Beats me to deaf 2 - axle lift blocks

[ntillm01]

Tagging on another thread posted recently, I have a little more direct question for those who have experience with fivers that have been lifted. I am not new to trailer towing, but am completely new to fifth-wheel towing. Here's my situation:



I know about the concrete/rough road/expansion joint bucking phenomenon. Miles and miles of Kansas interstate taught me that one year. Around Detroit, we gots lots of it and I get that push-pull bucking at in-town speeds pretty bad (like 30-35). That is where I am having problems with towing this fifth wheel trailer. When it happens, it is way beyond annoying and I would like some of your vast experience to help calm my mind about it.



One assumption I have is that the in-the-bed connection point forces the push-pull more aggressively into the truck, thus I feel it more. Secondly, this trailer being about twice the weight of what I'm used to towing has something to do with it.



Mostly for this topic, I am wondering about trailer design and set-up that I have read about. Some seem to work great, others not so great. One piece I read was that tandem axles with equalizers will tend to buck and jerk more. I bought this trailer used and the prior owner had two-inch steel blocks welded in between the spring mounts and the frame. (I presume to clear the higher 4WD they had). I want to take these out anyway, cause I don't need the lift. Can I expect that lowering the trailer will help with the buck and jerk also?



Thanks,

Nohr

 

[mikel]

Any time I have had a 5th wheel or gooseneck trailer buck and jerk my trucks real bad it has been from being too heavy on the pin. How is the weight distributed on your trailer? You shouldn't have more than about 25% of the total on the pin.



Mike

 

[ntillm01]

Unfortunately, I don't know that answer yet. I've just recently gotten this camper trailer and haven't weighed in anywhere. I actually added weight to the front of the trailer by draining the water tank (sits rear of the axles) and loading gear up front on the last trip. These things helped settle it down, which is opposite of what you said and what I have read.



Thanks for the advise.

 

[mikel]

I should have been clearer, sorry for the confusion.



I have run into this kind of violent bucking from either too much or too little pin weight.



As an example, I have a gooseneck trailer that I use to pull my tractor around with. The trailer puts about 1000lbs on the pin just by itself. Then I load the tractor which itself weighs 4000lbs, and depending on how far forward I load it I can go from a bad ride because the tractor is too far back, to a good ride when the tractor is about right and back to a bad ride again as the tractor get's too far forward.



I just assumed (which is never a good idea) that you were heavy on the pin because alot of 5th wheels are.



My bad, hope this helps.



Mike

 

[ntillm01]

No worries, I assume also that the 5th wheel is heavy on the pin, I just really don't know for sure on this one yet. That's good information to know that it can be bad both heavy and light. Thanks,

Nohr

 

[NIsaacs]

Beats me ot deaf 2- axle lift blocks

ntill01,



Getting to your original question of the lift blocks causing your rough towing conditions, I don't think that is the problem. It could be possible if they were not installed in the exact spacing to match the spring eyelets. I am taking a big guess here, cuz I don't know what your suspension looks like. On travel trailers, the suspension losses its spring arch sooner than other types of cargo trailers. The travel trailer is basically loaded all the time and gets heavier the longer you keep them. This causes the springs to weeken sooner than trailers that are empty most of the time. If the spring suspension has an eye in each end of the spring with a shackle attatched to the equalizer bar in the center, the spring could be so weak that the shackle stops the spring from getting longer as it compresses. This could be the problem. If the lift blocks were not spread the right distance to allow for this, than this made it worse. Suspensions with slipper springs pull smother than the shackle type, and suspensions independant of each other pull better yet. Check to see if the axle bottoms on anything and or if you have shocks, make sure they are not bottoming out. Hope this helps a little.





"IF IT AIN'T CUMMINS POWERED, IT AIN'T A TRUCK"





"NICK"

 

[ntillm01]

Nick, my trailer has two axles and the leaf springs sit on top of them. Each spring has an eyelet. Each spring connects to the equalizer rocker in the middle with the remaining end in a swing shackle front and rear. There are no shocks. The springs have a positive arch and don't look weak yet. They have plenty of room to move and the shackles are pretty much straight up and down sitting loaded.



I don't think I'll ever fix this "problem" because it is inherent in trailer towing. My theory is that the lifted trailer has a higher center of gravity that adds to the push-pull jerky effect because it has more tendency to see-saw over the tandem axles. I guess I won't know for sure until I get the spring mounts reworked back down to where they are supposed to be.



Thanks,

Nohr