Jack Stand Police, WOW! Did you know this; I didn't. See post #30 Options

[stinkindiesel]

I was curious why he didn't normalize all the tests for lift height, since lift makes such a difference.

Gary

[wonkipop]

That was really interesting, thanks for posting!

I don't use ratchet stands. Pin type only. I've always been a little annoyed because they have a large base and get in the way. Now I'm glad they are given how easy some of the smaller based stands tipped over!

170lbs can easily be the weight of a person walking up and leaning up against your car. "Whatcha working on....oops!"

Or your wife driving into the back of your 914 when you're under it. Ask me how I know! (IMG:style_emoticons/default/shades.gif)

I usually put a wheel or two under the car for that reason. I actually had an old safe with wheels that worked well for extra insurance. I’ve also added extra jacks so if one failed, it wouldn’t be an issue. I’m a big chicken about crawling under cars. But for the most part, if I have to get under a car to work on it, I’d rather it be on a lift.

i'm from the chookyard too.
get extra stuff under there.
wheels are ideal.

[ClayPerrine]

That was really interesting, thanks for posting!

I don't use ratchet stands. Pin type only. I've always been a little annoyed because they have a large base and get in the way. Now I'm glad they are given how easy some of the smaller based stands tipped over!

170lbs can easily be the weight of a person walking up and leaning up against your car. "Whatcha working on....oops!"

Or your wife driving into the back of your 914 when you're under it. Ask me how I know! (IMG:style_emoticons/default/shades.gif)

I usually put a wheel or two under the car for that reason. I actually had an old safe with wheels that worked well for extra insurance. I’ve also added extra jacks so if one failed, it wouldn’t be an issue. I’m a big chicken about crawling under cars. But for the most part, if I have to get under a car to work on it, I’d rather it be on a lift.

I am so paranoid I put a pole jack under the chassis even when the car on the lift is on the locks and allegedly safe. The pole jack won't save the car, but it hopefully will give me time to get out from under it before the car comes down. I love my cars, but I love breathing more.

[SteveL]

I built a set of wheel cribs out of lumber, solid all the way to the floor, with wheel stops, that are 12" high.
I lift up one side at a time with a big floor jack and drop the wheels on the cribs, then the other side. Totally safe laying under it.
If I need to have a wheel off, I then use the jack and another solid wheel crib under a jack point for safety.
I just never feel safe laying under a car on jack stands.

[914_teener]

Does the distance between stands really matter for that particular test on a solid axle? I’m trying to visualise the difference in how the required lateral force could vary based on jack separation distance and I’m not getting it?

BTW 170 lbs of lateral force is still a fair bit. That’s far more than someone casually leaning up against a car - that’s a serious deliberate push. If we’re worried about friends doing that perhaps we should pick our friends more carefully? (IMG:style_emoticons/default/biggrin.gif)

Some of this depends on where the lateral force is applied vs the center of gravity.

To try to keep it simple with no math.

Far left - simple block mass with a single jack stand under it. We would all agree this is dangerous and would be easily disturbed by applying a lateral force (F). That force would cause the mass to rotate (overturning moment) and it would tip over the jack stand in one direction on another depending on whether the lateral force F is applied higher than or lower than the center of gravity.

Middle - I’ve represented mass more like a car. Some of the mass is centralized but other mass is overhanging the jack stands. Although there are now two - they are too close to the vehicle center line.

Far right - same representation of mass. But now the jackstands are out underneath the outermost masses as far as they can go. In this scenario - force F is almost all lateral and doesn’t create the tendency for tipping due to rotation of the vehicle mass about the center line.

Hopefully this helps.

Ah...give me a "moment" and I'll be "normalized".

Yep...works for me.

(IMG:style_emoticons/default/smilie_pokal.gif) (IMG:style_emoticons/default/clap56.gif) (IMG:style_emoticons/default/pray.gif)


Imagine an elephant standing on the head of a pin that is 100 feet tall.

[914043]

With the possibility of a earthquake here in Ca. I can't trust anything that might tip over, like jack stands even Quick Jacks might do the same thing. A repurposed set of car ramps with a short length of 4x6 lumber gives me very comfortable access to work on the car from a creeper. Even more room with the wheels on. Here's what I use and a lot cheaper, safer and almost no chance of failure.

[bkrantz]

Here's my current (and typical) setup. Four quality jack stands, and the wheels and tires I took off the car stacked underneath as a backup.

[rhodyguy]

Those are nice pin stands. Looks like a wide base.

[wonkipop]

Here's my current (and typical) setup. Four quality jack stands, and the wheels and tires I took off the car stacked underneath as a backup.

thats me too. exactly. chicken little.

a bloke here got underneath his citroen raised to full ht. on hydraulic suspension to do some quick tinkering (because you can do it with one of those french things, but you have to disconnect your brain at the same time). no jackstands.

his wife found him in the garage. under the car. which had come down suddenly. as they do from time to time. he had left this world. (IMG:style_emoticons/default/sad.gif) (IMG:style_emoticons/default/sad.gif) (IMG:style_emoticons/default/sad.gif)

you can't be too careful esp if there is no one else around except little old you screwing around in the garage. (IMG:style_emoticons/default/beerchug.gif)

@914043 . like the earthquake thinking. we don't get them down here apparently.
until 2 years ago when we got a sizeable jolt. which shook the hell out of things.
and its had me thinking ever since.
i even look at the two post lift in the workshop sideways now!

[76-914]

https://apple.news/AScRwt4C3SLGBLYBtgjSWxg

[mgarrison]

https://apple.news/AScRwt4C3SLGBLYBtgjSWxg

Man, that just hurts to read in black & white... (IMG:style_emoticons/default/wacko.gif)

It's ironic; I was just explaining to my brother-in-law last weekend my biggest issue is I assume what's obvious/intuitive to me, is obvious & intuitive to everyone else. Nope. Don't even go there these days! As the Gunslinger always said "The world has moved on..." (IMG:style_emoticons/default/blink.gif)

[Justinp71]

A quickjack makes this easy, then I still put one massive jackstand with a pin under for safety. Just make sure you remove it when you put the car down (IMG:style_emoticons/default/smile.gif).