Mixed Tire Types

[phipps33]

We just bought a NTU travel trailer. I noticed that 3 of the tires are radials with one being bias. Is this a problem?

[valhalla360]

Bias will flex and give differently from radial as you go down the road.

It's kind of like putting a steel toe boot on one foot and a tennis shoe on the other. If you just walk around the house, it may be a bit akward but no harm. If you try to play a game of tennis, there is a good chance it will throw you off enough to trip you.

I'm guessing if they have different recommended pressure, they are not the same size/load rating. That's like having one properly fitted tennis shoe and another that is 3 sizes to big and always wanting to fall off.

Having tires of the same size & load rating all in radial but from different manufacturers is OK but mixing size, load rating and construction types is not a good idea.

[Atlee]

ZIf I were you, I'd replace all four of those tires with the same size, including load range, and I'd make them radials. And among the 50 psi tires, I keep the best and youngest one for the spare.

phipps33 wrote:
One more question, 2 of my tires require 35psi and 2 require 50psi. I'm guessing this means different load ranges. If they are different load ranges, should each load range be on the same axle?

Sorry for the questions, I'm trying to learn as much as I can.



Thanks!

[rbpru]

If we start at the beginning your tires numbers should all start with ST then the size. LT denotes light truck, P denotes passenger service.

The TT manufacturers prefer equal axle load on each tire. They want all the tires to share the load.

If you have a different tire type and different tire pressures it is difficult to predict the tire load distribution.

Most TT tire makers recommend replacing them every 5 years, because the compounds used in TT age quicker even though there is a lot of tread left.

How much attention each customer pays to the manufacturer's recommendations is unknown. They just tell you what they think is best.

[darsben]

phipps33 wrote:

darsben wrote:
ALL your questions are moot until you know how old the tires are.
Get the date codes then we will talk

Really?!? SMH

I'm well aware of replacing tires before they wear out, but I am trying to learn more about the various tire issues to look out for and your reply didn't provide any useful information

Thank you to all the posters who have answered my questions.

I am trying to tell you they do not wear out they age out. If the tires are over 5-6 years old THEY SHOULD BE REPLACED even if the tread looks new. SO until the age of the tires is known talking about replacing one or 2 is MOOT because of age they may all need to be replaced.
SO WHAT IS THE DOT DATE CODE

[phipps33]

darsben wrote:
ALL your questions are moot until you know how old the tires are.
Get the date codes then we will talk

Really?!? SMH

I'm well aware of replacing tires before they wear out, but I am trying to learn more about the various tire issues to look out for and your reply didn't provide any useful information

Thank you to all the posters who have answered my questions.

[darsben]

ALL your questions are moot until you know how old the tires are.
Get the date codes then we will talk

[jus2shy]

phipps33 wrote:
One more question, 2 of my tires require 35psi and 2 require 50psi. I'm guessing this means different load ranges. If they are different load ranges, should each load range be on the same axle?

Sorry for the questions, I'm trying to learn as much as I can.



Thanks!

There should be a numerical number noting the "Service Load Index" of the tire. Typically it's a number between 80 and 130. If you have different service load index values, then your tires aren't rated to carry the same load. The pressure thing could be an indicator of that very issue.

[phipps33]

One more question, 2 of my tires require 35psi and 2 require 50psi. I'm guessing this means different load ranges. If they are different load ranges, should each load range be on the same axle?

Sorry for the questions, I'm trying to learn as much as I can.



Thanks!

[BB_TX]

I would prefer to have all tires the same. But as long as the bias ply is the same diameter as the radials I would not worry about it.

Checking the date on all tires is certainly a good idea.

[harold1946]

The D14 is a bias ply and there is no reason to replace it just because it is mismatched.

[rbpru]

The short version is D means diagonal placed belts and R means radially placed belts. The Tire and TT folks will tell you they will respond differently under load, so it is best to have them all the same type.

[phipps33]

Could someone explain why this is bad? Not doubting your advice, I just like to know the reasoning behind for future reference.

I'm also assuming a tire size followed by D14 rather than R14 is a bias, correct?

[phillyg]

Yes!

[darsben]

yep
But you should check the tire date code on all the tires. ANY TIRE over 5-6 years old is a blowout just waiting to happen.
RV TIRES age out not wear out. If they are old they need to be changed no matter how much tread is left. EVEN IF they look brand new

[fla-gypsy]

Yes, get that corrected ASAP