Adjusting Bunks on my Trailer

[meedz]

So I'm picking up my new 2015 GTI 130 on Saturday, and from what understand I need to adjust my trailer bunks and neck. I was using the trailer with a 1993 GTX.

Someone had once told me that the engine block has to sit directly in the middle of the bunks or else the trailer will slightly fishtail at high speeds...

I did some searching and found that some manuals specify the exact distance from one bunk to the other, but I cannot seem to locate that in the owners manual. Any help would be appreciated.

 

[BigDfromTN]

To avoid fishtail you need to have it far enough forward to provide tongue weight. Too little weight on the tongue makes for a very unstable trailer.

Your bunks may need to be adjusted left or right to properly fit the new hull. If they are equal distance from the center of the trailer then the engine will be centered automatically. Being the newer boat is likely longer the main thing you will need to do is move your winch stand forward to provide proper tongue weight.

Enjoy your new Ride!

 

[Coastiejoe]

Fishtail is normally a direct result of the trailer axle being to close to the towing vehicle.

That said,, to far back and you will have to much tongue weight. As a general rule, the tongue weight should be 10% of the total trailer weight with the normal load that you will carry. So, of 1000 pound trailer you will want 100 pounds on the tongue weight.

From personal experience, no matter what the total is, do not get below the 100 pound tongue weight. If it is lower, when you go over a bump it can "float" or want to hop off the hitch.

In most cases, the left right placement if everything else is correct is not an issue as long as it is even remotely close to the center. Yes, it can put a load on one side, but the trailer does not really care

 

[meedz]

So I picked up the new machine Saturday, and had the dealer make adjustments to the trailer. They adjusted the bunks and spread them further apart, and also moved the winch stand way up closer to the car. They did this all while it was attached to the car.

Got home, couldn't get it off the ball. Heck, got a friend and both of us could barely get it off. They moved it wayyy too far up.

I made an adjustment today so the machine could lay further back, that being said my question is, where should the bow roller be sitting? Also another issue I'm having is, if I put the clip under the roller, when I crank it in I end up scratching plastic plate around the hook, any way to avoid this?

** Sorry for the crappy pic, cracked my iPhone screen this weekend and using a crappy blackberry for the time being.

 

[Tytan]

See attached pic, not my set up but I do something similar.

- Trailer stop roller should sit under the rub rail and above the connection point on the ski. The one in the pic should be higher.
- Winch strap should go under the roller and attach to the ski. If you are in an accident and the ski is forced forward this stops the ski riding over the roller and into the back of the tow vehicle, safety chain noted below also helps.
- Use the small strap looped through the ski then connected to the winch strap hook, see pic, don't put the hook directly on the ski.
- Buy a set of trailer safety chains and use one as a safety chain between the tailer and the hook on the ski.

For bunks I will adjust sideways so the ski sits level side to side and the bunks sit on a flat part of the hull not on a raised rib. Double check clearance to trailer fenders and frame when you're done. Easiest way to adjust bunks is go to the ramp when it's quiet and float the ski, adjust bunks then reload ski and double check.

 

[Coastiejoe]

Yep, roller above hook and strap passes under it. This keeps it on the trailer in the event of an accident and or large bump. Also, you need the rear tied down with winch straps. This is VERY important as they are what make the ski part of the trailer and not a projectile in sudden a stops.


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[RodInEscondido]

I guess I gotta ask the stupid question: how did the dealer measure the weight on the hitch when attached to your vehicle? We could go into all kinds of center-of-gravity calculations, etc but a simple addition of the approximate weights of load and trailer and shuffle the load until you get approximately 10% of that weight on the hitch. Ok, I will go away now; just my simple mind wondering.

 

[go_panthers]

I used a bathroom scale on the tongue jack


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[meedz]

I guess I gotta ask the stupid question: how did the dealer measure the weight on the hitch when attached to your vehicle? We could go into all kinds of center-of-gravity calculations, etc but a simple addition of the approximate weights of load and trailer and shuffle the load until you get approximately 10% of that weight on the hitch. Ok, I will go away now; just my simple mind wondering.

Oh they definitely didn't - the tech eyeballed it. Got home and couldn't lift it off the ball it was so damn heavy.

Thanks for all the info guys, got it all adjusted with the roller right under the rub rails, and the tongue weight at 130 lbs.

 

[lamajama]

Make sure you do have the safety chain at the nose, and use 2 separate winch straps at the rear otherwise the constabulary get their underwear in a knot.

 

[Spimothy Leary]

130 is a tad heavy for my personal preferences, I have no idea what my tongue weight actually is, I just know its heavy enough that i have to actually put some real honest effort into it on the VERY rare occasion that I actually need to lift the front of the trailer. I'm guessing with two ski's its between 150-170 lbs but its just a guess. I only have to lift it onto the hitch usually when i'm either a) in a hurry, or b) parked in the back yard in the grass and the swivel jack kind of sinks into the dirt and doesn't roll.

Every trailer of mine that I've kept for personal use had had a front swivel wheel jack installed, or I installed one the first or second day.

I back into the garage, swivel it down, pop the hitch clasp, crank it up 2 inches, and walk away. When hooking up for the next ride I back in very close to the ball, maneuver the trailer the last couple of inches, crank it down onto the ball, latch it up.

I don't like the first pic where you posted your setup, IMO that winch pole is way to short for that ski, way to easy for that thing to pop right over the top.

 

[BigDfromTN]

I too have the flip up jacks on both boat trailers. A VERY handy feature!

Im curious if the dealer simply placed the ski on the trailer based only on how the ski sat on the bunks. I assume these are like most fiberglass boats in that the bunks need to extend past the back of the hull to avoid the back of the hull from deforming a bit.
Can we get a pick of how the hull is in relation to the bunks on the trailer?

 

[bradmanuwf]

Here is how to actually calculate the correct placement. 7-10% of the jet ski weight is the threshold for tongue weight. For at 980lbs, that comes out to be 68-98lbs.

http://www.ehow.com/how_7900873_adjust-jet-ski-trailer.html

 

[Sajack]

I have a new GTI. My trailer bunks are under the strakes of the hull, which can’t be right. I can move them inward toward the edge of the grate, or outward. I’m thinking that if I move them outwards that front of the hull might hit the rear crossmember when loading. Am I correct that I should move them to the sides of the strakes toward the center of the boat?