trailer weight? Divide by axle or wheel for tires?

[joes new addiction]

The time is drawing near.
Finally after 6 months of nonstop working on her, she's ready for to sail, (well almost, but enough is done, is an old boat really EVER done?).
I have a slip at a local lake for a few months til my buddy get's his done.
I looked at my tires, they are all dry cracked.
Now let's set the record straight.
I only need to trailer her 25 miles to a lake, then I can run the trailer empty, I want to redo the trailer, I'll repalce the present tires.
The total weight of my PT 1/4 22' and trailer is close to 3500#
Presently, it has H 15 tires on it, with Max max load on tire side wall is 2250#
I have a set of 14" tires that will fit it, max load on tire sidewall is 1345#
So, IF I divide the weight by WHEEL, it's @ 875# per wheel, tires will work.
IF I divide by axle, it's @ 1750#, tires are over loaded.
How do I figure out what the tire weight should be?
Joe
I didn't think this would all be so hard!?
30 years ago I'd dropped the tires on and went on my merry little way, I guess as I get more "refined" I start to sweat the details!

 

[tkanzler]

Tire rated load is per tire, and axle rated load is for the axle and two wheels. You need better than 1750 lb rated tires for what's probably a 3500 lb axle (or more). I personally don't like to cut it close, and another pair of plys is not much more money. Use trailer rated tires (ST), not car tires, probably load range C or D.

I've bought them on line, mounted on wheels, and have been quite happy with the price and the product.

There's no shortage of online suppliers.

http://www.easternmarine.com/st225-75d-15-tire-galv-rim-0

http://www.etrailer.com/Tires-and-Wheels/Kenda/AM1ST92.html

Edit: All that is assuming it's a single-axle trailer, of course.

 

[Kermit]

I don't know how to do the math, but I can tell you what happens when you trailer a boat on dry, cracked tires. You blow out all three on the way to your destination, leaving yourself stranded the 2nd and third times. I'd replace them before trailering the boat anywhere. I know - it happened to me on a trip of less than 25 miles.

 

[victorhoisington]

When we got our H28 the current owner had tires rated at 1800# ea. for a total of 7200. Given the trailer weighed at least 2000#, and the boat weighs 7200# that set of tires was very overloaded. Trying to get the boat home (about 25 miles), I was limited to about 45 mph to keep the tires from overheating. Even then by th etime I got home they were very hot. If your tires are cracked on the outside but not flat, you should be fine for a 25 mile trip to the lake. Just go slow and take it easy and throw a spare tire and jack in the back of the truck just for good measure.

I spent $1000 on new tires and wheels so now my trailer is set for 15k lbs and I don't have to worry.

Cpt Vic
H28 "French Temper"

 

[Merlin Clark]

From your math your trailer is double axle? I'd put the new ones you have on it rather than trust old ones that will more than likely fail.
Like Kermit, BTDT. I was once trailering a 7,000lb 28' Army bridge building boat from Port Canaveral to West Palm to clean up after an old boat that sank just South of Peanut Island. We used the boat to push a small barge.
The boat was on a 3 axle trailer with 6 rotten tires that I'm pretty sure only the boss's wishful thinking kept from going flat in the parking lot. I asked for new tires and was told no by the tight fisted old fella.
We hadn't made it an hour down I-95 before 3 of the 6 had blown out (one at a time), each time we called back to the shop and they sent out the tire service with a new wheel and tire, on the third time, the boss finally broke down and had them bring and change 4 tires. Probably cost 5 time what just doing it right in the first place would have been.

 

[Benny17441]

On a double axle trailer with a load of around 3,500 lbs the proper tongue weight should be around 400 lbs leaving around 3,100 lbs to be borne by the tires or 775 lbs each. Either set will be OK as far as load is concerned so pick out the newer or best. Avoid major highways and keep your speed down and you should be fine for 25 miles. Do pump the tires to at least 95% of its rated max PSI to keep them running cooler. Also carry a spare and a jack.

 

[centerline]

the tires are rated as it shows on the sidewall, measured as a static load. providing you have the proper air pressure in them and the tires are in good condition. but that is MAXIMUM load at static. as you drive down the road, there will be increased stresses involved. (personally, I dont feel things should be pushed to maximum, everyday of its normal life.... so the numbers should only be an upper limit guideline and the actual normal load should be around 15 percent less.... IMHO)
the axle needs to be adequate to carry the weight as well.
your load carrying capacity is only as strong as the weakest link in the system. (it may be the frame, the springs, the axle or the tires)
I dont have a clue as to what the rating of your axle actually is, but if you install more than 1750# rated tires on a 3500# axle, it does you no good as far as weight carrying capacity goes. at 1750# x2 on a 3500# axle, its all evenly matched for weight.... the way it should be.
if you are quite a bit less than maximum weight on the tires, you could get away with a bit less air in them for a more even tread wear.
its all about how the tire "stands up" under a load. a low, squishy tire will overheat as you drive down the highway because the rubber is flexing more and at the same time is contributing to premature checking and splitting of the tire... an over inflated tire for the load it is carrying will usually result in extreme wear in the center of the tread and hardly any at the edges..... under inflated with be the opposite wear pattern. more air is always better than too little air in a tire.

 

[joes new addiction]

Tanks!
I'd never run on he cracked tires. When I picked her up last fall I limped home with them waiting for the big blow out!
Being one that loves info, I went to a guy who welds and builds trailers by where I work.
Although he builds dump trailers and heavy duty ones, not boat, heres what he told me.
Divide the trailer weight by the # of tires, you should have @ 1% of weight on tongue to keep the "ass end shakes" away.
IF I drop to 14" tires, and the truck is 15", I MAY get ass end low and the shakes, I'd have to drop the ball down. (I had pondered 14" tires so the boat wouyld float off in less water).
I SHOULD not screw @, get 15" tires.
Byas ply tires will track straighter, radial will roll better, carry more weight.
I COULD get away with light truck 6 ply tires, (in a pinch, as a emergency, when all else is gone), but he said new they run cost wise @ the same or more than trailer tires, and I get more "wander" side to side.
So, I bit the bullet and went and spent $97 a piece for radial 8 ply tires that are load rated for MORE than I'll ever need.
What the hell, I spent more than that on the 1 sail, the trailer I guess should get SOMETHING! Cuz ahppy trailer is one that get your toy there and back!
One tip he gave me, tires DON'T like sunlight. A "mushroom" tires is a non cracked tire
There is no oil, goo, magic lotion you can put on them, just keep them outta the sun light.
I wondered why car tires can sit for decades and still be ok, but a trailer tire cracks easy?
Joe
When I took the basis sailing class the instructor told me a boat is hole in the water where $$ is poured.
You know he's right!
But so are my motorcycles, old car projects, so I guess I can't win!

 

[Kermit]

My First Mate grew up in Upstate New York and did some boating on Lake Wallenpaupack. She says it's gorgeous there. Have fun with your boat. I'm glad you bought new tires!

 

[joes new addiction]

So am I (well til the credit card statement comes in)!
I've been toild by the sailing club there (I hope to join when things get rolling, er sailing?), that IF you can sail the 'Palpac, you can sail anywhere.
I dunno why, I'm thinking cuz it's in a bowl and the winds comes from everywhere?
Now to get a E-lectric brake set up......
Joe
I've noticed you never REALLY done.......

 

[Kermit]

I think it's possible to be done. First Mate took me to Florence, SC this past weekend and told me to drive my Honda Pilot. (We normally take her Accord.) I couldn't figure for the life of me what they had in Florence she would get me for my birthday for our boat. Turns out she bought me a new bicycle! We honestly don't need much of anything for our boat now.

 

[Benny17441]

You have chosen and purchased your tires so no use in discussing them any further. Are you sure your trailer man did not say 10% for the tongue weight instead of 1%?

 

[FourPoints]

There is no oil, goo, magic lotion you can put on them, just keep them outta the sun light.
I wondered why car tires can sit for decades and still be ok, but a trailer tire cracks easy?

Trick I picked up years ago at the classic car shows, armor all is WONDERFUL for your sidewalls... Not to mention they look great after.

get a nylon brush and scrub them clean then rinse them off. Once they are dry spray armor all on the side walls and use a heavy rag to rub it in. Do this once every ~2 months and your tires will last a lot longer.

For a trailer tire you might as well do the tread too, we sometimes did that one the muscle cars, but more because we needed a good excuse to lay down some rubber on the way out of the car show (But Officer... I had to remove the tire shine / armor all from the tires, otherwise what would happen when I get to the stop light and hit the brakes?)