Hi,

I have a 1977 Tee Nee trailer that was designed to hold up to a 17' speed boat with an I/O engine.  I currently have a 14" V hull on the trailer.  It has 4.80" X 12" 4 lug wheels and tires with a C Load rating.  

When we launch the boat, the trailer usually sits too high in the water to launch the boat.  Sometimes it will not even float off the tailer.

Would it be possible to change the 12" wheels to 4.80" X 8" four lug wheels, also with a C load rating.  The four inch drop would really make a difference launching.  

Does this sound like a good idea, and are there any safety concerns by turning more RPM with a smaller tire carrying the same weight as the 12" tires, however, they have the same load rating.

Thanks,

HW  

Possible?  Yep.

Would I do it?  Nope.  8" tires = bad mojo.

Any way to lower your bunks?

The bunks are as low as they can go, as they are resting on the frame.  When we are at the lake in the parking lot, I have seen alot of trailers with 8" tires that are towing 14' boats like mine and even 16'ers with decks and all.  

It will work, but pay special care to your bearings.

Just make sure you get the right offset on your new wheels.

Check load capacity of tires in weight, not just the fact they are C rated.  Make sure you are not getting too close to their max total load weight.

I would stay with the 12inchers. when I got my 14 footer it came with 8 inche wheels ( 12 was and option) after 2 years I moved up to the 12inch and was the right thing to do. The 8's are ok, but tire wear was a big issue. And the boat and motor was close to max weight with 8inch, add TM's a few batteries, gas and gear and I was just at or over max trailer weight with 8 inch tires, remember that is total weight boat, motor and trailer, alot of guys forget to add the weight of their trailer in.  Now, with 12 inch wheels, My trailer to does sit high, the thing I had to learn was to back in farther. I have noticed something at launches, people don't back in far enough. I see many guys back in and get out and push the boat off the trailer. Just back in farther, if there is another ramp try it, might be steeper

Stay with the 12's.  I have 8s on my trailer, and hate them.(I worry constantly, if I travel over 20 miles, at more than 55 mph.  And you are only gaining 2 in. not 4.  The other two inches in diameter are on the the other side of the tire/rim.  So, it is  only a 2 in. difference in height.  

depends on your towing habits...

if you just go to a local lake, on surface streets,  and are not hauling long distances or at expressway speeds...the 8" tires might not be a problem. ( but still keep a real good eye on your breaings)

If you ever plan to run at expressway speeds I would not use 8" tires.

I doubt the little bit of hieght you get from the tires will make too much difference anyway. Sounds like the ramp you are launching from is too shallow of a pitch. We have this problem launching at the Cal River launch near us...we have to darn near drown the back of our van to get the boat off...but there are other ramps where the boat floats right off....

do you have this problem EVERYWHERE you try to launch or do you mostly fish the same lake?

Are your bunk supports bolted or welded?

What is the rise on your leaf springs? ...if the present boat is much lighter and smaller that the one the trailer is built for...You may be able to go with a lighter weight leaf or remove a leaf or two from the spring and change the ride height that way...but I would have this done by someone who knows how to do this kind of thing...for safety reasons it is not really a back yard weekend project.

I also would like to get my boat a bit lower at the launch.  I have no more room to lower the bunks and am considering

relocating the axle to above the springs.  There is a single 'U' bolt holding the springs on top of the axle now.  The axle is approx a 2" upside down 'U' shape.  I am unsure if this would be recommended or safe.  I suppose i should ad some sort of shim plate to the bottom side of the axle to prevent the open ends of the 'U' from wearing on the springs too much.

Anyone done this ?

Thanks

There is alot that goes into flipping the axil to make it work right, be safe and strong enough. Its not just flipping it and bolting it up. I used to be into lowered trucks and flipping an axil is common, but there is alot of re enginnering that goes into it. Frame clearence is an issue. On truck you have to C notch the frame. I know the frame look far away from the axil, but when you hit a bump how much does it move, You don't want to be bottoming out.  I have 2 boats. one trailer ( small boat) has the springs ontop of the axil like yours. The bigger boat has the axil upove the springs and it does sit alot lower. I would stop by a trailer shop and see what they think. You might need to get a new pair of spring that can handle the flipped axil, or a set tha sits lower

I agree with the above responses. I had stock 18" wheels on my truck and was pulling a open trailer with 8" tires. Great trailer, don't know why in the world they put 8" tires on it. I had two blow outs. Those trailer tires were making over twice the revolutions to keep up with my truck tires. Ate the tires up regularly and two actually shredded and blew at bad times. Gave the trailer to my Dad for light local stuff. That's not even addressing the heat issue for the internals that were originally designed for 12" tires.

My Chevy has stock 17" wheels and my boat trailer has 12". I only have a 14' tri-hull FB boat, but wish I had 15" tires on the trailer. My trailer tires were brand new in March and you can tell they're not new anymore. They're not slick or anything, but noticeable tread wear and they're 3 months old.