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installing 2-post lift?

15K views 30 replies 15 participants last post by  KesekiSupra 
#1 ·
I've been shopping for a 2-post lift but I'm reading various different things about installation requirements. Most vendors web sites say 4" 3000psi concrete is all that is required. The anchors that come with most installation kits only go in about 3 1/2" deep. I don't know why, but I can't seem to wrap my head around the concept of only a few anchor bolts keeping the whole thing from tipping over forward or backward or collapsing toward each other. Am I just being irrationally paranoid or have they been installing these lifts with a few short anchor bolts for decades without incident?
 
#2 ·
Well I've seen one post rip out with 4" deep bolts....not pretty when a very heavy Jeep Wagoneer(sp?) is on said lift. In the shop we use 6 inch anchor bolts on a 2 post. Don't ever use the mounts in the package. Across the board it seems to be the same, high quality equipment all the way up to the smallest/most important thing.
 
#3 ·
The necessity of a permit analyses the concrete. It specs the pierce-strength based on load.

You could calculate by the area of the foot of the lift desired it's load distribution and approximate its pierce.

There are specs for nearness to cracks and others but since it's your safety you be fine.

I've erected numerous types of machines and handling equipment for industry and there is a respectable safety record.

It will change the way you work, too. At first I gave the vehicles the "ferris wheel" up and down until I learned to sequences what to do before lifting the car and what to do after...
 
#5 ·
yep, you need some pretty deep good concrete for a 2 post. but it actually depends on what type of rated lift you are using. we have a 10,000 lb lift and a 15,000 lift, both use 6" bolts, cept the 15k one has a lot more of them. im sure 3 1/2" is fine if your using say a 7k lift or so, but it actually has more to do with the concrete than the bolt. it can be the strongest bolt in the world, but it wont matter if ur floor cant keep it in.

btw, my 4 post drive on, that i have in my home garage isnt even anchored to the floor. never has been. works fine, then again, it cant exactly tip over or anything :D
 
#6 ·
Thats what I'm wrestling with. I have a 4" slab, 3000psi - exactly the minimum. I like the idea of the 2 post because its less "in the way", but on the other hand, you gotta fuss with making sure the car is properly centered and the lifting arms are properly positioned every time even if all you're gonna do is just change the oil. Goof up and the whole thing could topple over. The 4-posters by contrast seem less risky in a lot of ways but they take up so much room and are not nearly as convenient for suspension and brake work. To get near the same use out of a 4 post, I'd also have to get the rolling jacks and that adds another $1,000 so I'm up to $3,000 vs. about $1,500 for the 2-post. I have a 2nd job over the summer to make some play money and a 4-post basically spends all of it.
 
#7 ·
Hey Phil,

I share your concerns regarding the mounting of a two post lift. Look at the size of the mounting plate at the base of the posts. Maybe they are about 12" x 12" and have 5 or 6 4" bolts anchoring to the concrete. You could look into getting some heavy plate, maybe 18" x 18" , that you could mount to the floor, then weld or bolt the 2 post lift base onto this. Spreads the weight of the lift a little farther outward. Like others have mentioned, more bolts is better. Still, if the manuf says the 4" concrete is adequate, then probably is.
I wouldn't store a car on a 2 post lift though, at least not a home model.

I went with a 4 post lift due to my particular needs, and ceiling limitations. With a 8 ft ceiling, there is almost no way to get a 2 post lift installed. Even a 4 post lift only gets the car about 3-4 ft off the ground. I got the rolling jack option too. Expensive, but definitely a good option to perform the brake and suspension work.

Don L.
 
#8 ·
it actually isnt that big of a deal or threat of it tipping over. no offense, but you have to be retarded to drop a car off a lift by not setting the arms right. or just lazy by not actually getting on ur knees and looking to make sure all arms are making correct contact at the correct spots. for our cars, you can just use the normal pinch welds to lift the car up by, just run the swivel end of the arms long the welds so it has more contact area so it doesnt bend the pinch welds.

if you do the same car all the time, you'll have it all figured out easy and it wont be a hassle. i dont even look under my car when i throw the arms under it at work, i know exactly where to park it, how long each arm should be extended and swing them in. i still do the rock test when i get the tires 4 inches off the ground tho to make sure its solid.

Don is right, if you are using this lift to store a car on, its not the wisest choice, at least not for us Californian's because of earthquake threats. at work, we drop the cars to the lowest lock and leave them there if its staying up over night. I actually think its an OSHA requirement, or im just told that for safety's sake and scare tactics :p
 
#11 ·
Don is right, if you are using this lift to store a car on, its not the wisest choice,
I wasn't concerned with storing a car on the lift other than that a project might take me a couple of months. But I was thinking that I would need to be able to park a car in the space that is occupied by the lift. With the two-post, that means being careful of the doors. There are asymmetric lifts that put the doors behind the posts, but the concrete anchoring requirements go up I believe. With a 4-post, the doors are clear.

Another issue I'm not sure about is that to use a lift, I need to back the car into position. I have 12' horizontal between ceiling trusses so my plan was to position each car such that the hood could rise up just shy of the 8' high beam and the cabin of the car would rise into the 10'+ vertical cavity between trusses. For the supra and corvette, both long nosed cars, the placement of the 2-post works out about the same but if I ever work on anything else, I might be limited by the fixed placement of the posts vs the center of gravity of the car. Who would've ever thought this would be a hard decision. I wish I could just test each type for a month and see how I like it.
 
#9 ·
I think the concern should be not so much the proper placing of the car on the arms, but Phil's original question about concrete mixture, and thickness. I've had some good and bad experience with concrete, and I realize now that there is a bunch of specs and technique to good, strong concrete. Sometimes the basic 3000 psi, 4" stuff doesn't even have rebar, just that chicken wire stuff. Concrete also always cracks. Not a matter of if, but more an issue of when. I find the stuff very frustrating. Size of the post footprint, number of concrete anchor bolts, and type, all affect the quality and safety of the install.

I'm covering my concrete with tile :)

Don L.
 
#10 ·
Exactly. My garage was built in 2002, but already there is a foundation crack running across the floor unfortunately very near where I would be installing one side of the two-post lift. This area of Texas is known for foundation problems due to our clay soils. I do have lots of rebar tho and four 18" poured crossbeams in addition to the perimeter beam. I thought about making a larger floor plate, but the model I need for my ceiling height has the cables run through a channel across the floor rather than across the top so I can't raise the base plate off the concrete to slip a larger plate underneath. I thought about making some struts and securing the tops of the posts to the ceiling structure (its a steel building afterall), but I'm no structural engineer so I don't know if thats a good or bad idea.
 
#13 ·
phil...you can butt up a piece of the same thicknees steel and butt weld in to "spread out" the base plate...or do the above with another piece on top to strenghten the plate you butt welded to it...then you can keep it flat on the floor....Weve also use kind of a prop rod under the front or back of a large truck to keep it front tipping for or aft..pending on what needed done to the truck...its was a tall stand that threaded in and out on the top to adjust...HTH
 
#14 ·
OK, well, I went with the 4-post lift along with a pair of sliding scissor jacks.



At this height, I can just stand upright under the Corvette. Never thought I'd find an advantage to being such a short SOB! ;)
 
#15 ·
that looks like my lift. also noticed ur going ala no anchors like me :p

im not that tall either but i guess im blessed with the fact the previous owner built the garage around the lift they left :D plenty of space to lift up the cars since its almost 2 story's tall. (apparently he was a privateer in nascar!)
 
#16 ·
Very Nice Phil !

I'd suggest putting in some anchor bolts at base of each post. Masonry drill bit, a threaded anchor in the floor, and a lag bolt to tighten it down. Don't recall exactly what size I used, but I'm sure you can figure it out adequately.

I noticed that with use, the posts move around a bit, so line the posts up real well, run the lift up and down to make sure no binding during the length of the travel in each post, draw and outline around the post base, and drill away. If you need more info just let me know!

Beautiful garage, btw :)

Don L.
 
#17 ·
It looks great, Phil ! To answer your question as to how the lift can be supported by 4 small anchor bolts, see the diagram below. My structural engineering skills are rusty, so if I've made a huge mistake, someone please point it out. I've made some assumptions, like you have the load off center by 14" and it's 500 lbs out of balance from the center of gravity, and that the anchor bolts are 3 1/2" embedment with a conservative pullout value of 600 lbs. each. Plus, you said you had grade beams and a reinforced slab. A very strong floor. I assume you aren't getting closer than say, 6" to any significant cracks.



Still, I wouldn't want to be under this thing in an earthquake.
 
#18 ·
Well.. I am a structural engineer and I have specified a 2 post lift.

The one thing you guys are missing is that there is a support going across that you have to drive over. So only the frame of the lift is taking moment. The bolts are not really taking any prying action. In fact, I am pretty certain you can lift a car up WITHOUT any bolts. Of course you want bolts, but I am just trying to make a point. So the center gravity of the structure plus the car will somewhere in the middle of the support that you drive over. I hope you are making any sense.

About concrete, I guarantee you i your concrete was specified at 3000psi, you probably have over 4000 psi by now. The one you have to be very carefull about is the subgrade.
 
#19 ·
Another Engineer chiming in (BSCE). The ratings on concrete are at the 28-day point. Robin and Steve have it right, much stronger now. You aren't in an earthquake area so seismic load isn't an issue, but I'd still anchor 2 or three of the opposing posts (not all four, to allow a degree of freedom). If you bolt down all four you can end up with thermal stress prying one out, and weakening the others (expansion and contraction). Some folks want to restrain everything and that can lead to failure.

Realize that most of the calcs use a safety factor of 2 to account for variations in the quality of the raw products and variability of measurements. (they can go as low as 1.5 usually today, better modeling and quality control) Today 48ksi steel (rebar) is real close to 48k. 20+ years ago it was 35-60. Then there is the quality of the cement going into the concrete, wildly varying (cough, from Mexico; now Cemex produces great product). That is why nuclear power plants under construction had to test each cement delivery, before it got made into concrete (Um that was in the 80s when we last made a nuclear plant and I was working on the Alvin W Vogel design).

Sorry if I lost some of you. I haven't worked this stuff in 20 years, but concrete is concrete. And often what holds will amaze you.
 
#20 ·
Good setup you installed in the Supra shrine Phil. Am a "tiny" bit bummed that you're into C3's (I'm a BIG C1 (53 - 62) and C2 (63 - 67) fan) but this will work (ok, I'll admit that I also like 78 Pace Cars & 82 Anniversary cars).
 
#23 ·
Phil, would you mind posting links to where you bought the lift and lift capacities and center scissor jack and pricing? im finding them from $2500 for a 9000# lift and $1500 for a 8000# scissor center lift. Im sure you bought it locally since i think the DFW area probly has the best deals..I would drive there for one. if you have, do you have their contact 411?

I think im going to get the 4 post as well and get the caster kit so i can move it around the shop or out in front of the shop as well. When i build my shop next summer i will be putting a lift in the same time.

Thanks...those Corvettes look nice...I would like to get my wife one (u know its for me)with a twin turbo upgrade :thumbsup:
 
#24 ·
Here are the ProPark 8 Plus specifications which is the lift that I bought. I also got two scissor jacks to go with it. My choice was based on the specifications - this lift just did what I wanted, tho there were cheaper alternatives.

Luckily for me, there are several lift dealers with warehouses in Fort Worth.

Derek Weaver Company
Worth Equipment
National Auto Tools
Panther Lifts
Gemini Lifts

I wanted to buy it locally so they could deliver and assemble it. A lot of people order a lift over the internet, it arrives on a truck and then they are shocked that four husky guys can't unload it. You're not going to unload it without a fork lift, period. People think they can uncrate it and take it off the truck piece by piece, but trucking companies won't let you do that because they don't have that kind of time. If you can't get it off their truck inside 10 to 15 minutes, they're leaving. Even if they'd let you, the left runner with the cylinder and tackle in it weighs 800lbs. I paid an extra $350 for delivery and setup and it was worth every penny. They knew tricks to moving those heavy pieces. Weaver has an installer who travels, but I suspect its very expensive. If you can find a local dealer to order through there in ABQ, then its probably cheaper, but its worth it to have someone bring it and set it up for you.
 
#25 ·
I would 2nd Phil's suggestion of having it delivered and assembled, at least for $350. It's one heavy bundle! I picked mine up at the freight station, they forklifted onto my open car trailer, and I hauled it home myself. My son and I slowly (piece by piece) unloaded it and assembled the lift. Not complicated, but very heavy! Each of the ramps that the car rolls onto was a gut buster, the posts were manageable. I'd say anything less than $600 to deliver and install is a bargain.

Don L.
 
#26 ·
Noted...if you guys had a tracor with a front end loader to help lift all the heavy parts off the trailer and use a loader to erect the posts would it be feasable for 2 guys to install it?....I have a kubota B21 TLB tractor i could use.
 
#29 ·
Two big guys can assemble it. Just two guys can't really move it. You don't want to have to carry those runners for any distance at all. And a little guy like me doesn't want to try to lift one at all. If you can assemble it outside next to your trailer as Don says, then put the casters on it and roll it inside, thats probably doable. If like me, you have only a standard 7' high door and the posts are 8 foot, then it has to be assembled inside.

Here's the trick - I watched. As Don says, the posts are relatively easy to manhandle. Set those up first with the crossbeams and position them at the correct distance apart. On mine, they backed the trailer up into the garage, then lifted the runners off the trailer far enough to put pieces of PVC pipe under them. With several pieces of pipe and one of those rollers like they use when ripping long boards on a table saw (an extra heavy duty one), they could be rolled off the trailer supporting only the weight of one end at a time. Do the lighter runner (without the cylinder and tackle) first. Position the crossbeams on the first lock position, just below the level of the trailer floor. Back the trailer to the crossbeam. Roll the runner off the trailer and then have two husky guys position the runner in place on the crossbeams. Install the bolts to the first runner. Now roll the 2nd runner off the trailer and on top of the previously installed runner using the PVC pipes. This way you never really have to bear the weight of the 2nd runner. The second runner is upside down at this point and you can hook up the cylinder and tackle (which makes it a really heavy monster). Now flip it over off the first runner and slide it over into position on the crossbeams. The rest is easy.
 
#27 ·
There really is no need for a fork lift or tractor to unload the lift as long as you are not rushed to unload. If a freight company delivers the lift to your driveway, then you really do have to unload it as a single unit (bundled on a pallet, banded and boxed together with wood/bolts), and do it quickly. If you have a flatbed trailer of some type (that could carry 2000lbs+) then you can unband the bundled lift, remove it from the trailer piece by piece, its not impossible, just slow, and be careful. The posts are very manageable with 2 people. The ramps are tough with 2 people but we did it. I recall we used a few floorjacks to help position the ramps when assembling.

Don L.
 
#30 ·
I just had a used lift installed at my shop. It was $1400 installed (used) for a rotary type 2 post. I don't know anything about lifts, I was just told that it was a deal so I went for it.

2 guys installed it in about an hour. The concrete was drilled for the studs, it did not seem very thick. Once the holes were drilled, the studs were hammered in. They already had nuts pre-loaded at the top, while the bottom of the studs did not have threads. After they were in, each was tightened. The guy doing the hammering was one of those crazy bench 500lbs looking guys. Hammer, torque, it was all done pretty quickly.

The whole process was about 2-4 hours. Each side has 7 large nuts holding it down. They brought it on a flat bed heavy duty pickup and hoisted it somehow (I was not there for that part), but it was just 2 guys doing the work.

They told me that if I ever leave my shop, remove/sell the lift, and just hammer the studs down into the ground.

I'm glad I paid cash. I almost financed one for $1895 plus labor and probably would still be paying for it 2 years later.

 
#31 ·
rotary is top notch, and yes, u got a deal. i hate u
 
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