Changing tire - Page 2 - Montana Owners Club

**Rondo** · 10-18-2009, 04:23 PM

Dave-- Next time we're together we may be working on that jacking system on our "Old" rig.
Hey John-- How about some pictures of these new jacks you and Dave installed? It sounds a whole lot easier than digging out the hydraulic jack -- if and when you ever need it for a flat tire!

H. John Kohl · 10-19-2009, 01:40 AM

Quote:

quote:Originally posted by Exnavydiver

I just finished helping John attach his new 7 (k pounds)[s]ton[/s] scissors jacks right in front of the front tires on his rig. The original reason for these was to add a bit more support for the frame to nullify any frame bounce along with his JT's. The result of this addition was an already in place Jacking system for changing tires. All he has to do now is add about 6 inches of blocks under the bottom jack pad and either with the crank or a drill with socket he can lift the whole side of the rig to change tires. I am thinking of doing the same mod just for the ability to do a fast tire change without having to haul out the hydraulic jack. I always have enough 4x6 blocks for this operation and can have the rig jacked up and tire off in less than ten minutes. Just another option... Dave

Disclaimer. The claim the are not for jacking the trailer for changing tires. I will post photo and not sure I would use them for a jack.

Exnavydiver · 10-19-2009, 01:45 AM

OOPS!! My mistake! I have done several searches and found no scissors jacks over 7500 lbs. Which means in order to "safely" jack the rig I would need two per side plus I always use safety stands. I still like the idea of the extra stabilization but I guess the emergency tire jack idea may be out the window... Sorry.... Dave

mtpocket2 · 10-19-2009, 05:20 AM

8e3k0
You make perfect sense. As I have said in the past every time you go over a curb, hit a pothole on any bump in the road you are supporting the whole weight of the trailer on one axle. And doing it in a violent manner. Jacking by the U bolt the few number of times in the life if the trailer is not going to hurt anything. And I would bet 90 percent of the time when anyone has work done on their trailer such as brakes or wheel bearings they are raised that way especially if it is roadside service.

SlickWillie · 10-19-2009, 10:53 AM

It sure doesn't bother me for those that do so to block up and jack under the frame. Personally, I think a lot of the instructions given by any type manufacturer is for liability concerns. If they were to tell you to put the jack under the axle at the u-bolts and someone put the jack to far in, and bent the axle, I can imagine a good pissin' match. This way, they simply tell you that you jacked it up improperly; case closed.

tonycamacho · 10-19-2009, 05:29 PM

I have followed this post from the beginning. This is my question, why can’t you place the jack on the spring on one side or the other side of the axle near the u-bolts. You are still close to center and not pushing on the axle. I just did this to adjust brakes and really could not see any more stress place on the spring which would not be place by a bump in the road or uneven road surface. I used a 12 ton Harbor Freight Jack with a 4X4 under it
with really no problem.

Tony

8e3k0 · 10-19-2009, 06:48 PM

Because of the slope of the spring from the axle to the shackle is normally up, there would be a tendancy for the jack to slide or slip out and away from the axle area. The bottom overload spring may stay horizontal but I would be very careful and ensure that as you lift, the angle of the spring does not change and kick that jack out. IMHO: could be a potential for an accident will working on or changing the wheel.

Tom S. · 10-20-2009, 12:03 AM

I would NEVER lift using the spring! Besides what 8e3k0 stated about the lateral forces of the springs, using a jack on springs creates a 'stored energy' condition that spells danger. Instead of relying on a solid non-moving component (the frame) to hold the weight, you are betting that stacked springs, shackles and the Mor Ryde suspension (if equipped) will remain immobile, which they are not designed to do. It's an accident waiting to happen scenario.

mtpocket2 · 10-20-2009, 08:08 AM

I have a question about jacking using the frame. If the frame cannot support and additional weight other than what comes off the factory line how could you be safe jacking by the frame. We are told no hitches, Freezers in the trailer add too much weight etc etc. You are concentrating the entire weight of half the trailer in this half dollar spot on the bottle jack. I would bet the frame manufacturer will tell you the only safe way would to be to support the frame in many places along its length. Then you would need a rig similar to a house moving company to change a tire. There must be some kind of tire changing conspiracy going on here

. SlickWillie is right. There is no right way to do it so nobody is at fault if something bends or breaks.

scductman · 10-20-2009, 03:27 PM

I had a tire man start to jack mine up in the middle of the axel. he said that way he could change both tires at the same time. after a very short conversation he jacked one side at a time. that being said I jack mine at the u-bolt to change a tire and I have several times with no problems but I only jack high enough to clear the ground. besides GOD looks out for fools. I know this because I am still here.
bobby

1Happycamper · 10-20-2009, 04:08 PM

Bobby,after meeting you I know you ain't no fool

Bill

grampachet · 10-20-2009, 04:43 PM

Lifting on the frame or the u-bolt has always bothered me. Trailer weight around 12,000 lbs. Lets say that when you lift the frame with your hyd jack you are lifting say, 1/4 of the 12,000 lbs, or 3,000 lbs. The top of the jack is about 3 square inches. So wouldn't you be putting 1000lbs per square inch on that I beam, or u-bolt or what ever you put your jack under.
I always feel more confident putting a wooden block on the top of the jack to spread that weight over more surface.

Tom S. · 10-21-2009, 01:30 AM

Quote:

quote:Originally posted by grampachet

Lifting on the frame or the u-bolt has always bothered me. Trailer weight around 12,000 lbs. Lets say that when you lift the frame with your hyd jack you are lifting say, 1/4 of the 12,000 lbs, or 3,000 lbs. The top of the jack is about 3 square inches. So wouldn't you be putting 1000lbs per square inch on that I beam, or u-bolt or what ever you put your jack under.
I always feel more confident putting a wooden block on the top of the jack to spread that weight over more surface.

Except now you are concentrating that force on a piece of wood, which can cause it to crack or break. If you are concerned about the jack, use a piece of steel instead, maybe something 1" x 2" x 4".

8e3k0 · 10-21-2009, 03:36 AM

At home and in the shop we use a plate of 3/4 inch steel that is approximately 8 to 9 inches long and 3 inches wide to fit against the frame and the jack itself. Naturally we do not carry that with us when travelling. Good quaility hardwood will work if you use a 3 X 3 by 1/4 inch plate between the jack and the wood. I've used a 6" X 6" by 3 foot timber up against the frame when applying the above method. I then use rigid jack stands when working under the unit. You can be guranteed the shops do not go to any extent of caution to lift the 5ier on one side. It will be the easiest and quickiest method.

clbrandt · 10-21-2009, 04:06 AM

I had tires blow on me a while ago and was given the same excuse! Next camper I purchase I started using a tire protector spray on that protects it from the UV rays and winter weather supposedly. These products do keep the tires from drying out but I don't think anything can protect against separation that seems to be too be a manufacturer defect. Don't give up on the fifth though.

Art-n-Marge · 10-21-2009, 10:08 AM

There have been good conversations about jacking up our 12,000lb rigs but we mustn't forget that we typically only raise about 1/4 the weight (1,000, or 1.5 tons) at the frame or U-bolts when changing one tire. I suppose from what is written to not jack from the axle that that is the only concern point.

I think everyone's idea to use some wood on top to spread out weight, use a 6 or 12 ton jack and avoid any part of the axle, use a u-bolt or any parts of the frame I think we'll be okay.

Note to all, not to discredit tow truck drivers since I have some as friends and neighbors they don't always know everything about every vehicle or RV any more than I would want my Pep Boys auto mechanic to work on my custom motorcycle. There are many not familiar with RVs because they are used to light duty services and like to work fast. Jacking from the axle is easy for a tow man. IMO it is up to us to know what's being done to our RVs so we can educate and keep things working safely. Remember that they just want to get you back on the road as quick as they can and that the next problem YOU have may be on someone else's work order. I can't fault them for that, but Trailers are different than cars and truck. Again, just my opinion.

Tom S. · 10-21-2009, 10:55 AM

I wonder if we could use a half round cradle that either fit around the bottom of the axle tube between the U-bolts, or fit around the U-bolts themselves to lift the axle safely. I'm thinking about a piece of heavy wall tubing cut open to form the cradle and welding a 2" square flat piece on the bottom for the jack.

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