Upsizing trailer tires and rims

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nickihoyboy

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I recently purchased a new-to-me boat, motor and trailer package with an Aquasport 225 Explorer boat. The trailer is an aluminum Magic Tilt tandem axle with brakes on one axle. I plan on towing from my home in NJ to Lake Ontario in NY, a distance of about 350 miles. The trailer currently has ST205/75-14 tires, load range C. I would like to upgrade the tires to ST205/75R tires, load range D, but am having difficulty locating them in 14". The ST205/75R-15 tires,load range D, appear to be readily available from a number of locations. With a little further research I find that the overall diameter of the 14" tire is 26.3" and the 15" tire is 27.3", and it doesn't look like clearances between tire and fender or tire and tire will be any problem. Bolt pattern for both the 14" and 15" wheels is 5-on-4.5", so no issue there. Does anybody see any issues that I might be missing before I go ahead and make the switch?
 

alldodge

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I don't see an issue so long as there is room, which you said there is. Just more cost for the rims also
 

Starcraft5834

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How heavy are you in relation to the GTW on registration? larger tires assuming fit ok.. beneficial
 

Scott Danforth

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most 14" trailer tires are load range D. not sure why you are having an issue finding them.

stay away from the chinesium brands (carlisle, Kenda, etc.) and that leaves you goodyears (only available in load range D)
 

bruceb58

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Goodyear Endurance are available in a 205/75/14 load range D.

If you do decide to go to the 15" tire, it may not be an issue. I did it with my trailer but I had to raise my fenders.
 

Lou C

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I’ve done this on my trailer over the years since tires are often the weak link...started with:
205/75-14, then 215/75-14, then 225/75-15 C rated, the latest is 225/75-15 D rated.
if I do another upgrade might go to a six lug axle 15” rims 225/75-15 E rated. But the current set up has been fine for years including the drum surge brakes.
 

matt167

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most 14" trailer tires are load range D. not sure why you are having an issue finding them.

stay away from the chinesium brands (carlisle, Kenda, etc.) and that leaves you goodyears (only available in load range D)

Carslile Radial Trail is an OK tire. Goodyear Marathon is not, but the Endurance IS a great tire... Sadly the Endurance tire may be totally out of production. GY shut down the Alabama plant which produced them and the NC Plant although listed as producing them, My supplier says there are no more to be had
 

Scott Danforth

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when I was in outdoor power equipment, often we would need to reject entire shipments of Carlisle and Kenda tires as they would split on the 6 week shipping from china. we are talking 4-8 40' ISO containers full. granted they were not radials, however the quality of tires from Carlisle and Kenda has seriously plummeted in the last 20 years.
 

Lou C

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I know I posted this before, but I've had 2 sets already of Taiwan made Kenda Load Stars and both sets went 8 years and not one failure. So I bought another set, this time 225/75-15 D rated. I actually prefer bias tires because if they do fail, no steel belts flailing about to tear stuff up. For my use they are 100% fine. Local driving at low speeds.
 

JASinIL2006

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I hope the shortage of Goodyear Endurance tires is brief. They are really nice trailer tires.
 

42 Clyde

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So i may be a novice at almost everything boating but tires are what i do! I have ben working in the retail tire industry for past 15 years and on and off for years befour that.

Upgrading your tires can be the best thing you do for your trailer. As long as they fit in the space you have then going to a 15 inch wheel and tire cant hurt. The only time it becomes a problem is if you go way to big and the breaks are no longer efective or rubbing on something and cause a failure. Bias ply tires are good for putsing around town and short trips acrost town to the lake twice a year. But you dont want them for long trips. Radial tires will track better, stay cooler, last alot longer and if for some reason one looses air it wont sway the trailer as bad alowing you to come to a safer stop. I haven’t had any problems getting a hold of Goodyear tires for my customers and if your planning a trip of that length than i would strongly suggest the goodyear tires.

If you take nothing from this and only take one thing away i will tell you the absolute best thing you can do is get a spare and make sure you have the tools you need to safely change it. Unless you like the idea of leaving your boat on the side of the freeway while you try to find a place to patch a tire! Lol. I get at least 1 person a day at my shop with something stranded on the side of the freeway.
 

matt167

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Goodyear Marathons are widely available, just crap. The Endurance does seem to be coming back in stock but the date codes are not as fresh as they should be for having run out ( pre pandemic time period ). I think either Goodyear opened up another warehouse or the distributors are just scrounging and finding what they can


The other part I forgot to mention. Don't use cheap Carslile wheels on a boat trailer. They RUST... Get galvanized wheels
 

dingbat

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So i may be a novice at almost everything boating but tires are what i do! I have ben working in the retail tire industry for past 15 years and on and off for years befour that.
Question for you.

What percent of the trailer tire failures you see are “quality” issues?

What percent are age, neglect and abuse failures?

Interesting to compare notes from the manufacturer’s perspective (QA) and a good friend in the commercial tire industry.
 

ahicks

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Great Question!

My vote, based on 20 years working at a larger RV dealership from the 70's into the 90's, mostly as the service manager (a while back).

IMHO, the vast majority of total destruction or near total destruction, were due to neglect and/or lack of maintenance. These ran the entire gamut of time in service, from "oops, forgot to pack the bearings" on that brand new rig, to "how do you pack wheel bearings?" to tires obviously over heated due to overload or lack of inflation.

We did see some pretty obvious tire defects. These though, when looking at the big picture called "show stoppers", were in the minority.

I will grant that experience is getting old now, and the stuff I encountered back then were not made in China as often as they are now. That's NOT to say I don't have any respect for some of the Chinese made tires. That's not the case at all. Being they were playing catch up, many times they are using equipment newer and better than some of the stuff used state side.

The problem, as I see it, is that they are able and willing to build a tire to any spec they're given if they can make enough of them to turn a profit. There is little assurance that because that tire is new that you should trust it! -Al
 

matt167

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Most of the time, when I see an RV or camper that comes in with a blowout, you'll find the tires are old, there under inflated and the failure takes a toll on the fiberglass. They are usually some offshore company like towpower, powermax or similar. Swapped some junk Kenda's as well ( I know some swear by Kenda ).. The Goodyear Endurance are the easiest sell to a camper owner. They don't want to have to worry about the tires, but I've also sold 14 ply Super Cargo's to a few camper owners who needed the capacity/ size for their camper and for whatever reason, I'm pretty sure the Goodyear Unisteel 14 ply is no longer available. But even the Supercargo's hold up to my customers with equipment trailers..

Now my conclusion and what I've learned is that, Campers/ boats have a higher fail rate than equipment trailers.
I think the equipment trailers are used all the time, cared for, inflation pressures checked and maxed ( cool running ), and they have the tread driven off them... Had a couple where the suspension lost pins and dug the sidewall out of the tires

Campers get used only in the spring/ summer, they sit a lot, and inflation pressures are not always checked
 

42 Clyde

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Question for you.

What percent of the trailer tire failures you see are “quality” issues?

What percent are age, neglect and abuse failures?

Interesting to compare notes from the manufacturer’s perspective (QA) and a good friend in the commercial tire industry.

In my experience it is about 50-50. Under inflation and over loading are at the top of the list. And those two items are not mutualy exclusive. A tire is designed to run at a certain pressure and hold a certain amount of weight at that pressure. By not maintaining air pressure Sufficient to hold the load you’re instantly overloading the tire. Every trailer that comes to my shop has underinflated tires. Its just not something most people think about. Some trailer tires i see that fail are worn clean thrue to the cords. Those i see mostly on comercial landscapers. Those guys dont spend a dime till it bites them. Tire abuse by the owner is usualy Obvious.

Now let’s move onto the more controversial part.
When i have a brand new camper or boat trailer come in becouse one of the tires exploaded on the first trip i dig a little deeper. What i find more and more ofton are that all the tires are seperated. The diferent layers of the tire are no longer adhered togeather and are sliping apart. When you have an original equipment tire that may have 200 miles on it and it exploads. Thats a problem. I evin had one camper came to me becouse the spare tire exploaded. A tire that had never evin seen the ground had seperated and come apart. More ofton than not these are no name tires and trying to track down a manufacturer is imposable. No one will take responsibility for these things. Ofton i also find that alot of these tires are several years older than the camper or boat trailer they are on. Brand new trailer.... 4 year old tire.
Now lets get into age. I replace my trailer tires every 4 years reguardless of outward appearance. Most tire manufactures recomend 6 years for car tires and they no longer warranty them after that time. Trailer tire failure seem to peak after four years. With that being said i think the age of a tire is actually on the manufacturer to build a tire that can handle the necessary years of service or somehow make it painfully obvious to the world that their tires can’t last that long. I good friend of mine was a distructive testing engineer for Unroyal back in the day. He told me to think of a tire alot like a chocolate brownie. They bake at the same temp, same amount of time and are Similar consistency during manufacturing process. They are both organic structures that if you leave them out on the counter for too long they will become brittle and unusable.
In conclusion i think the line between abuse neglect and quality is a very hazy Line where the manufacturer, consumer and regulatory bodies all need to sit down and figure this one out.
 

ezmac

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What we need to understand is that rubber is a liquid. Put them together with heat, come apart with heat. A tire has only two jobs. Transmit traction to the road and contain the air in it. It's the air in it that carries the load, not the tire. It's a deal made in heaven. To carry X amount of load a certain amount of air cavity is required at a certain amount of pressure. Now you can step out of those traces a little by adding stronger tire cord and upping the pressure but generally basic rules apply. All tire manufactures adhere to the same basic rules.
'
 
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