Drill thru roof rack install

[two7overland]

Hey guys, I've got a smittybilt rack on my truck that I've attached to some cross bars to temporarily affix it. Well I recently purchased the correct mounts from smittybilt to anchor it to my roof, and since its warming up out here I think its about time to install it. Any tips to keep it as water tight as possible? I'm a little anxious about taking a drill to my roof lol

 

[smritte]

Drilling sheet metal can be a pain. Years ago, at the dealer, the cars came without roof racks and some came without the holes to mount one. I had to mark, drill and mount quite a few over the years. If I had to guess, well over 100 installed.

First you want 2" masking tape. I do all of my marking on that. I use two layers incase something slip's so I don't scratch
If your installing Riv Nuts (crush nuts), you really want the tool for it if your doing more than a couple. There's a technique that uses a bolt and a couple of nuts, it works but can be a pain.

Mark all the holes and set the rack on the vehicle to make sure you measured correctly. If its hard to put up and move around, cover a larger area in tape so you don't scratch.

Depending on the vehicle, your headliner will be between 1-2 inch's below the roof. I drill small pilot holes first, then lay the rack on those and make sure all the holes are good. If you don't own a drill stop (I don't), wrap a tight layer of masking tape around the bit leaving about 1/2 inch of bit sticking out. I normally wrap about 1/2 layer on my bits. If I drill a bunch of holes, it will squish the tape down some. If i dont put enough, I end up having to rewrap it to keep the end short.

Now the fun part, the main holes. I prefer a UNI bit here. If your holes are anywhere near or bigger than 3/8 inch, the hole wont be round and you have a chance of it leaking.
When all the holes are done, I install the Riv Nuts (or whatever your fastening with) with a small amount of RTV or silicon sealer then wipe off the excess when installed.

 

[Truckee]

Does the rack use rivnuts as fasteners? If so, I'd certainly find a different rack design or method... unless it will be a really light load.

 

[Billiebob]

What are you driving ??
Drill thru a Wrangler, no roof liner, fiberglass roof, no issues.
What do you own ?

 

[smritte]

Does the rack use rivnuts as fasteners? If so, I'd certainly find a different rack design or method... unless it will be a really light load.

Been using Rivnuts for years. Their fine. Factory racks use the same thing with some being just rubber. If I was going to put an eye bolt through a rivnut and tighten with a ratchet strap, that would be different.

What are you driving ??

His Avatar looks like a full size truck

 

[Truckee]

I have personal experience with rivnuts, roof racks and sheet metal and they didn't hold. But here is more...

 

[Old Tanker]

I have personal experience with rivnuts, roof racks and sheet metal and they didn't hold. But here is more...

Pop rivets and rivet nuts are different things, no?

 

[smritte]

Pop rivets and rivet nuts are different things, no?

Yes

I have personal experience with rivnuts, roof racks and sheet metal and they didn't hold. But here is more...

I'm sure you had some issue with them and obviously the guy in the video is an expert. Too bad he doesn't really say exactly what happened, he only goes on about load. That video is a perfect example of someone who shouldn't be modifying something. If you don't understand how it's designed, you shouldn't modify it. That is exactly why people shouldn't be allowed to modify things without training. Everything has a limit and if you exceed that, you shouldn't be allowed to blame anything but yourself.

If the Rivnuts are not the proper size, not installed correctly, yes you can have an issue. If you load a rack correctly and slam into a bridge you will tear your metal, properly installed and sized rive nuts wont pull out. The force is sideways. Put all the weight high and you change the lines of force. In the shop I would see people using pocket screwdrivers as pry bars them blame the screw driver when it bent.

So this thread started with someone asking about installing something. I have literally decades of experience with these. You had one issue and found a guy on the internet who said "I'm not an expert in any way but" so that makes them bad.
If you had a rack come off and the rivnuts pulled out, they weren't installed properly, there weren't enough, and/or the load was too high. Their designed to hold something flat using some down force. Even if you went under the sheet metal with washers you can still rip things apart. Ever seen someone in a collision with a High Lift jack mounted to their hood? It turns into a projectile. Again, someone modding something they don't understand.

 

[Grendel]

Watch-out for airbags. I recommend dropping the headliner. There where a few tundra guys that drilled their airbags when installing.

 

[Truckee]

If the Rivnuts are not the proper size, not installed correctly, yes you can have an issue. If you load a rack correctly and slam into a bridge you will tear your metal, properly installed and sized rive nuts wont pull out. The force is sideways. Put all the weight high and you change the lines of force. In the shop I would see people using pocket screwdrivers as pry bars them blame the screw driver when it bent.

So this thread started with someone asking about installing something. I have literally decades of experience with these. You had one issue and found a guy on the internet who said "I'm not an expert in any way but" so that makes them bad.
If you had a rack come off and the rivnuts pulled out, they weren't installed properly, there weren't enough, and/or the load was too high. Their designed to hold something flat using some down force. Even if you went under the sheet metal with washers you can still rip things apart. Ever seen someone in a collision with a High Lift jack mounted to their hood? It turns into a projectile. Again, someone modding something they don't understand.

Sorry, I am unconvinced rivnuts/nutserts are good for use with expedition racks that carry heavy loads. The biggest problem with them is they'll often spin when trying to unbolt them.

My roof is rated over 400 lbs capacity. I don't carry that much but I want the safety factor. I currently have 8 captive nuts holding my rack. Each captive nut is in a reinforced part of the roof. How many rivnuts and what size do I need for equivalent strength? 16? 24? You want me to drill 24 holes in my roof? haha.

Rivnuts are designed for sheetmetal thickness. Now what if I were to double or triple layer the sheetmetal? Could I get away with fewer rivnuts and still secure the rack? Sure. And there lies the issue. Most of the light load racks using rivnuts are fastened to just one layer of thin sheetmetal.

I've used riv-nuts with success on blind installations when I couldn't access the back, like in a frame. If one can access the underside of their roof, I'd suggest a different mounting system. Rivnuts are last resort.