4 jackstands on a5 degree sloped driveway?

[ajchien]

Ive for a driveway that is convex sloped. It's about 2 degrees near the garage door, but increases in its slope to about 6 degrees at the curb. Granted, I'd probably put the stands closer to the garage door where the slope is closer to 2-5 degrees.

Would you buys put a car up on 4 jackstands given this slope? I currently have two craftsman 4ton (china) stands, and 2 MVP (Walmart or autoparts store - china) 2 ton stands.

 

[retrobuilder]

Not at 6 degrees..at the least a wider counter 6 degree sloping wedge is needed.
The base of the 4 ton Craftsman stands are almost same as a 3 ton

 

[wise]

It would probably be fine, but don't risk it.

Cinder blocks or Wood Blocks would be a more stable bet, especially if you'll be crawling under it.

 

[PinkLinc]

It would probably be fine, but don't risk it.

Cinder blocks or Wood Blocks would be a more stable bet, especially if you'll be crawling under it.

I thought cinder blocks were a big no-no as they might crumble.

 

[NHBandit]

It would probably be fine, but don't risk it.

Cinder blocks or Wood Blocks would be a more stable bet, especially if you'll be crawling under it.

Cinderblocks can & do break from the weight of a car on them. Ask me how I know. Hard wood blocks would be my first choice and my second choice would be to use your jackstands with wood blocks under one side to make them level. For example a piece of 2x4 long enough to go under 2 legs of the jackstand. Whatever it takes to make them sit straight up as if they were on a dead flat driveway. Then adjust the height of them so the car sits perfectly level.

 

[Hiball]

Every jack stand that I have ever seen that failed was because it was used on a uneven surface. The cast portion is very strong when the forces are vertical, problems arise when that balance is upset.. Just my opinion based off the hand full of failures I've seen.

 

[The Ratchet Man]

It would probably be fine, but don't risk it.

Cinder blocks or Wood Blocks would be a more stable bet, especially if you'll be crawling under it.

Cinderblocks are not to be used in any form as part of a cribbing system. Period.

 

[retrobuilder]

btw- 6 degrees is around 10% of weight sideways on the stand. that's about 1/2 of a 2 ton car thats 200 pounds of side load on the tall tooth castings and if raised to 18" is a BIG bending load on those parts. The resulting reaction force to the base would have a shear load on the same castings..I would not get under the car without better support.

 

[LEVE]

Jack-stands on a slope? Nope, you're courting disaster.

Cinder blocks to support a vehicle? Nope, you're gonna die when they fail.

Wood? Will it be cribbing or a solid piece; I'm not a fan of either. I've done both, and won't do it again. I've had wood cribbing shift and fail. I've had sold pieces split under load.

So, what's the solution? Clean the garage and do the work on a flat, solid surface. Barring that, find another flat, solid surface for those jack-stands.

You might want to look at this:

http://www.garagejournal.com/forum/showthread.php?t=48904

 

[NHBandit]

btw- 6 degrees is around 10% of weight sideways on the stand. that's about 1/2 of a 2 ton car thats 200 pounds of side load on the tall tooth castings and if raised to 18" is a BIG bending load on those parts. The resulting reaction force to the base would have a shear load on the same castings..I would not get under the car without better support.

LoL.. I love it when the engineer types chime in with their slide rules & calculators. And good info to be sure. Tell me what you think about my suggestion to level the BOTTOM of the jackstands by putting hardwood under the legs on the low side ? Dosn't that completely eliminate the bending load you speak of and make them just as safe as if they were sitting on a dead level driveway ? The OP is talking about a slight slope, not a 45% angle like trying to jack up a car in turn 2 at Bristol Speedway.

 

[NHBandit]

LoL.. I love it when the engineer types chime in with their slide rules & calculators. And good info to be sure. Tell me what you think about my suggestion to level the BOTTOM of the jackstands by putting hardwood under the legs on the low side ? Dosn't that completely eliminate the bending load you speak of and make them just as safe as if they were sitting on a dead level driveway ? The OP is talking about a slight slope, not a 45% angle like trying to jack up a car in turn 2 at Bristol Speedway.

Edited to add.. my suggestion would only be safe with jackstands having 4 "legs". It's my humble opinion that 3 legged jackstands should be cut up and sold for scrap...

 

[LEVE]

Tell me what you think about my suggestion to level the BOTTOM of the jackstands by putting hardwood under the legs on the low side ?

I've thought about that a lot... and I don't favor it. Why? Things shift even when on a flat surface. Now, with the leveling wood you've introduced another point of failure.

Would it fail? That I'm not sure of... but since I've seen jack-stands shift on level concrete, I'd be wary of leveling with a wooden platform.

 

[retrobuilder]

Tell me what you think about my suggestion to level the BOTTOM of the jackstands by putting hardwood under the legs on the low side ? Dosn't that completely eliminate the bending load you speak of and make them just as safe as if they were sitting on a dead level driveway ?

Kind've like my wide raised wedge idea - you'll like this- the jack stand base is around 9 x10..needs about a 1.00" +/- .1" piece of ALUMINUM 6063 T5 PLATE, mill finish- (just make sure the neighbors kids or dogs all not around to knock it out and no wet concrete)..

 

[lilredex]

When I had a sloping driveway, the front or rear wheels were always on solid footings. Those stands are shop made from square tubing.......would never trust those cast ratchet sections you see on most stands these days.

They are probably made the same way lifting weights are made.......keep a few molds ready and have a place to dump your excess molten iron from larger pours.

Never, ever use concrete blocks to support anything (except your house, as intended)


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[alxdgr8]

Definitely would come up with a better solution. Lost a good friend when his car fell off jackstands on a slightly sloped surface. I always put some spare wheels/tires under the car too ever since.

 

[jmm]

me what you think about my suggestion to level the BOTTOM of the jackstands by putting hardwood under the legs on the low side ? Dosn't that completely eliminate the bending load you speak of and make them just as safe as if they were sitting on a dead level driveway ?

No. If you're placing something flat on an uneven surface, you're just increasing the height of the uneven surface. You're not changing the slope unless you add an angle, which I wouldn't try.

6 degrees doesn't seem like much, but you're getting under this thing. Can't be too hard to either find some level ground to work on.

 

[NHBandit]

Tell me what you think about my suggestion to level the BOTTOM of the jackstands by putting hardwood under the legs on the low side ? Dosn't that completely eliminate the bending load you speak of and make them just as safe as if they were sitting on a dead level driveway ?

Kind've like my wide raised wedge idea - you'll like this- the jack stand base is around 9 x10..needs about a 1.00" +/- .1" piece of ALUMINUM 6063 T5 PLATE, mill finish- (just make sure the neighbors kids or dogs all not around to knock it out and no wet concrete)..

I do like that suggestion and I think whether or not I'd trust jackstands depends on what I'll be doing on the car. Sitting beside it doing a brake job is something I'd have no problem with. Laying under it trying to wrestle a transmission into place, not so much.. Years ago when I managed an auto salvage yard what we used in the yard was old steel wheels welded together. One laying flat & one standing upright on top of it and welded together. We even had a few that were made up of a 14" wheel on top of a 15" wheel and then one upright on top of those and they were plenty strong even in the dirt on slightly uneven ground.

 

[retrobuilder]

....pulled out my old T.I. calculator (no slide rule found) and compared the strength of white pine to the what if condition is 2 tons, three of four jack stands actually support car. Civil standard design limit for pine is rated 6000 psi. If the jack stand has one side on edge raised up by wood one side. .06"x2" stand contact width...that's (yes theoretically on a six degree banked oval track) 2000/.12 sq inch or about 16,000 psi..even by numbers not truly a smart idea....ssspplllitttt.

 

[NHBandit]

LoL.. touche, but.. in all fairness I did specify hardwood which pine is not. And none of this really matters to me anymore since I put in my 2 post lift. I'm too old & too fat to lay on the ground under cars anymore and I don't know if you've ever had a ponytail get caught up in the wheels on a creeper but I can tell you it's NOT a fun event. ..

 

[2oolhound]

Cinderblocks can & do break from the weight of a car on them. Ask me how I know. Hard wood blocks would be my first choice and my second choice would be to use your jack stands with wood blocks under one side to make them level. For example a piece of 2x4 long enough to go under 2 legs of the jackstand. Whatever it takes to make them sit straight up as if they were on a dead flat driveway. Then adjust the height of them so the car sits perfectly level.

This works for me.

When I worked in construction we built scaffolding 80' and higher using the regular 5' wide x 5' high "H" frames that joined the second set with an X brace to form 2 parallel sets. The most important thing was levelling a base so they went up absolutely level.

Your plan of levelling the jacks AND levelling the car solves all but one problem. The possibility of slippage. Having the base on an incline allows the possibility that with enough weight and pressure the surfaces could slip particularly if they became wet or were on loose material.

The solution would be to concrete nail the levelling wedge in place or you could lay two long planks down and place the front and back jack set-ups on the planks so they were tied together. That way the planks would have to slide which is quite unlikely but if they did the whole set up would slide down the driveway and down the street leaving you staring up at the sky wondering "what was that torque value?"

 

[zkling]

This is not me telling you what to do, but simply what I would do if I was in your shoes....

For me personally I would pick the slightest slope to work on, measure it and then calculate / measure the shim height needed to get the stand plumb. I would make the shim out of steel and bolt it to the 2 ends that need shimming, that way it is permanently attached and can not slip off the jack stand.

Use the widest base jack stands possible. And as with all jack stands try to prevent rocking the car while on stands that means very limited breaker bar use.

Stay safe.

 

[Givl Reggin]

Would you buys put a car up on 4 jackstands given this slope?

No. You're asking for trouble working on a slope.

Move the car into the garage, where I assume it's level.

 

[Outlawmws]

I'm assuming you are talking about the Cast iron base jack stands. I don't trust those on a flat surface for anything heavy... An axle assembly? yeah; a car? No...

I'm personally not a fan of 4 jack stands supporting any vehicle. Get two ramps and get one end up (The end with a parking brake...)

Then lift and jack stand the other end. BUT, get the tube/welded stands....

Three legs are less likely to rock. Put the single let "down hill" if you absolutely MUST do this on a slope, and figure for 4 degrees its about 1/4" per 4" run. 8" from the two legs to the third, 1/2", 12" 3/4"...

That thickness is easy to space with aluminum or steel, or use plywood (not Solid wood or chip board) with 1/8" or more steel plate over that.

The only way I'll support heavy weight with wood directly is criss-crossed 4X4 or larger (See any rigging crew at work for steel girder supports for in the air concrete pours.)

 

[shiftdrift]

I've supported cars a lot of stupid ways, but after having one fall off the stands on a slight slope and almost crush me never will I work on a slope again. I've worked in gravel, grass and pavement and it doesn't matter what you have supporting it, they can fail.

 

[icor1031]

I hate to necro an old thread as a first post, but the comments here were great. If you want, I can make a new thread.

I have a 2-2.5 degree slope on my driveway. I use 6 ton jackstands with my ~2800lb FWD car. (but later I want a 3600lb RWD car.)


Is this amount of slope also dangerous?

Thanks.

 

[RedRabbit]

btw- 6 degrees is around 10% of weight sideways on the stand. that's about 1/2 of a 2 ton car thats 200 pounds of side load on the tall tooth castings and if raised to 18" is a BIG bending load on those parts. The resulting reaction force to the base would have a shear load on the same castings..I would not get under the car without better support.

As a non-engineer, it sounds good . I actually understand what your saying and agree completely.

 

[trackwelder]

I'm not a big fan of working on slopes but it can be done safely with the right materials. I have lots of hardwood cribbing in several sizes to make a sufficent base.