Thread: "China Bombs"
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Old 03-12-2019, 09:12 AM   #55
MattE303
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Quote:
Originally Posted by Charby View Post
I am looking for some info on tire inflation. I had Trailer Kings ST205-75-14 - Load C that had maximum rating of 50 psi, which I maintained. I upgraded to Goodyear Endurance of same size which have Load D with a maximum rating of 65 psi. My dual axle trailer has a dry weight of 4300# and cargo carry capacity of 2230#, which is way more than I use. My question is what pressure should I keep tires inflated at as not to create a hard ride, but not soft to increase heat in tire. I'm not sure what my alloy rims are capable of but high pressure valve stems were installed.
your trailer should have a placard somewhere on the outside that indicates the suggested inflation pressure for the OEM tires (often this will be the same as the max inflation pressure on the tire sidewall because trailer manufacturers rarely install tires that give you any "breathing room" on load carrying capacity). The number on that placard is the lowest pressure you should run. The max inflation pressure on the new (load range D) tires is the highest you can safely run. Anywhere in between those 2 numbers is the range you have to play with, basically trading off extra carrying capacity headroom for a more compliant ride. So in your case anywhere between 50-65psi.

Have you ever weighed your trailer at a cat scale to determine how much weight is actually riding on the tires? Once you do that, you can determine how much headroom you had with the OEM Load range C tires. If the OEM tires were close to being maxed out, you should probably run toward the higher end of the range (closer to 65), but if you had tons of headroom with the OEM tires and you like the way the trailer rode at 50psi, you probably don't need to run much more than that.

Giving yourself some headroom on the carrying capacity is a good idea safety wise because tires lose some carrying capacity as they age, and our loads aren't always distributed perfectly evenly, but it's possible to go overboard on this to point where your trailer rides like the tires are made of solid rock.

There are people on these forums that will insist you must always run the max inflation pressure indicated on the tire sidewall, but that definitely isn't necessary, and in some cases (such as going up one or more load ranges when you replace the OEM tires) may give your trailer a very rough ride. It certainly did when I installed load range G sailuns on my trailer and ran them at the tires's max inflation pressure of 110psi. I typically run 90-95 (the trailer placard suggested inflation pressure for the OEM load range E Trailer Kings was 80 psi).

As you mentioned, you definitely need to verify that your rims are designed to handle the higher pressure.
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