Sorry for delay. Wife is celebrating HS reunion and I am attending a number of functions. Also had to deliver seminar this AM at local library.
OK Back to tires & stuff.
Valves
Many TT come with low cost standard passenger type "snap-in" rubber valves. These valves are rated 65 psi max so some think they are OK for use on LR-C & LR-D tires. While technically correct I look at this like using a hoist rated at 1,000# to lift a 1,000# load above someone's head. May be OK on paper but as we all know rubber items age with time
and temperature and older rubber parts are not as strong as new rubber parts.
I would strongly suggest bolt in metal valves on any RV application. Especially if you are taking the precaution of running TPMS.
At about $3 each they are a good investment for higher pressure applications or when using external aftermarket TPMS or hose extensions and will last longer than low cost passenger valves when installed properly (correct nut torque spec)
OK TIRES
If you are following this thread I will assume you have read and understand my posts on the thread
"Why tires fail" as it outlines the main reasons any tire can fail no matter who makes it or where it is made or what color the building is where the tire is made.
What many seem to fail to really understand is that tire damage is cumulative and never repairs itself. Microscopic damage once initiated just continues to grow. Sometimes it will grow fast other times it grows more slowly but it is always growing. Also rubber strength and resistance to cracks or crack growth changes (gets worse) with time/age. So just because you were properly inflated or not speeding at the time of failure that does not mean that the reason for the failure is not related to the load or inflation or speed you were traveling days, weeks or even months earlier.
Every time you turn a corner or have a side wind blowing on your RV the tires on the outside of the turn or opposite to the wind get more loaded. This can be hundreds of pounds. This extra load results in a bit more damage occurring at a bit faster rate than when a tire is under-loaded and this damage is cumulative so the time at low load does not balance off the time at high load.
The other thing that is true is that not every tire is equally loaded, even when just standing still. So just because an RV company says your two axles are rated at 6,000 each does not mean that each axle supports 6,000# or your 4 tires is equally loaded to 3,000#. It has been seen that many RVs have one end of an axle carrying 53 or 54% or more of the total axle load so even if you have 6,000 on one axle you may have 3,200# or more on one tire and this is before you have the additional side loading from wind or cornering that can be an additional 200 to 500# or more.
You may also have a pressure gauge that is reading 5 psi high which leads you to think your tire is capable of supporting 3,080# when in fact it is only capable of supporting 2,960#.
Each of the above examples are relatively small and in themselves would probably not result in an early failure but if added up can be a significant overload. Couple than with ever decreasing strength as the tire ages and you are looking at an un-expected failure and none of the above are because you have a leak what leads to Run Low Flex Blowout.
I and many others strongly suggest that you confirm the actual load on each tire and ensure that you have at least a 15% margin. You also need to confirm your master hand gauge is accurate to +/- 2 psi or better. My master is accurate to +/- 0.5 psi and I check it at least twice a year.
Speaking of pressure. Some make the mistake of worrying about too much pressure in their tires and bleed down their hot pressure. This is absolutely 110% the wrong thing to do. When we are offering advice on margin of load that is based on the load/Inflation tables published and the inflation we are talking about is always the Cold Inflation pressure which is when tires are at air temperature and not in direct sunlight or having been driven on for at least 2 hours.
We tire engineers know that tire pressure will change as the temperature of the air in a tire changes with use. The pressure changes by about 2% for each change in temperature of 10°F. Unless you are driving when ambient temperatures are going to change by more than 70°F between checking your tires in the morning and stopping, I would not worry about tire pressure changes. All the above also assumes you NEVER exceed 90% of the max speed rating of your tires. Driving that fast or faster may artificially increase your temperature beyond normal range.
Finally we have the unique tire loading seen only on mylti-axle trailers. The suspension design can result in as much as 24% higher Interply Shear forces trying to tear tires apart simply because the tires are on a trailer. The link is to the results of Google search on the term. Warning the tech talk may put some to sleep.
OK I hope I have answered many of your questions. You can find more at my RV Tire Blog.
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