SUV/Truck jack stands. I have 2 sets of jack stands, one set for passenger cars, i.e. my GTO, and a larger set for my Tahoe. The Truck jack stands are 6,000 lbs and will lift to 24" off the ground.

These are not the ones I have, but are similar.

SUV/Truck Jack Stands

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Originally posted by Sig2340:

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Originally posted by MikeinNC:
It’s called “cribbing” it’s used in dry docks, and yeah I’d work under it and not be worried. I’ve been under a 300’ ship just held up by cribbing

And that drydock probably had a rule about walking under suspended loads. I never figured that one out.

All of them do, OSHA rules apply to dry docks…but the CG-being part of the military machine is exempt. So we did what we wanted!

The shipyards didn’t care as long as we wore hard hats, or at least one was found nearby when someone got crushed. We used to make a point of walking about with it under an arm or tied to your belt. Same with a PFD-it’s a freaking dry dock, prolly won’t drown.

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Originally posted by 1967Goat:
SUV/Truck jack stands. I have 2 sets of jack stands, one set for passenger cars, i.e. my GTO, and a larger set for my Tahoe. The Truck jack stands are 6,000 lbs and will lift to 24" off the ground.

These are not the ones I have, but are similar.

SUV/Truck Jack Stands

Jack stands work great, unless you want to load the suspension. I have some heavy duty ramps I use when I change my oil in the Sequoia/Tundra. They're not very tall, but they raise the effective working height under the car by quite a bit more than using a hydraulic jack and jack stands under the frame/axle.

And when rolling around under the car it's not not banging into the jack stands, which tend to be right in the way for some reason.


I'd have no problem using those stacks in the OP if they just added the bottom middle cross-brace.

I wonder how much those eight 2x4s are bending without the bottom middle cross brace. I suspect not at all.

If I were to build those, I’d start by building one with four short pieces and two long ones, putting that under the wheel of a car, and measuring how much the long pieces bent in the middle.

I’ve got a lot of hard maple 1.5 x 1.5 staves laying around… I don’t really NEED to make those at this point, but I sure want to. It’s right in my woodworking skill ballpark.

Actually, a set of ramps would be more useful for oil changes… back car up into drive way? Place ramps at front of car (downhill side of driveway) and then pull onto the ramps. I suspect I’d have gobs of clearance for the work while the car would be somewhat level.

Let's do some math:
3.5" x 3.5" (each corner of stand) x 4 (bearing surfaces/stand) x 4 (stands) = 196 in^2 bearing surface

ASSUME: car weighs 4,000 lbs conservatively, probably more like 3,600.
4,000 lbs / 196 in^2 = 20.41 lbs/in^2

This engineer says those blocks will hold WAY MORE weight than that assuming they are securely held in place. Notice drill in lower right of photo, probably sunk some screws in those 2x4's.

Even if the weight is 10,000 lbs, my GMC 2500HD with Allison and Duramax is 8,800 lbs, is only pushing just over 51 lbs/in^2.

I have tons of Jack stands and ramps.
And they work for the most part. However for this portion of the project they just take up so much room underneath.

I wonder what the math says about tip over.

Is there some formula we can apply to interpret tip-over/wobble risk?

Even jack stands give me the heebie jeebies if more than just a few inches off of the ground.

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Originally posted by jcsabolt2:
Let's do some math:
3.5" x 3.5" (each corner of stand) x 4 (bearing surfaces/stand) x 4 (stands) = 196 in^2 bearing surface

ASSUME: car weighs 4,000 lbs conservatively, probably more like 3,600.
4,000 lbs / 196 in^2 = 20.41 lbs/in^2

This engineer says those blocks will hold WAY MORE weight than that assuming they are securely held in place. Notice drill in lower right of photo, probably sunk some screws in those 2x4's.

Even if the weight is 10,000 lbs, my GMC 2500HD with Allison and Duramax is 8,800 lbs, is only pushing just over 51 lbs/in^2.

But weak point is the two 2x4s the tire is on. I’d like to run the numbers on those and looked up the shear strength and MOE, but since I’m not an engineer, I had no idea how to put the to practical use.