DIY: Ultra Low Profile Custom Rack / Crossbars for OEM TE Roof Rails

[rlporter507]

good points

Well, that's why I was asking #Socomanche what roof clearance he got using Series 10 bars on 2" high plates. If you drop it too low, the minute a load deflects the bar it will touch the roof. Dropping the 1" bars 3/4" and you could be getting very close. I think that's what happened to the OP, and he and everyone since him raised the bars up higher (top of the rails at least 5/8" above the side rails).

Also, putting two bars side-by-side will only make them stiffer if they are tied together along their length, or the load is sitting flat on both of them (and the increase in stiffness will only be "additive", meaning it will take twice as much metal side-by-side to make it 2x stiffer). It depends on what kind of load you are trying to design for. I got a substantial increase in vertical stiffness (> 2.5x) just by using a 1/2" taller bar (because of the increased vertical moment of inertia). I designed it that way so I could stand on it.

I think most of the people who've worked on this approach feel the 1/4 round 1" bar is only useful on the very front (unless you've got data to prove otherwise). Like putting an air deflector just on the front of any other rack (and nowhere else). Assuming the air is undisturbed when it hits the front bar, it will most definitely be turbulent behind that. I'm mostly concerned with wind noise, and if I end up with some, I will insert some slot covers or make some kind of deflector for the front bar to deal with it. If you're trying to get the lowest drag, you need something slim and air-foil shaped -- like the factory cross rails.

If you really want it LOW, then you should look at Artec Industries cross rails, which are flush with the factory side rails and have curved bottoms to clear the roof, but the general feedback is that there is a definite tradeoff between slimness and stiffness...

ok thanks for the input, dont want to buy it twice. i was thinking the 1/4 round just for wind noise, not really adding strength. im thinking ill buy just the parts for one bar, and try it to see if i like it. thanks. your set up is the simplest with all parts from the same place. ive seen some horror threads of rust and leaking taking off the original rack, so i dont want to break the seal on mine, probably more a reseal problem than anything else. but i do want a flat surface up there for a sun shade, and other stuff.

 

[itr1275]

f you drop it too low, the minute a load deflects the bar it will touch the roof. Dropping the 1" bars 3/4" and you could be getting very close.

3/4" of deflection? what the heck are you hauling up there a baby elephant?

You have 3 or 4 bars and the load will be distrusted over at least two of them. Even at 200 lbs you will have almost no deflection
This tool will calculate the deflection of profiles under different scenarios.

 

[rlporter507]

hes saying

if you drop the bars 3/4 it will be really close to the roof, and if it deflects from there its to close. not deflecting 3/4

 

[itr1275]

if you drop the bars 3/4 it will be really close to the roof, and if it deflects from there its to close. not deflecting 3/4

That makes sense. Thanks.

 

[AdventureMan]

ok thanks for the input, dont want to buy it twice. i was thinking the 1/4 round just for wind noise, not really adding strength. im thinking ill buy just the parts for one bar, and try it to see if i like it. thanks. your set up is the simplest with all parts from the same place. ive seen some horror threads of rust and leaking taking off the original rack, so i dont want to break the seal on mine, probably more a reseal problem than anything else. but i do want a flat surface up there for a sun shade, and other stuff.

Utility (and cost) is why this approach was so appealing to me. And I needed flat load bars, not curved ones. You can literally bolt almost anything (within reason) to slotted rails. Awning mounts, traction boards, Hi-Lifts, light bars, auxiliary lights, tie-downs (you just need to make sure you order enough Tnuts).

If you don't need the beefiness of the Series 15 rails, Socomanche's approach using Series 10 1" rails (one page back) is also plug and play. 2 or 3 1x3 bars on 6-hole plates, add 1x2's on 4-hole plates if you need additional surface area. If you want to use Series 10, a couple of things to note:

- The rails need to be 1/8" longer because the Series 10 side plates are each 1/16" thinner than the Series 15 plates.

- I recommend that you still use the (DT-045) 45 Series Drop-in Tnuts Leaf Spring I used for the factory frame rails. They fit perfectly. You will need to use the ones with the M6 thread size for them to be plug-and-play with the holes in the Series 10 side plates.

If you need help specifying Tnutz parts, PM me.

One of the reasons I decided to build a stronger rack was that I had been reading a thread about a 4Runner that rolled on its roof in Black Bear Pass, and watched some YouTube videos of the recovery. A local (I presume) commented that the strength of the rolled truck's roof rack probably helped stop it from continuing further down the mountain.

And besides, we're building this for a truck, right?

 

[rlporter507]

good advice

Utility (and cost) is why this approach was so appealing to me. And I needed flat load bars, not curved ones. You can literally bolt almost anything (within reason) to slotted rails. Awning mounts, traction boards, Hi-Lifts, light bars, auxiliary lights, tie-downs (you just need to make sure you order enough Tnuts).

If you don't need the beefiness of the Series 15 rails, Socomanche's approach using Series 10 1" rails (one page back) is also plug and play. 2 or 3 1x3 bars on 6-hole plates, add 1x2's on 4-hole plates if you need additional surface area. If you want to use Series 10, a couple of things to note:

- The rails need to be 1/8" longer because the Series 10 side plates are each 1/16" thinner than the Series 15 plates.

- I recommend that you still use the (DT-045) 45 Series Drop-in Tnuts Leaf Spring I used for the factory frame rails. They fit perfectly. You will need to use the ones with the M6 thread size for them to be plug-and-play with the holes in the Series 10 side plates.

If you need help specifying Tnutz parts, PM me.

One of the reason I decided to build a stronger rack was that I had been reading a thread about a 4Runner that rolled on its roof in Black Bear Pass, and watched some YouTube videos of the recovery. A local (I presume) commented that the strength of the rolled truck's roof rack probably helped stop it from continuing further down the mountain.

And besides, we're building this for a truck, right?

thanks for the help, i understand what your saying. im not going to put that much weight up there, and i like the look of the flush with the top rails look.
ive thought of just buying the steel crossbars, but i like projects.

 

[AdventureMan]

thanks for the help, i understand what your saying. im not going to put that much weight up there, and i like the look of the flush with the top rails look.
ive thought of just buying the steel crossbars, but i like projects.

Yes, I like projects too. I was just about to suggest that you at least buy two 1x3 beams (ends tapped for M6 x 1.0) and four 6-hole plates. That way after your experiment, you would at least have two load bars that are usable (instead of only one).

And then I was going to suggest that you countersink the upper plate holes, use flat head screws, and see how far you could lower the bar by slotting and countersinking the lower plate holes, and I discovered why that won't work:

When you lower a one-inch bar more than 3/8-1/2" below the top surface of the factory side rails, you no longer have enough access to any of the screws (top ones to the cross rails, bottom ones to the side rails) because the access to them are all blocked by the other pieces of metal (i.e., the fastener heads are now all sandwiched between the side rails and the side plates or the beam ends and the side plates). You would need to fab (or buy) brackets that allow you bolt the side plates to the side rails outboard of the cross bars, as the OP did. You might be able to modify/drill some extra holes in a wider Series 10 plate, like this one from 80/20.net: 4123

The other option is to use smaller 1x2 beams and rectangular 8-hole plates.

 

[uh0h50]

I was so inspired by Socomanche's approach, I decided to adopt it, but with a few changes:

- Higher stiffness, load capacity, and beefier construction using 1530 (1.5" x 3") rails instead of 1030 (1" x 3") rails and thicker (1/4") Series 15 side plates
- High-strength M8 hardware on both the factory side rails and the cross rail attachments (because it's so wrong to have to lug two sets of tools around)

The Series 15 rails are 1/2" taller than the Series 10 rails, but laying flat they're also 2 1/2 times stiffer (1530-ULS vs 1030-S). And the slots are wider than the Series 10 to allow larger 8mm (or 5/16") hardware. Yes, they're also a bit heavier; a set of 3 rails with side plates and fasteners come in at a total of 19 lbs. With shipping the parts for 3 rails came in under $145, all from Tnutz.com.

Just like Socomanche's approach, no drilling, filing, or rubbing. There is 1 1/4-1 3/8" of clearance between the bottom of the rails and the roof, and the top surface of the rails ends up higher than the stock fin antenna at the back of the roof (by about 5/8"). One could re-drill the side plates if they wanted to position the rails up to 1/2" lower and still provide adequate roof and antenna clearance.

I managed to use the 45 Series "Drop-in Tnuts w/ Leaf Spring" to bolt the side plates to the factory roof rails with a perfect fit in the rail slots; no filing or washers required. However, armed with M8 bolts they didn't want to "drop-in" to the roof rail slots, so they had to be slid in from the end of the rails. At least the leaf springs held them in place in the slots.

If anyone wants a detailed list with rail specs and hardware, let me know.

p.s. You already knew this in your heart, but black anodized parts are going to get scratched pretty easily. That's what an "ano pen" (black Marks-A-Lot/Sharpie) is for...

Nice work. How is the wind noise?

 

[rlporter507]

exactly what i was thinking

Yes, I like projects too. I was just about to suggest that you at least buy two 1x3 beams (ends tapped for M6 x 1.0) and four 6-hole plates. That way after your experiment, you would at least have two load bars that are usable (instead of only one).

And then I was going to suggest that you countersink the upper plate holes, use flat head screws, and see how far you could lower the bar by slotting and countersinking the lower plate holes, and I discovered why that won't work:

When you lower a one-inch bar more than 3/8-1/2" below the top surface of the factory side rails, you no longer have enough access to any of the screws (top ones to the cross rails, bottom ones to the side rails) because the access to them are all blocked by the other pieces of metal (i.e., the fastener heads are now all sandwiched between the side rails and the side plates or the beam ends and the side plates). You would need to fab (or buy) brackets that allow you bolt the side plates to the side rails outboard of the cross bars, as the OP did. You might be able to modify/drill some extra holes in a wider Series 10 plate, like this one from 80/20.net: 4123

The other option is to use smaller 1x2 beams and rectangular 8-hole plates.

the 8 hole plate would allow to attach to the side rails one in front and one in the rear of the bar. im looking to have the cross bar flush with the side rail, or not more than a 1/2 above. and getting 2 bars and hardware is a good idea. with your suggestions, i believe we are on the same page, and this will work just fine. i have the tools to modify the side plates to lower the holes. thanks for the brain work.

 

[AdventureMan]

Nice work. How is the wind noise?

Finally got a chance to get out of the house and drive with the new crossbars. Only went up to about 65 mph, but I didn't hear any wind noise. Only the rumbly "purring" of the KO2's...

 

[IASTATE01]

I'm curious, how close is the bottom of the crossbar to the top of the side rail? I was just daydreaming and wondered if you could replace the 6 hole plate for a 90 degree angle bracket and then use a longer crossbar (48"-60"?) and have it extend over the top.

Ryan

Finally got a chance to get out of the house and drive with the new crossbars. Only went up to about 65 mph, but I didn't hear any wind noise. Only the rumbly "purring" of the KO2's...

 

[AdventureMan]

I'm curious, how close is the bottom of the crossbar to the top of the side rail? I was just daydreaming and wondered if you could replace the 6 hole plate for a 90 degree angle bracket and then use a longer crossbar (48"-60"?) and have it extend over the top.

Ryan

Yes, that occurred to me; if you're using the Series 15 rails (1.5"), that is no problem. There is about 1 mm of clearance between the top of the side rail and the bottom of the crossbar using all the fasteners I mentioned, so you could use Series 15 inside corner brackets (pointing inward) instead of the 4-hole plate and have the crossbars extend out as far as you need.

However, if you're planning on using Series 10 rails, that is going to be a bit of a squeeze. The fastener gap in the factory siderails is 10mm, and from the top of the gap to the top of the siderail is another 13mm. Using normal 4- or 6-hole Series 10 plates, the bottom of the rail would be below the top of the siderail. If you use a slotted inside corner bracket like this (CBS-010-E) 4 Hole Slotted Inside Corner Bracket | TNUTZ AND you use a plain-faced (not stepped) Tnut that lets the bolt touch the top edge of the gap, that might just be enough to clear the top (this would not work with the stepped leaf Tnuts I used in the siderails because they center the bolt in the 10 mm slot). YMMV.

p.s. The best way to get dimensions of these brackets (if they aren't among the illustrations on Tnutz.com) is to go to 8020.net and search for the 80/20 part number equivalent listed on the Tnutz part description; there is always a dimensioned drawing for the part there...

 

[uh0h50]

I ordered a pair back in September and finally had a chance to install them. Really happy with the results. Honestly can't believe how affordable they are and results in an extremely solid setup. I will say though that the length of the aluminum extrusion + the end joining plates does make the overall width really tight. I'd recommend installing the joining plates onto the OEM side rails first and then installing the extrusion onto the plates.

I just purchased 2 more extrusions/rails with hardware. Can't wait to install them.

 

[Mitcheak]

Terrapod, did you ever finish up your bars? Haven't seen much since this thread got hijacked. Thanks
You can pm if easier, I tried to hit you up but not enough posts yet for me.

 

[Terrapod]

Terrapod, did you ever finish up your bars? Haven't seen much since this thread got hijacked. Thanks
You can pm if easier, I tried to hit you up but not enough posts yet for me.

Nah...ended up making a new Roof top tent instead. :hatsoff:

 

[joshik]

Yes, that occurred to me; if you're using the Series 15 rails (1.5"), that is no problem. There is about 1 mm of clearance between the top of the side rail and the bottom of the crossbar using all the fasteners I mentioned, so you could use Series 15 inside corner brackets (pointing inward) instead of the 4-hole plate and have the crossbars extend out as far as you need.

However, if you're planning on using Series 10 rails, that is going to be a bit of a squeeze. The fastener gap in the factory siderails is 10mm, and from the top of the gap to the top of the siderail is another 13mm. Using normal 4- or 6-hole Series 10 plates, the bottom of the rail would be below the top of the siderail. If you use a slotted inside corner bracket like this (CBS-010-E) 4 Hole Slotted Inside Corner Bracket | TNUTZ AND you use a plain-faced (not stepped) Tnut that lets the bolt touch the top edge of the gap, that might just be enough to clear the top (this would not work with the stepped leaf Tnuts I used in the siderails because they center the bolt in the 10 mm slot). YMMV.

p.s. The best way to get dimensions of these brackets (if they aren't among the illustrations on Tnutz.com) is to go to 8020.net and search for the 80/20 part number equivalent listed on the Tnutz part description; there is always a dimensioned drawing for the part there...

Working on a proj for my 4th gen using the ideas from this thread. Does anyone know if the 8mm 45 series Tnutz w/ leaf spring fit the 4th gen OEM rails?

Also, was going to extend the bars past the rails so a corner bracket is what I would use. However, I was going to go with the 10series as it is quite a bit more for the 15 series (1530 @ 47" is $40 and 1030 @47" is $25). I will need 8-9 bars. Going to make a Frontrunner style rack.

EDIT:
For the corner brackets I was thinking these 2 options:

1. use the 6 hole corner bracket for the 10 series but then use a shim of about 1/4" between the top of the corner bracket and the 1030 slat
2. use a 2 hole corner bracket x 2 per slat per side that way I can space them on the slots on the outer sides of the slat and not have to worry about spacing differences of the 10 and 15 series hardware. I get the height of the 15 series but get to use the 10series extrusions. I would use the gusseted ones too so even more strength.

Thoughts on strength?



Here is a mock up i did using an free online tslot designer. I'd blend this with the corner bracket and maybe secure 3-4 slats to the OEM rails.

Free CAD T-slot Aluminium | Modular Components & Automation

I just used this to mock it up to see how many parts, look, etc. I'm still tweaking the dimensions as well.

 

[smike95]

Been tossing around ideas about building my own cross bars after reading here. Anyone ever seen/used unistrut for crossbars? I’ve got some laying around and could easily weld a flange on each end to mount to factory rails. The unistrut has holes/slots to mount a plethora of gear and the weight rating is well over the capacity of the rails. Am I overlooking something?


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[itr1275]

Been tossing around ideas about building my own cross bars after reading here. Anyone ever seen/used unistrut for crossbars? I’ve got some laying around and could easily weld a flange on each end to mount to factory rails. The unistrut has holes/slots to mount a plethora of gear and the weight rating is well over the capacity of the rails. Am I overlooking something?


Sent from my iPhone using Tapatalk Pro

I haven't seen it but it seems possible. Also, f it's the right size you can use the Tacoma bed accessories. The bed rails are the same size as some uni-strut or superstrut.

The downside might be the weight and it's not as aesthetically pleasing as extruded aluminum.

How will you attach it to the rack? You might need an "L" style bracket and let is sit on top of the bracket?

 

[smike95]

How will you attach it to the rack? You might need an "L" style bracket and let is sit on top of the bracket?

I was thinking of welding some 3/16 flat plate on the ends of the strut. Then making some inserts out of 1/4 by 1-1/4 strap that will slide into the rails. Tap a couple holes in those and should be super strong. What’s the benefit of raising the cross bars above the rails? Trying to decide if I want to mimic the design of LFD cross bars or set them down flush with rails.


Sent from my iPhone using Tapatalk Pro

 

[itr1275]

What’s the benefit of raising the cross bars above the rails? Trying to decide if I want to mimic the design of LFD cross bars or set them down flush with rails.

Buried, somewhere in the thread are some pictures of the extruded aluminum flush with the side rails. It look very sleek, but the curve of the roof leaves very little clearance for any deflection when loaded.

I think someone even did some deflection analysis with the CAD drawings.