How much cab over clearance should one have?

3"-4". the bed and cab tend to move independently of each other less than that and you risk denting the cab and or damaging the cabover

I ahve four inches or so. If it's touching the top of her cab it will damage the cab and the cabover before long...they flex quite a bit. It is also possible that if the cab is in contact then so are the sides of the pickup bed, this can do real damage to the camper. People use a variety of things, 2x's plywood, rigid foam. I use some pallet like things so I have some storage underneath. She also needs a rubber or foam mat underneath or the camper will slide around and can damage her truck bed. She needs to address this before she drives it again.

path1 wrote:
Another lady (a friend) says "it's not touching much, no problem"

Famous Last Words. :S

Thank you for quick replies.

3/4 inch 4X8 piece of plywood nailed to maybe 4 2X4's evenly spaced and then another 4X8 plywood and then a 3X4 inch horse stall mat on top. That would be horse stall mat closest to camper and wood closest to camper bottom?

thickness equals:

2 4X8 plywood equals 1 1/2 inch thick
2X4's equals 1 1/2 inch thick
3/4 inch horse stall 3/4 inch thick

Total thickness equals 3 3/4 inch thick...Look OK?

gbopp wrote:

path1 wrote:
Another lady (a friend) says "it's not touching much, no problem"

Famous Last Words. :S

Boy oh boy:)

This whole thing started by me helping them take of her old camper. Her new camper is actually pretty sound but needs normal maintenance that has been postponed.

I'm going to re-seal one window with her watching, then she's on her own after that.

But YA I understand, Famous last words.

path1 wrote:


This whole thing started by me helping them take of her old camper. Her new camper is actually pretty sound but needs normal maintenance that has been postponed.

I'm going to re-seal one window with her watching, then she's on her own after that.

But YA I understand, Famous last words.

Yep, it's almost as good as: Hold my beer and watch this!
Or, Don't worry, it's not loaded.

You may want to print this thread and let her read it. :)

path1 wrote:
Thank you for quick replies.

3/4 inch 4X8 piece of plywood nailed to maybe 4 2X4's evenly spaced and then another 4X8 plywood and then a 3X4 inch horse stall mat on top. That would be horse stall mat closest to camper and wood closest to camper bottom?

thickness equals:

2 4X8 plywood equals 1 1/2 inch thick
2X4's equals 1 1/2 inch thick
3/4 inch horse stall 3/4 inch thick

Total thickness equals 3 3/4 inch thick...Look OK?

Yes but it will be heavy. The stall mats work great but a foam exercise mat from Walmart is far cheaper and mine has worked well for three years now. The interlocking foam squares work well too.

path1 wrote:
... I think plywood would dissipate weight better?

Nothing will dissipate weight. Weight is what it is.

There have been a number of threads about this over the years. In typical internet fashion, the answers are all over the place. Let me distill it for you:

You have to deal with the flex. For a long bed truck with a north-south cabover bed, plan on 4" of clearance. For a short bed truck with a east-west bed, you can get away with 2" of clearance.

Your math is good on the spacer thickness. However, you can use 2 x 2's instead of 2 x 4's to save some weight. Maybe, go with 1/2 or 3/8 plywood on one of the sheets. You only need the full 4" if you are doing some serious off roading.

Think load-bearing - camper over-hang supported through the truck cab frame. Allow for some flex.