New lifts from BendPac - alternative to Max Jack?
08-06-2017, 09:01 AM
#17
Instructor
08-06-2017, 09:11 AM
#18
Instructor
nice..
Curious, why dont they make the bottom feet a bit longer? (front to back) It would seem to me that it would add a tremendous mount of stability for those odd jobs where the balance of a typical car would be disrupted. (engine out..etc) Side to side doesn't see much shift in weight. Would also allow for greater pressure distribution on the floor.
Curious, why dont they make the bottom feet a bit longer? (front to back) It would seem to me that it would add a tremendous mount of stability for those odd jobs where the balance of a typical car would be disrupted. (engine out..etc) Side to side doesn't see much shift in weight. Would also allow for greater pressure distribution on the floor.
A very good point often overlooked.
BendPac should be able to advise on this concern.
Most YouTube 2-post failure Vids have the arms collapsing or posts tipping inward due anchor bolts pulling out (not a concern on this lift due to cross beam).
Residential Garages rarely have 3500 psi concrete
Chemical Anchors (Epoxy Injected) is preferred since it holds up much better on cyclic loads
If concrete has to be upgraded that would provide an opportunity to embed J-Bolts which is the best method.
I believe an authorized installer would test concrete psi and thickness in the process of providing an installation quote
08-06-2017, 09:59 AM
#19
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I just consulted the BendPac website to check on slab requirements - I'm about to have a slab poured for a new 40x28' garage. The remarkable answer is just 4 inches (3000 psi) up to and including a two-post, asymmetric, wide, 10,000 lb lift. They and their lawyers must have experience to support this, but ...
The metallurgist in me does not trust brittle materials in tension, so I'm going to specify a central 8-ft wide strip of 6" thick concrete. That's only $200-300 worth of extra concrete. Maybe just do the whole thing at 6" - $700 or so. That should also put the mesh below the holes - even with the better grade of SDS bits, hitting steel produces a lot of chatter and an ugly hole.
Initially, I'll just have a new four-post lift plus my existing MaxJax out there, but who knows.
The metallurgist in me does not trust brittle materials in tension, so I'm going to specify a central 8-ft wide strip of 6" thick concrete. That's only $200-300 worth of extra concrete. Maybe just do the whole thing at 6" - $700 or so. That should also put the mesh below the holes - even with the better grade of SDS bits, hitting steel produces a lot of chatter and an ugly hole.
Initially, I'll just have a new four-post lift plus my existing MaxJax out there, but who knows.
08-06-2017, 01:09 PM
#20
Administrator - "Tyson"
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According to my concrete guy, 4.5" slab at 4,000psi is common. At least around here (Wisconsin). I'm sure this could easily vary by region. When I had the garage slab measured in my last place (built in 1980) it was also a 6".
I just talked to him to get some specifics:
Disclaimer: Have you concrete measured. All the "known specs" in the world mean nothing if the guy who poured your slab cut corners.
Very common.
Direct Lift:
Our 2 post lifts require 4” minimum thickness and 3000 psi, if you choose to anchor our four post lifts we also require 4” minimum thickness and 3000 psi.
Rotary:
4" - 4.5" (depends on the model) @ 3000psi
Mohawk:
One company with a wide range of specs. The typical lifts for us hobbyist are the same 4.5" but 4000psi.
Their 12,000lb+ lifts require 6" or more of concrete.
They have the most comprehensive "how to" guide on concrete specs:
http://www.mohawklifts.com/library/m...mend_11_07.pdf
On that note, I'd love to get a Mohawk A7. Capable of fulling lifting a car like a 928 in a 10' 6" ceiling. But they cost $5,500 or more.
I just talked to him to get some specifics:
We pour floating garage slabs with 8" grade beam, 4-1/2" floor 6 bag mix with fibers and 1/2 " rebar criss crossed 3' o.c.. 6 bag mix gives you 4000 psi which is typical, fibers and rebar are additional insurance for longevity
Google grade beam slabs or floating garage slabs
We pour shed slabs 6" thick without grade beams...4" gravel base minimum
3000 psi is a footting mix, for strength it's fine, workability for a finish you need more cement.
Google grade beam slabs or floating garage slabs
We pour shed slabs 6" thick without grade beams...4" gravel base minimum
3000 psi is a footting mix, for strength it's fine, workability for a finish you need more cement.
I just consulted the BendPac website to check on slab requirements - I'm about to have a slab poured for a new 40x28' garage. The remarkable answer is just 4 inches (3000 psi) up to and including a two-post, asymmetric, wide, 10,000 lb lift. They and their lawyers must have experience to support this, but ...
Direct Lift:
Our 2 post lifts require 4” minimum thickness and 3000 psi, if you choose to anchor our four post lifts we also require 4” minimum thickness and 3000 psi.
Rotary:
4" - 4.5" (depends on the model) @ 3000psi
Mohawk:
One company with a wide range of specs. The typical lifts for us hobbyist are the same 4.5" but 4000psi.
Their 12,000lb+ lifts require 6" or more of concrete.
They have the most comprehensive "how to" guide on concrete specs:
http://www.mohawklifts.com/library/m...mend_11_07.pdf
On that note, I'd love to get a Mohawk A7. Capable of fulling lifting a car like a 928 in a 10' 6" ceiling. But they cost $5,500 or more.
08-06-2017, 03:29 PM
#21
Three Wheelin'
Thread Starter
Mohawk definitely takes the safe route -no matter if it's a cutout in an existing slab or an entirely new slab. Money and effort well spent. They seem to be the only lift company with detailed drawings of where & how much rebar etc. That seems more reassuring than some companies. No matter what lift you get it seems like a good idea to use their specs.
Peace of mind is worth something.
Peace of mind is worth something.
Last edited by Jim Devine; 08-08-2017 at 04:03 PM.
08-08-2017, 02:28 PM
#22
Instructor
What is concerning to me is the ALI testing and design criteria.
see attached snap shots of documents.
To me it is unreasonable to expect an untrained home owner or anyone else in the household that decides to use lift (authorized by owner or not) to select lifting points to recreate the perfectly centered and uniform distributed load set out in design criteria.
Then to work on vehicle in such a fashion to not impose dynamic loads on anchors that only have known load capabilities for static conditions.
The 150% overload test does not provide any assurance on how lift performs with a 100% rated load that is unbalanced.
Me being from the rust belt have had to use 6' breaker bar extensions and beat on rusted brake drums etc. with 15 lb sledge would certainly reduce holding power of anchors under load.
A factor of 10 to 1 load reductions on expansion anchors I have seen imposed by engineer of record in building construction when a dynamic working load is involved (analogous to wrenching on car) in brittle materials such as concrete.
I know that i have enough common sense and knowledge to use an ALI certified home owner garage lift in utmost safety.
But if others have access to my lift in my absence I cannot in good conscience buy anything less than an over designed commercial lift.
My 6000 lb pick up truck would overload any 7000 lift since a level frame pick up point cannot be found forward enough to balance the 59/41 weight distribution
see attached snap shots of documents.
To me it is unreasonable to expect an untrained home owner or anyone else in the household that decides to use lift (authorized by owner or not) to select lifting points to recreate the perfectly centered and uniform distributed load set out in design criteria.
Then to work on vehicle in such a fashion to not impose dynamic loads on anchors that only have known load capabilities for static conditions.
The 150% overload test does not provide any assurance on how lift performs with a 100% rated load that is unbalanced.
Me being from the rust belt have had to use 6' breaker bar extensions and beat on rusted brake drums etc. with 15 lb sledge would certainly reduce holding power of anchors under load.
A factor of 10 to 1 load reductions on expansion anchors I have seen imposed by engineer of record in building construction when a dynamic working load is involved (analogous to wrenching on car) in brittle materials such as concrete.
I know that i have enough common sense and knowledge to use an ALI certified home owner garage lift in utmost safety.
But if others have access to my lift in my absence I cannot in good conscience buy anything less than an over designed commercial lift.
My 6000 lb pick up truck would overload any 7000 lift since a level frame pick up point cannot be found forward enough to balance the 59/41 weight distribution
08-08-2017, 02:37 PM
#23
Instructor
I just consulted the BendPac website to check on slab requirements - I'm about to have a slab poured for a new 40x28' garage. The remarkable answer is just 4 inches (3000 psi) up to and including a two-post, asymmetric, wide, 10,000 lb lift. They and their lawyers must have experience to support this, but ...
The metallurgist in me does not trust brittle materials in tension, so I'm going to specify a central 8-ft wide strip of 6" thick concrete. That's only $200-300 worth of extra concrete. Maybe just do the whole thing at 6" - $700 or so. That should also put the mesh below the holes - even with the better grade of SDS bits, hitting steel produces a lot of chatter and an ugly hole.
Initially, I'll just have a new four-post lift plus my existing MaxJax out there, but who knows.
The metallurgist in me does not trust brittle materials in tension, so I'm going to specify a central 8-ft wide strip of 6" thick concrete. That's only $200-300 worth of extra concrete. Maybe just do the whole thing at 6" - $700 or so. That should also put the mesh below the holes - even with the better grade of SDS bits, hitting steel produces a lot of chatter and an ugly hole.
Initially, I'll just have a new four-post lift plus my existing MaxJax out there, but who knows.
Thus no liability if not followed to a T
08-08-2017, 02:41 PM
#24
Instructor
nice..
Curious, why dont they make the bottom feet a bit longer? (front to back) It would seem to me that it would add a tremendous mount of stability for those odd jobs where the balance of a typical car would be disrupted. (engine out..etc) Side to side doesn't see much shift in weight. Would also allow for greater pressure distribution on the floor.
Curious, why dont they make the bottom feet a bit longer? (front to back) It would seem to me that it would add a tremendous mount of stability for those odd jobs where the balance of a typical car would be disrupted. (engine out..etc) Side to side doesn't see much shift in weight. Would also allow for greater pressure distribution on the floor.
Again excellent point that is why some commercial lifts such as Mohawk measure 32" across front to back.
The 2-post lifts are also rated as storage lifts which is of interest to me
08-08-2017, 03:14 PM
#25
Instructor
It is interesting that for new concrete Mohawk specifies 12" thick minimum.
The bed of compacted soil needs allow a bearing load of 2000 lbs/sf.
see pg 4 of linked pdf
http://www.mohawklifts.com/library/m...mend_11_07.pdf
Does anyone have experience for testing soil bearing capacity?
In the case of an existing garage that need concrete cut out what equipment would a concrete contractor use to compact soil to 2000 lb/sf
This is important since to make the new 12" slab level with existing the original compacted soil has to be disturbed and dug out.
The bed of compacted soil needs allow a bearing load of 2000 lbs/sf.
see pg 4 of linked pdf
http://www.mohawklifts.com/library/m...mend_11_07.pdf
Does anyone have experience for testing soil bearing capacity?
In the case of an existing garage that need concrete cut out what equipment would a concrete contractor use to compact soil to 2000 lb/sf
This is important since to make the new 12" slab level with existing the original compacted soil has to be disturbed and dug out.
08-08-2017, 03:45 PM
#26
Instructor
Mohawk definitely takes the safe route -no matter if it's a cutout in an existing slab or an entirely now slab. Money and effort well spent. They seem to be the only lift company with detailed drawings of where & how much rebar etc. That seems more reassuring than some companies. No matter what lift you get it seems like a good idea to use their specs.
Peace of mind is worth something.
Peace of mind is worth something.
Worth repeating
Last edited by bertram928; 09-20-2019 at 11:37 PM.
08-09-2017, 05:00 PM
#27
Administrator - "Tyson"
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I'm usually in the overkill department on everything I do and I've been studying and shopping for a lift for the better part of 10 years.
However, in this discussion, are the specs really "bare minimum" or were the lifts simply designed around commonly poured concrete?
I've done countless searches on lift failures. I've seen cars fallen off, arms that bent (overloaded) ceilings crushed from going to high etc... finding a lift that ripped out of the concrete is few and far between. The few I have found, there was a clear case of user error, like a 1-ton pickup on a 7,000lb lift.
This is an interesting thread:
https://www.garagejournal.com/forum/...ad.php?t=44568
So again, not arguing against being overly safe, especially when lifting a vehicle. But with the popularity of cheap Chinese made "hobby" lifts, it really is a pleasant surprise failures are few and far between.
However, in this discussion, are the specs really "bare minimum" or were the lifts simply designed around commonly poured concrete?
I've done countless searches on lift failures. I've seen cars fallen off, arms that bent (overloaded) ceilings crushed from going to high etc... finding a lift that ripped out of the concrete is few and far between. The few I have found, there was a clear case of user error, like a 1-ton pickup on a 7,000lb lift.
This is an interesting thread:
https://www.garagejournal.com/forum/...ad.php?t=44568
So again, not arguing against being overly safe, especially when lifting a vehicle. But with the popularity of cheap Chinese made "hobby" lifts, it really is a pleasant surprise failures are few and far between.
The following users liked this post:
Nate Tempest (06-30-2021)
08-09-2017, 08:23 PM
#28
Instructor
I find this guy is knowledgeable about all things shop equipment and working on cars:
http://garage.grumpysperformance.com...-your-shop.98/
Thread started in 2008 but "grumpy" has updated as late as 2017 thus assume old info may have been corrected
Last post is a shocker but disagree with "Grumpy's" assumption for right arm swinging away.
Could be many other reasons such as:
- arm locks not manually engaged.
-Brain-fade operator in a rush not focused on locating arm and pad in a secure position.
-Or if main arm support pin worn loose due to lack of maintenance allowing deflection and insufficient teeth engagement of arm locking mechanism.
-The ALI spec of arm locking mechanism only having to resist a lateral force of 150-lbs needs to be changed by a factor of 10.
This would ensure a robust design that could function even if lack of maintenance.
Excerpt regarding pad thickness and anchor bolt length:
"read thru these links and this thread carefully, 4" of concrete is marginal, or even dangerous with a two post lift, Id strongly suggest talking to the lift manufacturer about options, personally Id strongly suggest sinking/installing 4' x'4' x 2' feet concrete footers, tied into the slab, having a car over your head that might pull the anchor bolts is stupid at best, and a few yards of 5000 psi concrete will cost far less than your medical bills and car repair if a car falls when the anchor bolts pull free
[IMG]
potential results of a small base, two post, lift installed on a 4" slab, in most cases manufacturers indicate a two post lift needs a MINIMUM of 6"-to 8" of concrete floor thickness and a minimum of 3600 psi concrete with 6"-8" anchor bolts to effectively and safely anchor a two post lift
http://garage.grumpysperformance.com...-your-shop.98/
Thread started in 2008 but "grumpy" has updated as late as 2017 thus assume old info may have been corrected
Last post is a shocker but disagree with "Grumpy's" assumption for right arm swinging away.
Could be many other reasons such as:
- arm locks not manually engaged.
-Brain-fade operator in a rush not focused on locating arm and pad in a secure position.
-Or if main arm support pin worn loose due to lack of maintenance allowing deflection and insufficient teeth engagement of arm locking mechanism.
-The ALI spec of arm locking mechanism only having to resist a lateral force of 150-lbs needs to be changed by a factor of 10.
This would ensure a robust design that could function even if lack of maintenance.
Excerpt regarding pad thickness and anchor bolt length:
"read thru these links and this thread carefully, 4" of concrete is marginal, or even dangerous with a two post lift, Id strongly suggest talking to the lift manufacturer about options, personally Id strongly suggest sinking/installing 4' x'4' x 2' feet concrete footers, tied into the slab, having a car over your head that might pull the anchor bolts is stupid at best, and a few yards of 5000 psi concrete will cost far less than your medical bills and car repair if a car falls when the anchor bolts pull free
[IMG]
potential results of a small base, two post, lift installed on a 4" slab, in most cases manufacturers indicate a two post lift needs a MINIMUM of 6"-to 8" of concrete floor thickness and a minimum of 3600 psi concrete with 6"-8" anchor bolts to effectively and safely anchor a two post lift
08-09-2017, 09:05 PM
#29
Instructor
I've been studying and shopping for a lift for the better part of 10 years.
So have I that is why I am buying now so not loose any more years of use. LOL
However, in this discussion, are the specs really "bare minimum" or were the lifts simply designed around commonly poured concrete?
well till they make cars a lot lighter there is no way a lift manufacturer can design around marginal concrete unable to take bearing loads on column base from weight of car or ability to hold anchors to resist load imbalances.
I've done countless searches on lift failures. I've seen cars fallen off, arms that bent (overloaded) ceilings crushed from going to high etc... finding a lift that ripped out of the concrete is few and far between. The few I have found, there was a clear case of user error, like a 1-ton pickup on a 7,000lb lift.
This is an interesting thread:
https://www.garagejournal.com/forum/...ad.php?t=44568
regarding WRECKED episode, golden rule for shop always open Van back doors prior to lifting, there could be 5000 lbs of cast iron plumbing fittings or welding equipment in there.
So again, not arguing against being overly safe, especially when lifting a vehicle. But with the popularity of cheap Chinese made "hobby" lifts, it really is a pleasant surprise failures are few and far between.
So have I that is why I am buying now so not loose any more years of use. LOL
However, in this discussion, are the specs really "bare minimum" or were the lifts simply designed around commonly poured concrete?
well till they make cars a lot lighter there is no way a lift manufacturer can design around marginal concrete unable to take bearing loads on column base from weight of car or ability to hold anchors to resist load imbalances.
I've done countless searches on lift failures. I've seen cars fallen off, arms that bent (overloaded) ceilings crushed from going to high etc... finding a lift that ripped out of the concrete is few and far between. The few I have found, there was a clear case of user error, like a 1-ton pickup on a 7,000lb lift.
This is an interesting thread:
https://www.garagejournal.com/forum/...ad.php?t=44568
regarding WRECKED episode, golden rule for shop always open Van back doors prior to lifting, there could be 5000 lbs of cast iron plumbing fittings or welding equipment in there.
So again, not arguing against being overly safe, especially when lifting a vehicle. But with the popularity of cheap Chinese made "hobby" lifts, it really is a pleasant surprise failures are few and far between.
08-09-2017, 09:18 PM
#30
Instructor
http://www.hse.gov.uk/mvr/topics/fallofflifts.htm
"Problems with the design, installation, use and maintenance of arm locking mechanisms continue to cause concern in newer machinery. Some new Chinese-manufactured 2-post lifts have been found where the locking mechanism has been poorly manufactured and failed to work from installation or within a short period of use. Further details are available in Sector Information Minute 03/2008/12 "Defective locking devices identified on modern 2-post lifts".
This advice emphasizes the importance of daily checks on the locking mechanisms and other critical parts of 2-post lifts."
"We have also received a number of reports of lift collapses resulting from anchor bolts pulling out of weak concrete. Lift installers need to be competent and the flooring needs to be of appropriate strength. If there is no supporting evidence for the flooring specification, a series of test holes may need to made and expert opinion obtained. One way in which businesses can help assure themselves that a lift is installed correctly is by using installation engineers who are accredited - The Garage Equipment Association (GEA) link to external website operate a one such lift engineer accreditation scheme.
See also Updated Guidance on Vehicle Lifts."
"Problems with the design, installation, use and maintenance of arm locking mechanisms continue to cause concern in newer machinery. Some new Chinese-manufactured 2-post lifts have been found where the locking mechanism has been poorly manufactured and failed to work from installation or within a short period of use. Further details are available in Sector Information Minute 03/2008/12 "Defective locking devices identified on modern 2-post lifts".
This advice emphasizes the importance of daily checks on the locking mechanisms and other critical parts of 2-post lifts."
"We have also received a number of reports of lift collapses resulting from anchor bolts pulling out of weak concrete. Lift installers need to be competent and the flooring needs to be of appropriate strength. If there is no supporting evidence for the flooring specification, a series of test holes may need to made and expert opinion obtained. One way in which businesses can help assure themselves that a lift is installed correctly is by using installation engineers who are accredited - The Garage Equipment Association (GEA) link to external website operate a one such lift engineer accreditation scheme.
See also Updated Guidance on Vehicle Lifts."