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phipps33's avatar
phipps33
Explorer
Oct 07, 2015

Mixed Tire Types

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

29 Replies

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