Ultralight
Grenadier Owner
Hi Ultralight, Wow, thanks for posting about the torx flange head bolts. They look even more substantial than I was thinking they would be. Not an engineer, however utilizing brackets like Leitner has designed, which appear to connect to 2 bolts per bracket and onto the tube should be good for most applications. If one wanted to spread the load onto the roof, it would not be too difficult to simply add some stiff rubber shims under a rack or cross bar to pick up where the rubber strips are. I have reached out to Bernard Leitner to get the exact measurement of how high the top of his bracket sets above the 4 rubber roof strips. Will report back once I speak with him. DaBull
The roof strips are plastic not rubber.
That explains the hole on the front of the mount that looks like a grub screw to lock the grab handle.
See my post above. The bars aren't carrying the load, the brackets are screwed to the roof.
With little, tiny screws that Ultralight shows above. I have stronger fasteners on my Fat Bike.
Yes, I stand corrected. The roof strips are plastic, which I first reported back on the forum long enough ago to forget. Another senior moment, of which I have earned every one of them. DaBull
Pick your poison. 16 of those "tiny screws" that @Ultralight says should take "significant force" screwed into the roof frame, or however many bolts the stock rack uses (edit it does look like 16 stock) to hold the pinched gutter which people have shown to have considerable flex.
Hi Tom109, It looks like the solid shank portion of the M6 Torx bolt as noted above is just shy of 1/4" thick. If you have two per bracket, that seems fairly stout, especially considering they are graded 10.9. It Take a lot to shear them at the solid shank portion. From what I have looked up, it would take 18 kilo-newtons or 4046 pounds to shear a single bolt like this. I would imagine having 2 bolts would double the total shear for one of Leitner brackets to 36 kilo-newtons or 8092 pounds. Not sure what down or up forces a rack has on a rough road. If someone knows, then we might have an idea if this bracket set up is adequate for it's intended purpose. Another thing to take into consideration is how stout the fixed nut the bolt goes into is and how well it is fixed to the Grenadier. DaBull
That's a lot of force. One mount could theoretically support the whole static load capacity of the roof and then some. I suppose, though, since I bought a frontrunner rack in the past based on a video of them lifting a jeep by it, the tops of our vehicles, and the bolts we put in them, are stronger than I have always given them credit for.
The gutter issue has been blown out of proportion. People will see this now that vehicles are off the computer screen and in owners hands. If a poorly designed foot is used, or positioned poorly along the gutter line, then yes, it could flex. But mine is rock solid, zero concerns at all compared to the idea of 16 little screws. To me, that is as silly as the early Range Rover racks that sat in the gutter and were bolted through from below.
Agree that it's overblown but there's still small bolts mounting it. Either way, even though I'm no engineer I feel like bolts directly into the roof frame is stronger than the gutter.
The issue could be resolved with a torture test simulator.
These are a much better design than Blacksheep as the load is transferred to the body via the fixings and doesn't rely on the roof for load bearing. Before I bought them I'd be finding the load rating for the individual cross bars. The Ineos Rhino rack dynamic load on each individual "foot" is 18.75kgs
