Bias Ply versus Radial Ply Tires

[SolingSailor]

I have a trailer for my sailboat, and I am intending to buy new tires/wheels this year. The current tires are passenger tires, over 20 years old, and I would like to buy real trailer tires. The trailer is used infrequently, perhaps twice in 3 or 4 years to transport the boat for maintenance. The trailer is rated for Class II, 3500 pounds, and is single axle.
I am confused about whether to buy bias or radial ply tires. They seem to be about the same price. The choice is ST225/75 D15 or ST225/75 R15.
Recommendations about brands would also be most welcome
Thanks so much
--SolingSailor

 

[kjsAZ]

as long as you can get radial tires with the appropriate load rating they are the better choice. Run less hot due to flexing layers and don't develop flat spots as easy as the bias ply. If you intend to go faster with your trailer (like ~35mph+ they are also netter even though the bias ply's are rated to 65mph too.

Brands is a real religion and in my experience no-one is ever right. Most trailer tires come from China or Korea and are badged to a certain brand. As they buy from various suppliers they are different. The best I found is to buy from a Far East brand which actually makes them in house (and sometimes sell to these importers). If they have a certain quality they are more consistent.
I had good experience with Gremax and Kanda.

If you use the trailer that infrequent it almost makes no difference what brand you buy. To prevent flats you should lift the tires (axle) up when you store it. Trailer tires for unknown reasons don't have to meet the stringent requirements for vehicle tires. They should be replaced every 3-5 years as they will dry-rot. If you store them cooler and out of the sun they may last a bit longer.

 

[robert graham]

Get the radials and for your infrequent use consider setting trailer up on blocks and remove wheels and store in your garage/somewhere out of the elements/UV light, etc.....they'd last a lot longer that way....

 

[H20Rat]

Other than potentially being cheaper, there isn't a single good reason to run bias ply tires, ever! If they are the same cost, no brainer...

 

[JimS123]

Yup, no brainer. If "auto" tires have the correct weight rating for your application, they are the hands down choice. If you can get them in bias, even better. Radial ST tires have to be the worst crap out there. Read the sidewalls....."not for use with passengers in the vehicle" (or something like that)....that's enough reason right there.

 

[kjsAZ]

Yup, no brainer. If "auto" tires have the correct weight rating for your application, they are the hands down choice. If you can get them in bias, even better. Radial ST tires have to be the worst crap out there. Read the sidewalls....."not for use with passengers in the vehicle" (or something like that)....that's enough reason right there.

Same text is on bias ply ST's. Yes the worst crap on earth and only available in North America and very few third world countries...... Basically no spec requirement on those. One warning, if you use P rated tires you have to reduce the load rating by 9% for trailer use. With LT tires the rating fits.

 

[SolingSailor]

Thanks everyone for the advice. 'Tho there does seem to be some disagreement. Oh well...
BTW, the trailer is on stands, the wheels off and covered. And the bias and radials seem to be the same price.

 

[bgc]

Im no tire expert but I'll share what I've learned.

I tried to save some money a put "Automotive/Passenger" radial tires on a tandem axle trailer with a 3500# boat. Everything went fine until I got into some grooved pavement on the freeway. The trailer, with a high center of gravity boat, started tracking the groves and swaying violently. I continued the rest of the 280 miles on back roads under 35mph.
Passenger tires have lower PSI and soft sidewalls for a smooth ride. I replaced them with Radial Trailer Tires with a 75psi with an F load rating.

My Cuddy weighs in at 5500 empty and runs on 116psi, G rated Bias ply tires. They're very stiff and make moving a breeze.

 

[frantically relaxing]

Actually, there IS a good reason to buy bias trailer tires over radials aside from cost, especially with 2 or more axles. We've all turned our trailers in a tight radius- ever watch the inside-radius tires when doing so? The sidewalls squish and twist substantially. With radial tires, over time, this causes the sidewall cords to fail. This is why you hear of so many trailer tire blowouts. Good bias trailer tire sidewalls barely squish or twist at all. In a hard turn the tires just slide. The sidewalls never get hurt, so blowouts with bias tires are extremely rare.

The compromise is that, especially on hot, rough launch ramps (for example) where you do your turning, tread can literally be peeled right off the tires. However, you can see missing tread, you CAN'T see broken radial sidewall cords..

I have bias tires on my Chaparral trailer, Goodyear Workhorse's. Speaking of cost, they ain't cheap at $250 a pop (for the odd 16.5"ers), but I'll never worry about a blowout. 2 of them are 11 years old, with peeled off tread courtesy of Bullfrog's boat ramp, and 2 are 2 years old. Maybe I'll make a video this weekend in the parking lot to show how these tires work in tight turn...

 

[hungupthespikes]

Another one here for bias. Tandem trailer scuffing like fran'-relax stated is the main.
Being over 35 feet long, getting in and out of tight places..... jumping curbs and sometimes rubbing the sidewalls against a curb.
Add an inch wider with radials?
huts

 

[JimS123]

Im no tire expert but I'll share what I've learned.

I tried to save some money a put "Automotive/Passenger" radial tires on a tandem axle trailer with a 3500# boat.

Wrong answer....A good auto or truck tire will cost more than the crap ST tires.

 

[kjsAZ]

Im no tire expert but I'll share what I've learned.

I tried to save some money a put "Automotive/Passenger" radial tires on a tandem axle trailer with a 3500# boat. Everything went fine until I got into some grooved pavement on the freeway. The trailer, with a high center of gravity boat, started tracking the groves and swaying violently. I continued the rest of the 280 miles on back roads under 35mph.
Passenger tires have lower PSI and soft sidewalls for a smooth ride. I replaced them with Radial Trailer Tires with a 75psi with an F load rating.

My Cuddy weighs in at 5500 empty and runs on 116psi, G rated Bias ply tires. They're very stiff and make moving a breeze.

Well, did you take into account that for "P" tires you have to reduce the load rating by 9% for single axle and 12% for tandems??? Very tough to find "P" tires which would give the load rating for your set-up. With "LT" tires that's accounted for already.
There are some good ST radial tires out there which are re-badged LT tires and simply rated for higher load rating at higher pressure. Unfortunately they are as expensive as the LT's. The standard ST tires are the bottom feeders from the factory as they have close to no safety spec to meet.

 

[bgc]

Soft sidewalls don't work....

 

[SolingSailor]

So bgc, I think you are in favor of the bias ply, right?

I want to thank everyone for helping with this. I would hate to damage my beloved boat because of an incorrect decision about the tires.
My trailer is single axle with hydraulic surge brakes. Not only are the tires old, but these auto tires do not quite add up to the 3500 pound class 2 spec.
And this is an area where I know almost nothing... So your responses are very much appreciated.

 

[bgc]

I am very happy with the performance of my bias ply tires on my trailers.
The high PSI (116psi Max, I run 60psi) and very stiff sidewalls make moving the rig easy. When shes on level smooth cement, two of us can spin her on the axles, and I can roll her fore and aft by myself. I cant say the same for many of the tandem axle bass boats we see in the boat shop.

Pete's Tire Barn, on the east coast, shipped two tries for 22 dollars to central Ohio. I bought them through their EBAY store, half the cost of local.

 

[redneck joe]

not trying to hijack thread, but related. I'm looking to rehab trailer very soon and that includes new tires/wheels. Would a 205 versus a 225 help the sidewall issues mentioned? Also in load rating, I see same load in lbs but different PSI. What is that about?

 

[dingbat]

Would a 205 versus a 225 help the sidewall issues mentioned?

What side wall issue?
I wouldn't put a bias ply tire on anything but a wheel barrow.

 

[UncleWillie]

The biggest thing you can do to make the tires last is to keep them out of the sun.
There is no such thing as "Dry Rot", there is nothing to Rot on a Rubber Tire.
"Dry Rot " is actually "Sun Burn", A.K.A. UV Degradation.

My brand new tires on my brand new trailer spent the first 12 month of its life on the West side of my house when it was not in use.
Our boating season is only 4 months long so it is parked stationary for the other 8 months.

The Left tire is only 18 inches from the house and next to a bush and is in the shadows all the time.
The Right tire faces a section of the neighbors lawn and gets the afternoon Sun everyday.
After 12 months, the Sun exposed, Right tire was starting to show cracks in the sidewall and tended to lose air pressure faster than the Left Tire. The sidewall of the Left tire still looked brand new.

At the beginning of the second season I added a spare tire with cover to the trailer and also purchased tire covers for the trailers main tires. When not in use I put a cover on the exposed Right Tire. The Left Tire is shaded naturally by the building and bushes.
Now, two years later, The covered spare Still looks brand new and the main trailer tires look no worse than they did two years ago.

Keep the tires out of the Sun as much as possible and make sure the Spare is covered 100% of the time, or it may be worthless the day you need it.

 

[kjsAZ]

^^^ +1! There also another effect causing the tires to crack: heat. As warmer the tires get as faster the softeners in the rubber will evaporate. Once it's evaporated the rubber gets brittle. This is mainly what causes the tires to crack inside the tread. Especially bad with bias ply tires operated at higher speeds. The internal webbing flexes against each other and generate a lot of heat.

Both effects together are called by many "dry rot" as it looks like the tire is rotten......

 

[redneck joe]

What side wall issue?
I wouldn't put a bias ply tire on anything but a wheel barrow.

This??


Actually, there IS a good reason to buy bias trailer tires over radials aside from cost, especially with 2 or more axles. We've all turned our trailers in a tight radius- ever watch the inside-radius tires when doing so? The sidewalls squish and twist substantially. With radial tires, over time, this causes the sidewall cords to fail. This is why you hear of so many trailer tire blowouts. Good bias trailer tire sidewalls barely squish or twist at all. In a hard turn the tires just slide. The sidewalls never get hurt, so blowouts with bias tires are extremely rare



Willie/kj I get sun rot; been there done that in Tempe - boat is stored under cover