Forum Discussion

Sam_Whiskey's avatar
Sam_Whiskey
Explorer
Jul 02, 2015

Travel Trailer Wheel/tire Size

We just purchased an 87 Kit Companion Classic.

Tire size on label states G78 14 ST (C). Which, according to a search, equals P215/75R14.

The actual tires are ST225/75R15.

Is there an advantage/disadvantage to having a larger tire?

Thanks!
Sam.
  • Sam_Whiskey's avatar
    Sam_Whiskey
    Explorer
    Jul 04, 2015
    Huntindog - I measured the clearances as you suggested and they are all well within what you mentioned.

    Thanks!!!
    Sam
  • coolbreeze01's avatar
    coolbreeze01
    Explorer
    Jul 03, 2015
    Sam_Whiskey wrote:
    We just purchased an 87 Kit Companion Classic.

    Tire size on label states G78 14 ST (C). Which, according to a search, equals P215/75R14.

    The actual tires are ST225/75R15.

    Is there an advantage/disadvantage to having a larger tire?

    Thanks!
    Sam.


    I have upgraded to 225 75R 15 E tires on two trailers. My theory is more is better.

    I have had tires delaminate in over 60 years of towing, but they stayed aired up.
  • Huntindog's avatar
    Huntindog
    Explorer
    Jul 03, 2015
    Sam_Whiskey wrote:
    We just purchased an 87 Kit Companion Classic.

    Tire size on label states G78 14 ST (C). Which, according to a search, equals P215/75R14.

    The actual tires are ST225/75R15.

    Is there an advantage/disadvantage to having a larger tire?

    Thanks!
    Sam.
    Yes, within reason.
    You need a minimum of 1" between the tires on a dual axle, and 3" from the top of the tires to the wheelwell. When doing this measurement, it is best to be on level ground. Otherwise you may have to compensate for one axle being higher than the other... It's not hard though. Measure them both and divide by 2. If it is 3" or more you are good to go.

    I have raised all of my TTs in order to be able to use bigger tires and for more ground clearance.
    The only negative I have encountered is a MPG reduction of about 1 MPG, but I have raised mine a lot more than the 1/2" yours was raised. Your difference is negligible.

    Enjoy your TT.:B
  • canoe_on_top's avatar
    canoe_on_top
    Explorer
    Jul 03, 2015
    The extra inch is only a 1/2 inch in added height, (axle to ground). It won't make a difference in whether you tip over or not.
  • Sam_Whiskey's avatar
    Sam_Whiskey
    Explorer
    Jul 03, 2015
    Mitch..I did respond to you yesterday but it appears the response did not get posted. Apologies.

    Sam.
  • Sam_Whiskey's avatar
    Sam_Whiskey
    Explorer
    Jul 03, 2015
    Good info all. The max load for each tire is 2640 pounds. Our intent is to keep the trailer light.

    My other concern, if it should even be a concern, is that extra inch and wind.
    I have seen many big rigs and TTs being blown over during high winds. Could that extra inch be the straw....

    Thanks.
    Sam.
  • Campfire_Time's avatar
    Campfire_Time
    Explorer
    Jul 03, 2015
    Keep in mind that while the bigger tires can take more weight, the axle is still the limitation. In my experience going to bigger tires is half a dozen of one, 6 of another. The bigger tires are nice but are little more than a "feel good". However if your rims look crappy and you're thinking about replacing those too, then now is the time to go a size bigger.
  • JIMNLIN's avatar
    JIMNLIN
    Explorer III
    Jul 03, 2015
    I like moving up to 15" from 14" on any of my smaller trailers.
    .. better tire selections.
    .. smoother ride over say rough RR tracks
    .. lower wheel rpm = less wheel bearing heat.

    Now if the ST225/75-15 is a 8 or 10 ply rated tire then its gonna' ride rough.

About Travel Trailer Group

44,027 PostsLatest Activity: Mar 04, 2025