front on a birm that was 4' tall (I'm 5'7 and my eyes were even with the bottom of my frame at the door) and the drivers rear still hadn't fully unloaded the shackle.
Justin
Justin
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I grease my shackels on a regular basis, so they move REAL easily. If I lift the truck by the frame, the shackle comes all the way around before a tire will lift. There was still at least an inch or so of movement left at the shackle. I also know it wasn't completely unloaded as there was still some bulge left in the sidewall.
Justin
Justin
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I've noticed that the yrs '80-'97, more so than others, have flexed a lot between the box and the cab. i dont see very many chevies that can do that at all, and if they do get to that point, the frame is cracked. I know that the early '80's trucks had more holes in the frame behind the cab then any other trucks, even in my buddies bronco. We had to go over a small exit from a huge embankment, maybe big enuff for a quad, and it flexed a bit and cracked the fan shroud. i wouldnt worry about it to much tho, obviously ford had a reason for it, my dads '96 is the same way, and nuthin has happened so far, still runnin strong.
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From: Spokane WA
A guy at work has a similar year f150 truck that we wondered the same question. We ended up hooking the forklift under a tire, and found the limit lol. They flex pretty far though, I was sure impressed