Jacking For Tire Change

[Bluedog]

Seems there is a lot of controversy over where to place a jack on a 2-axle travel trailer to change a single tire or service wheel bearings. Experts say under the U-bolt plate is not OK because of the danger of bending the axle. Question is how can the axle get bent when you are lifting the suspension system at the U-bolt location which is built to handle it. Same as driving the single wheel up on a 2 inch board. Some experts say to place the jack under the frame behind the wheel which appears to me to invite damage to the frame more so than the axle method. Also, this way the trailer has to be lifted quite high for the springs to extend and lift the tire off the ground. Under the U-bolt only requires a few inches to get the tire up.

Please enlighten me!

[FDNY38]

ford truck guy wrote:
Quote - "
Glad my kids won't be asking how to change a tire when they get older"

My 2 daughters were NOT allowed to drive until they :
1-could pay for the car, fuel, insurance
2- show me they could change a tire alone

My father made my sister change the oil before she could go for the road test.

[Sjm9911]

I use the floor jack at home and have 2 bottle jacks for on the road, I take extra cribbing incase I need it for stability. Either way works. Use whats comfortable for you. If you dont like floor jacks dont use them, same for the bottle jacks. But learn to use something safely.

[JRscooby]

Gdetrailer wrote:

I have been using a 3.5 ton floor jack for well over 30 yrs on a concrete floor to lift my pickup trucks. I have not once ever seen the wheels on that jack or trucks move even 1mm..

Seen, that is the issue. The fact that many people do not realize the jack wants to move points out to me there is a risk. The beauty of a floor jack is you roll it in place on hard surface, stroke it up to contact, check that it is right, then jack the vehicle up without watching it. You might be surprised if you marked at start.

That floor jack I have also has a contact point which looks like a castle and is 5" in diameter. Never had it offer to slide on that contact point either.

But when using the jack on a hard surface, like a concrete driveway, there is very little side force applied because the wheels roll. On the side of the road, wheels sunk into asphalt, there is a good chance of slip. (I have seen a little trolley jack lift it's rear wheels, wedged against bottom of car, when it rolled off 2X10)

I think you have a piece of junk floor jack if it moves that much distance, you need better floor jacks.

Not ALL floor jacks have a large arc swing, junky cheapos and 50 yr old ones perhaps but not all.

Well, my Walker is pretty old, but I have had several. All seam to work pretty much same way. I think how much the carriage moves could be calculated by somebody that paid attention in math class, knew length of arms, (Radius) and how much lift

You make a good point about only using part of the travel. This is best no matter what style of jack you use. That is why I suggest pulling the flat up ramp to get center of hub normal height before jacking. Little lift, pull ramp out, got all room needed

Floor jacks and even smaller cousin the trolley jack both have a large base foot print over a much greater area making them by far more stable and less likely to tip over provided you only use the absolute minimum lift needed.

Large contact area? Compared to what? All mine, even the 10 ton capacity I don't use anymore, each have 4 little bitty steel wheels that contact the floor. Now the contacts are spread out over a large area, are stable on hard surface. But the wheels will sink into asphalt sooner than the same weight on even the smallest bottle jack. Yes, the carriage will bottom out, spread the load, but not stable.

[Tvov]

Gdetrailer wrote:

....
If you jack directly under the axle you would only need to lift the tire about 1".

Now if you had a flat, my tire sidewalls are about 6".

Basically to change a tire you only need the jack to lift 6".

I measured my jack at 12" (6" min height + 6" lift).

The result?

the contact plate was now 3 5/8"..

The difference, 1/8"..
....

Ok, I understand with a large rolling floor jack only lifting 6" you will have minimal movement. Especially if it is not near the maximum lift height. As you point out, 1/8" of movement.

But go from all the way down to all the way up, every rolling floor jack I've seen (with a single pivot at the rear) will move on its wheels while jacking on a solid floor.

I think we are all talking about the same thing except in different ways.

[Grit_dog]

Gdetrailer wrote:

Now my floor jack tops at 18" lift and at that top the plate moves back about 2".. At that height would be stupid to consider to be usable.

But one could say the exact same for using any jack once you get past a couple of inches worth of lift, they all get unstable. Bottle jacks, scissor jacks since they have very small base foot prints get scary unstable the higher amount of lift you go.



If one ever needed full lift height offered by a floor jack, one might wish to rethink the approach which reduces the amount of lift required..

Lol, jack up something that isn't a pavement pounder and you'll use that travel. Heck, I have to put a wood block on top of my (not junky, whatever you called them) floor jacks fairly often.

I know you're trying real hard here to be right, but maybe time to pump the brakes a bit.

That, and I'm not familiar with a scissor arm floor jack.

[Grit_dog]

JRscooby wrote:



I don't know where you guys get the magic floor jacks that don't move. Just for snots and grins I just put a tape on 1 of mine (standard 7000 lb capacity that I load if I know I'm going to need a jack, or grab if I need to lift a car in the drive) I put the wheels against the wall and measured to center of pad. 5 inches. Jacked to top, 13 inches.

I'm with Scooby here. GDE, I am genuinely interested in seeing a pic of your rolling floor jack that doesn't just have a single pivot on the arm, which by default as the angle changes, the jacking point gets closer to the rear part of the jack.
Hard to believe 5 pages about changing a flat tire, but I guess that happens when people have magic floor jacks!

[Gdetrailer]

JRscooby wrote:

B-n-B wrote:


Actually it has a swivel saddle with a "scissored" lift arm and doesn't roll. Or, if it did I didn't notice enough to matter. I have actually used this jack twice without issue, so I'm not speaking hypothetically about its effectiveness. Once in a parking lot (on my car hauler) and once in sand (on my camper) at the CG. The 1x6 worked like a charm with the jack in the sand.
I don't know how I lived to tell about it.

Gdetrailer wrote:

Thin board UNDER the floor or trolley jack just like you SHOULD use under ANY jack solves your objection.

Was taught many yrs ago to never use any jack directly on ground as that ground can give way unevenly resulting in the jack tipping over.

Something else to consider, with a floor or trolley jack, the arc is small, maybe 1/4" inch in total travel for the entire lift. The vehicle also moves with that arc, your assuming the vehicle stays put and never moves which is not true. Trailers and vehicles are on wheels, the brakes, drive line have slop in them which allows the vehicle to move back and forth.

I don't know where you guys get the magic floor jacks that don't move. Just for snots and grins I just put a tape on 1 of mine (standard 7000 lb capacity that I load if I know I'm going to need a jack, or grab if I need to lift a car in the drive) I put the wheels against the wall and measured to center of pad. 5 inches. Jacked to top, 13 inches.
Junking cars around others junking cars, I have seen more than 1 slip off the jack because the little steel wheels would not roll on soft wood, or because the jack rolled off the end of the board.

I have been using a 3.5 ton floor jack for well over 30 yrs on a concrete floor to lift my pickup trucks. I have not once ever seen the wheels on that jack or trucks move even 1mm.. That floor jack I have also has a contact point which looks like a castle and is 5" in diameter. Never had it offer to slide on that contact point either.

I think you have a piece of junk floor jack if it moves that much distance, you need better floor jacks.

Not ALL floor jacks have a large arc swing, junky cheapos and 50 yr old ones perhaps but not all.

On edit..

I do want to add that I figure that you are considering that one would have to use the FULL lift height of a floor jack.. You are also wrong on that assumption.

So, for the heck of it, I measured my floor jack.

At lowest part of the range, it is six inches tall, I put the jack against a wall and measured the contact plate edge as 3.5".

That jack just fits under my trailer axle at 6" with fully inflated tire.

If you jack directly under the axle you would only need to lift the tire about 1".

Now if you had a flat, my tire sidewalls are about 6".

Basically to change a tire you only need the jack to lift 6".

I measured my jack at 12" (6" min height + 6" lift).

The result?

the contact plate was now 3 5/8"..

The difference, 1/8"..

The reality is very few people will ever need to use the entire lift of a floor jack to change a trailer tire. Basically only using a small fraction of the arc and that fraction is statistically insignificant.

Now my floor jack tops at 18" lift and at that top the plate moves back about 2".. At that height would be stupid to consider to be usable.

But one could say the exact same for using any jack once you get past a couple of inches worth of lift, they all get unstable. Bottle jacks, scissor jacks since they have very small base foot prints get scary unstable the higher amount of lift you go.

Floor jacks and even smaller cousin the trolley jack both have a large base foot print over a much greater area making them by far more stable and less likely to tip over provided you only use the absolute minimum lift needed.

If one ever needed full lift height offered by a floor jack, one might wish to rethink the approach which reduces the amount of lift required..

I am not a fan of placing boards or ramps under one tire to change the other nor the other gadgets that you must drive up on.. You have to lift the good tire very high in order to lift the blown tire high enough to get the new tire on.. Do that on the shoulder of the road (which isn't flat) on the high side and you risk toppling the trailer over..

[JRscooby]

B-n-B wrote:


Actually it has a swivel saddle with a "scissored" lift arm and doesn't roll. Or, if it did I didn't notice enough to matter. I have actually used this jack twice without issue, so I'm not speaking hypothetically about its effectiveness. Once in a parking lot (on my car hauler) and once in sand (on my camper) at the CG. The 1x6 worked like a charm with the jack in the sand.
I don't know how I lived to tell about it.

Gdetrailer wrote:

Thin board UNDER the floor or trolley jack just like you SHOULD use under ANY jack solves your objection.

Was taught many yrs ago to never use any jack directly on ground as that ground can give way unevenly resulting in the jack tipping over.

Something else to consider, with a floor or trolley jack, the arc is small, maybe 1/4" inch in total travel for the entire lift. The vehicle also moves with that arc, your assuming the vehicle stays put and never moves which is not true. Trailers and vehicles are on wheels, the brakes, drive line have slop in them which allows the vehicle to move back and forth.

I don't know where you guys get the magic floor jacks that don't move. Just for snots and grins I just put a tape on 1 of mine (standard 7000 lb capacity that I load if I know I'm going to need a jack, or grab if I need to lift a car in the drive) I put the wheels against the wall and measured to center of pad. 5 inches. Jacked to top, 13 inches.
Junking cars around others junking cars, I have seen more than 1 slip off the jack because the little steel wheels would not roll on soft wood, or because the jack rolled off the end of the board.

[Gdetrailer]

JRscooby wrote:

B-n-B wrote:


This exact jack would not get under a flat tire on my trailer, at least not under the spring perch. I carry a small floor jack with a 1x6 if needed.

Do you also carry the important part needed to safely use that jack? By that I mean a floor.
With no load on it, run the jack up. Notice the lift pad goes up in a arc? Normal lifting, the pad stays in contact with lifting point be cause the jack rolls under the load. If the wheels are setting on soft or rough surface the pad must slide on you lift point. At least you're not under when it drops.

Thin board UNDER the floor or trolley jack just like you SHOULD use under ANY jack solves your objection.

Was taught many yrs ago to never use any jack directly on ground as that ground can give way unevenly resulting in the jack tipping over.

Something else to consider, with a floor or trolley jack, the arc is small, maybe 1/4" inch in total travel for the entire lift. The vehicle also moves with that arc, your assuming the vehicle stays put and never moves which is not true. Trailers and vehicles are on wheels, the brakes, drive line have slop in them which allows the vehicle to move back and forth.

[Grit_dog]

@jimlin, good mention about being careful to not flip the equalizer link when getting one wheel jacked up on a leaf sprung multi axle trailer.

That always s ucks to bar those back over center!

[B-n-B]

JRscooby wrote:

B-n-B wrote:


This exact jack would not get under a flat tire on my trailer, at least not under the spring perch. I carry a small floor jack with a 1x6 if needed.

Do you also carry the important part needed to safely use that jack? By that I mean a floor.
With no load on it, run the jack up. Notice the lift pad goes up in a arc? Normal lifting, the pad stays in contact with lifting point be cause the jack rolls under the load. If the wheels are setting on soft or rough surface the pad must slide on you lift point. At least you're not under when it drops.

Actually it has a swivel saddle with a "scissored" lift arm and doesn't roll. Or, if it did I didn't notice enough to matter. I have actually used this jack twice without issue, so I'm not speaking hypothetically about its effectiveness. Once in a parking lot (on my car hauler) and once in sand (on my camper) at the CG. The 1x6 worked like a charm with the jack in the sand.
I don't know how I lived to tell about it.

[ford_truck_guy]

Just get a 6 point leveling system, problem solved! !:B

I did, along with a Milwaukee 18V impact gun makes the job easy and safe..

Heck, the hardest part is once I lower the spare, getting it from the center of the RV to the side....

[pbeverly]

Trailer Aide alone may not get the bad tire off the ground so you have to be prepared for that. I had to put aide on 2 boards once to get the bad tire high enough to change.

[Tvov]

So... 4 pages so far. Same as every other "jack" thread. Have we solved anything?

Whichever method you use, practice it at home first.

One thing (just to extend this thread... lol) I don't get is when people say to use the "frame" of the travel trailer. I would not trust putting a jack anywhere under the frame of my TT... it is so lightweight. I think the axles will hold up against bending long after my TT's frame might get damaged.

[JRscooby]

B-n-B wrote:


This exact jack would not get under a flat tire on my trailer, at least not under the spring perch. I carry a small floor jack with a 1x6 if needed.

Do you also carry the important part needed to safely use that jack? By that I mean a floor.
With no load on it, run the jack up. Notice the lift pad goes up in a arc? Normal lifting, the pad stays in contact with lifting point be cause the jack rolls under the load. If the wheels are setting on soft or rough surface the pad must slide on you lift point. At least you're not under when it drops.