Increasing Tire Size on Jet Ski Trailer

Question:

I have an old 97 Yamaha jet ski with the original single axle single ski trailer. I would like to put 13inch tires on it to replace the tiny 8inch so it will pull better at high speeds. Reason being I have to drive a lot of interstate to get around here and Im planning on pulling it 6 hours away from my house later this year. How would I go about that without having to flip the axle over? I would like to maintain the low center of gravity. Also, Im wanting to add 2ft to the tongue of the trailer to help with backing. How will this affect trailer sway? Will I need to move the jet ski further forwards?

asked by: Christian C

Helpful Expert Reply:

Going with a 5 inch increase in wheel diameter will only increase the trailer height by about 2-1/2 inches, which isn't too big of a deal. If your trailer is equipped with fenders, ideally you'll want to see at least three inches of clearance between the top of the tire and the underside of the fender. You might be able to raise the fenders if they're long enough, if not you'd want to replace them. I've linked to our fenders that are suitable for a 13 inch wheel.

Flipping the axle over is actually kind of a misnomer, you don't really flip them, you just relocate them in relation to the springs. In your case, if the axle is currently u-bolted to the underside of the leaf springs, you could relocate them to the top which would lower the trailer a bit if you feel it necessary, but you're not gaining much height with the wheel/tire size increase.

Those PWC trailers aren't easy to back, are they? Adding some length to the tongue should help that a bit but you would want to keep the ski where it is in relation to the axle so as not to affect the weight distribution which could cause some sway issues.

expert reply by: Mike L