Potential Road Hazard

[westysplace]

We have just returned from a 3,900 mile roundtrip as newbie snowbirds. The FunFinder X-210 performed admirably. However, the roads, in certain areas, left a lot to be desired. Some metro areas experimented in the past with concrete low-wear road surfacing, which would purportedly save maintenance costs. This road construction came with expansion joints which are noticeably noisey. Out of the 3,900 miles, there was about 50 miles of this type construction, which was in less than good shape due to settlement, etc. This was most noticeable around the I-5 corridor in Tacoma, WA and the Sacramento and Stocton, CA area. There was also a section of HWY 99 around Bakersfield, CA. The rest of the time, the trailer performed well, tracking the truck in wind and rain.
My problem is that over a relatively wide range of speeds a harmonic vibration was set up, which was unsettling! I felt that some traction in the rear tires might have been lost, at times I also feared that the trailer coupler might come loose. I have experimented with acceleration, deceleration, and tow truck weight distribution. Changing speed helped for a time only to have this harmonic come back sometimes, at the new speed! Weighting up the back of the truck seems to have helped the most, but hasn't completely eliminated the vibration. My hitch weight distribution can not be adjusted as with chain tensioners.
This harmonic might be a function of the trailer and truck suspension as well as tow vehicle wheel base. However, I also towed this trailer with a Toyota 4Runner for awhile, and the same problem was exhibited. The 4Runner has a shorter wheel base and is a bit lighter.
I have checked the level of the trailer and vehicle hitch area and the fender to center hub distances on the tow vehicle hitched and unhitched. Camping World seems to have done their job.
Will air bags help? Anybody out there want to tackle this one? Thanks.

[LJAZ]

So are you saying this problem developed over the course of the trip? Or you've had it all along/

Sounds like you've already checked a verified quite a bit. One other thing comes to mind though, how are the tires? From your description it sounds like the rough roads might possibly have inflicted some damage? Just a guess really.

[westysplace]

This problem only exists when running over evenly spaced expansion joints with this type of road construction. The ride is perfectly normal on other highway surfaces and sometimes I don't even know the trailer is behind being towed. I think that hitting this small bump (expansion joint)every 40 feet or so sets up a relatively rapid vertical bouncing motion at the hitch area. I just can't be the only one out there experiencing this one?!

[profdant139]

I suffer with the Calif freeways -- I put air bags on my SUV and they help a lot. Easy to do it yourself, depending on your vehicle. I have a Pathfinder and it was no problem.

[westysplace]

The Tacoma TRD has an off-road tuned suspension. Airbags were the only viable option I and others came up with other than going to a different set of shock absorbers and new leaf springs. This approach would certainly not be Toyota approved. This seemed much more effort than it was worth for the relatively small amount of road surface involved. Even then, we wouldn't be sure whether this would resolve the situation.
Airbags represent a relatively cheap alternative, which can be easily removed turning the truck back to the same state, when desired. I would think that the air bag pressure would be adjusted for non-towing situations once the trailer is set.
Thanks for the feedback!

[profdant139]

I like my air bags -- but they need air every week or two. Otherwise, they could deflate and become damaged by the springs. So that is a minor hassle. I knew that this would be necessary, and I still do not regret installing them.