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Friday, December 27, 2019

I run TPMS but the tire still came apart. Why?

I found a post from a fellow RV owner who has a TPMS but still had the tire come apart as seen below.

The tire in the picture shows clear signs of a "Run Low Sidewall Flex Failure" i.e. that sharp line around the sidewall with the melted body cord showing.
Yes, the driver got a warning of air loss but I wonder what the Low-Pressure warning level is set at, or if the system has a "rapid air loss" setting.

The "melt line" takes a few miles to develop with significant loss of air (maybe 25 to 40%) while still running at highway speeds. Just driving a mile or so with a 10% loss as you slow down to pull over is usually not enough time to get the body cord to the 350 to 400F required to melt the Polyester cords.

As I have covered how I program my TPMS in this blog back in August 2017. I suggested that the Low-Pressure Warning level be set such that the driver gets a warning as soon as the pressure has dropped to the pressure needed to support the tire load based on scale load and tire Load / Inflation table numbers.  Hopefully, those who subscribe to the blog or those who have gone back and read the posts followed my procedure and have adjusted their TPMS settings according to their RV vehicle needs.
This may take a little thought and effort depending on the brand TPMS. Some may allow you to directly set the low-pressure level while others may require you to calculate the required "set" level as they have a fixed percentage of air loss before they start the warning "beep".

Some systems provide a warning as soon as just a few psi is lost (from the higher hot pressure level) from a puncture.
Example  Your cold set pressure is 80 based on a minimum required inflation to support the load of 70 psi.  When running down the road at 60 mph your tire is probably at 88 to 90 psi. If your system only warns with a 25% pressure drop from the "set" pressure that means you can travel many miles before you get a warning at 60 psi. At that point, you have overloaded your time for many miles.
"Early Warning" or "Rapid Loss" feature might warn you as soon as your pressure drops from 90 to 87. This allows you to monitor the pressure as you look for a location to pull off the road.
TPMS is a powerful safety device but to get the maximum benefits it provides you need to do a little more than just screw the sensors onto your metal valve stems.


Friday, December 20, 2019

Are there stupid questions about tires?

Recently ran across a thread where there was a rather basic question on inflation where someone claimed to have "searched everywhere" to find how much pressure to put in his tires.

After dozens of posts on this blog, I have to admit I am disappointed that he hadn't found any of my info. I do know that many times a simple Google search on the tire-related topic will show this blog a few times.
There are no stupid questions. Ask questions and learn something new every day. But clearly, stupid answers are a real possibility.

I sort of agree but do wish that more people learned how to use the "search" function on forums as many questions have already been answered more than once. Also, learn how to efficiently use Google.
My problem is that I simply do not have the time to answer the same question multiple times a week.
For example "How much air do I need in my tires?"

When it comes to Motorhome tires and inflation it doesn't make any difference if your MH is blue of silver. The way to learn how much air the tires need is the same.  Without making a minimal effort to learn what to do and simply expecting someone to give you the proper answer i.e. "You need to inflate your tires to 94.565 psi" is not the correct answer.

The saying about teaching someone how to fish rather than just giving them the fish applies here.
How do we "teach" people that they need to learn how to search the Internet as the answer to most questions is already there?

 I am pretty confident that with over 400 posts I have at least touched on just about any question people might have relating to Tires or valves in RV application.

 If I have missed a topic please feel free to send me an email (address is shown under my picture on the right).

I do hope we all have a Happy and tire problem-free Holiday.


Friday, December 13, 2019

How I avoid problems with Dualie tire hose extenders.

The key to avoiding problems with a hose or any type of valve extension is to be sure the outer end is

 S O L I D.

Some hose kits come with small brackets that can be pop-riveted to hub cap. Others have brackets that attach to lug nut.
People often fail to support the hose or bracket when checking or adding air. The force needed to get a good air seal is enough to bend or loosen the hose mounts. or they inadvertently twist the hose and end up with a leak where the hose screws onto the metal valve.

You need to hold the outer end of the hose firmly to prevent movement or twisting or you can expect to eventually have problems.
In THIS blog post, you can see my set-up (42,000 mi) w/ no leaks or failures.

Since I run a +10% psi margin over the minimum pressure I need on my Class-C based on 4 corner weights and since I always run TPMS (that I have tested) I simply use the TPMS to tell me the inflation each morning before I start out.
During a cross country trip OH > OR > OH over 7 weeks I only needed to add air once so since I am not messing with the hose extensions, I am not pushing on their mounts or applying a force that might result in a slow leak.

If/when I ever do need to remove a sensor to change a battery or add air, I ALWAYS spritz Windex to check for any leaks after I am done.


Friday, December 6, 2019

The tire was "Defective"

Originally Posted by tap4154 View Post
They are now defective tires and should be replaced under warranty. Heck, maybe the dealer even knew they were defective? Do not let the dealer or Goodyear get away with not replacing them for free. BTW that the dealer even suggested putting the defective tires on the back tells me they may be shady...

I suggest you look up the definition of "Defect".
A belt separation in a condition that has a cause. The cause may be a defect such as some contamination was built into the tire between the belts or the wrong rubber compound was used on a batch of tires, as I discovered when inspecting tires back in 2000. As I pointed out in THIS post there are also external usage factors that can contribute to the initiation of a belt separation.
If you worked in a coal mine and after 30 years were diagnosed with "Black Lung" would that simply mean your body was defective which would make the condition your parent's fault?

If you had a sidewall flex failure due to running with only 20% of the air pressure required to support the load is that an indication of the tire being "Defective". You can learn more about this condition by reviewing THIS post in 2011 on Sidewall "Blowouts".

Simply claiming a tire is "defective" is the go-to excuse used by many that have no working knowledge of or don't want to spend the time investigation the "Why" tires develop various conditions.

If you have a tire failure and even if you don't know why it failed. Even after reviewing the posts on this blog that identify various reasons for a tire to fail, I still suggest you file a complaint with NHTSA. Please however just describe the condition of the tire and be sure to include the vehicle VIN and the full tire DOT serial.