Tires -- Bias or Radial?

[Night Sailor]

I read a description of an Avion trailer with three axles and six wheels. The writer stated that bias tires worked better because radial tires would act like springs and increase sway?

Does anyone have direct experience using both
types on the same trailer.

[Francesca Knowles]

My Trillium came to me with brand new radials, though P-rated, not ST's. I changed them to bias-ply ST's on the advice of my RV guy when I went to him about the really awful sway I was experiencing at speeds over forty. He was absolutely correct in the diagnosis of the problem- sway problem permanently solved as soon as I got the new tires. Though radial ST's would certainly perform better than those miserable P-tires did, my long-time tire guy also advised that the stiffer bias-ply would serve best for my particular trailer.

I'm a stickler for age-related tire changeout on my (single axle) trailer, and am now on my third set in seven years (45,000 miles). I've stuck with the bias plies even though the ones I'm using are a little more expensive than radial ST's.

I did consider trying radial ST's this last time, but I'm reluctant to change since radials are in fact "flabbier" than bias-ply. But since the rigidity of the sidewalls is an important part of my whole antisway "system" (which does NOT include mechanical add-ons such as bars, etc.), I decided to stick with the bias-plies that have worked so well for me.

Francesca

[calindor]

Francesca, how much is a 'little more' expensive for the bias ply tires? Are we talking 10% or 50%?

I am curious if there are other differences such as wear or overall life of the tire? Do you know?

[Brian B-P]

Originally Posted by Francesca Knowles

I've stuck with the bias plies even though the ones I'm using are a little more expensive than radial ST's.

Although I don't question what Francesca paid, in this century bias ply tires are generally the cheap old product line, as an economical alternative to the premium radial choice.

As a quick example, Eastern Marine's Trailer Parts Superstore (also presented as www.trailertires.com) sells only obscure-brand tires, and in the same brand (Loadstar),
Load Range C: ST175/80D13 $57.25 versus ST175/80R13 $73.88
Load Range C: ST205/75D14 $72.25 versus ST205/75R14 $84.50
Load Range C: ST215/75D14 $83.99 versus ST215/75R14 $96.00
Load Range C: ST225/75D15 $89.88 versus ST225/75R15 $121.00
Load Range D: ST225/75D15 $99.00 versus ST225/75R15 $123.00

A better-known brand might be Carlisle. Simple Tire carries both Carlisle Radial Trail RH and Carlisle Sport Trail (bias ply), and the price differential is similar to what I listed above. Local suppliers that I could find easily (Princess Auto, my usual source of economical tools and supplies; and Kal Tire, my favourite car/van tire supplier) carry Carlisle radials, but not any brand of bias ply trailer tires in the same sizes... I wonder why?

The following is only my opinion:
My suggestion would be not to use bias ply tires, but if you choose to do so, certainly don't pay a premium for them as compared to radial tires of the same brand, size, and load capacity.

[Francesca Knowles]

Originally Posted by calindor

Francesca, how much is a 'little more' expensive for the bias ply tires? Are we talking 10% or 50%?

I am curious if there are other differences such as wear or overall life of the tire? Do you know?

The bias plies I've been running are from Les Schwab, and cost about twenty dollars more per tire than their comparable ST. Per length-of-wear, I don't know- I replace my ST's at between three and four years or 20,000 miles (whichever comes first) and would do so regardless of type. That rotation is what's recommended by most trailer tire makers, and an easy safety admonition to heed. (For various design/use reasons, ST's aren't designed/anticipated to "wear out". More info at this link)

Prejudices linger against the use of bias-tires, probably based mostly on folks' experience using radials on passenger cars. Certainly that's a use for which radials are in most cases better. But for some applications bias remains the preferred type, and one of those applications is on my trailer, based on my experience with my very specific setup. For others, radial ST's will likely work just as well, and certainly better than passenger vehicle tires such as P's or LT's.

It may be that the narrowness of the market contributes to the cost of higher quality bias-ply ST's.

Francesca

[cpaharley2008]

Let's try to help the OP via helpful answers in lieu of criticizing what others may have said.

[Hambone]

I went from st175/80/13 to a st205/75/r/14 on my scamp, found with the new tires tires ran 100% cooler (hand thermometer) upgrade in size? or was it the radial design? Trailer does seem to have more spring, but it isnt as jarring as the bias plys where, same handling as regards to sway, if any, is concerned

[Brian B-P]

Originally Posted by cpaharley2008

Let's try to help the OP via helpful answers in lieu of criticizing what others may have said.

Absolutely!

Specific information, such as sizes, load ratings, brands and models, would be helpful in making comparisons.

[841K9]

Bias tires are great, but you have to be very attentive to air pressure. The plies are at angles to one another and cause more heat buildup when run with low air pressure which leads to more blowouts. The other problem with bias ply tires is that they tend to flat spot very, very quickly.

Anyone here ever drive a HMMWV with the old bias tires? Those were the worst bias tires for thumping and out of round. The newer radials are smooth as silk in comparison.

That being said. I would have no problem running bias tires on any vehicle I own as long as they're good quality and I stay on top of air pressure.

[Jared J]

I've ran bias tires on vehicles, and they could take 10 miles for the tires to straighten up. I would hate to do that on a loaded camper, that thing might rearrange itself 5 times by then.

I've always ran radials, no sway problems running up to 11k#'s.

[Night Sailor]

The reasoning asked this question was because I found a 35' Avion 10.6 which needed six tires and a new spare. The price is right at under $4000.

My first instinct was to buy Goodyear Marathon radial tires. Then I discovered these tires have a high failure rate.

While bias ply tires are cheaper...a big factor. I decided to let this camper pass because of the costs to operate it. I am guessing my fuel economy to be 9.5-10 mpg. It I had a nice place to keep it on a lake somewhere. It also needs new upholstery and flooring, plus who knows what else.

In any event, I do find the topic interesting. If I had only two tires on a light trailer it would not be important. I would choose the best tires possible without concern about the cost. On a trailer with six wheels on the ground the trade off would seem to be lower rolling resistance versus anti sway properties.

[Night Sailor]

Is anyone running tire pressure monitors in their TV's and trailers? I have one TV switched over and want to add them to my other TV, and then trailers.

[MC1]

The RV dealer I deal with is Can AM here in Ontario.

They once wrote that a few of the trailers they ordered recently arrived with bias ply tires. Being a knowledgeable, safety conscious dealer they (at their own expence) upgraded the tires to radials. As one who is from the tire industry I agree with what they did.

[Carol H]

Originally Posted by Night Sailor

Is anyone running tire pressure monitors in their TV's and trailers? I have one TV switched over and want to add them to my other TV, and then trailers.

Only have the system on the TV (it came with them) only short fall is it doesnt tell me which tire - so I actually have to get out of the car and use a pressure gauge to figure that out myself! Imagine that! Its a serious design flaw.

If you Google this site you will find a thread on the topic of pressure monitors on the trailers a few months back.

When I got my trailer it had bias tires on it and I used those tires for one year before changing them out for radial ST's. Was on a long highway trip when I had them changed out - only difference I noticed right away was the trailer seemed to ride a bit smother on rougher sections of the freeway and I didn't and still havent notice any sway issues mentioned above & I'm on my second set now.

[Carol H]

Originally Posted by Night Sailor

My first instinct was to buy Goodyear Marathon radial tires. Then I discovered these tires have a high failure rate. .

LOL that topics been well covered here but again if you do a google of this site I suspect you will find there are probable as many if not more folks happy as can be with the Goodyear Marathon's performance as those who are not.