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minnow's avatar
minnow
Explorer
Mar 01, 2016

Suggestions for Tonneau Cover with Auxilary Fuel Tank

Looking for advice from anyone that is towing a fifth wheel with a long bed that has an in-bed auxilary tank and is using a tonneau cover. Ideally I want a toolbox/auxilary tank combo. It appears there is a couple of ways to go with this; one with a tonneau cover that either folds or rolls up to the front of the tank as pictured here:

toolbox tonneau

Or get a tank that sits below the bed rails and utilize a full bed tonneau cover.

I see potential issues with both. With the cover that either folds or rolls up to the front of the tank, the concern is that the rails for the cover either are too high or encroach too far into the bed(reducing the width of the bed) which may cause the pin box to hit the rails when making a turn. Another manfacturer uses rails that sit on top of the bed (1 1/2" higher than the bed) which will reduce the clearance between the truck and the underside of the fifth wheel.

Now with the full bed cover that sits overtop the auxilary tank, one will need to roll up or fold up the cover to access the tool box/tank. This could impact the accessibility of the tool box lid as the cover would be in the way. I looked at the Bacflip and it appears that folding the cover all the way up against the rear window might impede the opening of the toolbox lid.

Bacflip

Any suggestions ? Thanks !!
  • GoPackGo wrote:
    I have an RDS combo 40 gallon tank/toolbox in the bed of my F350 dually LB. It sits about an inch lower then the bed rails. I also pull a fiver.

    Here's the way I looked at the situation and what I found:

    Many hard cover tops seem to have framework that extended low enough below the bed rails that it would contact the tank, so I crossed those off the list. I think I also had the same problem with the hard top retractables. There always seemed to be components that would extend too far below the bed rails.

    So next I looked at the foldable, stackable hard tops. Some of these might work, but then the rear window would be blocked during hitching and unhitching and I'd be running down the road with a rear view window that was completely blocked. Not something I wanted to do.


    So I finally looked at soft top roll ups and that's what I went with. I'm very satisfied and a little surprised. For $300 installed, it fits tight and cannot be opened without opening the tail gate. Yes, a knife will do it too but I'm trying to stop the guy walking by and looking in every truck bed to see what he can grab. I have a Truxedo Truxport. Made in USA.

    One thing you might investigate is maybe call RDS and ask if they will build a custom tank for you (I've heard they will). Then you could have one made up that is much lower then the rails. Also check out the RDS website - they have a zillion tanks.

    * Remember that when towing, the cover will be rolled up, so access to the toolbox is not impeded.


    WIth your Truxedo are the tonneau rails on top of the bed rails or inside the bed? And do the rails impact the distance between underside of the fifth wheel ?
  • I have an RDS combo 40 gallon tank/toolbox in the bed of my F350 dually LB. It sits about an inch lower then the bed rails. I also pull a fiver.

    Here's the way I looked at the situation and what I found:

    Many hard cover tops seem to have framework that extended low enough below the bed rails that it would contact the tank, so I crossed those off the list. I think I also had the same problem with the hard top retractables. There always seemed to be components that would extend too far below the bed rails.

    So next I looked at the foldable, stackable hard tops. Some of these might work, but then the rear window would be blocked during hitching and unhitching and I'd be running down the road with a rear view window that was completely blocked. Not something I wanted to do.

    So I finally looked at soft top roll ups and that's what I went with. I'm very satisfied and a little surprised. For $300 installed, it fits tight and cannot be opened without opening the tail gate. Yes, a knife will do it too but I'm trying to stop the guy walking by and looking in every truck bed to see what he can grab. I have a Truxedo Truxport. Made in USA.

    One thing you might investigate is maybe call RDS and ask if they will build a custom tank for you (I've heard they will). Then you could have one made up that is much lower then the rails. Also check out the RDS website - they have a zillion tanks.

    * Remember that when towing, the cover will be rolled up, so access to the toolbox is not impeded.
  • Nutinelse2do wrote:
    Here is a recent thread on the subject.


    Thank you. I obviously missed that discussion. Some good advice.
  • I have a roll n lock on my truck. I build a backwards L tank and my roll n lock covers my tank and my box of my truck when not pulling.
    It only a extra 45 gal but with a long box you probably could get 70-80 gal