Fuzion 342 Axle Problems

[Fuzion342]

Guys.. NEED HELP!
Long story short. We have about 55,000km on our trailer. In the time I have had the original axels straightened, then last year we replaced the the tubes only with in kind 7k Dexter tubes. Spring packs have also been upgraded to 3500lb packs from the 3000lb originals. 10 ply tires kept bulging ( rear axel only) actually all my issues are the rear axel only, front axel has never been a issue. Now have 14ply tires on.
This last weekend I just had custom built axels installed, the tubes are a heavy wall ( stronger) new brakes, spindles, hubs everything...
In a 700km journey home I have bent the back axel again.. the company who installed them are sending another axel, they are great to deal with.
Trailer is not over loaded, never had anything beside pedal bikes, cooler and baby toys in the garage, never travel with full fresh water tank.

My question is... why does this keep happening to the rear axel only??? It’s level with the truck when hooked up. Has anyone seen this happen before? Has anyone had axel issues yearly??
In Alberta some of our highways are brutal, potholes, frost heaves etc. I do my best to avoid potholes and will tow as slow as I need to to try and not beat the heck out of everything.. but it doesn’t seem to matter.

[bobbecky]

I found that when running with the front high, I too had issues with the rear axle, but never bent it, just had bearing issues and tire issues. Once I installed 2" blocks to raise the back end so it runs level now, the load is balanced equally between the axles. All this to ask, does your trailer ride level when you are towing?

[Fuzion342]

Sorry I forgot to mention, I just installed 2” blocks along with the new axels. It most definitely sits level now but it wasn’t very bad before. On a 2’ level maybe 1/3 of a bubble.

[dpcrf450]

curious if you ever found out what the issue was.

[Fuzion342]

Well after lots of thought and research I narrowed it down to how I was hooked to the truck. When I had a 2011 F 350 we pulled all over the place with no issues. In 2017 we got a new f 350, these truck came with a little taller box sides and the truck in general sat higher, this is when all the rear axel issues started.

I used to run a Reese 16K with Ford adapter ( for the built in 5th wheel prep) and about 70-80 lbs in my air bags. I had 6.5" of clearance between the top of the bed rail and trailer, on the high side i know but again truck to trailer it all sat pretty good. My Reese hitch did have some play in it, it would make the odd clunk noise but nothing I thought was serious. The fact that it was the rear axel only meant that it was sitting nose high and it did not like it!!

I now have a Reese Elite 18K, no more adapter giving me more adjustment up and down. I am running 5' bed rail clearance and only put 50lbs in the air bags. My theory behind the lower air pressure is to let the truck take more of the weight and absorb it instead of transferring it to the trailer. So far so good... no more clunking noise from the hitch, and with the lower pressure the chucking is eliminated. I am only 500km into this theory ( lol) but so far so good and its all on the same highways i had issues with before.

[Big 417]

That's what I was going to suggest. If the truck can't absorb, the trailer in essence hinges on the pin. Now draw a line from the pin to the back bumper. The further back, the more the trailer squats. I notice this in our tri axle 417, not bad with a normal load. But when I throw the sxs in the back I can sure see it squat the rear over dips

[CWtheMan]

I wonder why, after all those problems, there is no mention of actual loaded axle weights?

[Big 417]

We almost need an engineer to chime in and do the math for us lol. Say when I'm loaded an average #18500, pins around #3800. Static on the axles say around #14800, I wonder what that weight feels like to the axles when it's in motion at the bottom of a dip in the road lol.

[JRTJH]

I wonder why, after all those problems, there is no mention of actual loaded axle weights?

We almost need an engineer to chime in and do the math for us lol. Say when I'm loaded an average #18500, pins around #3800. Static on the axles say around #14800, I wonder what that weight feels like to the axles when it's in motion at the bottom of a dip in the road lol.

$21 at the nearest CAT scale would probably give us the answer or at least the information needed to get to the answer...

Pull the trailer onto the CAT scale with the front trailer axle on the trailer pad, weigh the trailer, then pull forward until both trailer axles are on the trailer pad, then pull forward again until only the rear trailer axle is on the trailer pad (that will put the front trailer axle on the rear truck pad). Then pull off the scale, unhitch and return to weight the truck with the front axle on the front truck pad and the rear axle on the rear truck pad.

With those five weights, we'll know how much the rig weighs, what the pin weight is, what the truck is carrying, and most important, we'll have the "trailer weight is on each axle and how much trailer weight is on both axles as well as how much the total trailer weighs (pin weight plus individual axle weights)....

The only "missing weight" will be the individual wheel weights, something you can not do at a CAT scale (they don't allow you to drive one side on the pads)....

[Badbart56]

If you were "friends" with a Canadian MOT officer or an American DOT officer, they carry portable scales in their vehicles that can weigh each axle at the tire point of contact.....:D

[Big 417]

There's more to it than just what the static weight is per axle. Take a board, it holds your weight just fine till you do a little bounce. Then it goes snap. So say your rear axle carries #5000 static, what does that climb to when the weight comes down on a bump. #20000, #30000?

[Ken / Claudia]

You're right in my book about "static" and live/rolling weight. All vehicle's when moving have pitch/roll/yaw adding or subtracting each vehicle tire weight as it moves on a roadway. And add what tire/wheel bounce also does. If we start at weights near max. at static, we will be over max. tire weights at times as the trailer is towed. Like other things, start with a reserve not max'ed out.
In crash investigations as an example we seen what stresses the front tires go through on a high speed emergency stop of a motor vehicle.
On the trailer tires I never seen any testing like that done. It's just guessing what extra load a tire may carry for a second over a bounce.
Just my opinion, some suspension, axle and tire failures should be from such events.

[Fuzion342]

I haven't had a chance to pull into a scale and weigh the trailer loaded up. However I do know that I am no where near overloaded. The garage has pedal bikes a few coolers and other kids toys. The axel issues I feel were %100 my own doing. Between the ride height and possibly too much air in my airbags I was transferring too much to the trailer. Our highways in Alberta are quite bad and between pot holes, frost heaves and " whoops" the back axel was taking the brunt of it, the front axel has always been good.