DIY prinsu style shell rack

I'm also in the middle of a cab rack project.. I'll post pics when finished

 

I taped cardboard to the side of the truck and traced the roofline to get it close. Then i cut that and it in the drip rail to refine the shape.

 

is that 3/4 inch wide flat bar?

 

Sending the design for cut tomorrow AM.

Can someone tell me how big is the diameter on standard ratchet straps' hooks (often rubber coated)? I made my slots 3/8 in order to use them with bungee cords, but maybe ratchet straps would fit in them?

Standard ratchet straps like these:

Badass Moto Ratchet Straps Heavy Duty Motorcycle Tie Down Straps. 1.5 in X 10 Ft. 3300Lb Break Str. Heavy Duty Ratchet Strap Set. Motorcycle Straps. Cargo, ATV/UTV Tie Down Straps. Hi Vis Orange

https://www.amazon.com/Badass-Heavy-Ratchet-Straps-Padded/dp/B016QR3C4Q

Thanks

 

The ones i have in my truck are 3/8" ive seen smaller and larger. 1/2" would be safe i'd say

 

Thanks, they were 3/8, that seems to be the standard but could be tight, but .5 is better...

Here's current final design now with 05.

I've added holes to mount rear bar vertical (or extra bar).

 

Do you know what Nuts work best in the Thule Tracks that come on Shells?

Looks like there are 2 options :

https://www.etrailer.com/Accessories-and-Parts/Thule/853-5147.html

https://www.etrailer.com/Accessories-and-Parts/Thule/853-2106.html

 

If i were planning a permanent install or one meant to max out the load capacity I would increase the length of the t-slot nuts used (maybe a 3-holer with 2 outside for nut/top plate and center for rack attachment). I've noticed deformation of the slot around the stock Thule nuts. The track edges are very thin and seem to be a weak link. Possibly a good thing if that's where you want it to fail, perhaps not. Would definitely use every screw hole provided in the track/shell connection as well.

 

How's it look!? Also hows the cabrac design coming along?

 

I had to do small changes due to the laser cutting constraints. It's been in their production queue since yesterday morning and takes 5 days so I expect to go pick it up next Wednesday, fingers crossed.

For cabrack I am still figuring things out for the curve design (I want it to hug the roof perfectly), I am either scanning the truck (tried once without any good results) or buying a 3D model. I found a very accurate one online, but it doesn't have the mounting hole precise location so that will be a challenge. WIll keep everyone posted.

 

I would think it would be a good idea to use longer feet then since the feet are the only part of the rack that contact the tracks.

If you wanted to make a really strong and low profile rack you could run 1" x 1/4" thick aluminum strips the length of the track and use counter sunk holes for everything. You would have to install it to the rack first with countersunk Allen Bolts and T nuts in the cross bars. For the Track you could use as many nuts as you would like. With every 47" channel making contact with the mount/track you could probably reduce the side plate from 3" down to 2" or even 1.5".

 

Nice!! Have a pic of how it's mounted to your roof?

 

Its not right now, but should be tomorrow.

 

The tracks are the failure point, as shown here. A downed power line tore my roof rack off. Think it is by design the weakest point.

 

Well got an email at 4:50 pm and the tracks are ready, will pick up Monday.

 

I'm also going to have to make my own for my access cab. Kinda annoying since AT Habitat, I have to go custom since Prinsu is too slow to make one with a notch. DIY is good tho, cheaper too.

I get to break out my CNC router. I just need to figure out a way to get a 4x8 sheet of 3/16" 5052 home. I just can't decide if I want design it with mounting tabs and then use a press brake to bend, or use Aluminum Angle Bracket. It's probably more efficient to use Angle Bracket since I can get more side rails cut out per sheet.

 

Cut it to 6' since there's nothing longer than that on either roof. The 2' x 4' off cut can be used for deflector material.

 

I'm also debating bending vs brackets. If the brackets are attached to the crossbars then you are stuck with fixed positions for 3 of the crossbars. If you use brackets attached to the side rails then you whole rack holds by bolts in shear strength... Which IMO is not very good long term.

So for now I'm still leaning towards bending tabs, but open to discuss ideas.

 

Considering making one of these, this solution to mount the rack was suggested elsewhere on TW. it's hinged design eliminated problems with the sloped roof. You could use some hardware to mount to a track, and the kit comes with 6 mounts.

Smittybilt Adjust-A-Mount Brackets Q Qty: 6

https://www.amazon.com/Smittybilt-AM-6-Mounting-Brackets-Requires/dp/B00AQFEBE0

 

Finally finished the cab rack and the sides for the cap rack. Just need more extruded bars.