Replacement for Tonneau Fabric - Coroplast

[kach22i]

Replacement for Tonneau Fabric - Coroplast

My button snap fabric tonneau cover shrunk too much to go back on. I even tried soaking it for hours in warm water to expand it, and all I got was a dirty bathtub out of it.

I used a dusty 4'x8' piece of black coroplast which has been sitting in my garage for the last two years (for a project I never did).

$25 for the coroplast (cuts with utility knife for trimming)

$10 or so in screws

$10 for two 3"x48" ABS plastic strips

So for less than $50 I have a removable cover, will need a 1/4" hex driver and a flat-head screw driver to remove it. I suppose I could have used Velcro or snap latches but I was trying to keep the costs down.

This project takes just a couple of hours to do, you don't need your old tonneau cover frame, but I suggest you do reuse it, or at least cut up some angle iron or aluminum angles for some cross members for those of you which get snowfall.

If you can get the ABS strips the full length of the bed do so, I was using scrap and limited in length. You could also use 1/16" x 3" flat stock aluminum or some other material you find at the scarp yard or hardware store.

S10 4x4 Pick Up Photos by kach22i | Photobucket


I suggest weighting the cover so it lies flat when drilling and screwing.

Don't over tighten the hold-down screws.







This is the one detail which did not come out well, like I said use a full length 6-ft or 7-ft strip of something to avoid this kind of thing.


I did not use any foam rubber gasket material, I did not want something easily damaged when I take the cover off, plus this allowed me to use shorter screws.

I made all the holes in the coroplast oversized to allow for expansion and contraction.

I still have to test drive this thing, and will report any testing problems which may show up over time.

I'm just to cheap to spend over $300 right now, this will just have to do.

[gone-ot]

Lookin' good!

[kach22i]

All the aero modifications combined have greatly increased down-force, and with no loss of mpg (a balancing act).

This is a much safer vehicle to drive in wet weather than it used to be. Next time you get "ice out" conditions, check to see which vehicles are in the ditch, they will mostly be pick-up trucks.................but not me.

I just have to do one more oil change and check the air pressure in the tires and I'm ready for winter.

I suspect that there will be much less deflection from snow sitting on the new cover than there used to be with the fabric cover. This might even save me some time with the old push broom this winter.

When this cover gets worn out, I'd like to try one which is the proper width and hinges up, some Monopan from Canada would be fun to experiment with.

I'm expecting to get 2-3 years out of this, much will depend on the UV resistance of the Coroplast.

About aerodynamics; the fabric cover would deflect some from the redirected air over the roof, and flutter at high speed. The flutter is not good for airflow from what I've read. This more rigid material should perform better than the old fabric despite the extra drag caused by the hex head fasteners.

As a bonus, the old fabric cover serves as a travel sized bikini top for when my old Targa 911 is parked. No hot leather seats, bird poop or leaves to worry about now. I just drape the old tonneau cover over the top. I might add some grommets to it so that I can bungee it down on windy days.

[Slow_s10]

Awesome job man, I have never really cared for fabric tonneau covers but this seems like a legitimate comprimise of light weight and durability. Also I see that your S10 is 4wd have you considerd lowering it a little? Lowering it will help reduce your frontal area and improve the handling.

It's actually crazy easy to do on a 4wd S10, as long as you don't want to go really low. In fact to lower the front up to 2 inches all you have to do is loosen the torsen bar adjustment bolts in the crossmember. If you take them completely out it will give you around "1.75 ~2.5" inches of drop just depending on how high they were set at the factory. This is exactly how I lowered my Bravada and it handles so much better and it also had a positive impact on it's fuel efficency. The best part about this is if you don't like it all you have to do is tighten those bolts back up to return it to the stock height.

Lowering the rear is a little more invloved but it's still not that hard and can easily be done with normal hand tools.

[kach22i]

Originally Posted by Slow_s10

........ your S10 is 4wd have you considerd lowering it a little?

I think my truck was raised about 2-inches by the previous owner. I kind of like the pseudo SR-2 look I have going on.

I did some test driving today, some observations below.

45 mph:
You can really feel the aero down force, I'd say there is just as much at 45 as there was at 50 mph before.

70 mph:
The truck tracks really good, better than before - likes to stay in a straight line (which is good).

80 mph:
More down force than before, just shy of that feeling that you are towing something, feels very secure for a vehicle which sits so high off the ground.

There is still some buffeting and deflection of the material past the last spar - just before the rear spoiler. However it is 1/8th to 1/4th of what it used to be. I can see that a perfectly rigid top for the bed would be an even greater improvement.

I was seven pounds low in tire air pressure, huge improvement in rolling resistance now.

I was so happy with the results, that I went to the self-serve car wash and gave her a bath.

[kach22i]

Six Month Update/Report:

The black colored product tends to swell in direct sun and remains quite distorted once it cools back down.

S10 4x4 Pick Up Photos by kach22i | Photobucket




A stiffer heavier material may be warranted.

I've replaced the hex screws/washers with slightly longer ones at locations where they were sneaking back up.

I've had the cover off once or twice, much faster/easier than removing a fabric one.

Maybe if the screw holes were much larger there would be half as much swelling/buckling as currently shown.

It works and that's all I care about.

[some_other_dave]

I would suggest using all the same type of fastener for removable bits. Only having to remember one tool is significantly easier than two.

You could glue stiffening ribs onto the last section, since it sees higher aero loads than the front. You might consider trying a shorter spoiler on the back as well. It might be hard to quantify any gains, but a coast-down test can tell you some of it.

Looks good, though!

-soD