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Old 06-05-2008, 10:16 PM   #1
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Trailer Tire Inflation Range

OK, so the tires on my trailer have a MAX of 50. I searched through the forum, but I did not see a question like this:

What I am wondering is: What is the Min, or Average most people set their pressure?

Where do you run your trailer tires? Max, Max -1, -5, -10.....

What would be unsafe?

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Old 06-05-2008, 10:53 PM   #2
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When I had a coach with C range tires, I ran 45 all around, with close to 50 in the spare. I personally didn't like going anywhere with them under 40, but I would consider under 35 unsafe. 40 would be the min at highway speeds. There is no facts behind any of that, just personal ethics. When I bought my 270, all four tires were around 35 after sitting for a few years, and I pumped them all up to 45 before hitting the road.

I haven't put any air in the 286 yet. Being D range tires (65 max) what do those of you with those run? I'm thinking between 55 and 60.

I heard somewhere that with trailer tires, you should run them close to the max.

I'd also consider the load put on the tires. If it were an open cargo trailer weighing like 1000#'s, I could probably run with 35 all day long with no problems. But if they're on a TT, that's a problem.


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Old 06-06-2008, 12:14 AM   #3
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I’m not a tire expert, but this is what and why I do this.

I run my “dual” TT tires at max side wall air pressure. This is not entirely for loads ratings but has a level of load to it.


A TT is not exactly balanced left to right. One side is heavier then the other due to floor plan and stuff inside. Going max side wall prevents the one side from going over the loaded tire pressure.

When the TT is going around a turn, the higher center of gravity moves some and weight shifts to one side of the camper taken by the tire. Max tire load rating adds a level of safety here.

Heat builds up in the tire pending inflation pressure. Less heat at max side wall pressure.

TT sway. Soggy TT tires will add to sway just like soggy TV tires.

Now to the biggest one I know of. “duals” when going into a hard turn. The duals really scrub hard, the side walls flex really hard. By going to max side wall pressure, the bead is seated in the rim stronger and will take the side flexing better at max pressure then less then max side wall pressure.

Hopefully we can find a tire expert here and they can add to my list or help point out the miss conceptions in my thought process.

Hope this helps

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Old 06-06-2008, 05:14 AM   #4
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max on my tires is 65psi I run them at 62psi this allows for 3psi for heat build up, when I check my pressure right after a tow I'm usually right at 65psi.I agree with John lots of stress goes on these tires so running them at max psi makes the most sense,also to get your max load carrying capacity out of the tires they need to be at max psi.
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Old 06-06-2008, 09:49 AM   #5
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Has anyone else experienced what I have at Max. inflation .......It took me an hour to clean up everything that was flung all over the trailer After an hour on the road... Drawers open, refrigerator door open, it was ugly (and yes they were checked before leaving). I have found around 60 psi is a good balance between proper tire inflation and an extremely rough ride.

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Old 06-06-2008, 10:39 AM   #6
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Two things that may be very helpful to this discussion:

First, here is Goodyear's inflation chart for trailer tires:

And here is their summary of Proper Tire Inflation:

Correct tire inflation is a key component in tire care. The recommended inflation pressures for your tires are indicated on the certification label or in your owner’s manual. Since RVs can be loaded with many different configurations, the load on each tire will vary. For this reason, air pressure should be checked based on the load on each individual tire. Inflation pressure should be adjusted to handle the maximum tire load, and all tires on the axle should carry the same inflation pressure. Check your tires’ air pressures at least once a month, before each trip and each morning you drive during a trip. Tire pressure should be checked cold, or before you have driven that day, as tire pressure ratings have been designed with typical running heat/pressure build-up in mind. Remember to check the air pressures of the inside tires in dual fitments and make sure the valves and caps are free of dirt and moisture. It may be necessary to inflate your tires at a truck stop or truck service center in order to find adequate air pressure for your coach’s needs.

I currently run ST205/75R14 Load Range B's at max. cold inflation of 35 psi with no problems. If these tires get replaced, it will be with Load Range C's, and then I will probably have to do some experimenting to figure out the best pressure for our trailer and load.

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Old 06-09-2008, 10:56 AM   #7
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Thanks for this answer.

For the last trip, I bumped them up to 45, and I saw that after towing for two hours, they were about 3 PSI higher.

This is they key passage for me:

....... tire pressure ratings have been designed with typical running heat/pressure build-up in mind.

Which means I need to go all the way up to 50 before I leave this weekend. Makes me sad that I was at 36 PSI when I started this discussion.

I have seen anecdotal evidence before that the max rating is for load, and unlike tow vehicle tires, was also where you should run at, as trailer tire sidewalls are weak and max pressure keeps them properly maintained.
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Old 06-09-2008, 07:45 PM   #8
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More pressure

All radial tires have flexible sidewalls (except for the super low profile ones on slammed Hondas) which is why trailers were one of the last adopters of radial technology. There is also far less reserve capacity in typical LRC trailer tires than there is in the LT tires--mostly LRE--some of us have on our trucks. For example, a loaded 2499 carries 6000 lb on the 4 tires, so even running them at 40 psi would be dicey not to mention the tire squirm as others have already stated. I have run mine at 45 psi looking for a softer ride, but these tires are already so heavily loaded that there is plenty of flex at 50 psi to smooth out the ride. However, knowing my axle weights, I will not bother airing up in the morning if they are all at 47 psi because I know I have plenty of reserve.

NEVER play with load inflation tables unless you know what your rig weighs and build in a generous reserve of 5-10 psi. What do you know?--that gets you to 50 psi!

The door sticker on my truck lists the LT245/75R16s at 50 psi front and 80 psi rear. Not at all by coincidence, that just happens to put the tires at the exact GAWR for both axles. Because these are LRE tires there is lots of reserve, and again, knowing my axle loads, I run them at 45 front and 60 rear all the time for a reasonable compromise of a decent ride solo without messing with airing them up and down all the time.


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