Emergency Factory Jack use and measurements

[aseibel]

Another thread go me thinking about my emergency jack and how it would work if I needed to put on the spare. I've had my truck almost 3 years and never accessed the spare tire or jack on this truck. So today I exercised the spare tire cable and checked out this jack.

 

It is a piddly little thing with a narrow base that doesn't even sit flat on a concrete floor due to the shape of the base. It does extend higher than I expected for a unit that folds down to barley over 6" tall when retracted. I was wondering how high it would go, so I ran it all the way up. Just short of 18" tall.

 

Now I'm wondering how high I need it to go to lift the front end of the truck to change a tire. With stock 265/65R18 tires (31.5" dia), I need almost 14.5" under the frame rail to lift the tire off the ground. That is fine for my situation, but only leaves about 3.5" of extra travel for anyone with a lift/level or bigger tires.

 

The rear end jack point is under the axle, I needed about 14" to lift the rear wheel off the ground.

 

Cliff notes: If you have any mods that lift your frame more than 3.5" higher than stock, you will not be able to change a flat tire with the factory emergency jack. And if you are on any kind of soft ground and the jack sinks in, it would be difficult even with a stock setup. I'm probably going to keep a block under the seat with my jack just in case.

 

Notes: I have Timbrens on the front and Hellwig helper springs on the back, so my truck probably sits a fraction of an inch higher than a bone stock crew cab, but its pretty close.

 

Photo captions:

1) factory jack at full extension

2) front frame height when sitting on factory tires/wheels

3/ front frame height when wheel is off the ground. (Yes, I used my floor jack to measure, its much faster)

[chrispassas21]

I actually tested this out before with my truck with 4.5” lift and it 100% works with the back wheels....I didn’t try with the front but I don’t see why it wouldn’t work. Just my .02 cents


2015 Silverado LT Midnight Edition
4.5” CST suspension lift
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[Madcow2020]

I’ve used it with 34 inch tall tires on the side of the road in the desert and it worked just fine for the rear end. On the front it would probably be best used under the control arm if you can get it in there. It would eliminate the suspension droop out.


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[Pearl2017]

Put the jack under the LCA and not on the frame. Been doing it this way as long as I can remember without issue. Of course if the tires are really fat maybe you cant get it out far enough on LCA to lift properly?

[aseibel]

On 4/6/2018 at 4:14 PM, Madcow2020 said:

 On the front it would probably be best used under the control arm if you can get it in there. It would eliminate the suspension droop out.

 

On 4/7/2018 at 2:14 AM, Pearl2017 said:

Put the jack under the LCA and not on the frame. 

Yes, that would be the only solution. It would probably work just fine. I was just pointing out that the "suggested" jack point would become unusable for those with larger tires unless you either have blocks under the jack or some alternate way of doing it.