Karavan Trailor Losing It's Rollers

[Captain Caveman]

I've got a 2007 Karavan trailer rated for 2,200lbs. It's carrying a 16.5ft Alumacraft boat with a 90hp motor. The dry weight of those is 1,400lbs. Add in another 300-400lbs for three batteries, trolling motor, props, and gear and I assume that my rig weighs around 1,750lbs. That puts me 450lbs under the max capacity of 2,200lbs.

I have now lost my third roller assembly from the trailer in four years. I assume that the bolts holding the roller assemblies onto the trailer are snapping. I just swapped all of the bolts with hardened stainless steel replacements (F953C). I once lost a front roller and now I've lost two in the rear where the transom sits.

Is it possible that I am strapping my boat too tightly to the trailer, or is more likely that the boat is bouncing around too much and causing the roller bolts to snap? I trailer twice a month about 500 miles round trip to the lake. The trailer gets a lot of mileage, going through a set of tires every 1.5 - 2 years.

 

[dingbat]

Trailer ratings have substantial padding built into the numbers. Typically in the 25-50% range.

Doubt you could put enough of a bind on the straps to cause a problem.

Stainless steel bolts are weaker than steel of the same diameter. I have grade 5, hot dip zinc bolts on my trailer #5200 boat.

What type of rollers (bunkers of wobble type) and how many rollers?

What size are the problem bolts?

Have the rollers ever been adjusted for the boat?

Getting 1.5 to 2 years on a set of tires? I'm going on 3 years and my tires still look like new

 

[JimS123]

Karavan has awesome technical service. Call then for their opinion.

If you are using chinacrap tires that's about all you can expect.

 

[Captain Caveman]

The tires wear faster because the trailer was built for a heavier boat. I didn't realize this until several years into ownership. Therefore the tires have a slight positive camber and wear faster on the outside. I typically flip the tires on the rims just before the cord starts to show, to use the side of the tire with full tread. If I put enough weight into the boat while trailering, the tires flatten out. The trailer gets about 6,000 - 7,000 miles per year using Goodyear Marathons.

Back to the rollers, they are wobble rollers. I found a stock image below that looks like my setup. I've lost the front roller assembly on the top left bracket and the rear roller assemblies on each of the rear brackets. All of the bolts that broke were Karavan's OEM bolts. I'll look at finding some Grade 5 or 8 bolts and replace them all again. They are a lot cheaper than roller assemblies!

 

[JimS123]

I have a Karavan with the same setup. I don't put on that kind if mileage, thouigh.

I don't understand why they would fall off. Do the nuts come loose and the bolts fall out? Or, do the bolts break?

Turn or wobble each roller when the boat is sitting on them. How tight are they?

 

[Captain Caveman]

In each case, the roller was just gone. I have no clue if they backed out or snapped. Since they are all nylon locknuts, I assume that the bolts snapped. For the ones that I replaced, all of the nuts were snug. If they were working their way off I would have expected a few of them to be backed off to some degree. That was not the case.

Before being replace, the assemblies all were tight enough to move by hand with some force but did not wobble freely.

 

[JimS123]

Sounds like the setup is OK. Try grade 8 bolts. Tie a line to the assembly so if the bolts comes off the assembly will dangle but you won't lose it.

 

[Captain Caveman]

Good thought. I will do exactly that!