Why it’s important both not to exceed the weight capacity of your floor jack and to choose one rated higher than what you actually need.
A member of the Average Middle Class Garage Goals Facebook groups shared photos of his newly purchased Pittsburgh 1.5 Ton Low-Profile Aluminum Racing Floor Jack shortly after it failed lifting the rear of what looks like a Full Size mid-’90s Chevrolet C/K 1500 truck.
He’s since deleted his post, but group members screenshotted it and re-shared it for posterity’s sake. I’ve also erased out his name because it’s the polite thing to do.
“I JUST bought this Pittsburgh 1.5T Aluminum jack over the weekend and used it for the first time today to lift the rear of my truck,” OP captions his photo. Level ground, front wheels choked, and well within capacity, and this is how it ended up. Please use caution.”
OP originally deleted his post because he was being called out by other group members that the jack was used not within its rated capacity, despite his claim that it was.
According to Chevrolet truck owners of the same generation, their C1500s weight north of 4,000 pounds (closer to 4,500 pounds)
Typical full-size American trucks have a 60/40 weight distribution split front and rear. Seeing how this is a 4×4, this truck is probably closer to a 55/45 split.
4500*.45 = 2,025 pounds which is well within this jack stand’s rating, right?
Technically, yes, however, there are rules of thumb for a reason.
According to CarTalk and most experts recommending floor jacks, ” a floor jack needs to be rated for at least three-quarters of a vehicle’s gross weight.”
With that in mind, OP should’ve chosen a jack rated to lift over 3,375 pounds or greater than 1.5 tons.
While the floor jack wasn’t technically underrated for the job, it obviously was.
Many, myself included, attribute this jack’s failure to a load shift (as evidenced by the way the jack failed.)
Presumably because of physics, a load shift might exert a force greater than the jack’s rated capacity, which might’ve contributed to this particular jack’s failure.
One can only guess, but if OP selected a 2T or 3T floor jack, it might’ve been able to handle said load shift.
Floor jack material might’ve also played a role in this floor jack’s failure, as even Harbor Freight’s cheapest steel floor jacks are rated up to at least 2 Tons (4,000 pounds.)
For small cars and most compact SUVs, those $90 Aluminum floor jacks might suffice but, if you’re working on larger vehicles like trucks, vans, and full-size SUVs, it would behoove you to choose a jack with an appropriate (larger) capacity.