Forum Discussion

lawrosa's avatar
lawrosa
Explorer
Mar 09, 2018

Load C to load D tire inflation?

So I have Jaxxon tires now on the RV. Rated 81 mph load C @ 1760 each.

205/75 r14 @ 50psi

Note: Im not upgrading rims, tires to 15". No way. Cant afford it.

The tires are ok. Seems wear for only 5000 miles is a bit off if you look at the tire. You say in your mind and ask the question to knowledgeable people , " Do these tires look right to you?"

So to replace of course not going with jaxxon... But choices seem to be something like

Taskmaster load C. Has 2 year warranty and 81 mph rated 70 bucks

Westlake load C. 5 year warranty (wow) but a 75 mph rating. 80 bucks.

Now I do like the endurance tires from GY. But they only come in load range D. These are 65 psi tires.

If I went this route I dont want or need the capacity. Its a 7000 GVW trailer maybe loaded to 5500 lbs max fully loaded. Lets just say I can get it up to 6000 lbs for giggles.

Also note the dry weight was/is 4730lbs. No way to fit close to 2200 lbs in any of the available storage areas.

So GY inflation tables shown here show I can do 50psi for the same 1760lb rating as c rated tires.

GY endurance inflation tables.

The question. How will lower PSI affect the tire regarding heat?

I was thinking maybe running 55 psi in them. But I dont want the trailer bouncing all around.

Thanks in advance.
  • time2roll's avatar
    time2roll
    Nomad
    Mar 09, 2018
    With the reduced load and the reduced pressure it is a wash on heat. As long as you are good on the chart there is no worry.
    Check the wheels for a pressure rating but I would still run the Ds at 60/65 psi without worry.
    Get high pressure snap in stems as they seem to be better built.

    And yes I did the same thing a decade ago with my ST205R15
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Mar 09, 2018
    I switched from 14 inch Cs to 14 inch Ds, and follow the manufacturer's recommended 65 psi - Provider ST215/75R14 Radial
  • SoundGuy's avatar
    SoundGuy
    Explorer
    Mar 09, 2018
    lawrosa wrote:
    Now I do like the endurance tires from GY. But they only come in load range D. These are 65 psi tires.

    If I went this route I dont want or need the capacity. Its a 7000 GVW trailer maybe loaded to 5500 lbs max fully loaded. Lets just say I can get it up to 6000 lbs for giggles.

    Also note the dry weight was/is 4730lbs. No way to fit close to 2200 lbs in any of the available storage areas.

    So GY inflation tables shown here show I can do 50psi for the same 1760lb rating as c rated tires.

    GY endurance inflation tables.

    The question. How will lower PSI affect the tire regarding heat?

    I was thinking maybe running 55 psi in them. But I dont want the trailer bouncing all around.


    I replaced my LR C 205/75 R14 China bombs with LR D Endurance and run them at the max 65 p.s.i. and wouldn't consider running them any less even though the trailer typically averages ~ 4800 lbs fully loaded and at least 1000 lbs below it's GVWR. Trailer tracks true and steady, better than it ever has with those soft wall bombs that were supplied stock with the trailer. Do what you want but I see zero advantage to running these tires with anything less.
  • JimBollman's avatar
    JimBollman
    Explorer
    Mar 09, 2018
    SoundGuy wrote:

    I replaced my LR C 205/75 R14 China bombs with LR D Endurance and run them at the max 65 p.s.i. and wouldn't consider running them any less even though the trailer typically averages ~ 4800 lbs fully loaded and at least 1000 lbs below it's GVWR. Trailer tracks true and steady, better than it ever has with those soft wall bombs that were supplied stock with the trailer. Do what you want but I see zero advantage to running these tires with anything less.


    I did the same thing and was also happy with the feel of the trailer and the tires ran a lot cooler than the Cs I took off.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Mar 09, 2018
    “I replaced my LR C 205/75 R14 China bombs”

    Anything else to rant on the Chinese, Sound guy?
  • BFL13's avatar
    BFL13
    Explorer II
    Mar 09, 2018
    It is all about the wheels and their rims for what you can do when keeping them. If your spare has the same wheel as the others (no change since the rig was new) get a garage to remove the tire and confirm what the wheel and its rim specs are.

    You can go to Ds from Cs if the Ds are not wider than the rims will take (watch out for that!) and you do not inflate the Ds above the spec PSI for those rims. Also watch out for tire diameter so they will fit in your wheel well)

    EG with 15s (no idea about 14s) you get OEM steel wheels with C tires and the wheels/rims can take 75 lbs. So that means you can go to Ds from Cs using those same wheels and go from 50 to 65 lbs if you want for the Ds.

    But with the 14s, first you need that spec info on the wheels which you can't get unless you take the tire off--so do that with the spare to make life easier.
  • lawrosa's avatar
    lawrosa
    Explorer
    Mar 09, 2018
    I replaced my LR C 205/75 R14 China bombs with LR D Endurance and run them at the max 65 p.s.i. and wouldn't consider running them any less even though the trailer typically averages ~ 4800 lbs fully loaded and at least 1000 lbs below it's GVWR. Trailer tracks true and steady, better than it ever has with those soft wall bombs that were supplied stock with the trailer. Do what you want but I see zero advantage to running these tires with anything less.


    Not really the answers I was looking for.

    So with your light weight and tires to 65psi dont you get a pongo effect at the trailer? I mean its bad enough they pongo as it is at times over certain slower speeds and like railroad tracks.

    And and 65psi and not much weight on them will they not ride more on center of tire?

    Sidewalls are 8 ply vs 6 ply on the c's I believe.

    Thats just my thoughts.

    Also GY has the inflation table. Isnt that supposed to be used for something?

    And ok I assume we are talking a 100 psi valve stem replace.. With brass end..



    .
  • BFL13's avatar
    BFL13
    Explorer II
    Mar 09, 2018
    You want to run your Ds at 50lbs the same as the Cs is the issue. My understanding is that you can do that with LT Ds but not with ST Ds.

    I may have this wrong, but from reading various tire posts, STs should be fully inflated, but you can do the weight/PSI table thing ok with LTs.

    EG I have LT Es on my wheels that came with Ds but limit the LT Es to 65, even though they can go to 80, but the wheels might only do 65 as for Ds (have not checked the actual wheel specs in case they can do more than 65. Don't need more than 65)
  • lawrosa's avatar
    lawrosa
    Explorer
    Mar 10, 2018
    BFL13 wrote:
    You want to run your Ds at 50lbs the same as the Cs is the issue. My understanding is that you can do that with LT Ds but not with ST Ds.

    I may have this wrong, but from reading various tire posts, STs should be fully inflated, but you can do the weight/PSI table thing ok with LTs.

    EG I have LT Es on my wheels that came with Ds but limit the LT Es to 65, even though they can go to 80, but the wheels might only do 65 as for Ds (have not checked the actual wheel specs in case they can do more than 65. Don't need more than 65)


    Thanks for that.. Hmmm

    The inflation tables are for st tires.

    So @ 50 psi they are 1760 just like my C's.

    x 4 thats 7040. If I loaded the trailer to max 7000 lbs. ( Will never happen I can tell you but if I did whats the impications of running 50 psi?

    Alright alright, somehow in my head I feel I will do something drastic if I dont inflate to 65 psi is why I asked the question..

    To meet someway towards a middle point I stated I would be willing to do 55 psi.


    I have to admit when I did my trip to florida and back my 81 mph jaxxons saw 75 mph most of the trip down rt 95 b lining it there. I checked pressures every morning before heading out. Maintained 50 psi diligently.


    https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

    What other tires are recommended here? I read something on maxis tires?
  • BFL13's avatar
    BFL13
    Explorer II
    Mar 10, 2018
    It boils down to confirming or not that you can use the PSI vs weight for STs same a with LTs. (which I was saying I doubt, but can't confirm)

    I ended up getting the newer kind of Carlisles for the 5er, never mind the bad rep of the previous line of Carlisles.

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