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PeterH-350LE · 10-09-2014, 04:37 PM

Michelins LT 225-16's, 65-67 cold, triple axle, 1500 miles trip, max speed 65 , max pressure increase 4-5, max tire temp 100 with temps around 90

AnnArborBob · 10-09-2014, 04:52 PM

Quote:

Originally Posted by SteveH

If your travel trailer sets in one spot all the time and never moves, it really doesn't matter what the tire pressures are.

SteveH, that's not a Travel Trailer, that's a Mobile Home!

dkottum · 10-09-2014, 04:52 PM

We're hitting the road in the morning so I took the consensus here and used the load information and recommendation of Andrew T. and set them at 65 psi as a good place to start. It's very cool here and early November we'll be in the desert, so will check them along the way.

Slowmover, I did some reading on your max weight recommendation and only found a reference that matches your thoughts when using ST tires. And then the concern was more about overloading and uneven wear ST tires on trailers in general rather than stability. Apparently LT tires are not used enough in our application for a specific recommendation. Maybe one of the expert engineers will weigh in, they often do.

Meantime we have to sort out the wide range of experience and wisdom and settle on something reasonable. For us it looks like 65 psi for our 16" Michelins. If there is sway our ProPride hitch will make it hard to detect, for better or worse.

AnnArborBob · 10-09-2014, 04:55 PM

Quote:

Originally Posted by dkottum

We're hitting the road in the morning so I took the consensus here and used the load information and recommendation of Andrew T. and set them at 65 psi as a good place to start. It's very cool here and early November we'll be in the desert, so will check them along the way.

Slowmover, I did some reading on your max weight recommendation and only found a reference that matches your thoughts when using ST tires. And then the concern was more about overloading and uneven wear ST tires on trailers in general rather than stability. Apparently LT tires are not used enough in our application for a specific recommendation. Maybe one of the expert engineers will weigh in, they often do.

Meantime we have to sort out the wide range of experience and wisdom and settle on something reasonable. For us it looks like 65 psi for our 16" Michelins. If there is sway our ProPride hitch will make it hard to detect, for better or worse.

Doug, I am confident that you will be fine at 65 psi

.

Safe travels and have a good winter! We "launch south" on 11/11.

dkottum · 10-09-2014, 05:02 PM

Thanks Bob. We may cross paths, we're headed SE first to tour, visit friends and family. No hurry, some of the most interesting experiences are not planned. We're WBCCI# 1211.

Have a great trip as well.

SteveH · 10-09-2014, 05:05 PM

Quote:

Originally Posted by dkottum

We're hitting the road in the morning so I took the consensus here and used the load information and recommendation of Andrew T. and set them at 65 psi as a good place to start. It's very cool here and early November we'll be in the desert, so will check them along the way.

Slowmover, I did some reading on your max weight recommendation and only found a reference that matches your thoughts when using ST tires. And then the concern was more about overloading and uneven wear ST tires on trailers in general rather than stability. Apparently LT tires are not used enough in our application for a specific recommendation. Maybe one of the expert engineers will weigh in, they often do.

Meantime we have to sort out the wide range of experience and wisdom and settle on something reasonable. For us it looks like 65 psi for our 16" Michelins. If there is sway our ProPride hitch will make it hard to detect, for better or worse.

Doug,

You will more than likely be fine with 65 PSI in those tires on your trailer. The way to know if you are underinflated is if when towing at highway speeds in hot weather the air pressure increase is 10% or more of static pressure, you need more.

slowmover · 10-09-2014, 08:08 PM

Lateral stability is the top reason . . . not causing internal tire damage in turns is the lasting problem. This has been discussed on this forum and elsewhere. The Load & Pressure Tables do not apply to trailer tires.

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AL’ UM- MONEY · 10-09-2014, 08:12 PM

I picked up my new Michelins this week. I lost two ST tires within 300 miles recently so the reason for the change. The dealer knows tires but probably not load etc. They came to me at 70 psi so that is what I will run unless someone changes my mind.

dkottum · 10-09-2014, 08:21 PM

Quote:

Originally Posted by slowmover

Lateral stability is the top reason . . . not causing internal tire damage in turns is the lasting problem. This has been discussed on this forum and elsewhere. The Load & Pressure Tables do not apply to trailer tires.

First Google gave a manufacturer's load and pressure table for trailer tires:

Trailer Tire Load/Inflation Chart | Maxxis USA

Moflash · 10-09-2014, 09:04 PM

Quote:

Originally Posted by slowmover

Sure. Try the TT manufacturers. Ask either of the tire engineers who post here. The problem in upsizing to use 16's is that load range is hard to match

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Huh???

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slowmover · 10-10-2014, 02:41 AM

Quote:

Originally Posted by dkottum

First Google gave a manufacturer's load and pressure table for trailer tires:

Trailer Tire Load/Inflation Chart | Maxxis USA

Good luck. Leaving the TT parked in such a way as to leave the tires twisted is also hard on the torsion axles. Be careful as there are effects you are not considering. Leave the TT tires alone and work on the TV loading per wheel. Get that balance as good as can be and then apply the chart for a baseline.

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CapriRacer · 10-10-2014, 05:29 AM

My recommendation is that the tire should be inflated such that its load carrying capacity is at least 115% of the maximum load.

dznf0g · 10-10-2014, 06:08 AM

Quote:

Originally Posted by CapriRacer

My recommendation is that the tire should be inflated such that its load carrying capacity is at least 115% of the maximum load.

This is good clear advice! Now we need no further discussion....right?

dkottum · 10-10-2014, 06:57 AM

Quote:

Originally Posted by CapriRacer

My recommendation is that the tire should be inflated such that its load carrying capacity is at least 115% of the maximum load.

Thanks CapriRacer.

The chart for a 225/75R x 16 LT gives 2335# carrying capacity at 65 psi. Our heaviest weight ever (last spring) at 6700 on four tires puts us at 140% of this load. We are somewhat lighter today ready to travel with gear placed to balance the load as best I can.

AnnArborBob · 10-10-2014, 08:13 AM

Quote:

Originally Posted by dkottum

Thanks CapriRacer.

The chart for a 225/75R x 16 LT gives 2335# carrying capacity at 65 psi. Our heaviest weight ever (last spring) at 6700 on four tires puts us at 140% of this load. We are somewhat lighter today ready to travel with gear placed to balance the load as best I can.

Doug, when you are looking at your trailer's weight per tire, unless you weighed each tire separately to arrive at the 6,700 lbs figure, make sure to account for the part of the trailer's weight that is carried by the hitch. In your case, a 25' FC has a tongue weight of about 835 lbs. So if your total trailer weight was 6,700 lbs you could subtract 800lbs or so to get the actual weight carried by the tires (5,900 lbs in this example or 1,465 lbs per tire.) And, once again, unless you weigh each tire separately you still need to bake in a margin for uneven trailer loading. So, your 140% of capacity is likely more like 165% of capacity so you are quite well covered at 65 psi.

SteveH · 10-10-2014, 08:30 AM

Just my opinion here, but I always compute needed tire capacity based on the GVW of the trailer to be on the safe side. And then there's the transient weights that occur when on the road like around curves, and bumps. Better to be on the safe side, but again, just my opinion.

dkottum · 10-10-2014, 08:36 AM

Thanks Bob, 6700# was trailer weight hitched and weight distribution applied. We were really loaded after a winter's shopping by one of the world's great bargain hunters including H F Coors' nice heavy dinnerware/serving sets for family, and full water.

Steve, that load put us at or a little above GVW of the trailer if we add approximate hitch weight back in.

dznf0g · 10-10-2014, 08:42 AM

I'm with ya, Steve. I like more margin for variables, like differences between each tire, when I run with full tanks or more gear....etc.

I am well over the minimum 115% formula, but I have seen no difference in ride quality clues at 75psi as opposed to 65psi.

dkottum · 10-10-2014, 08:45 AM

Remember you guys have 30' Classics, we have a 25' FC with of GVW 7300.

dznf0g · 10-10-2014, 08:49 AM

Oh, I understand Doug. It is all relative to actual axle weights. My discussion was just to convey my desire to utilize more than the MINIMUM 115%. Utilizing a single weight ticket and assuming that as a baseline over many years is a dangerous way to do it. RVs almos always gain weight over time, not to mention trip to trip variables.