OK, I'll try this again but with a different tack.
I am of the opinion that ST tires should have a 15% reserve capacity (85% of the load at a given pressure) in order to be reasonably sure they won't fail. There are a couple of ways of estimating what the actual load is on a given tire of a trailer, but the best way is to actually measure each tire. The RMA has a procedure to follow:
I am of the opinion that this 15% reserve capacity is likely to require higher load ranges and larger sized ST tires - or both. And maybe even a step into LT type tires - and here is where it gets tricky.
While I feel uncomfortable recommending that LT tires be loaded to their maximum load, that is in essence the result. I feel uncomfortable with that because I don't have enough experience to say it with confidence. However, I have no hesitation in recommending replacing ST tires with LT tires if it can be done with enough clearances around the tire.
A couple of other points:
ST tires can be inflated 10 psi over the maximum pressure listed in the sidewall of the tire - and I'd recommend that if you can't get to a 15% reserve capacity.
Recent bulletins from the tire industry indicate that tires degrade simply due to time. The age of a tire is important even if the tire is unused.
There is some disagreement over how to best express this age limitation,
but my take is:
If you live in a hot climate (AZ, CA, NV, TX, and FL) then the limit is six years. If you live in a cold climate (MN, ND, WI, MT, etc), then the limit is 10 years. States in between are ..... ah ........ in between.
A rule of thumb for estimating if you need more load carrying capacity:
Check the cold (ambient temperature) tire pressure before starting off. Measure the inflation pressure after an hour of driving.
If the tire pressure build up is less than 10%, it's OK. If the pressure build up is between 10% and 15%, then continue to monitor until you are sure it is not above 15%. If the pressure buildup is 15% or greater, add load carrying capacity (and one of the ways to do that is to add pressure). For ST and LT tires, NEVER use more than 10 psi over the sidewall pressure.
ST tires can be inflated 10 psi over the maximum pressure listed in the sidewall of the tire -
Any questions?
With a nonsense statement like this (from at least some of the tire manufacturers), how can you take any of the specs seriously? I thought the definition of maximum was pretty clear cut. Must be my outdated dictionary.
2009 Fleetwood Icon 24A
Honda Fit dinghy with US Gear brake system
LinkPro battery monitor - EU2000i generator
CapriRacer
Thanks for coming back and giving it another try. I was following your previous thread (now closed) with interest.
Hopefully everyone will stay on topic and stay polite so that it will remain open..
"If we couldn't laugh we would all go insane."
GMC Duramax LBZ
Komfort
Reese Dual Cam HP Our Rig Picture...CLICK HERE
CapriRacer wrote: If you live in a hot climate (AZ, CA, NV, TX, and FL) then the limit is six years. If you live in a cold climate (MN, ND, WI, MT, etc), then the limit is 10 years. States in between are ..... ah ........ in between.
Do you recommend using any tire treatment chemicals if so what and why, if not why? The obvious would be to keep the tires covered, and not park on dirt or wet ground. Anything else to prolong tire life?
Thanks in advance!
Nathan
You say that an ST tire needs a 15% reserve and should not be loaded beyond 85% of sidewall capacity. Also, you indicate that the LT tire can be used at 100% of it's sidewall capacity.
If this is true, then a lot of manufacturers of RV's are doing their customers a disservice by putting underrated tires on their vehicles. One that comes to mind is JAYCO that still installs 16" load range "D" ST tires with a 3000# load capacity on rigs with 6K axles. Don't believe me? Go to your nearest dealer and take a look.
Keith
Keith, Gloria & Charlie(Spoiled Rotten Boston Terrier)
2010 Damon Astoria 3470
2012 Jeep Grand Cherokee Overland
USAF 1968-1976 Viet Nam Veteran
kedanie wrote: Let me see if I understand correctly.
You say that an ST tire needs a 15% reserve and should not be loaded beyond 85% of sidewall capacity. Also, you indicate that the LT tire can be used at 100% of it's sidewall capacity.
If this is true, then a lot of manufacturers of RV's are doing their customers a disservice by putting underrated tires on their vehicles. One that comes to mind is JAYCO that still installs 16" load range "D" ST tires with a 3000# load capacity on rigs with 6K axles. Don't believe me? Go to your nearest dealer and take a look.
Keith
Or most Montana's with GAWR OF 6750 and tires rated to 3420. Do the math 90 full pounds of extra capacity per axle. Chris
* This post was
edited 02/07/12 04:39pm by Chris *
You mention monitoring the rise in air pressure. Based on my knowledge of the ideal gas law, what you are in effect measuring is the increase in temperature. For me, twisting the valve caps off an on that often is a real pain, plus, the guages available that will handle my 80 psi tires are not exactly high fidelity.
I know you have said you are not an RVer, so I will let you in on what some of us do. We carry these infrared non contact thermometers that are available from Home Depot, Lowes, Harbor Freight, or an auto parts store. Whenever we stop, we check the temperatures of our tires, our hubs, and our brakes. It is real quick and convenient. If we knew the air temperature outside the tires (i.e. have a wireless thermometer stashed somewhere where the sun doesn't shine underneath the trailer), shouldn't there be a maximum temperature above that for the tire?
Offline
