2-post car lifts

[frostbite]

I'm thinking of treating myself to a 2-post car lift in what will be an extension to my garage. so no concrete floor yet. It seems to me that a two-post lift must have a lot of strain and therefore reliance on the bolts holding the posts down and then the concrete that the bolts are in, as unless the car is placed with its centre of gravity exactly between the posts, they will want to try and tip over. Then even that will change if, for example, the whole rear subframe is dropped out, moving the centre of gravity further forward.
I've e-mailled a couple of suppliers asking about the depth and spec of concrete, but no answer yet (probably as it's still the weekend).
Obviously as these are in such wide use, I'm imaging a problem. But I was curious about the science of it....

 

[-Ian]

For peace of mind just get it professionally installed. You won't be the first person to think this. I'm sure the company you are thinking of buying from can recommend somebody to carry out the installation for you.

It will probably cost a few quid but the fact that 2 tonne of car isn't about to fall on your head is a good thing

 

[John Jones Jr]

Then even that will change if, for example, the whole rear subframe is dropped out, moving the centre of gravity further forward.

Not an issue as far as I'm aware, providing you have the right lift.

I've had one in the past and I'm considering another one. Besides having the correct spec concrete for bolting in the lift - thickness, strength along with overall concrete dimensions you'll need to buy the correct spec lift for your vehicles. I noticed you have a 4x4 for instance, may need a 3.0 tonne lift rather than a 2.5 tonne for example. Don't forget overall height requirements too.

Ideally, as -Ian mentioned have the supplier, supply & install. Might be worth checking your home insurance policy also.

 

[John Jones Jr]

I forget to mention, consider a four post one (my preference) also but you'll have to weigh up the advantages and disadvantages.

 

[st13phil]

I've e-mailled a couple of suppliers asking about the depth and spec of concrete, but no answer yet (probably as it's still the weekend).

Most seem to recommend reinforced concrete slab minimum thickness of 150mm, rated for at least 25MPa compression.

Personally, as well as getting recommendations from the manufacturer I'd talk to a Structural Engineer and take their advice as it's likely to depend on the stability of the ground under the slab too.

 

[Druk]

I have a two post hoist at home. The garage was designed and built to accommodate it. It's a Dunlop 4ton electro-hydraulic bought from ebay and converted to single phase.

The main floor slab is 6" high-strength concrete with 2 layers of 4" mesh overall. At the sides in way of the hoist feet that is increased to 9"thick x 24"W with several 3/4" rebar running through. I made a wood pattern for the hold-down bolts before pouring so that I wouldn't be drilling into steel.
My main worry was the hoist 'clapping hands' at the top so I made a crossbeam that spans the two pillars and fits up into the roofbeams. Also the legs are pinned at the top to the main garage walls fore and aft to stop any tendency to tilt. The lever moment up there is great so the fixings don't have to be massive.

Before and after. The hoist is in the right side.




Since this pic was taken the floor has been raised with packing and ply so I don't have the cross trunking to bother about.







And I've since done this http://www.mbclub.co.uk/forums/general-discussion/172682-new-toy.html to make life easy.






.

 

[Halcyon Days]

garage envy!!!

 

[frostbite]

Thanks to everyone!
I'll be getting the same builders that built my house and the garage to do the building, with the floor done to the lift makers spec and then the lift makers to do the installation. I'm still considering a 4-post, it's a matter of weighing up how often I'll need to work with all four wheels off load. The sills on my car are now completely sound, so no worries about any creaking or crunching as the car is lifted. a 2-post gives more access I suppose, yet a scissor lift may be sufficient.
Lots of thinking still to be done!

 

[John Jones Jr]

Thanks to everyone!
I'll be getting the same builders that built my house and the garage to do the building, with the floor done to the lift makers spec and then the lift makers to do the installation. I'm still considering a 4-post, it's a matter of weighing up how often I'll need to work with all four wheels off load. The sills on my car are now completely sound, so no worries about any creaking or crunching as the car is lifted. a 2-post gives more access I suppose, yet a scissor lift may be sufficient.
Lots of thinking still to be done!

A four post with rolling lift jack/s will allow you to jack up the wheels. Certainly worth considering.

 

[Chrishazle]

Who was it on here (or was it t#other side?) that ran a thread about building his new garage with a 4 post lift and enough space above that he had storage/office in part of the "roof" and his classic Rover on the lift with another car underneath? OP might get some answers/help if someone knows where to find the thread!

Edit - looks like it's on t'other side, this thread links to his Detailingworld write-up

http://www.mbclub.co.uk/forums/ot-off-topic-forums/98691-single-most-amazing-thread-ever-lol.html

and this is his thread on t'other side :

http://forums.mercedesclub.org.uk/showthread.php?t=66147&highlight=garage

 

[wywywywy]

I forget to mention, consider a four post one (my preference) also but you'll have to weigh up the advantages and disadvantages.

What are the advantages/disadvantages 2 vs 4?

By the way, are these lifts supposed to be services yearly?

 

[John Jones Jr]

What are the advantages/disadvantages 2 vs 4?

By the way, are these lifts supposed to be services yearly?

From the way I see it, the only disadvantage of a four post is the extra floor space required and extra cost. As for servicing I don't know. I had one (two post), it came with the property and it was serviced by the supplier biyearly from what I recall but have no real idea what a service involved. Maybe, it was more of an inspection than anything else? .

 

[gegs88]

Loler regs say inspection every 12 months as its a lifting machine. The inspection covers all the safety features and a bit more. The service is usually check the oil levels, grease where required (dependant on model) check chain tensions (again model dependant) then walk off with a big wad of your cash while sniggering.
For what its worth i used to service and repair both types, get a 4 post if you can. The bradbury lifts have a frame that goes up with the ramp so if you need all 4 wheels off load you just lock the frame up them drop the ramps.......cracking bit o kit.
Dont forget also that if you go for a cheap version and you need any spares you will be water ski'ing uphill for service and delivery.

 

[a111r]

Loler regs say inspection every 12 months as its a lifting machine.

LOLER doesn't apply, it's private kit not in a workplace.
Obviously, keep on top of the inspection and servicing, rules aside.

 

[gegs88]

LOLER doesn't apply, it's private kit not in a workplace.
Obviously, keep on top of the inspection and servicing, rules aside.

And loler says every 12 months for the inspection. Or do you just make up your own service and inspection schedule......in which case its a pointless exercise.

 

[V12]

From the way I see it, the only disadvantage of a four post is the extra floor space required and extra cost. As for servicing I don't know. I had one (two post), it came with the property and it was serviced by the supplier biyearly from what I recall but have no real idea what a service involved. Maybe, it was more of an inspection than anything else? .

For most day to day stuff, I much prefer to work on the 2 post. Just much better access to the vehicle with nothing getting in your way.

If I could only have one then I would certainly keep the 4 poster and get rid of the 2 post.

 

[a111r]

And loler says every 12 months for the inspection. Or do you just make up your own service and inspection schedule......in which case its a pointless exercise.

HSE's guidance to industry is pretty clear.
"May we also remind owners of their maintenance and inspection responsibility under the PUWER and LOLER Regulations - Vehicle lifts should be regularly serviced (maintained) by a competent engineer and undergo a thorough examination by a competent person every 6-months. Thorough examination is in addition to, not a substitute for, regular inspection and on-going maintenance".

A good read for those thinking of a DIY installation.
SIM 03/2010/02 Risk of vehicles falling from two-post vehicle lifts in motor vehicle repair (MVR)

 

[wywywywy]

From the way I see it, the only disadvantage of a four post is the extra floor space required and extra cost.

What about safety? About the same?

 

[frostbite]

Thanks for all the posts.. I'm going to just get the garage built for now, with a spec-that-covers-all-angles floor. Still favouring the 2-poster though.

 

[frostbite]

I have a two post hoist at home. The garage was designed and built to accommodate it. It's a Dunlop 4ton electro-hydraulic bought from ebay and converted to single phase.

The main floor slab is 6" high-strength concrete with 2 layers of 4" mesh overall. At the sides in way of the hoist feet that is increased to 9"thick x 24"W with several 3/4" rebar running through. I made a wood pattern for the hold-down bolts before pouring so that I wouldn't be drilling into steel.
My main worry was the hoist 'clapping hands' at the top so I made a crossbeam that spans the two pillars and fits up into the roofbeams. Also the legs are pinned at the top to the main garage walls fore and aft to stop any tendency to tilt. The lever moment up there is great so the fixings don't have to be massive.

Before and after. The hoist is in the right side.




Since this pic was taken the floor has been raised with packing and ply so I don't have the cross trunking to bother about.







And I've since done this http://www.mbclub.co.uk/forums/general-discussion/172682-new-toy.html to make life easy.




/QUOTE]

I particularly like the old two-person handsaw!