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Old 08-17-2019, 12:08 PM   #261
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Then you see how dangerous a prediction can be.

Trew it trough my made extra safe calculator and system, and for the old it came already to 59 psi.
The new came to 67 psi. Both not allowed anymore nowadays, so keep it to 65 psi for the new.

My system is to lower the maxload of ST tires with 6 loadindex steps, if I dont do that , old came to 49 psi.

With my advice , yust no screws trembling loose, and max reserve, and longest live of tires, 6 years or more.

That you now did not have any tirefailure, is then because no overloading, and no overspeeding( 60mph.) What time did you do with the old tires?
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Old 08-17-2019, 03:04 PM   #262
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I have been googling the sise 205/75R14 in LT or C( omercial) eur equivalent.
Found from Michelin XCA 109/107P, and this is maxload 2270 lbs AT 65 psi upto 150kmph/ 93mph!!!!.
This is even higher then the D- load ST .
I have seen this more in the sises fi Goodyear gives for ST .
Now I already learned from TM9 that some sises have been given a maxload in the past, that is different from the official used calculations for that.
I think many of the smaller ST are these exeptions.
It would mean that my substraction of 6 LI-steps
Then could mean still a hard ride, but still I keep to my system. Because if the LT/C maxload then is to low to laws of mother nature, and I dont lower by 6, it would give to low pressure, and tiredamage could happen sooner.
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Old 08-17-2019, 04:41 PM   #263
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Originally Posted by JerryR View Post
I am replacing the tires on my small (12-14 ft, depending on how you measure) travel trailer. I plan to buy Good Year Endurance ST205/75R14, load range D to replace the brand X Chinese ST205/75R14, load range C.

Vehicle manufacturer says to inflate to 50 psi. Sidewall on existing tires have 50 psi listed as max.

The replacement Good Year tires have max of 65 psi on sidewall.

I see that the opening post on this thread says use the sidewall pressure. But I have always gone with the vehicle maker's suggestions which are often lower than the max tire rating. For example, my F-250 wants 65 psi in front and 80 in rear.

Do I use the 65 max on the tire or with the vehicle manufacturer's 50 psi?
Because your replacement tires are of the same designated size as the Original Equipment tires, the 50 PSI is the correct cold inflation pressure. Because the new tires have a higher load capacity as the result of the LRD, you have options that are from 50 PSI to 65 PSI. To use those options you need to confirm that the wheels and their valve stems are pressure rated/load rated for the higher pressure rating/loading for the LRD tires.

There is a standard recommendation for at least 10% in load capacity reserves above the vehicle certified GAWRs. Most, including me, will recommend 15%, if possible with the replacements.
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Old 08-18-2019, 10:39 AM   #264
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made a mistake when filling in my calculator.
Before I had set the pinload to zero, for another calculation, and forgot to set it back when doing your calc, so pressure was calculated for axleload of 3150 lbs instead of total weight.

Set it back so 10% = 315 lbs less on axles, and it gave for the new D- load 60 psi( first gave 67 psi.
So still dont go down to 50 psi, dont go lower then 60 psi.

Your old C-load would need 53 psi , for the same safety and durability standards I use.
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Old 08-18-2019, 12:52 PM   #265
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If all of this is true, then trailer tires need to be built better.
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Old 08-22-2019, 08:38 PM   #266
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Originally Posted by ppine View Post
If all of this is true, then trailer tires need to be built better.
Not really. Treat your car or truck tires like most people treat trailer tires and their life expectancy would be the same. Low pressures, long periods of sitting in one spot, constant sun on one will kill any tire.
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