Passenger tires on trailer?

veritas honus

Lieutenant Commander
Joined
Jun 13, 2010
Messages
1,876
I have Carlisle trailer tires which I need to replace. They're 185/80/13 bias ply.

I can get a set of Douglas radial tires, 175/70/13 for about half the cost of what I have now. The weight rating is 1047lbs per tire, which would allow for a max load of 4188lbs.

The dry weight of my boat is 3000lbs. I do not trailer the boat loaded. I transfer everything into the boat from my truck at the staging area of the boat ramp. The four tires will be supporting less than 4000lbs including the trailer.

The passenger tires being radial as opposed to bias ply, I see as a bonus.

Anyone see any problems with this? Any thoughts?
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Passenger tires on trailer?

Car tires and trailer tires are constructed differently, vh. An engineer could explain how and why, but it is enough that one has ST in its number and the other doesn't.

Years ago I was offered a set of car tires (185-12) for my trailer that had a much lighter load than you are dealing with. Bad error. Both failed on the Interstate before I had gone 1000 miles. Lesson learned.

Trust the people who make these things. ST tires, load rating C or D, inflated to the sidewall pressure.
 

DoGood

Seaman Apprentice
Joined
Apr 16, 2010
Messages
46
Re: Passenger tires on trailer?

they may be half the cost but the won't last for half as long. in a pinch they'll work fine as long as the load rating is good (which you said it was), but they are going to dry rot before they wear out.
 

wifisher

Chief Petty Officer
Joined
Mar 9, 2011
Messages
578
Re: Passenger tires on trailer?

I disagree. As long as you do not overload the tires, they will work fine. The largest differences between car and trailer tires are: 1) modern car tires are radial while trailer tires are bias ply. 2) Tread pattern on trailer tires have much less traction. They are not meant to drive or steer, just follow.

The load is not carried by the tire, the load is carried by the air within the tire. Most tire failures are caused by overheating. This can come from overheated wheel bearings, overheated brakes, or improper inflation.
 

H20Rat

Vice Admiral
Joined
Mar 8, 2009
Messages
5,204
Re: Passenger tires on trailer?

I disagree. As long as you do not overload the tires, they will work fine. The largest differences between car and trailer tires are: 1) modern car tires are radial while trailer tires are bias ply. 2) Tread pattern on trailer tires have much less traction. They are not meant to drive or steer, just follow.

You can buy both bias and radial trailer tires.
 

wifisher

Chief Petty Officer
Joined
Mar 9, 2011
Messages
578
Re: Passenger tires on trailer?

You can buy both bias and radial trailer tires.

you can also buy both bias and radial passenger tires. But the most common for passenger tires is radial, and the most common for trailers is bias.
 

'78 Crusader

Chief Petty Officer
Joined
Mar 15, 2011
Messages
407
Re: Passenger tires on trailer?

Use a trailer tire on your trailer and a car tire on a car.
 

Cannondale

Petty Officer 1st Class
Joined
May 22, 2010
Messages
278
Re: Passenger tires on trailer?

I disagree. As long as you do not overload the tires, they will work fine. The largest differences between car and trailer tires are: 1) modern car tires are radial while trailer tires are bias ply. 2) Tread pattern on trailer tires have much less traction. They are not meant to drive or steer, just follow.

The load is not carried by the tire, the load is carried by the air within the tire. Most tire failures are caused by overheating. This can come from overheated wheel bearings, overheated brakes, or improper inflation.


Most trailer tires today are radials these days, not bias ply. True, on older boats you find bias ply, but new boat sold these days, and even within the last 20 years if it was any decent brand, come with radials, not bias ply tires. Bias ply still exist for economy buyers.....but are quickly being replaced in the market with radials. You get cooler running tires, better gas mileage and a better ride for the trailer with radials vs. bias ply tires.

The MAJOR difference is that car tires have many fewer plies in the sidewall vs. car tires. Car tires at most have two plies of material in the sidewall, some manage to get by with one. Trailer tires, on the other hand, have at least four plies, six plies is very common, and there are even eight-to-ten ply tires. This gives trailer tires much stiffer sidewalls compared to car tires which reduces the side-to-side sway in the trailer as it's pulled. There is a reason for this.....car tires are built with many compromises.....fuel economy, ride comfort, handling, hydroplaning resistance among others.......while trailer tires, while they do benefit from the radial construction with cooler running temps, smoother ride for the trailer, are purpose built for supporting a load that's being pulled.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,313
Re: Passenger tires on trailer?

The National Highway Traffic Safety Administration specifies that when passenger cars tires are used on trailer, the passenger car's load rating is to be decreased by 10%.



Radial Vs. Bias Trailer Tire
By Kyle McBride,

In evaluating radial versus bias ply tires for trailers, it must be said up front that tires for cars and trucks are not suitable for use on trailers. A common misconception is that radial tires are car tires and so are not appropriate for use on a trailer. The terms "radial" and "bias ply" are descriptive of the way a tire is constructed and in no way indicates what its use should be. In all cases, whether you pick radials or bias ply tires to put on a trailer, be certain the tire is rated for use specifically on trailers and is rated for the weight of the load and the speed at which you will be using them.

1. Tire Construction
o Bias ply tires--also known as cross-ply tires--are made of plies, which are layers of rubberized textile cords laid on opposing diagonals and anchored around the tire's bead wires. The diagonals are 30 or 45 degrees off the tire's circumferential centerline. Radial tires have reinforced steel cable belts beneath the tire's tread that run 90 degrees to the circumference centerline.

Puncture Resistance
o Radial tires, because of the durability of the steel belt construction, are more resistant to punctures in the tread than are bias ply tires. Radials are also less prone to punctures in the sidewalls because the tread and the sidewall act as independent components of the tire. The radial's tread stays flat on the road surface when the sidewalls flex under the weight of a load. The sidewalls on the bias ply tire will flex under a load and deform the tread, squeezing it and making the sidewalls susceptible to abrasion and vulnerable to punctures from objects on the ground surface.

Heat Resistance
o The same construction factors that make radial tires more puncture resistant also make them more resistant to blowouts from heat. The steel cables of the radial tire will aid in heat dissipation allowing them to run cooler. The heavy rubber and textile cording of the bias ply tire will hold heat, and so they will run hotter under a load[/B]. For occasional use trailers that are run short distances, the lack of heat dissipation of the bias ply tire may not be a factor at all. Radial tires may be the better choice, however, for long distance, frequent use trailers that will see many highway miles on a regular basis.

Handling and Traction
o Radial tires handle corners better than bias ply tires. This again goes back to the construction of the tires. The radial tire has more tread stability because of the independent nature of the sidewall. The radial sidewall can flex while going around a corner, but the tread will still maintain full ground contact, whereas a bias ply tire will roll and deform the tread, reducing stability around corners and reducing the amount of tread that is in contact with the road surface. When properly inflated, a bias ply tire is inherently strong, however, and so would make a good choice for straight line towing where cornering and traction are not factors.

Ride and Cost
o Radial tires give a smoother, quieter ride than bias ply radials. Radials also have longer life expectancy than bias ply tires. In listing the benefits of radial tires, it might seem like they'd be the obvious choice, but bias ply tires are less expensive.

Weighing Benefits
o The benefits of radial tires may not be fully realized enough to justify the additional cost if the trailer is used infrequently and for short distances. For long distance and frequent use, factors like cornering, puncture potential, expected life and heat buildup will need to be evaluated as they apply to the specific intended use of the trailer

http://www.ehow.com/about_5329987_radial-vs-bias-trailer-tire.html
 

dt342

Cadet
Joined
Mar 21, 2011
Messages
10
Re: Passenger tires on trailer?

As someone who worked for a major manufacturer of tires for over twelve years, before I tired of them closing plants, I can tell you that for basic tires there is hardly a difference at all. For instance Widetrack radials, Dayton tires, Firestone, and some Bridgestone only differ by slight compound changes and a different design in the curing press. If you ever saw how your tires were actually made you would wonder how they stay together and understand why they sometimes don't. I will never put a doughnut spare on a vehicle and drive more than an inch. Load rating is determined by the number of polyester plies (body ply) contained in the tire, contain heavier stabilizer ply insert, goes under the edge of the steel ply during construction, and bead construction. Many other differences in components but these are the main ones. Basically, most tires in a specific range of use are very similar but there is a major difference between truck tires, passenger car tires and trailer tires. Again construction is very similar but the compounds used and specific number of plies change. Especially when you get into the D and E load ratings. Just my .02 from a former tire builder and supervisor. Take it for what it's worth.
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: Passenger tires on trailer?

Car tires are fine if not overloaded, but this application is way too heavy for car tires. Yer already to the extreme limit with just the boat, trailer, and a little fuel. No safety margin at all.

Go with the trailer tires. Radial trailers work fine. Any of them inflate to higher pressures than car tires and carry more load without complaining.

I ran a set of car tires under my bass boat. They didn't last long, wore unevenly, and if even the slightest bit under inflated gave me noticeable handling headaches. Next set was radial trailer tires. All good now.
 

veritas honus

Lieutenant Commander
Joined
Jun 13, 2010
Messages
1,876
Re: Passenger tires on trailer?

Thank you, all of you!!!

Trailer tires it shall be. Seemed like a no brainer, but I know that things are not always as they seem on the surface. Figured the load rating would be what dictated whether or not it was feasible. I thought I'd be increasing the safety/handling as opposed to compromising both.

Again, a BIG Thank You to everyone!!!
 

wbc1957

Petty Officer 1st Class
Joined
Apr 26, 2010
Messages
261
Re: Passenger tires on trailer?

I have Carlisle trailer tires which I need to replace. They're 185/80/13 bias ply.

I can get a set of Douglas radial tires, 175/70/13 for about half the cost of what I have now. The weight rating is 1047lbs per tire, which would allow for a max load of 4188lbs.

The dry weight of my boat is 3000lbs. I do not trailer the boat loaded. I transfer everything into the boat from my truck at the staging area of the boat ramp. The four tires will be supporting less than 4000lbs including the trailer.

The passenger tires being radial as opposed to bias ply, I see as a bonus.

Anyone see any problems with this? Any thoughts?

At least get tires that are the same size. The 175/70/13's are a great deal shorter and fatter than the original 185/80/13's. The middle number is a height to width ratio, and you already lowered the height with going from 185 to 175. Now you wish to make it worse with the ratio?
 

cribber

Lieutenant
Joined
May 29, 2008
Messages
1,338
Re: Passenger tires on trailer?

I just go with what the manufacture put on it when I bought. That philosophy has kept me between the ditches for a very long time. Just remember replacing tires are like changing your oil... if you see sidewall cracks start shopping for a new set.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,234
Re: Passenger tires on trailer?

My big trailer came from the factory with auto bias ply tires. Only the heavier models with the same frame were equipped with ST tires.

I can't complain about the handling or wear characteristics. OTOH, my other little trailers that came with ST tires from the factory didn't have nearly the same longevity.

The only tire failures I've had were with ST.

Just replaced the car tires on the TeeNee with new STs. We'll see how they do!
 

'78 Crusader

Chief Petty Officer
Joined
Mar 15, 2011
Messages
407
Re: Passenger tires on trailer?

Thank you, all of you!!!

Trailer tires it shall be. Seemed like a no brainer, but I know that things are not always as they seem on the surface. Figured the load rating would be what dictated whether or not it was feasible. I thought I'd be increasing the safety/handling as opposed to compromising both.

Again, a BIG Thank You to everyone!!!

Smart man, glad it worked out for you.
 

veritas honus

Lieutenant Commander
Joined
Jun 13, 2010
Messages
1,876
Re: Passenger tires on trailer?

Trailered the boat to work last night. Went this morning, to a great local tire shop straight from work. Got 5 175/80/13 ST radials installed and balanced, with new valve stems for under 300.00 out the door. They open at 8:00am. I was on my way home before 8:30. Load rating 1360lbs per tire. I'm good with a 5440lb limit.

Thanks again for all the replies.
 

'78 Crusader

Chief Petty Officer
Joined
Mar 15, 2011
Messages
407
Re: Passenger tires on trailer?

Excellent news! Glad you went with the trailer tires....smart thing to do.
 

TireSkeptic

Recruit
Joined
Jul 24, 2011
Messages
3
Re: Passenger tires on trailer?

I disagree. As long as you do not overload the tires, they will work fine. The largest differences between car and trailer tires are: 1) modern car tires are radial while trailer tires are bias ply. 2) Tread pattern on trailer tires have much less traction. They are not meant to drive or steer, just follow.

The load is not carried by the tire, the load is carried by the air within the tire. Most tire failures are caused by overheating. This can come from overheated wheel bearings, overheated brakes, or improper inflation.

I agree with the above. I drove truck for some years and the tires used on tractor, trailer, or steering axle differ only in tread design. I have found no one to date with a convincing argument for not running light truck tires on a trailer, boat or RV. Aside from puncture, the greatest enemies of any tire are under inflation and overloading, both of which cause a buildup of heat which can lead to ply separation.

Most RV's for example come from the manufacturer with tires that are pretty much overloaded even with the rig empty! A good light truck tire with a load rating at least 75 to 100 pounds over its 1/4 of the load on a tandem trailer, and maintained at or near the maximum loading pressure on the sidewall should never blow unless it receives a major puncture. One could also have them nitrogen filled to aid in keeping the temperature lower.

A further note, there is a date stamp on at least one side of the tire usually near the DOT serial number. It is a four digit code such as "4710" with the first two digits indicating the week of the year of manufacture and the second pair indicating the year. Thus "47" would indicate the 47th week of the year, and "10" would indicate 2010. Tires over five years old should be discarded, REGARDLESS of whether or not they've ever been mounted or run.
 
Top