Trailer shaking

I bought my first boat about a month ago. It is a 1995 21ft Glastron ski boat weighs about 4,000 pounds total I guess with trailer. Trailer is a tandem axel and I am pulling it with a 2011 F150 Ecoboost ( now anyway, just traded in my 5.4). The trailer shakes so bad at 60 - 65 mph the whole truck shakes. I have pulled boat with three trucks so I know it is the trailer.

I took it to discount tire for a reblance, they replaced one tire. Truck shaking just as bad. Took to my ford dealer for a test drive and they thought it might be the truck axel. Test drove another truck ( Ecoboost which pulled so much better I traded ) but still had the shake so knew it was trailer.

They looked at tires and said one about ready to blow. Went back to discount for three more tires and dealer put on and tried best to balance. When boat trailer is on lift and you spin tire there is still a slight wobble. Pulls better but still shaking. There is no obvious damage. Bearings are good. Could it be a rim? Called two places today and one told me most trailer tires basically suck because they are made in china.

Discount tire sold me Carlise tires, are these okay or junk?

Where would you start next? I would prefer to not just start replacing things....will add up really fast.

Re: Trailer shaking

Well I would think you could make a homemade displacement measurement tool. Using a straightedge/ruler. To turn each wheel when on a jack and make sure there isn't any wobble. Ahtought i dont know if you could get it exact enough to make much of a difference.

I would suspect a bent rim or axel/hub.

ALSO - can't lack of tounge weight have somewhat similar issues? Might be worth a check (want ~350-500lbs?)...

Re: Trailer shaking

Describe "Shaking".

At 60 mph+ a 17 inch tire is rotating more than 10 times a second. Smaller tires even faster.
A bent rim/unbalanced tire is going to shake so fast it would better be described as vibrating.
New tires still on the lift should not be wobbling!

If you mean swaying back and forth 2 or 3 times a second. That is an entirely different issue.

Re: Trailer shaking

A bent rim is very obvious and you apparently saw that when the wheel was spun while jacked up. Geez -- the tire guy should know better. Loose wheel bearings are also a possibility. And saying "tried best to balance" is rather odd statement since balancing tires is their business. They either did or didn't. You cannot half way balance a wheel. Worn suspension parts on the trailer can cause high speed vibration and rapid tire wear as well. Worn spring eye bushings, worn equalizers and bushings, and broken spring leafs can all cause things to move around.

Re: Trailer shaking

I suppose bad vibration is a good way to describe it as well. It is definatley fast! The tongue weight is a good 500 pounds and I have pulled other trailers with no issue. Guess I will just pull it to a trailer place and hopefully they can figure out. I was so worried about getting a decent boat guess I should have worried more about the darn trailer!!!!

The only real boat place in my area is booked up until mid august. Hopefully the horse trailer place down the street will know what they are doing. What i cant belive is how bad of a job discount tired did. One of the tires they kept on the trailer was in really bad shape. Could of easily blown. The wobble looks very slight on the lift but I sure feel it!!!!

Re: Trailer shaking

As others have said, jack one wheel at a time off the ground and spin it. I'll bet you see at least one wheel wobble. Could be a bent rim or a hub could be machined wrong on the bearing surfaces (or bearing race squeezed in crooked), making it hub wobble a little bit, amplifying it at the outer edges of the tires, making for a bad wobble / vibration. A bent spindle probably won't make the wobble, unless it was so far off, the tire was cupping / scuffing.

My bet is on a rim or hub.....

Re: Trailer shaking

How do you know the bearings are good? Sounds like a bearing problem. Pull them out and inspect them.

Re: Trailer shaking

Do you have a good spare? Use your spare and replace each tire and test to see if it makes a difference. If that doesn't change anything, I would look at your springs as other have said, axle and hubs. Make sure your bearings are packed with grease too. I had a similar problem with my drop down ice fishing house. In my case I found multiple issues and changed spindles and all.... problem went away.
Come to think of it, a ever so slightly bent spindle might be the culprit as well. Good luck! let us know what it was!

Re: Trailer shaking

Some basic questions are in order here.
First off, were the original tires worn funny?
When does the vibration first occur and does it stop at higher speed?
Is there any noise associated with the vibration?
Have you simply rocked each wheel to check for play in the bearings?
Is the trailer tracking straight, does it wander or follow your truck dead straight at speed?
When hitched to the truck are both axles level?
Got any pics of the trailer hitched to the truck, and of the trailer tires and suspension?
60-65 is a bit high for towing speeds, in many states have a 55mph towing speed limit for small trailers.

If you have a bad or loose wheel bearing or even a bent rim, it should have been pretty obvious to whomever changed the tires.
It sounds to me like your dealing with isn't much of a mechanic. What I've found around my way is that most tire guys are just low paid help taught to run a tire machine and wheel balancer and taught to do it fast and move onto the next job ASAP.

Re: Trailer shaking

slowleak said:

Some basic questions are in order here.
First off, were the original tires worn funny?
When does the vibration first occur and does it stop at higher speed?
Is there any noise associated with the vibration?
Have you simply rocked each wheel to check for play in the bearings?
Is the trailer tracking straight, does it wander or follow your truck dead straight at speed?
When hitched to the truck are both axles level?
Got any pics of the trailer hitched to the truck, and of the trailer tires and suspension?
60-65 is a bit high for towing speeds, in many states have a 55mph towing speed limit for small trailers.

If you have a bad or loose wheel bearing or even a bent rim, it should have been pretty obvious to whomever changed the tires.
It sounds to me like your dealing with isn't much of a mechanic. What I've found around my way is that most tire guys are just low paid help taught to run a tire machine and wheel balancer and taught to do it fast and move onto the next job ASAP.

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I made the mistake of not really looking at the tires before I replaced them ( lesson learned ). The vibration starts about 60 - 65 and is worse up hill. The hitch is even with the boat - three people have now looked at it and cannot find anything wrong. I picked it up from a trailer place today and the only thing he found was the dealer that worked on it last did not fill the tires correctly....two were way underfilled. He checked bearings, axel, spindles and cannot see anything wrong with the rims. He pulled it and did not feel any vibration. When I brought the boat home I took it on the highway and it felt pretty good....I got up to 80 ( I know not how fast you should go but wanted to see how it felt ) and it felt great. When I slowed back to 65 it started up a little and then stopped. The new tires and having the balance checked three times now has made a difference. I guess this will just force me to drive at speeds I should be driving at anyway.

Taking it to the lake tomorrow, will see how it goes. It is really hard to go 60 when the speed limit is 75 and you are driving across the desert!

Re: Trailer shaking

vibration starts at 65 and smooths out as you go faster is usually a sign of out of ballance problems. All tires will wobble at different speeds when ballance is off.

Re: Trailer shaking

04fxdwgi said:

vibration starts at 65 and smooths out as you go faster is usually a sign of out of ballance problems. All tires will wobble at different speeds when ballance is off.

Click to expand...

Yup. Must still be a balance issue. Not sure why three people cant get it right though. It stops a little over 70 so I just avoided going 60-65 for the most part this weekend. It pulled much better than last time but there was a still a little vibration in that range. If I only would have remembered to put the boat the key back in the boat Oh yeah...and get in shape....wakeboarding kicked my butt!!!!!