Weight causing tires to rub inside of trailer

jgos929 wrote:

Im interested in how you fixed the flexing. If you could point me in the right direction as far as what I need. A good buddy of mine is a fabricator and master welder and assures me he could weld me in some bracing if need be. Thanks

The lower flange on the RV industry I shape frame rails is really weak. If you unhook the spring and put a 12" adjustable wrench on the spring hanger with very little effort you can flex the entire lower flange. Your crack lines are from frame flex.

Here is what I did to correct the problem with hanger flex. However if you notice I already had 2 x 2 square tubing inside the frame down at the lower flange on the inside and I had a gusset on the middle equalizer. Yours has no gussets at all and may be missing 2 x 2 cross braces.

TT Spring Hanger Stiffening (Long, lots of pics)

Here are the cross 2 x 2 square tubes. These pics are before I added my cross tubes at the hanger and the frame gussets. These are more stock from my TT manufacture. I was looking for these on yours and there was no good pic to tell.

Rear spring hanger area

You can see it left to right here


Front spring hanger. This tube is burried under my tank cover, but it is just like the rear one


The equalizer area spring hanger. Here I have a fresh tank angle iron and the end of the enclosed tank compartment wall


These frame supports on the inside need to be down at the lower flange.

In my case I have 5" long spring hanger and the 2 x 2 cross tubes helped the frame but did not help the spring hanger lower flange flex. So I beefed up the hanger, put reinforcing tubes inside the hanger and then cross tubes on the hanger. I also needing and 1 1/4" lift so I made longer hangers too.

If you show these to your fabricator he can reproduce this using channel iron of more 2 x 2 x 1/8" wall tube. He is going to have to fix the frame cracks and should add the 1/4" x 2" flat bar gussets from the lower flange to the vertical web of the main frame rail.

Hope this helps and good luck

John

PS, the frame crack you have is semi common

Here are a few,

Fisherguys Komfort

This one is the worst I have seen. Maybe this will make you feel a little better... It can get worse...
frame cracks

That's good that your GVWR is 8800 lbs with 4400 lb axles. The info. I got from a dealer's site was wrong then.

If a person were to predict where you'd get cracks in the frame, it's where you can see them in your photos. Picture the bottom of the spring hangers swinging left to right all the time like a pendulum with the fulcrum being at the bottom of the cross-bracing where it attaches to the I-beam. It ends up being a case of when it will crack, not "if"... I would think you need gussets from the cross-bracing to the top and bottom of the beams in the area of the axles. Some type of gussets or bracing on the outer side of the I-beams will help a lot. It doesn't look like you need it, but a section of 2x2 welded to the underside of the beams from the rear-most spring hanger to the front-most would help to strengthen things up. If you did that, you could use 4" tall spring hangers which would help too.

The axles could be somewhat bent and aligment should be checked. I'd also check welds to see if any have failed. A frame shop told me that welds should be continuous at joints and I think they (the frame manufacturer) often only does partial welds, and this would make it easier for them to fail/crack.

Again, a good frame shop will recommend the best way to handle it.

Curious - what height is your I-beam and is it a one-piece type? What is the dimension of the cross-bracing and where is it located?

jgos929 wrote:

myredracer wrote:
Another thought, have you ever weighed your TH before and after loading the utv to see where you are against the GVWR? Our KZ Spree is exactly the same length as your KZ TH. It looks like you have the same 3500 lb axles. Your GVWR is 7000 vs 6800 lbs for ours. Based on our experience with scale wt. after being all loaded up, you may not have much CCC before you load the utv in. If we were to tow with just one full tank of water, we'd be overloaded. I wonder if you've been towing overloaded for some time and didn't realize it? That might explain why the springs have lost some of their arch?

My axles are 4400# and my GVWR is 8800# I haven't weighed it yet but I don't think I'm overloading it. But weighing it is on my to do list for sure now just so I have piece of mind.

myredracer wrote:
Another thought, have you ever weighed your TH before and after loading the utv to see where you are against the GVWR? Our KZ Spree is exactly the same length as your KZ TH. It looks like you have the same 3500 lb axles. Your GVWR is 7000 vs 6800 lbs for ours. Based on our experience with scale wt. after being all loaded up, you may not have much CCC before you load the utv in. If we were to tow with just one full tank of water, we'd be overloaded. I wonder if you've been towing overloaded for some time and didn't realize it? That might explain why the springs have lost some of their arch?

My axles are 4400# and my GVWR is 8800# I haven't weighed it yet but I don't think I'm overloading it. But weighing it is on my to do list for sure now just so I have piece of mind.

JBarca wrote:

jgos929 wrote:
This is the gab between the tires and where it was rubbing.




Wondering if I could go t a beefier spring and that would help?

I believe I see part or all of your problem.

In the 2 pictures above, I see horizontal rust lines above the spring hangers. This is a tell tail sign of a cracked camper frame from excess flexing of the lower flange of the main frame. If you cannot see them, later tonight I will copy your pic and circle them. Then go check it out on the camper.

Your spring hangers have no gussets to stiffen up the lower flange from flexing and there are no left to right braces between the hangers. A double wammy for frame flex. As you turn the lower flange of the I shaped main rail flexes and the entire axle shifts allowing the tire to rub. You have very little clearance to begin with, problem 1, and then the flange flex does the rest.

This is especially prevalent on toy haulers as those who have toy haulers often go off road to get to the camp site. That off road higher degree of up's and over causes extra flexing of the hanger and rips up the main frame rails. Many toy hauler guys add extra reinforcing from day 1 to offset this problem.

Your prior reply on tire size leads us to believe you bought this camper used. The frame may have been cracked from the prior owner and they may not have known about it either.

I will post later tonight how I fixed my flexing hangers. I would not change springs or even an axle flip until this issue of the hanger flex/ possible frame crack is addressed. After fixing the flex, then have at it if needed.

Hope this helps

John

PS Take some pics of the inside of the frame so we can see left to right how the frame by the spring hangers is built.

Im interested in how you fixed the flexing. If you could point me in the right direction as far as what I need. A good buddy of mine is a fabricator and master welder and assures me he could weld me in some bracing if need be. Thanks

Ok that is clearly a crack. Its on both sides and is where a beam attaches between the frame.


The crack is on the opposite side of this beam on both sides of the trailer

Another thing I noticed is my axles are clearly misalighned from one side to the other. After doing some measuring the wheels on the blowout are clearly more "pushed in" than the other side. You can clearly tell by the next two pics just by looking at the side distance from the tire to the side skirt.
Blow out or rubbing side

Good side


Im considering taking this to a dealer close to me that services and repairs KZ trailers because the frame appears to obviously be a manufacturing defect

Moderator I apologize I tried resizing it like you did in my other pics and I got an error saying bad format or something like that. Thanks

I know a few toy hauler owners that have had outside walls droop from carrying heavy weight to off-road campsites. Some of them found the droop by seeing tires rub while others found corners inside the toy hauler no longer match up and there were gaps along cabinets. It's something else to look for...

I think you may have frame problems.

Are those cracks in the frame that you can see above the spring hangers? I would check for cracks pdq before you use it again.

The spring hangers are the 6" tall version (not 4") so you can have greater leverage action on side to side movement. I can't see if you have an enclosed underbelly or not. If you do, is there 2x2 cross-bracing going left to right between the I-beams? If so, that allows flex in the vertical web of the I-beam and coupled with tall spring hangers, you can get side to side movement from weight transfer from cornering or lane-changing or off-roading.

I can't see distortion in the lower flange of the I-beam where the spring hangers attach. You *could* be having flex in the I-beams above the spring hangers where the cross-bracing is. You could even have separated welds on the cross-bracing. You appear to have a one-piece forged I-beam and if there is flex going on, I think it is more likely to have lateral movement mid-way vertically up the beam. You essentially have the effect of leverage of the spring hanger height (6") plus another 3" (if 6"tall I-beam) of 9" acting against the side of the beam as the trailer moves left/right while towing and eventually something will be damaged or fail.

I know what I would do. I would take it to a frame shop that has experience in travel trailers and frame issues. If you have a 3-piece fabricated I-beam, that's even more reason to take it to a frame shop. They can put it up on a hoist and see exactly what's going on. For the couple hundred $$ it would cost, it'd be money well spent and you may find more going on than you think. They can recommend remedial work to repair and strengthen the frame. I would consider tying the spring hangers together with the Mor/Ryde X-bracing or making up something similar. Shocks would probably help too I think. Higher rated axles may help.

Another thought, have you ever weighed your TH before and after loading the utv to see where you are against the GVWR? Our KZ Spree is exactly the same length as your KZ TH. It looks like you have the same 3500 lb axles. Your GVWR is 7000 vs 6800 lbs for ours. Based on our experience with scale wt. after being all loaded up, you may not have much CCC before you load the utv in. If we were to tow with just one full tank of water, we'd be overloaded. I wonder if you've been towing overloaded for some time and didn't realize it? That might explain why the springs have lost some of their arch?

Good eye!

jgos929 wrote:
This is the gab between the tires and where it was rubbing.




Wondering if I could go t a beefier spring and that would help?

I believe I see part or all of your problem.

In the 2 pictures above, I see horizontal rust lines above the spring hangers. This is a tell tail sign of a cracked camper frame from excess flexing of the lower flange of the main frame. If you cannot see them, later tonight I will copy your pic and circle them. Then go check it out on the camper.

Your spring hangers have no gussets to stiffen up the lower flange from flexing and there are no left to right braces between the hangers. A double wammy for frame flex. As you turn the lower flange of the I shaped main rail flexes and the entire axle shifts allowing the tire to rub. You have very little clearance to begin with, problem 1, and then the flange flex does the rest.

This is especially prevalent on toy haulers as those who have toy haulers often go off road to get to the camp site. That off road higher degree of up's and over causes extra flexing of the hanger and rips up the main frame rails. Many toy hauler guys add extra reinforcing from day 1 to offset this problem.

Your prior reply on tire size leads us to believe you bought this camper used. The frame may have been cracked from the prior owner and they may not have known about it either.

I will post later tonight how I fixed my flexing hangers. I would not change springs or even an axle flip until this issue of the hanger flex/ possible frame crack is addressed. After fixing the flex, then have at it if needed.

Hope this helps

John

PS Take some pics of the inside of the frame so we can see left to right how the frame by the spring hangers is built.

I think an axle flip would be the obvious answer to all my problems. I think first I'm going go with a stiffer spring and see if that helps any. My axles are 4800# so i can only assume the 4 leaf springs on there now are rated to 2400#. I think I'm gonna try a set of 5 leaf 2900# springs and see what happens. I know this doesn't mean I'm gaining any capacity but It will provide me a firmer ride and should help with the sag when loaded