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Rolling Jack Question - Extending the Arm Reach

DerStig

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Jun 15, 2015
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441
I have an Rj45 for my 4 post lift. Unfortunately one of my cars have a 64" inch from side to side whereas the jack has 59" or so. This particular car has no other accessible areas that I can lift from, no K member, no pinch welds or other body panels. Everything is covered with hard plastic/rubber panels.

The question I had was, can I use a 2x4 or a 2x8 or any other wood based basic solution to extend the reach. Or do I need to build a steel based long adapter. I could probably have a custom made adapter that is in U shape and use it upside down so it fits right on top of the pads and slides in. However, if wood works thats even better.

Suggestions are welcome.
 
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matt_i

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Definitely can use wood but the size (height) of it is likely going to be higher. Is the 2x8 going to be used the "flat way horizontal"?

Steel has the helpful advantage of being able to have cups and stops welded to it to keep it from slipping off the jack-pads. Although wood has a higher coefficient of friction than steel on steel. Steel is more homogeneous than wood, iow no knots or woodgrain defects to split out on you at an inopportune moment.
 
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DerStig

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Yes, the wood will be on its flat horizontal side. It will span across side to side with a length of approximately 6'.

I m not too worried about friction and I think I can make the grooves with a small piece of wood so the large piece slides on to the adapters/arms of the rolling jack.

My concern is bending and if it can actually support the weight. The weight will be at the tip of the wood so imagine 1200 lbs on each end pushing down and the center of the wood will be un supported.

I guess the question is can a 6' 2x8 support 2400 lbs evenly distributed on its tips? Not sure what is the bending limit of a piece that long.

Or, should I get 2 of the 2x4 doug fir and sister them so that instead of 1.5" thick wood, I have 3.5" tick wood. So in this case it would be vertically positioned.
 

rburke65

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Just know that there is a difference between the 'soft' wood of a typical 2x4 and one of oak. Oak is a lot harder.
 

matt_i

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I personally think you are way overloaded for a piece of timber, flat, at that weight and span.

The 2x4 box tube should do a lot better although it will be heavy. I would source from metal suppliers in your [unknown] area...metal supermarkets, etc.
 
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DerStig

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Jun 15, 2015
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I misunderstood what you had meant with box tube, now got it. This one I can find no problem.

Wouldnt it be better though to custom weld a piece in a U shape and slide this in over the arms of the jack and the fact that its a U will prevent any kind of movement and sliding it. The box tube idea is good but you have to always make sure its right in the middle of the pads/arms. Plus it will add unnecessary height and can cause clearance issues.

I wonder if I can find a place to custom do this for me. Not aware of any metal shops, need to look.

So the timber is a no go I guess.
 

WhiffySpark

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Oct 22, 2009
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Again, what kind of car? We lift cars daily with that rolling rack and I've yet to find one I can't lift
 

WhiffySpark

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You can jack on the control arm or where the rear control bolts to the subframe. It can be done, you don't need to build a contraption that will probably get something damaged or someone injured
 
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DerStig

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Well, first of all if I were to indeed get an adapter made it would be made out of thick steel. Not sure how this can cause injury. It will literally slide on to the rolling jack from one side and will be 6' long. Then I will place hockey packs on each end where it touches the frame/jack points. I m curious why you think this can cause injury.

The front of my car has no visible suspension component that I can lift from. The rear does have the control arms however, they are too high with respect to the exhaust and rear differential. In other words, the jack will be touching the exhaust or rear diff before it meets the rear control arm. Yes I could use a small piece of 4x4, but to be honest, wouldnt it be so much easier just to slide 1 solid piece of steel and lift from the jack points rather than this?

Also what happens if you have to do any suspension work? Thats the other bit. If you lift from any of the control arm area, you may have issues no?

But with all that said, front of the car has absolutely nothing useful for lifting.
 

lakeroadster

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Jan 19, 2015
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I have an Rj45 for my 4 post lift. Unfortunately one of my cars have a 64" inch from side to side whereas the jack has 59" or so. This particular car has no other accessible areas that I can lift from, no K member, no pinch welds or other body panels. Everything is covered with hard plastic/rubber panels.

The question I had was, can I use a 2x4 or a 2x8 or any other wood based basic solution to extend the reach. Or do I need to build a steel based long adapter. I could probably have a custom made adapter that is in U shape and use it upside down so it fits right on top of the pads and slides in. However, if wood works thats even better.

Suggestions are welcome.

Bolting your adapter to the jack is the best situation. This keeps the tube from rolling off the jack.

Perhaps remove the adjustable adapters and bolt the adapter there, then thread the adjustable adapters into your adapter.

If you were to tell us the weight of the vehicle at the lift point, and the width of the jack, we could run the numbers and tell you what would be the best material/size for the adapter.

Have you called Bend Pak to see if they have any recommendations?
 
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DerStig

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Jun 15, 2015
Messages
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Bolting your adapter to the jack is the best situation. This keeps the tube from rolling off the jack.

Perhaps remove the adjustable adapters and bolt the adapter there, then thread the adjustable adapters into your adapter.

If you were to tell us the weight of the vehicle at the lift point, and the width of the jack, we could run the numbers and tell you what would be the best material/size for the adapter.

Have you called Bend Pak to see if they have any recommendations?

My vehicles weigh 4400 lbs and 3800 lbs respectively. They both have around 50/50 weight distribution.

Just to clarify here, the adapter will be one solid piece of metal, 6' long that will extend from side to side. How can it slide off? 9-10 gauge steel that long will probably weight at least 20-30 pounds and considering my lift/the jack are level. It shouldnt really slide.

I would have preferred to do this using wood so I could it on my own but I dont know if wood will be strong enough and not break in the middle. Because what will happen is the edges will make contact and start bending.

The length of the jack with the adapters, tip to tip is 60 3/4". The longest of my vehicles that needs the extension is exactly 64". So I need merely a 2" extra extension on each side. If a 2x4 can handle that (or perhaps 2x8), maybe I can try that? Not sure.
 

rjacobs

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Jul 24, 2015
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Bmw 5 series.

I checked today, there is no way. But i m happy to hear your thoughts.

What year.


E60's have a front center jack point then you can put stands under the rockers. The rear center jack point is the differential and again, stands under the rear of the rockers.
 
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DerStig

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Jun 15, 2015
Messages
441
What year.


E60's have a front center jack point then you can put stands under the rockers. The rear center jack point is the differential and again, stands under the rear of the rockers.

Its 2015. The rear diff is a no no, they say that everywhere? The techs I spoke to say that can only be used for a very short period of time no more than a min or so to quickly raise the car. I cannot use it say for brake work.
 
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