LarryJM wrote:
Not just you, but I get a kick out of each of these stability threads and all what at best I call BANDAID fixes to fix a poorly designed and executed system in the first place which is there for the glitz and WOW factor than from a sound engineering execution. Most of these BANDAIDS require you to put more "STUFF" under the trailer exposed to road grim, harsh environmental elements such as water, dirt, etc. and require periodic maintenance (lubrication, painting, etc.) which in an of it's self is counter intutitive ... the less you put in that environment the better off you are and then they try and add exposed electrical stuff there like the power assisted stability jacks:R Of course we also have the not so seldom issue where someone has bottomed out the rear of their TT and bent up those expensive "stabilizer jacks" and now have a whole other issue to deal with.
The trailer movement when parked comes from two main sources, the tire and suspension flex, and the inherent frame flex over the longer spans in bigger trailers. Two secondary sources are axle movement mainly from spring type suspensions and the inherent "SLOP" in the stabilizer jacks because of the multiple joints and moving parts. To solve or address these two MAIN sources one needs to remove or mitigate the former and reduce the latter. Things like chocks etc. at the wheels and these stabilizer bars only address the less important IMO SECONDARY sources and do little to FIX the main sources of movement.
Lets stop and look at why this common problem in TTs/5ers is not an issue with MHs especially Class As. The two distinct differences are these MH type RVs are supported with their suspensions at the corners and have much robust frames designed for less flex over the span of their WBs. Also, they generally employ not the typically sloppy expanding stabilizer jacks like we have in most TTs that are placed far away from the suspension elements, but use bottle type jacks capable of actually supporting and hence also leveling the RV at the same locations as the suspension points. Thus these type RVs don't suffer the "ROCK-N-ROLL" syndrome we have in the TT world.
Back to our TT ... A lot of success is noticed when folks put an extra pair of jacks closer to the axles since now they are attempting to address better the suspension/tire component of trailer movement and the more they can crank up these jacks near the suspension area the better stability they see. However, we have then added two more "THINGS" under the trailer to worry about from a maintenance point exposed to that less than optimum environment when not in use unless you don't attach them to the trailer permanently. What I believe are only marginal improvements can be gained with things trying to stabilize the wheels with chocks/supports or adding supports to the stabilizer jacks and the level of success IMO is more on how much one spends on these bandaids and the placebo effect based more on the amount of $$ spent that have to improve the situation over any actual improvement.
I do have a solution, but it's not that popular and in general is met with a lot of resistance since as a first step it requires one to accept that what they have now is basically a piece of "JUNK" and is better served in the recycle bin than on their trailer for the most part. My solution reduces by 1/2 the "STUFF" hung under the trailer and requires two additions, one of which is a good idea in general anyway and serves extra purposes which is generally the main reason folks have it anyway. A HUGE benefit of what I'm suggesting is the worst you can spend and fail is around $50 and that $50 isn't totally wasted since it can be used for other things. The most expensive thing needed is to upgrade if you haven't already to an electric tongue jack. The second purchase is to buy a decent set of the aluminum "OLD SCHOOL" screw type jack stands like the ones shown below:
One caveat to what I recommend below is that unless you have a really long (30' and over) trailer with a normally occupied area in the rear you may or may not be able to remove the existing rear stabilizer jacks, but testing and experimenting will tell you if that is the case. In our case the bedroom is at the rear and it's just the two of us and while you can definitely get the "ROCK-N-ROLL" from excessive movement back there it's just the two of us and we just don't do our "morning jumping jacks" in the bedroom so the movement that we get from how we use our trailer is acceptable w/o needing any stabilizer jacks at the rear of the trailer.
HERE is my system and you can test this one out for just the price of the 4 screw stabilizer jacks and leave what you have on there until you test out my system and see if what I'm advocating works for you. I'm not going to get into the back and forth about how convenient the existing system is over having to actually bend down and put something under the frame like these new jacks ... never mind all the posts about having to put blocks of wood under the existing jacks to limit their extension, or dropping, attaching or adjusting these add on stabilizer bars that you might consider adding anyway. All things considered, I think my system is in the end simplier, easier and with out a doubt about the best you can do unless you are willing to use 4 like 10T "BOTTLE" hydraulic jacks instead of the screw type jack stands.
The whole "SECRET" here is in the where and how you put and set these 4 jack stands. You might have to do a little experimenting based on the specifics of your trailer and it's living layout and who uses it. The first secret is to get the support much closer to the suspension points and I have found based on our 31'+ TT that about 4 to 6 ft in front and to the rear of each axle is a good target area. The second just as important step is in how you set these jack stands up. This is where that electric tongue jack is a life saver. You need to start with the trailer about 1" down by the tongue and put the rear jack stand in and "SNUG THEM UP" hand tight. Then you raise the tongue of the trailer about 2" "TONGUE HIGH" and put in the front jack stands and again "SNUG THEM UP" hand tight. Then you lower the tongue till all weight is off and then raise it again to just get a good pressure on it. Some will caution about "tweaking" the frame when putting pressure on these jack stands, but IMO that just is not an issue since we are only now talking about most support being across a span of between 8 and 12 ft and to the close to 30' if trying to support the entire span of the trailer on the existing stabilizer jacks. Also, you're not "LIFTING" the wheels off the ground you just need to get a real good upward force on the frame at those points. I actually measured the force when I dialed in my new system with my Sherline tongue scale and had around 400lbs of force on each jackstand. Now if once you find the best new locations for these jackstands you can remove and discard the old front jacks and depending on how well the overall stability is from movement in the rear of the trailer you might be able to also remove those rear stab jacks or if needed deploy them to just take out the "FRAME FLEX" component from that 10' or so span between your new rear jack stands and the actual rear of the trailer. As a consideration you might even store the removed jacks and put them back on when you get rid of the trailer so the next clueless owner won't feel he's not getting what is generally installed on trailers now days.
Worst case is you hate my idea and now have spend $50 on 4 jack stands that you can probably find a use for or sell.
Larry
Just wanted to post an update. I used 4 automotive jack stands (its all I had and wanted to test before I bought other ones) under my travel trailer the last time I set it up, following Larry's suggestions. Since I did not have an electric tongue jack I used a carjack to raise and lower the tongue. The trailer is solid as a rock and I will continue to setup my trailer like this, I highly recommend it. Thank you Larry!!
