Rack Floor idea...

[off-roader]

OK, I've been asking a few questions on here recently about Tslot tubing and stainless 1/4-20 eyelet availability. Here's what I've been thinking...

I currently own a 60" long Garvin Wilderness Trails Roof Rack. Illustrated below.

I want to lengthen the rack but the cost of new side pieces and the floor bars is quite prohibitive (>$300). For $80 I had new longer side bars made locally. For the floor I was thinking of simply buying long 3/4" square tube & mounting it like the original floor... but after seeing the Equipt racks (Eezi Awn & Front Runner) and their use of extruded aluminum T-slot tubes I realized that would be a better way to go. Unfortunately the cost of the Eezi Awn & Front Runner rack is well beyond what I'm able to do right now.

Instead, I realized I could do something similar using readily available extruded aluminum tubing (made for commercial/industrial shelving & equipment mounting systems). So I'm looking at using six 72" x 2" x .75" (LxWxH) T-Slot tubes (80/20 Corp's 2012 tubes).



This way I still have a very solid & flexible attachment point anywhere along the full length of the floor.

I could get six 72" pieces which is ~$140-150 shipped to my front door. 1/4-20 Stainless T-Slot Nuts are available from 80/20 and various local resellers (Grainger, etc) & Stainless Eye Bolts are also available as well.

Any thoughts or concerns?

Unfortunately neither the EeziAwn or Front Runner racks are in my budget range or they'd already be on my roof.

TIA,

Ray

 

[off-roader]

Nearly 150 views and nobody had any concerns, comments or ideas?

 

[AndrewDM]

My concern would be if those t-slot tubes could support the weight with only two attachment points to the rack. I think they are designed to be mounted on a flat surface that would provide support and they may buckle under load without that support. Just my thoughts.

Andy

 

[off-roader]

Good question. While I will likely only put relatively lite items there, I've asked 8020 for its weight bearing stats.

 

[4xdog]

You're planning to replace the box-section floor slats now with the aluminum extrusions? Sounds pretty simple. If you're happy, we're happy -- the deck on a rack isn't critical.

If you're looking for other ideas, one could use synthetic wood (there's a thread on that for a LR and it looks great) or you could use aircraft floor tie down tracks for near-infinite mounting options.

By "flexible attachment point" I'm assuming you're using it in the sense of "versatile", not "easily deformed", yes? If the unsupported length between the cross rails or overhanging the ends is too great, it could flexibly in the second sense.

Don

 

[off-roader]

After Andrew's comments I rang up 80/20 (awesome cust service btw) and after speaking with one of their tech's, we determined that with the rack design, these bars would deflect ~2.5" if I stood rightin the middle of 2 of them (or 4.5" if I stood on just one)... So instead, I'm looking at their 1"x1" stock instead which are far stronger & would only deflect 1.5" if I stood on one.

 

[off-roader]

Thanks for the ideas Don. The design of the rack probably wouldn't support the synthetic wood floors. I've worked with it before and its even more flexible than the aluminum unless you have supporting cross members. In my case its a 5' unsupported span which is too much for that.

As for the aircraft tie downs, I've considered that as well but I think the t-slot solution will be fine. The reality is, I'll most likely only be putting light weight things up top that are more convenient to store there than inside.

i was considering the aircraft tie downs for use inside the rig but in fact I may go with the Tslots in there instead as well... It will depend on how the rack turns out.

 

[AndrewDM]

After Andrew's comments I rang up 80/20 (awesome cust service btw) and after speaking with one of their tech's, we determined that with the rack design, these bars would deflect ~2.5" if I stood rightin the middle of 2 of them (or 4.5" if I stood on just one)... So instead, I'm looking at their 1"x1" stock instead which are far stronger & would only deflect 1.5" if I stood on one.

That would be the type of load bearing support you will need for a light load on a roof rack. I think the 1x1 will work great, but you will have to install more to get the coverage of the 2x.75.

Andy

 

[off-roader]

That would be the type of load bearing support you will need for a light load on a roof rack. I think the 1x1 will work great, but you will have to install more to get the coverage of the 2x.75.

Andy

Agreed although the rack normally only comes with eight 3/4" square tubes so I tink I'll be ok with 8 of these.

 

[off-roader]

tslots ready to be mounted. Will simply use 1/4-20 Carriage bolts that will go down through the 2 bars on each end and will be fastened with a nut and washer from the bottom.

 

[Colonal Angus]

Looks great

 

[AndrewDM]

tslots ready to be mounted. Will simply use 1/4-20 Carriage bolts that will go down through the 2 bars on each end and will be fastened with a nut and washer from the bottom.

That turned out nice. I am thinking of using those to build an internal rack for my Jeep.

Andy

 

[off-roader]

Looks great

Thanks.

That turned out nice. I am thinking of using those to build an internal rack for my Jeep.

Andy

I bought these from 80/20 Inc. (www.8020.net) and they have a calculator to help you determine roughly how much weight they'll be able to handle. It shows you how much the bar will deflect depending on the weight put on it and how the weight is distributed (all in 1 spot mid-span, distributed evenly, on one end with the other end fastened to a structure).

The extrusion sizes & shapes vary and I chose mine based on what I wanted.

HTH.