Tire Bias or radial

[LI Pets]

I read thru the posts but I don't see a clear cut position.

I have a 31' that needs all 4 tires 7.00x15 or 225/75/15 load D

Are radials going to absorb more of the road shock on bumpy roads what are the advantages of each.

Bob

[overlander63]

Bob, you can use either, but not both.
The advantages of 7.00X15 is:
costs less
taller (more ground clearance/ less trouble getting inside fenders)
chance of belt separation approaches zero.
Disadvantages are:
Rides rougher
wears faster (usually not an issue)
lack of dealer support

Advantages of 225/75R15 are:
Rides smoother
longer tread life
depending on manufacturer, dealer support is good
slighlty better fuel mileage
Disadvantages are:
wider tires may interfere with fender during installation.
lower profile (less ground clearance)
cost more
sidewalls are not as strong
belt separation

[LI Pets]

So should I be looking for a slightly taller tire in a radial then the 225/75/15?

[overlander63]

Originally Posted by Lipets

So should I be looking for a slightly taller tire in a radial then the 225/75/15?

7.00x15's are available as radials, just not as metric radials. 7.00Rx15.

[azflycaster]

OL63 could you explain what you meanby lack of dealer support? I would think that a tire dealer would give you the same level of support for any tire that they sold.

[Frank S]

Hi overlander63--I have been recently researching 7.00x15 vs ST225/75R15 in the Goodyear family and came up with the following prices at WalMart for D load range: $107.20 vs $90.28, which now makes the 7.00x15 more expensive. This was not the case in the past. All of the other factors you list above are identical to what I have found. I have stayed with the original size 7.00x15 and never had a problem or flat with them, however availability on the road, is beginning to concern me so I may switch to ST225/75R15 next tire replacement.--Frank S

[moosetags]

I would trust a Load Range D radial over any bias ply tire; this is a pretty heafty tire. Bias plys simply don't have the road holding quality of a radial. This could be be particularly important in a wet hard stop situation.

[Frank S]

Hi Lipets--In a Goodyear ST radial tire for a 15" wheel ST225/75R15 is the largest tire dia you will find. It has a dia of 28.3", vs the 7.00-15LT with a dia of 30.0".--Frank S

[mustang]

The only real towing difference between the 2 is Bias ply tires tend to follow the road groves or grain and Radials Make there own Path so Radials Useuaally tow better

[SafeHarbor]

I'm looking at replacing tires, too. On my recent trip, I had a destructive blowout of the left-rear tire that damaged the trailer and then 150 miles later had the left-front separate.

Right now it's sitting on a purchased used Marathon (from the local tire dealer's RV) and my spare.

According to the owner's manual, the trailer came with 7.00-15XC steel-belted radial Load Range D. It has ST225/75R15s on it now. Well, I HOPE that spare is. Guess I'd better go check.

Anyhoo, I wouldn't mind a slightly taller tire. Anbody know what the "XC" meant?

Lamar

[oxblood]

Well I blew out two front Marathons ST227/75R/15 on my recent May/June trip in hot weather. Admittedly, I was going too fast 70-75 mph. There are no warranties on these tires. I had moderate damage to the A/S lower panels. A replacement tire locally was $120 - but installed and balance and discarding the old tire --total $160. Because I'm taking off again in 2 weeks I bought 2 Marathons from TireRack.com for about $164.00 which included shipping to Texas. We need better tires I think.

[Beginner]

SafeHarbor
The 7.00-15XC stands for the Michelin XCA. It was a radial but looked like (had the profile of a Bias Ply tire).
Is is no longer made in our size (15 or 16 inch rim).
The sidewalls are not the problem. The belts shift causing an air leak. The heat generated by running flat causes catastrophic failure. You cannot look at a radial and determine whether it has 60 PSI in it or 40 PSI. There just isn't that much difference in sidewall bulge.
Help us help ourselves.
Report these failures to the people responsible for investigating these problems.

http://www-odi.nhtsa.dot.gov/cars/pr...callsearch.cfm

These tire failures are not our fault folks. We have just been putting up with them for so long that we think it is a normal way of camping. It is not.
There are save, reliable and dependable alternatives to getting away from these failures other than going 45 mPH and changing tires every 3 to 4 years.
I have gone that route along with others.
I will await the hammering for this message.
Begginer

[SafeHarbor]

Hi, Beginner,

No hammering here. You make a very good point.

I'm not blaming the tires - I don't even know how old they are. One even has a slightly different sidewall from the other three.

My blowout was 7.5 miles into the trip going 45 mph, and I know how much air was in the tires. They all had 65 psi upon departing.

The separation, well, I wonder if I'm using the right word. The tread departed the tire in chunks, leaving the belts showing. Even after this, I had to drive another 5 miles (30 mph with the flashers going) to find a level place to change the tire. I checked that tire today. It STILL has 65 psi in it!

The trailer, except for some playing around in the pecan grove a couple of weeks ago, had been sitting since last October.

That was Saturday. On the previous Wednesday, I had all the tires off the trailer because I installed new backing plates. I critically looked at each tire for weather checking, bulges, irregular wear, etc. and I found no problems.

And how annoying - these were the tires that always had the Zip-Dee covers shading them.

I called Wal-mart. They can get the tires, but they won't change them on the RV. No problemo. I'll jack it on my ramps in their parking lot and carry them in one by one.

Next, question. I have the centramatics. Should I let them balance the wheel/tire anyway? (So far, I don't really see any reason not to.)

Then again, I might call around town and see if anybody's got the Snap-On balancer that Inland Andy recommends so I can get the hubs balanced with the wheels.

Lamar

[LI Pets]

Marathon's are getting negative reviews HERE

Anyone use Maxxis

Found this info
because the design of most trailer suspensions dates back many decades, ST tires are designed for as soft a ride as possible so they don't transmit too much shock to the trailer and its contents. Trailer-tire sidewall stiffness is a compromise between P and LT designs. The desire for stiffer sidewalls is still occasionally cited as the reason for choosing a bias-belted trailer tire. While passenger-car tires are nearly all radials these days, ST tires are still available in bias-belted construction. Radial trailer tires are superior in all respects to bias-belted tires except in sidewall stiffness. Reduced tire heat, lower rolling resistance and softer ride are among the benefits of radials, not to mention extended wear. On the road, ST tires share some characteristics of passenger-car tires, but are closer to the design of light-truck tires. Trailer tires typically employ heavier steel or polyester cords and somewhat lighter sidewall construction than light-truck tires, and trailer tires typically run lower air pressures than their truck counterparts. This gives ST tires good load-carrying capacity, but with the desired softer ride, ST tires also have the advantage of rubber compounds that are specifically designed to resist deterioration from the elements, including sunlight and ozone, during extended storage.




Bob

[Beginner]

You are still left with the fact (at least when I wrote as many manufacturere as I could find, Denman, GoodYear, GreenBall, LoadStar, Maxxis, Nankang, to name a few) had a Speed rating over 65 MPH except Cooper(for the ST225/75R15 of course). I personally don't like running that close to the maximun designed limit of anything, so I don't. The tire I went to has a speed rating of 99 MPH (Q). No I never intend to go that fast, but for a few dollars more I hope to not be loosing tires instead of enjoying the vacation.
Beginner

[joel]

I know I am probably 1 of the few who think this,but I run 235/15 radial truck on my 86 31'. I had them on my 73 31' for over 25,000 miles without a failure and I have 37,000 on my 86 31' witout a problem.They are the same tires I use on my 1/2 ton truck. They are 235/15 AT lemans radials and they come from firestone load range c.I have pulled thru 100 degree heat at 70 mph many times and I pull at least 200 miles a month thru the ozark mtn,s.I repeat I have never had a problem..The trailor pulls extremely smoothly With them.

[Beginner]

joel
No you arn't the only one that thinks that.
A pattern seems to be forming here.
1. 31 foot trailers seem to have more trouble than the shorter trailers.
2. Any LT tire seems to better than the ST tires on the 31 foot trailers.
I say this then Bambi owners chime in and tell us of blisters and shifted belts on their ST tires.
I have never had difficuilty with Michelin or BF Goodrich(Michelin), so I went with that, selecting a tire that was suggested by others that turned out to be the same Outside Diameter as the original Michelin 7.00-15 XCA that came on my trailer and the same width as the Marathon and is a LT tire.
Havent had a single problem yet.(knock on wood)
Beginner

[LI Pets]

Beginner, what size tire did you go with?

Maybe that's the trick when you go to 28.3" 225/75 tire it has to turn more rev's per mile than a 30" tire 7.00x15 ?

[SafeHarbor]

Boy, DO NOT go to coopertires.com if you're using a wireless card outside of an EVDO area. It's flash hell.

Lamar

[Coloradobus]

Before you buy, check the "load rating" on Load Range "D" belted tires. NO one should be putting these on a 31 footer. Max carrying capacity on a 7.00X15 belted tire is 2,040 lbs, The 7.00R15's carry a little more. ST225X75X15, doesn't matter who makes , max poundage carried is 2,540 lbs.
My only gripe about "ST" tires is the speed restriction of 65mph. May try LT's on our '79 Trade Wind International.