Howdy Folks...

Been on this forum...mostly as a lurker learning about my 4Runner. But at home, I am an industrial designer and an inventor of sorts. Simply put, I love tinkering.

Seeing all the ridiculously expensive solutions out there for racks made me think about another potential solution. But instead of offering it for sale, I prefer help those do it themselves.

Now...with that said - A disclaimer. I am not a manufacturer. I am not a professional mechanic. By doing this - you are on your own. Know that I am not responsible for what you do to your vehicle.

So here goes:

THE IDEA:

JUMP TO THE FABRICATION HERE: Crossbar fabrication Post

On my personal off road trailer. I built an aluminum extrusion based rack. It uses the very same rails that are on the Prinsu aluminum 4runner roof rack.

I was curious if the rails fit the height and space needed between the rail and curvature of the roof.

Here is the test fit with a total clearance of approx 1/2"








Next I worked up a design that allowed an easy installation while also providing a robust mounting option. The solution is an aluminum mounting plate adapter that bolts directly to the crossbar with 1/4-20 bolts that have been countersunk into the mounting plate.

The mounting plate is then bolted to steel plates tucked into the stock rail tracks. This is similar to the stock Toyota crossbars. The plan is to maintain a flush surface at the top of the OE rails and the crossbars.


Here is the design (side elevation):

Subscribed. Thank you for thinking this up.

You bet. I have ordered the parts and should be receiving them in the coming days. Stay tuned as I work up the final prototype.

Parts Sources:

http://www.tnutz.com or http://www.8020.net (tnutz is cheaper and their shipping is crazy fast)
http://www.mcmaster.com
Home Depot (misc raw materials, etc)

C

What's the max carrying weight of the side rails... and would the extrusions flex at all, causing them to bow in the middle and make contact with the roof?

My guesses are no, but wanted to check!

Great idea. Subscribing and interested.

My first thought as well

Stock rating on the side rails is supposedly 150 pounds evenly distributed. The rails I am using are presently being used on the full length Prinsu roof rack. I am also using these very same rails on my off road trailer. The trailer is presently holding about 125lbs with zero deflection.

Note - the rails chosen are the 1x3, which will offer a bit more beef. Lastly, this rack would be considered a light duty version. It will not be large enough for a RTT.

Examples:

nice! keep going. I want to see how much the bars can take.

Sweet websites you linked man thank you.

Hello:

I am interested in this workup. If I recall from when I powdercoated my rails the stock side rails (front to rear orientation) are not parallel but start maybe an inch narrow and widen toward the rear of the vehicle. Something to bear in mind.

I would love to have a total of 4 cross rails front to back but have been stymied by the non-parallel nature of the side rails.

Best wishes, Steve.

I'm all for budget builds, watching intently. Thanks for sharing with us!

Hey Steve,

Oddly, my rails are indeed parallel. The width across is 40.5". I am aiming for 4 rails for light storage on my travels. Once the 3D CAD design I am putting together is complete, I will post it up.

C

Correction: After further investigation, I found out that the stock 'crossbars' are rated for 150lbs. However IMO, that is a good starting point. The extrusion used in the stock crossbars are nowhere near the bars I am planning to use.

More to come. Stay tuned.

C

8020 has a deflection tool if you want to check your center clearance

As promised. Here is the working drawing for the mounting plates / crossbar attachment details.

Parts shown:
- Qty 1: 40.25" x 1 x 2 Tnutz 10 series extrusion profile
- Qty 1: 4" x 1.5" x .125" aluminum plate
- Qty 1: 4" x 1" x .125" Steel plate (cold rolled stock)
- Qty 2: Stainless hex flathead 1/4-20 x 7/8" bolt (for best results, get the versions with locking thread inserts)
- Qty 2: Stainless hex rounded cap 5/16 x 1/2" bolt
- Qty 2: Stainless 5/16 flat washers
- Qty 2: Stainless 5/16 lock washers

NOTE - THIS IS x2 PER CROSSBAR.

Notes: I am choosing to go with the 1x3 10 series crossbars for more mounting tracks and surface area. I am planning to create a total of 4 crossbars.
In addition, I will be mounting a 1/4 round 1x1 to the front of the 1st forward rail for airflow. This is all optional.

More: I am planning to cut 5/16-18 threads into the steel backing plate. I am also planning to cut 1/4-20 threads into the 2 crossbar holes on each end.

Costs so far:

Crossbars: Total of 3 1x3 10 series, 1 1x2 10 series, and a 1/4 round 1x1 10 series ordered: $86.21 shipped
Hardware: Includes all bolts, washers, and steel and aluminum stock via Mcmaster - $92.95 shipped

Total project parts cost: $179.16