Survey, are the holes threaded on your frame rail to mount rock sliders?
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Jjbailey930
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New member - TRD Sport Premium owner. Got a set of OEM running boards from a local. There are existing 12mm bolts in the chassis where the board brackets fit. Check to see if those match your installation.
All the oem ones bolt to the body not the frame. This is about rock sliders which bolt to the frame not the body. Some frames have threaded holes already ready for rock sliders, and some don't.
Jjbailey930
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The nutserts will hold up on the road and through general use (stepping on them), but if you're going to use the rock sliders for off-roading, you should consider through bolts.
Through bolts are stronger than nutserts when it comes to frame rails that dont have existing holes. It's a process to prepare the holes, but it will offer a much stronger and reliable rock slider on the trail.
Why:
Load path: Through bolts clamp the outside frame rail with large washers or a backing plate. The load spreads over a larger area. In a perfect world, you would have a crush sleeve inside the frame rail to support the load even more, but we don't have that access, so large square washers, 5/8" or 1/2" bolts, and Nylock nuts are the true solution for our use case.
Clamp force: Through bolts accept higher torque, which raises joint preload and friction.
Fastener strength: A 5/8 in grade 8 through bolt in single shear carries several thousand pounds more than a typical steel rivet nut of the same size. Expect roughly 3x higher or more shear and pull resistance.
Serviceability (this is a huge one): Through bolts can be re-torqued and inspected. A spun nutsert usually requires drilling or cutting to repair/replace. You can only thread bolts into a nutsert so many times before it will spin out on you. Which ultimately leaves nutserts in your frame rail, requiring you to install new nutserts. They're just a pain in the ass.
Use nutserts only for light-duty attachments like steps. For true slider loads, use large diameter washers, and grade 8 or 10.9 hardware sized M16, M12, or 5/8" to 1/2".
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5G6G4R
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@5G6G4R
Blind bolts are better than nutserts but still inferior to through bolts.
Like nutserts, structural blind bolts anchor to a single point on the frame rail wall, so impacts concentrate bearing on one point. Through bolts pass both walls with backing plates, which put the joint in a clamp and spread the load across both walls. Do not confuse that with double shear; a through bolt is still single shear.
Also, most rivnuts and light blind fasteners cannot be torqued to the levels of grade 8 or class 10.9 nuts/bolts, and if over-torqued, they will spin or collapse inside the frame rail. That limits clamp force, so big hits on rocks will cause slip, and then the insert can spin or pull out of place... then the preload is lost, and the joint goes loose. Blind bolts can clamp harder than nutserts for sure, but they still load a single wall and are more prone to failure compared to a through bolt.
Use through-bolts with heavy-duty square washers and nylocks for true slider loads on these 4Runners without threaded holes.
Blind bolts are better than nutserts but still inferior to through bolts.
Like nutserts, structural blind bolts anchor to a single point on the frame rail wall, so impacts concentrate bearing on one point. Through bolts pass both walls with backing plates, which put the joint in a clamp and spread the load across both walls. Do not confuse that with double shear; a through bolt is still single shear.
Also, most rivnuts and light blind fasteners cannot be torqued to the levels of grade 8 or class 10.9 nuts/bolts, and if over-torqued, they will spin or collapse inside the frame rail. That limits clamp force, so big hits on rocks will cause slip, and then the insert can spin or pull out of place... then the preload is lost, and the joint goes loose. Blind bolts can clamp harder than nutserts for sure, but they still load a single wall and are more prone to failure compared to a through bolt.
Use through-bolts with heavy-duty square washers and nylocks for true slider loads on these 4Runners without threaded holes.
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@5G6G4R The frame rails aren't thick enough to tap. We have about 1/8" to 1/4" walls, which dont provide enough material for proper thread engagement for say, a 5/8" bolt. And if you're in the position to drill and tap something, you might as well drill a hole in the other wall of the frame rail and slide a bolt through.
I don't like the idea of squeezing the frame box from the outside with nothing in the middle but it's for sure better than any kind if insert for all the reasons given plus the simple fact that the 14mm is all bolt instead of a nut with an 8 or 10mm in the middle.
I have a tow hitch kit on another car that came with big square nuts with a steel wire spring clip to fish the nut into the frame box from the end to position it to the spot behind the hole.
I would prefer that myself if there was some way to do it without drilling an excessively large hole on the other side or somewhere else.
Barring that, I'd want a very large back plate, like one big plate that covers two holes and the plate isn't flat but bent to curve around the top & bottom of the frame, and maybe one on the front too. The two plates sould not touch each other, they just wrap around the top & bottom enough so you're transferring load to the top & bottom instead of only squeazing the middle of the unsupported vertical walls. (actually thinking a little more I'm not sure that would help much since it's not a 90 degree but a radius. It probably wouldn't be any better than just a flat plate, so a lot of work for nothing)
Even if the numbers and actual experience says it's fine, I just cannot make myself accept squeezing the sides of a box like that. My brain just says "I don't care la la la I can't hear you do not do that." haha
I have a tow hitch kit on another car that came with big square nuts with a steel wire spring clip to fish the nut into the frame box from the end to position it to the spot behind the hole.
I would prefer that myself if there was some way to do it without drilling an excessively large hole on the other side or somewhere else.
Barring that, I'd want a very large back plate, like one big plate that covers two holes and the plate isn't flat but bent to curve around the top & bottom of the frame, and maybe one on the front too. The two plates sould not touch each other, they just wrap around the top & bottom enough so you're transferring load to the top & bottom instead of only squeazing the middle of the unsupported vertical walls. (actually thinking a little more I'm not sure that would help much since it's not a 90 degree but a radius. It probably wouldn't be any better than just a flat plate, so a lot of work for nothing)
Even if the numbers and actual experience says it's fine, I just cannot make myself accept squeezing the sides of a box like that. My brain just says "I don't care la la la I can't hear you do not do that." haha
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