tireman9

The picture posted by Wayne is classical "Zipper" failure. Wolfe is spot on with the fatigue flex due to running low with steel sidewalls. While a stone caught between the duals can cause tires to fail there will be significant localized abrasion of both sidewalls where the tires held the stone. I also doubt that you could manage to abrade through both tires at the same time so one would almost certainly loose air first, leaving the companion damages but still holding air. Note to all... Including pictures ( in focus and close up if possible) as Wayne did will help those with tire inspection knowledge provide more accurate analysis allowing more likely information on the probable Root Cause of the failure. Verbal descriptions from non-tire engineers are seldom sufficient as tire engineers have a vocabulary we use when discussing tire conditions.

dbik86i Sorry to hear about your problems. If you don't mind, let me add a few observations based on 40 years as Tire Design & Quality engineer and Tire Inspection Specialist with about 15,000 "autopsies" under my belt. You didn't say if the "service co" was a Goodyear company store or independent dealer that happened to sell that brand. Very few if any tire techs get training in tire failure analysis. It's not their job as tire manufacturers have engineers specifically trained to do basic tire inspections to make a call on warranty replacements. The info about matching OD is spot on. I suspect that trying to match a tire with >5,000 mi with a new one might not be a good idea so all things being the same I would move your two fronts to the dual location and "mix" new & worn on the front axle. Finding no dimensional difference between LR-F and LR-G is rather normal as manufacturers normally will use the same mold and make internal structural differences between the two load range tires. I doubt that you will be able to feel any ride difference between a F and G tire if both inflated to same psi. Your additional info on discovering the inner tire with no air is very telling. This means it was probably run some unknown number of miles doing permanent internal structural damage. The damage weakened the tire and that is why it blew. Duals with one tire at 15 psi "Zipper" failure of steel body tire Glad you were not injured. Clearly with the TPMS showing all OK there is a problem with that system and I strongly suggest you get it checked out ASAP. I am also concerned about the tire that was mounted next to the dual that blew. Not knowing if or how much usage at 100% overload it was exposed to it is very suspect. I urge you to have a GY COMPANY STORE dismount it and do a complete internal inspection. Tell the store manager exactly what happened to both tires. Good luck

RVSEF data is not for sale. It is "owned" by the major sponsors of the Foundation. I understand the likelihood of loads changing over time but since I am doing statistical sampling that should be no problem. So far I have some answers from non FMCA folk.

As a tire engineer I am interested in developing some statistics on the actual load on RV tires. I have found a number of posts with axle weights but I know that very few vehicles have a 50/50 side to side load. If you have had your rig weighed with individual scales for each position I would appreciate knowing the results. I don't need info on the make or model RV or even the size tire as I am only interested in learning how much out of balance different type RVs are. Your post or PM me with this basic info Example TYPE ( Class-C or Class-A) RF - 3212# LF - 3810# RR - 8111# LR - 9100# If you have a Tag please include RT - 3210# LT - 3222# Thanks in advance for your assistance.

Well I don't have all the info needed to be sure, but if you are running 8% low and your normal heat gain is 40 degrees above ambient you might see enough pressure growth to get to your normal tire pressure but at the expense of running the tires hotter than they would normally run. As we all know heat is the killer of tires and the more hours you spend running your tires hotter than normal the more tire life you are using up. Now if you know that 90psi is the minimum required to carry your load based on actual weights on each corner then it's no big deal. That's why you are inflating your tires to Minimum + 5 psi, to allow for day to day temperature variations. If 95 cold is what is the MINIMUM required to carry your load you are in fact running your tires overloaded. Not a lot but overloaded none the less. Damage to tires is cumulative. Putting air back in a tire you operated while overloaded/underinflated does not "fix" the damage you have done any more than putting the burnt hot dog back in the fridge "fix" the burnt dog. Now a couple of hundred miles at 3 psi low is not going to fail a tire BUT you are still doing damage and there is no clear answer as to how many miles you can run a tire X psi low before it fails.

OK, I have been informed my post was useless. How about if you see which system that you can afford has the greatest number of features than are in my list?

Both tires on dual application usually means one had a slow leak which resulted in the mate being overloaded. Three pieces is give away of what is called a Run Low Flex failure. The picture in the start of this thread is sometimes called a"zipper" failure when the steel sidewall ply does exactly what Brett described. The steel flexes too much, much like a paper clip. Have you confirmed your TPMS reads correct pressure and that they do go to alarm when you get to the low level? Sounds like a nice afternoon project when you have access to air to re-inflate each tire. Going down to 75 while not driving is not a problem. I would not trust a visual inspection to see low tire.

Sorry Bill but not just my "personal speculation" but based on 40 years of extensive work with tire compound chemists and research scientists in the tire industry. I have seen data on cross link density which is a good predictor of rubber properties and ultimate tire performance and durability. The math does hold up as I personally did an experiment on "cure equivalents" which took 35 years to complete as time is one thing we can't accelerate in the lab. Link was just to give simple background info. Actual cross-link density numbers for individual compounds are proprietery unless you want to spend the $$$$ to have an analysis done.

Unbeleavable, A manufacturer knowingly selling units with design & manufacturing defects. You should send a request for compensation for all your out of pocket to Spartan & Newmar. If they don't pay up then send request for help to RV magaxines and name names. Isn't the RV industry just wonderful!

"Best" is always a challenge as we all have slightly different value systems. BUT In my opinion the "best" would be: - Internal to the tire air chamber - Senses pressure and temperature - Allows you to set upper and lower temperature warning levels - Allows you to set lower pressure warning level - Costs less than $200 - You can buy individual replacement sensors at under $35 - Allows all tires on coach and toad to be monitored Now the problem is... I don't think there is such a system.

Have you changed the "stuff" you carry around since you got your corner weights? On large TBR size tires ambient +60 °F is not unheard of. Some consider that normal for Interstate speeds. Can you get temperature readings in the morning when all tires are "cold". Do all the sensors match a regular thermometer reading?

Few additional comments and hopefully clarifications. Brett's post of 10/14 7:09 AM is spot on. My only clarification is that the inflation pressures in the charts are the inflation at ambient. This is called "cold" inflation but do not be mislead. "cold" is NOT any specific temperature. What is meant by "cold" is when the tire has not been driven on more than a couple miles in the last couple of hours. This does not mean 10 miles down the road. The tire should not be in the sun for more than a couple of minutes. Best time to check is first thing in the morning before you start driving. The Max pressure on the sidewall is the max "cold" pressure not the max you might measure when the tire is hot. You should not bleed down a hot tire to get to your "cold" inflation. I also agree with the +5 or +10 psi over your minimum inflation. ==== BobFike is correct IN THEORY. The problem is that to get the real temperature you need to take a measurement within less than two or three minutes from running at speed. I do not mean two minutes after stopping. You also need to be sure to get the same spot within the tread design as different parts of the pattern will give different readings. I would not use this method for setting proper tire inflation. You could use this method for checking suspension or looking for a bent axle on a trailer.

I completely agree that there are other factors that contribute to turning radius. What I do not understand is why magazine reviewers provide this relatively meaningless number when the number I would like to know is the actual turning radius. This is an easy measurement to get, even in a dealer parking lot. Another contributing factor is the cornering coeficient of the tires. This is the side force generated as a % of load at given turning angle. I see no way for a reader to include this information in the buying decision and of course no way for the reviewer to get the number. Given the technical shortcommings in magazine "reviews" this media hype is just wasted ink in my opinion. I could come up with a list of dozens of "measurements" which might make a "review" I could write sound very detailed but in reality provide no meaningful data that would allow a more informed purchase decision to someone trying to decide which RV to buy. In my opinion, RV magazines need to do a much better job of presenting real reviews rather than "puff pieces" which many times read more like press releases. Reviewers need to take a look at the work done by car magazine writers to see how real, meaningful information can be presented. How should I compare vehicle A that has a turning radius of 75'-6" than... than Wheel cut is 55 degrees, wheel base if 30'-10", Cornering coefficient is 0.234 at 2 degrees slip, and there is a tag axle which carries 9,850#

As I read various write-ups on new motor homes I many times see reference to "xx degrees wheel cut". While I understand this has some impact on the vehicle turning radius this number seems to be of little value when trying to understand the ability of MH-A to turn around in a circle that is larger or smaller than MH-B. There are many other factors which have a more significant impact on turning radius than the number of degrees the front wheels can be turned. Isn't this just some marketing hype?

My son does off-road Jeep driving and is constantly replacing tires due to damage. He does not get replacements from the tire mfg. Also using sealant or liquids or sand can also destroy a TPMS valve ($50 - $90). so again you might be better off having your tires balanced with external weights or "trued" on your RV.

I have added detailed info on the results of my study on RV tire Temperatures to my "Tire Basics for RV Owners" seminar. This was first presented last week at Gypsy Journal Rally in Elkhart, Indiana, but I thought you would find this interesting. ++++++++++++++ It is well known that heat is one of the major killers of tires. It is a little less well known that one of the reasons tires seem to age at different rates is their different temperature history and tires are basically always "curing". Ever seen how hard a 40 or 50 year old tire is? It is known that chemical reaction rates (1), in general, double every 10°C (18°F) so the more hours we keep our tires at higher temperature the more cumulative "accelerated aging" we are doing to our tires. While keeping the proper inflation pressure in our tires can keep the operating temperatures relatively under control ( +20°F to +50°F) above ambient while driving down the highway. One area I have not seen any data on is the temperature of a tire just sitting in the Sun. The attached shows the temperature using an inexpensive IR Thermometer. Pictures are: Of side of RV in the shade Of side of RV in the sun Of a tire in full sun for an hour Overview of my white tire cover Temperature of the cover Temperature of the tire under the cover. I think it could be argued that your tire "ages" between two and four times faster if you do not use a white tire cover than when your tires are in full sun when parked. Another way to think of this could be that 6 months of full exposure to bright sunlight does as much heat damage to a tire as two years under a white tire cover. I will have to leave it up to someone else to do a test on black tire covers. How "old" are your tires? (1.) http://chemistry.about.com/od/stoichiometr...eactionrate.htm

Ended up double posting. How do I delete one of my posts?

Not sure about the "paint". I have confirmed that white tire covers can lower the temperature by over 35°F in full sun. Don't forget damage, including heat damage, is cumulative so every hour you spend at elevated temperatures cuts into your tire life.

Be sure to check with the manufacturer of your tires. Adding "stuff" to the inside may void any warranty.

I would think that having the radiator fail after only 3 months would be considered proof that the replacement radiator was defective to start with. Radiators are not particularly "high tech" so in my opinion there is little reason for them not to last 100,000 miles. Do you think truck companies would tolerate a failure at 41,000 miles never mind 3 months? You may not be covered under a reasonable drivetrain warranty (5 year 50,000mi) but someone needs to answer why the failur occured in the first place. While oil in the water isn't something you want I would be surprised if it did damage. However water in the transmission and low trans fluid ("ton of trans fluid in the water" means "tons not in or cooling the trans). This low oil could spell MAJOR long term durability problems down the road. Who sold and installed the defective replacement radiator? Are they willing to stand behind their product? If not why not? Are they willing to stand behind and fix the damage to the trans that might have been caused by their defective replacement radiator? Have no idea what baking soda is supposed to do to the trans oil in the engine. Think the soap would work better.

Glad to hear the virus was removed. Has anyone made an attempt to contact Symantec so they update their warnings?

Norton continues to report FMCA site as having virus. Down to 23 from 24 a couple weeks ago. http://safeweb.norton.com/report/show?url=fmca.com

Might this thread point out the need for FMCA coach reviews to include actual corner weights? We need to do as much as possible to educate owners of the importance and Safety improvement if they know their real loads. We might also see some improvements from manufacturers if they see their real weights posted where MFG A has good balance side to side as well as appropriate reserve spread across all axles when MFG B doesn't.

I would suggest you NOT mix different brands or different type tires from same brand as a pair of duals. You need to keep the Outside Circumference (more accurate measure than Outside Diameter) as close as possible to the same. The reason for this is that the larger tire of the pair will be forced to carry greater load (probably by multiple hundreds of pounds). Different brands and in many cases even tires of the same brand but different designs will have different dimensions. In general it is also desirable to have all tires on any axle all the same brand & type and should always be of the same size. Only exception would be a VERY temporary slow speed drive if you had suffered a tire failure and were running a spare to get to the tire store to get a replacement tire. Sorry if this makes your situation more complex.

Having done autopsies on over 25,000 tires that were at the end of their life, I can assure you that few people have the training or experience to make a statement that is much more than their personal opinion. Might just as well ask if Ford or Chevy makes a better car. What you end up with is someone talking about their experience with a 1995 Corvette while another talks about their 2000 F150. Another thing to consider is that without detailed knowledge on the actual load, which roads you drove on at what speed and what was the temperature etc, etc you have no way to be sure you are comparing equivalent service. Based on my 40 years experience as a tire design and quality engineer, I can tell you that I have seen many tires from each of the majors perform just fine and at the same time I have seen individual tires made by the same companies suffer various “failuresâ€. Some and possibly most of these so called “failures†were the result of abuse and poor maintenance. Remember: There is no such thing as a fail proof tire. Re: what to buy. If you know your real load for each position on your RV, and you select a tire size and load range that is capable of carrying your individual loads, and have included at least a 5 psi cushion, and run a TPMS and never run less than your personal minimum inflation, you should be able to go the expected 5, 7 or 10 years with little or no problems. But you can also run over a nail as you leave your tire dealership and have a flat at zero miles usage. Select your brand based on your expectations to be able to receive service and quickly and easily obtain a replacement if needed, as you travel across the USA.