Forum Discussion

crcr's avatar
crcr
Explorer
May 04, 2013

Need recommendation for tire pressure for TT tires

Hi,

We have a 21.5' Travel Trailer, with a GVWR of 4769. We are getting ready for our first camping trip of the season, and I'm looking for a recommendation of how many pounds of pressure to carry in the 5 tires, 4 on the ground plus a spare.

Here are some stats on the tires: Brand is Karrier, "for Trailer service only", Tubeless radials, Size is 205/75R14, Load range C, Max pressure, 50 psi cold, and yes, made in China. The TT is only a year old now, and these are the OEM tires. I understand the principle that more pressure in the tires means cooler running temps for the tires, but the trade-off is a rougher ride for the TT and its contents. We travel only 120 miles each way throughout the summer to our camping spots where we stay 3 or 4 days, then return. The roads are pretty much all paved and of good quality. However, we live in Phoenix, AZ, and tow to the high country, so at the lower elevations in summer, temps can be 100 degrees or more, though we leave early enough going or coming to avoid towing in over 100 degree temps.

The tires are all currently sitting at 37 psi cold. I'd be interested in any recommendations as to what pressure to carry in them throughout the summer. Thanks much for any input.
  • JJBIRISH's avatar
    JJBIRISH
    Explorer
    May 05, 2013
    enblethen wrote:
    Cold pressure temperature is somewhere around 80 degrees. You fill your tires to max 50 psi in this discussion and temperatures get over 100 degrees, tires will be well above max pressure. Bamb! No more tire.


    Baloney…

    Tire mfg. suggest that for every 10 degree increase or decrease in ambient temperature, a tire will show a 1 psi change…

    If the ambient temp is 80* and you fill the tires to 50 PSI and the ambient temp rises to 100* the ambient temp alone will only cause about a 2 PSI pressure increase…

    Cold inflation pressures are engineered while considering the ambient temp changes, sun and road temp effects on the tire… a 20* ambient temp differential would be easily within the normal operating range...
  • NanciL's avatar
    NanciL
    Explorer II
    May 05, 2013
    50 PSI cold.
    That is what mine call for, and that is what I have used in two different trailers and over 30,000 miles of traveling without a flat.


    I personally would get rid of the chinese tires and get US made ones

    Jack L
  • Slowmover's avatar
    Slowmover
    Explorer
    May 05, 2013
    TT tires, any type or brand, are always to be run at sidewall maximum. Side shear forces predominate. It is the fact that the tires are on a trailer, not the type of tire mounted.

    See the posts/blog by retired tire engineer (failure analysis expert) Tireman9.

    .
  • FastEagle's avatar
    FastEagle
    Explorer
    May 05, 2013
    crcr wrote:
    Hi,

    We have a 21.5' Travel Trailer, with a GVWR of 4769. We are getting ready for our first camping trip of the season, and I'm looking for a recommendation of how many pounds of pressure to carry in the 5 tires, 4 on the ground plus a spare.

    Here are some stats on the tires: Brand is Karrier, "for Trailer service only", Tubeless radials, Size is 205/75R14, Load range C, Max pressure, 50 psi cold, and yes, made in China. The TT is only a year old now, and these are the OEM tires. I understand the principle that more pressure in the tires means cooler running temps for the tires, but the trade-off is a rougher ride for the TT and its contents. We travel only 120 miles each way throughout the summer to our camping spots where we stay 3 or 4 days, then return. The roads are pretty much all paved and of good quality. However, we live in Phoenix, AZ, and tow to the high country, so at the lower elevations in summer, temps can be 100 degrees or more, though we leave early enough going or coming to avoid towing in over 100 degree temps.

    The tires are all currently sitting at 37 psi cold. I'd be interested in any recommendations as to what pressure to carry in them throughout the summer. Thanks much for any input.


    I’m a little surprised this thread has gone this far and no one has come up with the right answer.

    Vehicle manufacturers SET the recommended tire pressure (s) for your trailer tires and certify those pressures on the vehicle’s certification label. Look on the LH forward section of your trailer for its certification label. I’ll bet it recommends 50 psi. That will be the CORRECT tire pressure for your tires at all times unless your owner’s manual has other pressure’s for special circumstances.

    FastEagle

    p.s. Tires with less than 80% of the vehicle manufacturer’s recommended cold tire pressure (s) are considered in the a “run-flat-condition. If they have been up to highway speeds in that condition they need to be removed for inspection by a tire professional.
  • ktmrfs's avatar
    ktmrfs
    Explorer II
    May 05, 2013
    Virtually all the ST tire mfg specify that the tires should be run at max sidewall pressure regardless of load. Has to do with tire design and the very high side loads on trailer tires when you turn.

    Done that for many miles and tread wear has been even. I get 25K-30K miles/set and the wear is even at max pressure. Neighbor has 200K+ miles on his cargo hauler, does the same, same thing for wear.

    As to worrying about heat buildup, it is a non issue if the tire isn't overloaded. Tires are designed for a max cold inflation pressure knowing that pressure will rise as they heat up or you go to higher daytime temps.
  • enblethen's avatar
    enblethen
    Nomad
    May 05, 2013
    Any type of vessel whether it is tire or a cylinder when exposed to heat will cause the pressure to increase. Tires increase in flation due to resistance of rolling on the road. Sure a tire may have a safety margin, how much is the question.
    Tire inflation information
  • Gdetrailer's avatar
    Gdetrailer
    Explorer III
    May 04, 2013
    enblethen wrote:
    Cold pressure temperature is somewhere around 80 degrees. You fill your tires to max 50 psi in this discussion and temperatures get over 100 degrees, tires will be well above max pressure. Bamb! No more tire.


    :R:R:R:h:M

    TOTAL B.S.

    "Cold Pressure Temperature" is ANY temperature at which the tire has NOT BEEN in use for a PERIOD OF TIME.

    Follow YOUR "recommendation" is folly and WILL result in damaged or premature tire failure and or excessive tire wear.

    UNDER INFLATION will result in overloading the tires in most cases with travel trailers (travel trailers tend to be rather close to the weight ratings of the tires to start with). This in turn results in tires blowing up at the least opportune time.

    In the case of trailers unlike autos you want to fill to the max SIDEWALL PRESSURE which is listed on the tire. Don't worry about how "soft" or "hard" the ride of the items in your TT those items will be fine.

    By the way as a "public service" item, check your valve stems for weather checking.

    I was prepping my TT a few days ago for the camping season and found a flat tire. I discovered that the valve stem over winter cracked and leaked.

    The tires have been on the TT for 6 years so it was time for some new tires anyway. So, $400 later we now have new tires AND valve stems...
  • LarryJM's avatar
    LarryJM
    Explorer II
    May 04, 2013
    enblethen wrote:
    Cold pressure temperature is somewhere around 80 degrees. You fill your tires to max 50 psi in this discussion and temperatures get over 100 degrees, tires will be well above max pressure. Bamb! No more tire.


    I think that is just incorrect and have never heard of that re ST tires. In fact even on vehicles the only downside is a rougher ride, strange wear and potentially a slight less traction.

    Larry
  • time2roll's avatar
    time2roll
    Nomad
    May 04, 2013
    50 psi cold. Cold is before driven and before the sun hits the tires.
    Tire is designed to have more pressure due to heat when running.
  • coolbreeze01's avatar
    coolbreeze01
    Explorer
    May 04, 2013
    enblethen wrote:
    Cold pressure temperature is somewhere around 80 degrees. You fill your tires to max 50 psi in this discussion and temperatures get over 100 degrees, tires will be well above max pressure. Bamb! No more tire.


    In thousands of miles towing at max PSI, in over 100 degree temps, I never blew a tire. The slight rise in pressure due to temperature is a non-issue.

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