tireman9

Just published a post on Front tire failure and possible things to do to maintain vehicle control on my RV Tire blog.

IMO that amount of "rim slip" is excessive. Wonder what they are using for tire mounting lube. The good stuff is designed to be slipery when wet but to actually be sticky when dry

Yes tire / rubber failure can occur at 200F and above but your TPMS is not going to tell you the temperature of the hot spot. I suggest you stay with the 158F +20% pressure cold to hot is not too unusual.

Best advice I can give about driving speed is to think of the speed rating of tires as you would would think about engine red line. While it may be possible to run just under the max speed rating of a tire you will most likely see shorter tire life. Is it good to run for hours on end at 93% of engine Redline? I read a lot of questions or complaints about tires not lasting as long as the owner wants but I don't hear anyone acknowledging that they made the decision to run near the limit for load and speed. No I can't tell you that every hour at 70 cuts the life of your tires by a day or a week out of the possible 10 year life but I am certain it will have some negative affect.

Tire & wheel pressure ratings are based on cold inflation, not hot running pressure. What is the warning level for TST? is it only 15% below the baseline or set pressure? IMO its a good idea to get a warning before you hit the MOP.

I have only heard of one large RV tire with a rating higher than L and as I recall it was an M (81) I strongly suggest you stay below 70 mph unless you also run 200 RPM above your engine red line a lot.

Load Range in large RV tires is a letter F, G, H, J Speed rating in RV application is 75 mph which is Symbol "L" Read all the words associated with various letter symbols.

Based on questions I received after my tire seminars in Indy and some statements overheard at various TPMS vendor booths and in other seminars, I decided to offer a detailed example of how I set my TPMS for those that might be wondering how to get the best possible "early warning" from their system. HERE is the link to my blog with all the details for those interested.

The size comparison web page is interesting but IMO it is not a substitute for printed (or web page) dimensions from the tire manufacturer. Tire "size" is a generic goal and all tires have some variation. Sometimes the variation in one dimension can be significant for one tire design because it might have been designed in Europe to meet a different application. I am aware of some tires being "tweeked" to fit a specific application. I also note that a critical dimension "Minimum Dual spacing" is not provided by the web page. It might be ok to use the page for a quick check but I would NOT rely on it for final, actual dimensions.

Sometimes there are marketing decisions that dictate who sells or advertises certain products to different markets. For a variety of reasons some companies would rather not be confronted with the problems of improper maintenance (low inflation & overload) seen on too many RVs. Some are making the conscious decision to go after the "niche" market of RV application. IMO many "truck" tire would work satisfactorily in RV application. Some tire companies do identify generic types of service as more applicable to different designs. For RV service it is generally suggested "all position" and "delivery" or "regional haul" or similar service. While "Bus" may seem similar to RV it really isn't as many Bus tires are speed limited and have extra tread depth (increased cost) for in city service.

I bought Tire Traker system after review of features. Easy set-up (15 to 20 min max), replaceable sensor batteries, Lifetime warranty and no power cables to monitor along with multiple warning levels had me sold. I especially like the "Morning Reset" mode that gives me readings without having to move the coach to get readings. Just turn on, hit buttons and 15 to 20 min later after i finish my coffee I have my tire pressure readings. I have a new post on my blog scheduled for Tuesday on how I program my TPMS.

If you unknowingly (no TPMS warning) operated the tires at significant loss of air, that is not the fault of the tire company.

Didn't Lazy Days set-up the TPMS? or were they just too lazy (sorry could not resist). If you really had only 58 psi the TPMS is set wrong as it should have warned no lower than -15% to -25% from your baseliine pressure (Cold tire inflation) If they screwed on the sensor it is possible they created a leak. Since your TPM is giving you a reading I suggest you review the instructions and confirm the inflation. If only 58 then call service and tell them the tire was operated when "flat". This is a real safety issue. Steel body tires can explode (zipper failure) when being re-inflated.

Don't think so 58 kpa = 8 psi 58 psi is 400 kpa

x2

"Blowout" is a generic term used by the un-trained to mean the tire failed. There are two different conditions that cover probably 95% of failures. 1. Run Low Flex Failure. This is failure of tire sidewall due to operation at significant low inflation, usually due to active leak in tire or valve. This can happen in just a few miles of operation. 2, Belt/tread separation. This is a longer term (thousands of miles) of operation at improper inflation and/or speed for the load. The heat generated from this improper operation accelerates the degradation of the rubber at the belt edges which can eventually lead to separation. NOTE the operating condition at the moment of failure is seldom the cause of the failure except for impact from a large pot-hole or road debris. Damage is usually microscopic and cumulative but remember tire damage never repairs itself. the cracks only grow.

Even with 40 years experience as tire engineer and "looking at" tens of thousands of tires, I do not have X-Ray vision. That is what is needed if you want to know the real condition of your tires. Tires come apart because of physical changes in the chemical bonds between components of the tires in the internal structure of the tire. Sometimes the early signs of catastrophic failure can be discovered through X-Ray and/or Holographic examination of tires. While this type of inspection can be done it is expensive (multiple hundreds of $$) for someone to remove tires from the coach, dismount and process a tire. 10 years is a reasonable MAXIMUM age. This does not mean that all tires are fine at 9 years , 11 months and 30 days then are bad a couple days later. Some tires should be removed at 7 years but it is hard to be 100% certain they will be OK 3 years later. In my professional opinion I would replace the 10 year old tires at once. ( I like KPSmith's suggestion of 15 mph max)

Brett is correct. 1. New tires must be able of supporting the same or higher load than your 9R-22.5 LR-F 4540# @ 105 psi SIngle 4300 Dual 2. I assume Dual rears Be sure to confirm "Minimum dual space" spec on new tires. Spec on 9R-22.5 is 10.3 3 9R was approved on 6.0, 6.75 & 7.0 rim width so you need to confirm which you have.

First you need to more clearly identify the problem. Vibration through steering wheel or through floor in front? Both driver & passenger floor vibrating or just one side. Is the vibration felt at rear of coach? When did you first notice the vibration Second you need to be sure you have identified the actual cause of the problem. Is the tire at the location of the vibration withing established tolerance for run-out? I have seen demonstration of balancing a cinder block so problem may not be balance Have you confirmed tires are fully seated and concentric on the wheel? Have you confirmed the wheel is properly centered on the hub? With a large center hole I assume your wheels are "lug-centric' so it is more important that the nuts are tightened in steps and in sequence.

Ray Neither Brett nor I nor others are saying ignore the sentence you seem to focus on. What we are suggesting is to consider the entire set of instructions from the tire companies. If you know for a fact you have no tire in overload you are more than OK to run the inflation shown on the tire placard. That inflation is based on the assumption you are running your axles at GAWR. If you would like a bit better ride then you might consider following the section in the tire companies current detailed instructions and consult the charts. and ensure you always have no less than the minimum inflation shown. I suggest you do an even better job and set your TPMS low pressure warning level at the minimum pressure needed to support the heaviest end of that axle. You set your CIP to the minimum +10% and set the high pressure warning on the TPMS to the CIP + 25%. I would consider the best all around solution to the question of what pressure to run. or if you prefer just follow the Placard. Your choice. Any chance you will be at Indy. If so I suggest you attend one or both of my tire seminars.

Can you provide the specific design name of your Toyo tires?

You say it showed +50 psi when parked. While heat soak from hot brakes can warm a tire, that sounds a bit excessive. There wasn't another RV parked nearby by any chance? RE TPMS I bought Tire Traker TT500 system. I like the Lifetime Warranty, the ability to program my own warning levels and the cool "Morning Reset" mode to allow me to get cold inflation readings in the AM without having to get outside the RV. I will be at Indy if anyone wants to see my system. Send me a message so we can connect.

To all who replied: Well I did finally pay attention to the combined knowledge of the group here. I have a DPDT switch that selects Shore Power or RV inverter power. The Inverter is wired to a relay that gets it's power through a lighted switch to the Ignition so I can't drain the coach battery by running the inverter. I will be at Indy Monday late afternoon till Sat Noon after my last Seminar. Drop me a message if you are interested in seeing the install and leave your contact info so I can call you. I am scheduled to give 6 seminars so have a rather full schedule of Genealogy and Tire seminars. (at least I know those topics

According to the schematic my Refrig is wired directly to the 110v line that runs to the shore power plug. No Inverter was provided by Coachmen I have no 110v AC if I am not plugged into shore power. Short term (on trip to Indy) I will shut off breaker at power center to isolate refrig 110v circuit. Then when others can look at what i have at Indy we can decide best next step. We never run anything on 110v when driving.

RE back-feed. I did not think that if I applied 110v to the output side of a AC>DC converter it would act like a DC > AC Inverter. I picked up a DPDT switch. Am looking for ways to run cords to various devices. Not a lot of room in my Class-C