downtheroad
Pacific Northwest
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kedanie wrote:35 pages of mainly 3 posters flapping their gums and inflating their egos about what experts they are. No real information given out, just insider stuff.
What a waste!!!!!!!!!!
Keith
Since this Forum is for giving and receiving advice....Here is some advice...Don't read this thread if you feel that way.
"If we couldn't laugh we would all go insane."
GMC Duramax LBZ
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Tireman9
Akron, OH
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FastEagle wrote:No matter who starts and sets some discussion guidelines for a thread such as this it is doomed from the start. The brand loyal and design loyal posters are mostly firmly set in their beliefs and only solid well presented information that the everyday user can rely upon to get them from point A to point B safely will be successful. Everything else is just a lot of talk.
Try taking information found in this thread to your local tire retailer and convince them that it’s authentic. They may ask you if your source represents the interests of the vehicle manufacturer or particular tire manufacturer. Most well established retailers are only going to follow the SOP of the tire manufacturers they represent. And, they will keep on the good side of their legal counsel by following the existing government regulations for fitment and safety.
There is a lot of confidential information about tires that none of the posters are at liberty to reveal. Actually, being on a particular tire manufacturers payroll and having direct access to confidential materials information may be the only way to have that information. Anybody can go out and get a durometer and measure the hardness of their tire treads. And the answer is? You know how hard they are but NOT their composition.
FastEagle
p.s. I went to a local RV show yesterday. It was a disappointing experience when checking some of the RV trailer specs and then looking at the OE tires. I found that a large dual axle fiver with 6750# (GAWR) axles listed on the certification label was fitted with ST235/80R16E tires rated at 3420# @ 80 psi. That particular trailer had a basement so large it looked like a Smart Car would fit in it.
Travel trailer tire fitment wasn’t much better. I found Certified GAWR 4000# axles fitted with ST205/75R15D tires rated at 2150# @ 65 psi.
FE didn't ask a question but if he asked what would be an acceptable alternative....
I find no acceptable alternative ST type tire except possibly an ST235/85R16 LR-F run at 85 psi assuming he can find a rim rated for the 95 psi 3520# load that matches the tire. But he would still be speed limited. I find a LT285/75R16 LR-E size in the tables but the tires I find are traction type which would not be suitable for trailer application. So his only easy option if he stays with the OE tires is to be sure he is lightly loaded (below 3360 on the heaviest loaded tire) and never exceed 65 mph or run less than 80 psi cold. He might be OK.
Clear enough answer?
You can learn more if you visit my tire blog RVTireSafety
In my opinion as a QS9000 and ISO/TS 16949 Quality auditor the word "Quality" does not appear to be in the RV industry dictionary.
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CKNSLS
Northern Utah
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It's really ironic that there have been others on this board for years telling others to switch to LT tires. When, in reality that (in many cases) IS NOT what you want to do.
When you look at the majority of blow outs - I still maintain excessive speed is THE BIGGEST issue.
It's my own personal observation spending time on the freeways (10-15-40-5frwys) heading in to So. Cal on a Sunday afternoon.
I am in the right hand lane doing the LEGAL 55mph are there are many pulling TT-TH passing me like I am standing still.
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Tireman9
Akron, OH
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Chris wrote:OldGreaser wrote:Thanks Chris,
"You might also look at the Bridgestone Duravis R250. Another steel ply carcass tire that cost a little less than ribs. Chris "
I've written this up in my maintenance records, i.e. the exact details/size of the Michelin LT's needed and have added a note to consider Bridgestone Duravis R250. I'm still giving preference to the Michelin ribs but will continue to watch for further info on usage of Duravis.
I ran ribs for 6.5 years and around 40+K and sold them on CL for $200. This time I installed the R250. The are actually a little heavier than the ribs and have one Nylon ply that the the rib does not. Steel plies and belts are the same. Track record is similar. Chris
Are you sure the Nylon ply is the body material? I thought this was 1 or 2 sidewall plies of Polyester and the tread was 1 or 2 plies polyester + 2 plies steel + 1 ply Nylon.
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Francesca Knowles
Port Hadlock, Washington
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FastEagle wrote:
p.s. I went to a local RV show yesterday. It was a disappointing experience when checking some of the RV trailer specs and then looking at the OE tires. I found that a large dual axle fiver with 6750# (GAWR) axles listed on the certification label was fitted with ST235/80R16E tires rated at 3420# @ 80 psi. That particular trailer had a basement so large it looked like a Smart Car would fit in it.
Travel trailer tire fitment wasn’t much better. I found Certified GAWR 4000# axles fitted with ST205/75R15D tires rated at 2150# @ 65 psi.
Yes. Thanks, FastEagle!
Deliberately undersized original equipment (O.E.) tires is a problem almost always completely overlooked in these endless wrangles about tires.
People are so quick to blame a tire (especially if Chinese) itself for a "failure". Who stops to consider the LIKELIHOOD that the American Hero that built the RV for them put undersized tires on it to begin with?
This is an industry-wide practice, and yet it gets almost no attention. It seems to me that instead of hollering about foreign tires as some like to do, we might be better served by reading the American Made RV industry the Royal Riot Act as regards this glaring O.E. deficiency.
As for difficulties attributed to specific tire types/brands/etc.:
No matter WHAT a tire is made of, which letters it has stamped on it, or where it was made, it's going to fail "prematurely" if it isn't sized right for the job.
Duh!
" Not every mind that wanders is lost. " With apologies to J.R.R. Tolkien
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Chris
Shelter Bay, Wa
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Tireman9 wrote:OK based on the lack of data on actual usage I must have mis-interpreted the interest in formulas. So lets go back to the Cliff Notes suggestion
NHIrish wrote:
1. Buy tires of a load rating sufficient to carry the load you have.
2. Allow a safety margin in the tire you choose.
3. Ensure that the valve stem used is appropriate for the pressure rating.
4. Keep your tires inflated to the max pressure rating for the tire.
5. Check said pressure frequently.
6. Don't overload or underinflate.
I will provide a couple of examples on how I would apply this good summary.
Starting with a trailer with loading at LF 2675 RF 2995 LR 2890 RR 2545 and 6000# axles
1. I consult the load tables and find the tires with at least 3000# capacity. ST245/75R16 LR-D or LR-E and ST235/75R16 LR-D or LR-E and ST235/85R16 LR-d or LRE all are rated at 3000# BUT they are ST tires and I admit to driving faster than 65 mph so I need to look at LT type tires which are rated for at least 75 mph per the Speed Symbol marked on the tires. (Note. There are errors on tire company web pages)
2. Also my safety margin is 10psi. I find the LT245/75R16 LR-E will carry 3042# at 80 but with my 10 psi Safety margin I need to look at the 70 psi capacity. I find a LT265/75R16 LR-E is rated at 3000# at 65 psi. Before I get these tires I will need to confirm the rims are rated for at least 3000# and the 75 psi I would run in this application. Wheel inflations are the cold inflation you will be setting the tires at. The original 16 inch rims that came with the ST tires may not be rated for more than 65 psi. You MUST check and get the answer in writing or marked on the wheel. I also need to confirm I have the clearance for the 265 width.
3. New bolt in valves will be part of the purchase.
4. The high inflation shown on the tire will decrease lateral sway and tire loading but will have a slight increase in the potential for impact damage.
5. I will check the inflation before each trip and monthly while parked. To get early warning of a puncture I will also get a Tire Pressure Monitor System and confirm it's accuracy is within +/- 3 psi by using a digital pressure gage as a reference. The chance of both the TPM and the hand gage going bad by the same amount is negligible.
6. I will run across a certified truck scale at least once a year and compare to my reference individual tire load weights to make sure I haven't managed to creep up in loading. If I make any modifications to the RV by adding or moving any component weighing more than 50# I will check individual tire loads. Finally I will have the wheel alignment checked when I apply the new tires & wheels, to avoid irregular wear due to camber(bent axle) or out of spec Toe (impact damage)
I feel that if I do the above and follow the suggested practices I can minimize tire problems and be alerted to air loss due to punctures.
Again someone out of touch with 5th wheel trailers. LT265/75R16 tires call for a wheel that is wider than most available zero offset trailer wheels. If a LT245/75R16E or LT235/85R16E is under rated, then LT235/85R16G is the next logical 16" tire to fit under a 5th wheel. Or move up to 215/75R17.5's. I have only seen two others push the 265's. One said rebuild the trailer make them fit and the other said to run them on a wheel that is narrower than spec. Chris
* This post was
edited 02/25/12 01:51pm by Chris *
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Howaboutnow
AZ
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Francesca Knowles wrote:FastEagle wrote:
p.s. I went to a local RV show yesterday. It was a disappointing experience when checking some of the RV trailer specs and then looking at the OE tires. I found that a large dual axle fiver with 6750# (GAWR) axles listed on the certification label was fitted with ST235/80R16E tires rated at 3420# @ 80 psi. That particular trailer had a basement so large it looked like a Smart Car would fit in it.
Travel trailer tire fitment wasn’t much better. I found Certified GAWR 4000# axles fitted with ST205/75R15D tires rated at 2150# @ 65 psi.
Yes. Thanks, FastEagle!
Deliberately undersized original equipment (O.E.) tires is a problem almost always completely overlooked in these endless wrangles about tires.
People are so quick to blame a tire (especially if Chinese) itself for a "failure". Who stops to consider the LIKELIHOOD that the American Hero that built the RV for them put undersized tires on it to begin with?
This is an industry-wide practice, and yet it gets almost no attention. It seems to me that instead of hollering about foreign tires as some like to do, we might be better served by reading the American Made RV industry the Royal Riot Act as regards this glaring O.E. deficiency.
As for difficulties attributed to specific tire types/brands/etc.:
No matter WHAT a tire is made of, which letters it has stamped on it, or where it was made, it's going to fail "prematurely" if it isn't sized right for the job.
Duh!
Maybe it would be also wise if the tire companies would protect themselves by putting a 20% safety margin in their weight ratings and then the margin would not have to worried about! If the RV manufacturers would do the same maybe the whole problem would become noise level.
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kedanie
Albuquerque, NM
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Tireman9 wrote:kedanie wrote:35 pages of mainly 3 posters flapping their gums and inflating their egos about what experts they are. No real information given out, just insider stuff.
What a waste!!!!!!!!!!
Keith
And your specific question is?
Yes, once again, please explain your formula!!!!!!
Keith, Gloria & Charlie(Spoiled Rotten Boston Terrier)
2010 Damon Astoria 3470
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Tireman9
Akron, OH
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kedanie wrote:Tireman9 wrote:kedanie wrote:35 pages of mainly 3 posters flapping their gums and inflating their egos about what experts they are. No real information given out, just insider stuff.
What a waste!!!!!!!!!!
Keith
And your specific question is?
Yes, once again, please explain your formula!!!!!!
Simple Answer
The air volume at a given pressure carries the load.
More complex answer is that the formula L=KxP**.585xSd**1.39x(Dr+Sd)
calculates the air volume of the tire based on its dimensions (Dr is rim dia, Width "Sd" which is calculated considering the Aspect Ratio) and applies the inflation pressure P and a service factor (expected usage) K to get the load capacity L.
Do you want more detail or would that be too much info?
You really don't need to understand the formula as the results are published in the Load & Inflation tables.
The various versions of the load formula have been around for well over 50 years and accepted by vehicle industry and regulatory agencies around the world without them asking for proof of the formula as has been asked in this thread.
The reason I "demanded" the information was that I believed that most of those that were questioning the knowledge and experience of posters who were just "flapping gums" did not know the basic facts needed to provide sound answers to the question of what tire will work on my RV?
Without complete information along with the question, us gum flappers end up wasting our time repeatadly asking for the information needed to provide an informed answer. This is just how engineers and scientists work. We deal with facts.
Some facts make sense (how much load capacity is needed). Some are not really important (what is the address of the factory that made the tire).
As FE has pointed out the enemy is the RV manufacturer who provides no margin of safety when they select the lowest cost component and seldom properly informs the customer of important safety considerations (max speed) as they rush to make the sale for once the unit goes out the door they could care less about the sucker that bought the junk they slapped together and called it a "Quality" built product.
I doubt there is a single RV namufacturer that is ISO certified or that even knows what real Continuous Quality Improvement means.
Want to get the industry to change? Then simply demand that they provide enough tire, wheel and axle load capacity before you buy their product.
* This post was
edited 02/25/12 02:52pm by Tireman9 *
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FastEagle
Taylors, SC
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Chris wrote:
Most ST tires rated above 3420 lbs require more than 80 lbs inflation. Just shows to go you that industry standards for ST tires do not exist or vary a lot. Chris
Can you show us some references?
Here is mine.....TowMax
FE
New Post - 4-30-2013
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