Non-truss lifts that depend solely on the concrete pour scare the you know what out of me. I saw your picture and kept scratching my head saying - they depend on the structure of the floor for resisting that much lever-arm? OMG. Who poured the floor, how well was it poured, the concrete mix? If I wasn't there, I'd be hesitant to trust my life to hoping the floor was good. Am I missing something?
I have not gone to their site yet, but this morning I saw a Summit sale ad and that same lift was there and I looked at again, and said again - What holds it up? I assume they are both bolted to the floor with long concrete anchors? I see wheels.
Non-truss lifts that depend solely on the concrete pour scare the you know what out of me. I saw your picture and kept scratching my head saying - they depend on the structure of the floor for resisting that much lever-arm? OMG. Who poured the floor, how well was it poured, the concrete mix? If I wasn't there, I'd be hesitant to trust my life to hoping the floor was good. Am I missing something?
Look at Max Jacks web site. Check out the FAQs. Each anchor bolt and there are 5 per lift rated to 20,000 pds each. I put them originally in 4.5 " concrete that isn't reinforced and one side cracked with my 49 Chev on it because the concrete had cuts in the cement for expansion? The other side was good. They say you need 5" or more and I would trust that. Since I dug it out for thicker concrete, 8", I bolted the anchors on then welded steel bars to them, took them off the lift then when the pour was going in I positioned them in the concrete so the anchors were flush with the leveled floor. WAY overkill.
Well I was curious so I went next door to the mechanics shop and looked at their lifts. The tall big boys they have are only bolted into the ground as well? No cross bar on the floor and the only thing over head was a 3/8" rod that served as a shut off if you go up to high with it?? They owner said they are lag bolted down in 8" concrete and they had 8 bolts on each foot.
So I guess this is "normal" but I think it still seems a bit weird but I'm not an engineer. Hell im barely a car builder.
Bolts can fail many ways. There is pull, twist, shear, and bend to name the most common bolt failure methods. Each have differing rating values. My guess, in this case, it is more "pull failure" we'll need to be concerned with. But we have at least 3, maybe 4, more variables, at the very least, to consider in this application. The interface of the bolt into its threaded "insert" portion, the interface of the threaded insert with the concrete, the thickness of the concrete, and the quality of the concrete. That's the engineering side. You can have subsets of each, like on the interface of the insert and concrete; was the hole drilled into the concrete in spec with the need of the insert? Or did the insert "flare" as it should have when driven into the hole? You'll never really know.
Anyway, I did watch a lot of YouTube videos on lift failures and didn't see too many where the lifts pulled out of the floor. Only one I can recall and it was a lift used on a vehicle far out-of-range for the rating of the lift. Most other failures were ID10T moves.
I think you can safely assume if you drill a hole and don't break though to earth or gravel, and there are no nearby cracks already, then you can get one of these lifts and follow the instructions to a satisfactory end. Certainly not a process you want to skimp on, or ignore any warnings or evidence of something not-going-just-right. But if everything happens as their instructions say they should for a sound install - it should be safe. This lift anyway.
Note, one video I saw was testing a lift rated at 10,000 lbs, but indicated the lift was probably no good for any more than half-of that. A 10,000 lift has to survive 15,000 without failing to get a 10,000 lb rating. So be leery of the cheap stuff. This company knew the lifts failed at the 10,000 lb rating, yet refused to change the rating.
Last edited by Luva65wagon; July 21st, 2016 at 10:51 AM.
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Originally Posted by Luva65wagon
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