"Bikini" style cab top

[MyothersanM1]

My old three color camo soft top became a little beat up and was not good enough to be my primary cab covering. I replaced it with a solid OD top about a year and a half ago. However, the camo top was not bad off enough to trash it. I decided that a “bikini” (AKA bimini) or half top would be a good idea. Sun protection from the top but open in the rear for nice ventilation on hot days. As we all know the cab top pillars fit to the cab tub by gravity alone, so I had concerns of the top becoming “airborne” at speed. I decided I would tie down the top to the cab tub via a grommet/rubber tie down system.

I started by cutting the rear vertical/window portion off and disposed of that portion. I cut just below the “welded” seam that parallels the bottom bow on the support system. The original colors looking faded and some threading showing through on thin spots; I painted it Rapco 383 Green. I bought a ½” brass grommet kit (available at most hardware stores) for top securement. I installed six grommets roughly corresponding with the hooks along the rear of the cab top. The grommets were installed through the welded seem for extra strength.


The tie-downs are made from 5/16” super rope (polyurethane cord) McMaster-Carr part # 3961T3, same type found issue cab tops and cargo covers, and nylon adjustable hooks, McMaster-Carr part #3862T2. The two outer cords are approximately 52” long and the center is 68” measured from the inner side of hook. The hooks can also be used with regular bungee cord material and are adjustable.


The top attaches to the windshield channel, snaps and turn buttons in the normal full cab top fashion. I attached the outer cords (52”ers) using the outer most cab hooks and the outer most two top grommets on each side. The inner cord (68”er) attached to the center cab hooks and top grommets in an “X” pattern. The hooks interfere with the bows slightly, but not enough to be ineffective.

 

[MyothersanM1]

"Bikini" cab top cont'd.

I drove the truck at speed, approximately 55mph, and the top sat firmly to the supports with no vibration or flapping. The ventilation was great and it kept me from baking in the sun. I really like the look of it and I wish I could keep it on the truck full time. However, because of storage issues I won’t be able to do that.


This write-up is for the M44 (M35) series 2 ½ ton and M809 series 5 ton cabs. M939 series 5 ton cab tops could be modified using this same method making adjustments for their wider width.
Please feel free to contact me if you have any questions or concerns for this mod. Thanks for viewing this post.

 

[lavarok]

How does it look from afar? I like the concept.

 

[MyothersanM1]

Here are some overall pics.

 

[cranetruck]

You will love it!
Had it on the deuce for almost ten years and also on the 5-ton xm757.
Details shown below and note that the top is painted white for reflection of the sun rays.
You will need a separate cover for when truck isn't used (last image).

 

[MyothersanM1]

You will need a separate cover for when truck isn't used (last image).

I just put the full cab top back on for long term coverage. The bikini top is sort of like "Sunday-go-da-meetin'" clothes. I've gotten quite adept on the donning and doffing of cab tops.

 

[215Dave]

Neat idea! Well executed by both of you.

 

[wheelspinner]

I just aquired a soft top and wanted to do this same thing, but wasn't sure how. Def going to copy this one! Thanks for the great pictures.

 

[mcmullag]

Thanks for posting the info and pictures. Good idea, great work.

 

[gunboy1656]

Nice idea, was just considering something like this during the parade the other day.

One question I had was why use the hooks at all and not just use the rubber rope like the regular top?

 

[bigboy44]

Thanks for posting the info and pictures. Good idea, great work.

Ditto

 

[mhb285]

I like your new seats........

 

[MyothersanM1]

One question I had was why use the hooks at all and not just use the rubber rope like the regular top?

I did consider just threading the rope through the grommets and leaving the rope on the top when removed. Then I thought it would be easier to install the hooked rope after putting the top on. That way I didn't have rope flopping all over and potentially getting tangled on something while fitting the top to the windshield, but either way will work. It is pretty much personal preference.

 

[Ford Mechanic]

Great job guys! I've been kicking around this same idea for a couple months now, definatly going to referance this when I try to do mine!

 

[emr]

Like almost everything we do, Uncle sam already did it, The cckws had a removable rear section, the one you cut off and threw away, then just the bikini was left, Factory issue. I used to drive me cckw 352 all the time like that 10 years ago, it sure is a good ride that way...

 

[Jason O]

Anyone with an M939 truck try the bikini top yet? How did it turn out? I'm wondering how bad the exhaust from the stack will be sucked into the cab. I had planned on making one from scratch, but after seeing the photos I think I'll go with M1's mod. Thank you for posting this M1!

 

[MyothersanM1]

I'm wondering how bad the exhaust from the stack will be sucked into the cab.

If you find you have exhaust issues, put a taller straight stack on to help lift the fumes up and back. The taller straight stack does really make a difference.

 

[Jason O]

Here is my attempt at the bikini top. I cut out the rear section above the window zipper, and cut a strip about 4" wide along the very bottom. I spliced the bottom strip on to the rear of the roof so that it has loops/ attachment points. The rubber rope is tied to the top frame causing the rear of the top to wrap around. So far it has kept the seats dry during tonights storm.

I used HH-66 solvent and glue to splice the top and repair the broken front channel. The rear splice is solid, and i hope the front channel holds.

Went for a ride - not as fun as no roof, but it keeps the sun off my shotgun riding toddler, and will keep the seats dry when we're not using the truck.