I've had my lowered MINI on a friends 2-post lift a number of times. We have to drive up on some 2x4 blocks to get the pads under the factory jacking points on the car (and lower it back down on the same blocks of wood to get it off the pads). As a side note, I also have to drive up on blocks to get my floor jack under the car so it's not just the 2-post lift.
We also have the max jax portable, I cant say we have ever taken it down, and we have been using in daily for 2 years now, good investment. if you have the height, a full height lift is the way to go though. )
alfadriver wrote:Giant Purple Snorklewacker wrote:It's not the compression of the stand on the concrete (and concrete is very, very strong in compression)- it's the tension that the bolts put on the floor. You see that the post is assymetrically loaded, right?- each post wants to lean toward the inside- so each of the outer bolts put a large amount of tensile load into the concrete. The deeper and higher quality concrete- the more area that the threaded rods get to distribute this load. It's one of the reasons 4 post lifts are "easier" to install in a normal garage- being ballanced, and self supporting- it's all compression load.dmyntti wrote: Another thing to think about is if you trust the concrete floor in your garage to handle the torque from a two post.I hear this all the time on the "which lift" posts - but if you can use a jack... you are supporting the heaviest part of the whole car on four little steel wheels on that same pad. In the case of my truck - its about 4000lbs on the front subframe. If the jack, or jack stands don't break thru then neither will a lift (which usually has a huge foot on a 2 post to spread the load). So, while you need to consider the pad - if you have been using it to support a vehicle and its not crumbling... you are probably OK.
Alfa is right on this. The loading on the concrete is COMPLETELY different on a lift than on a jack.
Most standard residential slabs ARE NOT sufficient for most lifts. Most residential floors are 4" thick. Most manufacturers of lifts require at least 6" thick reinforced floor. That's 50% thicker, PLUS the reinforcing.
Regarding safety...
I would bet that most lift failures are related to the floor or the attachments (bolts) failing, not the lift. Every lift I've ever seen has mechanical dogs for safety. If the hydraulics or cables fail, the mechanical dogs support the weight. The likelihood of both failing simultaneously is nearly impossible.
Of course, the one other HIGHLY likely failure is operator error. Disengaging the mechanical safety dogs has surely led to many deaths.
I'm not suggesting I'd be completely comfortable with a Chinese made lift, but I might be.
I bought mine (well made US built 2 post Western unit in full working condition) for $750 from the local tech school when the upgraded.
fack, that could screw me right off the bat, unless I wanna throw in a new slab, and I'd rather spend that money at the snappy truck. /me wonders if they'd notice me, my drill, and a concrete bit taking "core samples".....
You don't need an entire new slab. Most lifts require an area at the base about 2'x5'.
It's a bit of work, but not that hard to cut out 2 piers and pour them thicker.
Giant Purple Snorklewacker wrote: Well, the MAX JAX two post I posted a link to has no fasteners. It has a huge stable foot on each side and retractable casters. They are designed such that the load is stable and the force is straight down. That isn't to say that you don't get variances due to the load on the forks - but the foot is not attached to the floor so there isn't a twisting load "pulling" on anything. We are discussing two different designs. Even the four posts I have considered were on casters.
i looked into that question after you posted those and it sounds like theyre 'portable' in the sense that they arent permanently bolted to the floor but they have a pre-determined location (or locations) where they bolt down when you need it and hide away when you dont. here's a quote from their website
max jax said: Flush Mount Anchor Bolts Flush-mount anchors are installed in your concrete floor and remain there permanently. The columns are bolted to the floor using 5/8" anchor bolts that thread into the flush-mount anchors.
My four post isn't bolted down and it's perfectly stable. I can do anything on it that I could do with a 2 - post, but you can't say the same thing the other way around. 
WilberM3 wrote: i looked into that question after you posted those and it sounds like theyre 'portable' in the sense that they arent permanently bolted to the floor but they have a pre-determined location (or locations) where they bolt down when you need it and hide away when you dont. here's a quote from their websitemax jax said: Flush Mount Anchor Bolts Flush-mount anchors are installed in your concrete floor and remain there permanently. The columns are bolted to the floor using 5/8" anchor bolts that thread into the flush-mount anchors.
EDIT: Sometimes I see only what I want to see. Yeah, they need permanent anchors in the floor so you gotta have 4" of healthy concrete to bed them into.
how easy would it be to drop out a complete rear subframe/suspension or would it be possible to lower a body or cab onto a frame on your 4 post? not knocking em, ive only used a 2 post so i'm just picturing those types of jobs as difficult.
In reply to Giant Purple Snorklewacker:
i'm not sure it'd be a dealbreaker for me as you could put anchors in multiple locations, though i guess i'd be a bit worried about filling them with crap over time.
Giant Purple Snorklewacker wrote:WilberM3 wrote: i looked into that question after you posted those and it sounds like theyre 'portable' in the sense that they arent permanently bolted to the floor but they have a pre-determined location (or locations) where they bolt down when you need it and hide away when you dont. here's a quote from their websiteEDIT: Sometimes I see only what I want to see. Yeah, they need permanent anchors in the floor so you gotta have 4" of healthy concrete to bed them into.max jax said: Flush Mount Anchor Bolts Flush-mount anchors are installed in your concrete floor and remain there permanently. The columns are bolted to the floor using 5/8" anchor bolts that thread into the flush-mount anchors.
Even with that, it's a pretty cool system. I very much like the idea of a jack that I can move out of the way.
If it were just a little higher, so I could store a car under it, it would be even better.
In reply to WilberM3:
To change the subframe you would jack the vehicle up on the ramps and use a jack just like you would on a 2-post. It obviously wouldn't be as easy, but you can do it.
The body dropping thing you kind of got me on. I actually have done it with my 4 post, but it was a very small car. I guess if you anticipate a lot of that kind of work, then a two post would be preferred. BTW, and Just for the record, I didn't say everything on a 4-post would be as easy as on a two post, just possible.
well my experience with dropping subframes is while standing underneath said lift using a hydrualic ram type big transmission jack to lower it which makes stuff really easy, but thats extra cost for somewhat expensive tools too. i just found that i really liked the freedom of movement under a 2 post and imagine i'd feel confined on a 4 post.
sounds like the best way is to just have one of each!
WilberM3 wrote: sounds like the best way is to just have one of each!
Yup. It really all depends on what you need it to do. For instance, I have severe back issues and bending down to adjust the arms on a two post isn't something I want to do, so the 4-post is a no-brainer for me. There are definitely times I wish I had a two post, but I always find a way to get the work done.
I have used my four post to remove and reset the bed of my pickup truck and could use it to loft a body if needed. What I did was use straps down from the ramps to attach to the bed at the stake pockets. If lifting a body off of a frame you would have to come up with an arrangement to attach the straps but I have done a Corvette body with an engine lift before so it could certainly be done on a four post. It all depends on what you want to do and if you trust the concrete slab. If I was buidling a new garage and was going to have just one lift I think I would go with a two post lift. If you are doing mainly oil changes and body work I would go with a four post as it is quicker to drive on and lift. It is amazing the things that become easier when a car is on a lift. I really like not having to contort my self to work under a dash board. Now I just rais the car to a nice height and stand next to the car and work from there. It is also nice to be able to lift things other than cars. On my lift right now is a lawn tractor getting the motor replaced, a four wheeler getting a new starter and my generator getting wheels and handles added to it so that I don't have to drag it.
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