Trailer vibration

[Fishndav]

I'm having some issues with vibrations on my '15 Cougar trailer: Sometimes the grab bar vibrates at speeds over about 70. Also, When I go over seams in the highway many times when the trailer tires hit the seams, it causes my whole truck to vibrate (1500 Suburban). From what I can tell looking in the mirror, the rear of the trailer does not look like it is vibrating, but hard to know 100%. The front definitely is when I hit those seams though.

Anyone ever have this problem? 30 years towing, and never had this until recently. Torsion Axles..

Thanks

[javjoe]

Most likely culprit is the tires. I would get them balanced!

I just went on my fist trip with my new boat and noticed a slight vibration as soon as i hit 70. At 69 it was smooth but at 70 it started.

[riverrat29]

Make sure all is good with the brakes, bearings,and axles. I would put my money on tire balancing. I had the same issue as well and balancing made most of that go away.

[Bass Cat Boats]

The grab bars have harmonics at speeds. We have balanced trailer tires, reset bracing, bent poles and more to remove harmonics and they improve, though not remove. Balancing might help if it’s bad, though it did not effect any of ours significantly in testing and we used an out of balance tire(s) intentionally in the testing.

The best resolution we have to harmonics was the S Bend Pole.

[sbargercpa]

I'm having some issues with vibrations on my '15 Cougar trailer: Sometimes the grab bar vibrates at speeds over about 70. Also, When I go over seams in the highway many times when the trailer tires hit the seams, it causes my whole truck to vibrate (1500 Suburban). From what I can tell looking in the mirror, the rear of the trailer does not look like it is vibrating, but hard to know 100%. The front definitely is when I hit those seams though.

Anyone ever have this problem? 30 years towing, and never had this until recently. Torsion Axles..




Thanks

I have had the same issue with my 2017 Cougar. I thought it was the truck at first. Feels like hitting rumble strips from about 55 - 70 but not consistently. I'll get the tires balanced and see if that helps.

[riverrat29]

The tire balancing took allot of it out of my 07 trailer. Harmonics is most of it and I do have the first gen model with straight pole and brass ball up top. The S bend was an improvement. I always could visually see the vibration in mine, but really noticed it when I bought another vehicle and the vibration transferred to the tow vehicle. My Tahoe rides so well I guess the suspension absorbed most of the vibration at the higher speeds. My 2012 pickup, not so much. Always a good idea to balance those tires !

[Bass Cat Boats]

The bronze ball did add to harmonics and they moved to the phenolic ball.

[billnorman1]

One thing you can do at home is jack up a wheel and spin it to make sure you don't have excessive radial runout due to a bad belt or mismounted tire.

[lpugh]

I would recomend you have the tires Match mounted and Load Force Balanced, verify zero movement in wheel bearings. Will cost a little more though. Use a weight chart to determine correct air pressure for your rig, do not go by the max pressure rating on the tire. On a tandem axle in many cases you will running way to much pressure in many cases if you do. Many things can effect

harmonics and air pressure can also effect it. Once these things are done if problem persist there other measures than can be taken if needed.

[Fishndav]

The best resolution we have to harmonics was the S Bend Pole.

Interestingly, my previous 'Cat had the Straight pole, and I didn't have any problems. This one has the S bend (bend looks to be a couple of degrees off "true north") and this one vibrates quite a bit. I have been wondering if re-doing it so the S is in line will make a difference.

I've balanced the tires now with no improvement. I have a HB 360 on my TM and I hate seeing that vibrate like it does going down the road.

[marathonman]

Can u remove the pole or even the entire step and pole to eliminate that source.
If that does not eliminate the vibration then reattach pole and look elsewhere.

[basshole51]

I noticed this on my 2013 trailer too....brand new axles, end units, brakes, brake actuator, and brand new tires with wheels balanced and around 68 MPH the grab pole vibrates and gets worse the faster you go...certain roads make it vibrate like crazy....I keep thinking I have something wrong with the trailer but after replacing all above said parts the vibration is still there and still no better. I hardly feel it in the truck but when I look in rearview mirror I see my TM and grab pole vibrating like crazy it concerns me.

[OldTimer57]

One other thing. Remove each wheel and roll them. I had a similar vibration a couple of years ago. One of the tires was experiencing tread separation. Could not see any trailer/boat vibration, but could certainly feel it in my truck when towing.

[castforcash]

Make sure your hub assemblies are tight on the axle spline. I believe they need to be torqued to 150 lbs. If they are even a tiny bit loose this can cause some issues as well. It should be part of yearly maintenance or checked before going on long trips. One of mine was very loose and I ended up snapping one of the 5/8" bolts as the shoulder of the bolt was too long and wouldn't tighten up. I couldn't see that was the issue until the bolt broke. Hopefully it didn't damage the splines too bad on the axle. If that part gets damaged I believe a new axle will be required. My trailer is a 2011, and the grab pole vibrates really bad.

[BCCougarFTD]

With the grab pole have you done any testing with sand as a fill material to change the natural frequency?