Cab Movement

[RLDSL]

About how much is the most a cab will move front to back going down the road, or I guess the more important question is how much clearance do I need to leave between the cab and anything on the headache rack?
The cab bushings are all fairly new urethane with one layer of hockey pucks in there for good measure. All still good and stiff. The bed is a Western Hauler and is solid mounted to the frame with no flex.

I mounted something up on top of the headache rack and now I got to thinking about it getting in a pinch and wonder if i need to move it back any or if it's OK where it's at.
Thanks--------Robert

 

[Dsl_Dog_Treat]

With the urethane bushings the cab is gonna be solid.
Only thing that's gonna give will be the frame twisting and loads will vary that depending on the terrian you roll over.
I would say 2" would be a safe guestimation as that's bout what they give for clearance between the bed and cab space.
That's bout what I have for clearance on my air deflector mounted on the top of the rack on Goldie and I've flexed the frame haaaard on that truck just getting in and out of my drive.

 

[duaneboggs]

I don't believe there should be any front to back movement, the clearance between a factory bed and the cab is what...a couple inches?

However the frame will twist or torque side to side if you go through a big dip or driveway and you aren't square to it, I know that my truck will twist a couple inches if I back into the bar ditch across from my house. I've always left about 3 inches or so over the top of the cab if I've had a cabover camper on so that it won't smack the top in those situations.

Duane

 

[MIDNIGHT RIDER]

I don't believe there should be any front to back movement, the clearance between a factory bed and the cab is what...a couple inches?

o through a big dip or driveway and you aren't square to it, I know that my truck will twist a couple inches if I back into the bar ditch across from my house. I've always left about 3 inches or so over the top of the cab if I've had a cabover camper on so that it won't smack the top in those situations.

Duane

He said what I was fixing to say; a factory bed is screwed solid to the frame and most barely clear by maybe an inch.

On older 4x4 trucks that have seen a lot of rough terrain, and most likely never had the old worn-out cab bushings replaced, you will see a very shiny paintless strip across the back of the cab, where the front of the bed has been rubbing.

 

[bike-maker]

The front of my bed is creased in towards the cab pretty severely; there's only about 1/4" between the cab and the bed where it's bent forward. Been like this as long as I've had it. It has just barely rubbed the paint off so far. And this is on a truck with a long frame - CCLB = alot of frame flex. Watching the bed mounted tool box through the rear window of the cab shows that the bed and cab move around ALOT in relation to each other.

 

[RLDSL]

He said what I was fixing to say; a factory bed is screwed solid to the frame and most barely clear by maybe an inch.

On older 4x4 trucks that have seen a lot of rough terrain, and most likely never had the old worn-out cab bushings replaced, you will see a very shiny paintless strip across the back of the cab, where the front of the bed has been rubbing.

That's kind of what I was thinking. although mine is a pavement queen and the only rough spots it hits are some of the hard binds that they have at some of these campgrounds at the corners
It looks like I left just a hair under 3" clearance at the closest point and it's mounted on top of the headache rack at the top of the roof . The rack has about 2" clearance at the base of the window.

If that 3" doesn't sound sufficient, the frame on what i mounted ( an oil cooler ) is just aluminum so it would be no big deal to move it back.