Sizing a jack and jack stands

[chrisclark]

I recently purchased a tractor and a trailer and want to have an appropriately sized jack and jack stands on hand in case I need to work on them. Actually, the trailer could use a couple of new tires.

Am I correct in assuming that the jack and jack stands need to support roughly half the weight of the object they're lifting?

The tractor with RimGuard and front end loader weighs about 6600 lbs; the trailer weighs about 5250 lbs. Would a 2- to 3-ton jack and stands would allow an adequate safety margin?

Thanks,
Chris

 

[Looking4new]

Not in my mind. 3 tons is only 6,000 lbs. What are you gonna do with the other 600 lbs you are left with? I would go for 10,000 lb stands and jack. Better too much jack and stands than too little.

 

[chrisclark]

Since a jack only lifts half the vehicle, wouldn't the other half of the weight be supported by the ground or jack stands that are already in place?

Do the weight ratings show what the jack can lift or an individual jack stand can support? Or do they assume part of the weight is being held by the ground / other jack stands and therefore show the weight of the vehicle that can be safely lifted / supported?

Thanks,
Chris

 

[Looking4new]

I'm just saying that I would want more jack capability and more stand than I really need. Assuming of course that it is my life that would be under the stands. As far as I am concerned, more is better when it comes to jacks and stands.

 

[bcp]

A quick search shows there is confusion about jack stand ratings being per pair or each. Some are one way, some the other. Try to get that information from your jack stand source.

The weight of a vehicle may not be evenly distributed. A jack on one side or end may be holding more or less than 1/2 the total weight.

I like a safety margin beyond that of the jack rating itself, so I would use at least a 3 ton instead of a 2 ton for a 2 ton load.

Bruce

 

[chrisclark]

Yes, I agree that excess capacity is desirable, both for safety and equipment longevity. A 20k jack / stands would provide an even wider margin than the 10k you mentioned.

I've never shopped for a jack or jack stands before. I suppose I have 3 questions:
- How do I interpret the weight rating on the jack / jack stands in terms of real world capability?
- What fraction of a vehicle's weight should I expect the jack / individual jack stands to carry?
- What is a healthy margin for safety?

I've read that one should never get under something supported by a jack—the object should be on adequate jack stands first. I also assume that a vehicle's weight is not evenly distributed and that, in the process of setting a vehicle on jack stands, the jack and an individual stand will have to carry at least half the vehicle's weight at some point.

I figure the answers to my 3 questions above will validate or refute my assumptions.

Thanks,
Chris

 

[chrisclark]

Thanks!

A quick search shows there is confusion about jack stand ratings being per pair or each. Some are one way, some the other.

You'd think that there would be consistent standards for that sort of thing.

I would use at least a 3 ton instead of a 2 ton for a 2 ton load.

I definitely agree with a generous safety margin. My 14k trailer has a single 10k jack stand built in for when it's not hooked up. Assuming the stand would have to support half the weight of the loaded trailer, that's also approximately a 50% margin.

Thanks,
Chris

 

[RedNeckRacin]

I would think that getting real close to the jack's operating capacity would make it a chore to operate. I think 2 ton would be the minimum but a 5 ton bottle jack would work well with some crib blocks. I would make sure that the jack stands I got were based on the single loading rating and not the double. Who knows what you may be working on later. If you already had a 3 ton floor jack, I'd say worst case scenario you do a corner at a time.

 

[oosik]

I get the feeling that there may be some misunderstanding here. First is the assumption that wherever the jack is placed under a tractor it will only experience 50% of the weight of the tractor. That assumption is not necessarily true and a sudden shift of the tractor could seriously overload the jack and cause failure.

The exact same condition will apply to a jack stand. Besides why would you want to take on the unnecessary risk of where to place a jack so that you do not exceed its rated load.

My tractor as now loaded weighs 9875 pounds. My floor jack and jack stands are six ton rated. I have no concern where I lift or place the jack stands.

Yes, it may be more than ever needed but I do not want something falling on me either.

 

[sixdogs]

I use the three ton jack stands under my 3800 lb tractors and six ton under the 9000 lb tractor. In all cases I add backup extra jacks if I plan to crawl underneath. Don't forget most our jacks came from China and you can never be sure of the quality. Better to have an extra jack underneath and not need it than need it and not have it.

 

[SPYDERLK]

I recently purchased a tractor and a trailer and want to have an appropriately sized jack and jack stands on hand in case I need to work on them. Actually, the trailer could use a couple of new tires.

Am I correct in assuming that the jack and jack stands need to support roughly half the weight of the object they're lifting?

The tractor with RimGuard and front end loader weighs about 6600 lbs; the trailer weighs about 5250 lbs. Would a 2- to 3-ton jack and stands would allow an adequate safety margin?

Thanks,
Chris

Yes but no. If you find yourself unable to use common sense, thereby jacking too near the horizontal location of the center of mass you will need a jack with capacity closer to the total weight. Of course jacking or jackstanding anywhere near this position presents an unstable construct ... balancing on a single point. You will do fine with a 3T jack.

Jackstands have to be considered for their capacity AND inherent height range and base stance. You will need a set of 6T as well as the smaller sets. You will pay for the 6T. The smaller ones are cheap.
larry

 

[Threepoint]

A quick search shows there is confusion about jack stand ratings being per pair or each. Some are one way, some the other. Try to get that information from your jack stand source.[snip]

Good point. I used a pair of 6 ton Harbor Freight jack stands to lift the rear, and later the front, of a 14+ K lb motor home a few years ago for a brake job. HF's website says a pair of the 6 ton will handle 12 K lbs. 6 Ton Jack Stand Set I did not work under the RV while doing this, though. Jacking was done with HF's 4 ton jack. I've not used either the jack or the jack stands yet on my Kioti NX4510HST Cab with loader and filled rear tires. But seems to me that this combination would be quite sufficient.

 

[bcp]

From HF:



Bruce

 

[SPYDERLK]

Good point. I used a pair of 6 ton Harbor Freight jack stands to lift the rear, and later the front, of a 14+ K lb motor home a few years ago for a brake job. HF's website says a pair of the 6 ton will handle 12 K lbs. 6 Ton Jack Stand Set I did not work under the RV while doing this, though. Jacking was done with HF's 4 ton jack. I've not used either the jack or the jack stands yet on my Kioti NX4510HST Cab with loader and filled rear tires. But seems to me that this combination would be quite sufficient.

6T ... 12K#. Makes sense. :confused3:

 

[Utopia Texas]

Whenever I use jack stands for repairing my vinetage cars or my tractors I always use a backup also which is usually 3' long pieces of railroad ties or wood 12" x 12" blocks stacked. One can never be too safe.

 

[chrisclark]

Wow. There are quite a few factors I hadn't considered.

…jacking too near the horizontal location of the center of mass you will need a jack with capacity closer to the total weight.[/QUOTE[

Aren't there designated hard points where a jack can be positioned to lift the tractor without causing damage, like with my car? Or are they strong enough that they can be jacked anywhere underneath? Or is the center of mass movable, such as if I need to perform emergency maintenance in the field and the nature of the problem makes it impossible to disconnect an attachment from the 3-point-hitch?

Thanks,
Chris

 

[SPYDERLK]

No special designated hard points. I would jack from the axle housing or other visually massive parts of the assembly to be safest. You dont want to apply intense pressure in the center of a broad flat expanse. If in doubt put a section of 2x6 on the jack saddle as a cushion.
larry

 

[stingray1]

Whenever I use jack stands for repairing my vinetage cars or my tractors I always use a backup also which is usually 3' long pieces of railroad ties or wood 12" x 12" blocks stacked. One can never be too safe.

I agree 100%

 

[Scooby074]

Jackstands are rated in pairs.

I use 6ton for everything. Not only for capacity but for added working height.

Get good stands. Not cheapies from Princess Auto or HF. I had some PA 6 Tonners colapse on me. Luckily I wasnt under when it happened, but was sitting a truck down on one side before moving over to the other so the stands were unevenly loaded. It was only a f150 though.

Im using ones by Napa now that are 7 ton and ASME rated.http://www.napaonline.com/Catalog/C...cheting-Jack-Stands/_/R-NLE7915160_0344221454 They are substantially better made than the cheap chicoms and not that much more money considering they are a safety item. I also have a set of really oldskool made in the USA Blackhawk 6 tonners that are decent.

Just came across these ones that look real nice. Canadian made too which is rare. Pin style though. Wonder what the price is like? Request Rejected

EDIT: Catalog price doesnt look that bad for a NA made product. Price per 1 stand though. Request Rejected

 

[TomSeller]

You'd think that there would be consistent standards for that sort of thing.

That would take Gubbamint intervention. In this day and age with the need for less big brother, buyer beware.