tireman9

I see back-up camera systems for RVs advertised for $300 to $1600. I have a Class-C and installed a Peak/Wireless back-up camera system with 2.4 in. LCD monitor for $80. It turns on whenever I shift to reverse and is wireless to the driver seat area. Not as big a screen as the thousand dollar units but it works for me. You can check the auto parts web sites to locate a store near you that has the unit. Now if you want the camera on full time you will need to run 12v power to the back of your RV but if you are only concerned when backing up this unit works just fine.

RJ I do not recommend mixing brands in a dual application even if the size is listed as the same there will be different deflection characteristics that result in one carrying more than it's mate. Since you have a GY and the rest are BS I strongly suggest you run the GY on a Front position or if you have a Tag axle with just single tires on each side that would be OK also. RE Riverwear. Can't comment on one brand tendency or not to develop this condition or not. It is a form of localized wear that goes around the tire but not side to side. Kind of meanders a bit. Lets see if this link works.

Wayne If you can't get actual corner weights then your approach would seem to be the best you can do. If your wear is OK then you are probably not too far off. You might touch base with RVSEF and ask what their schedule is. Never know if one of their guys will be traveling near where you expect to be. The only other option is to keep an eye out for a truck scale that has enough level space to allow you to do the multiple weigh that would allow you to calculate the individual corners. I have seen scales with enough side clearance to allow this. You first get the full axle weight then drive through again with one side on the scale and one side off then do the math. Hopefully there are some FMCA members who have had the corners weighed and are willing to share the data here. So far not so much.

Bill My goal is to develop statistical analysis to allow me to make a suggested adjustment for estimated load when individual corner weights are not known. I note that many folk do not know their actual corner loads and are unlikely to ge them as they do not attend large Rallies and Conventions where RVSEF or similar organizations offer the weighing service. However everyone can get to a truck scale and at least know their axle load. I am expecting to be able to say something like... If you do not know your side to side loads but only your axle load then If you estimate a 50/50 load split you have a xx% probability of overloading one of your tires by yy% If you estimate a 45/55 load split then.... and if you estimate a 40/60 load split then .... Initial data suggests that if you estimate at a 45/55 split and then inflate all tires based on the 55% load when using the tables you have a 25% chance of still having one tire overloaded. Note the 25% figure is NOT based on a detailed analysis of the data but is provided here as an example based simply on eye-ball look at limited date. To make the data analysis more reliable I need at least 25 more coach weights in Class-A plus 30 in Class-C. On another forum I am also attempting to address the question of side to side and axle to axle variation for 5th wheel trailers. Note I already have confirmed unbalance at more than 10% level for two Motorhomes out of 27 and confirmed unbalance axle to axle of more than 60% of 5th wheels in addition to side to side unbalance at about three times the rate found in Motorhomes. This preliminary data clearly supports the need for developing reliable prediction statistics to encourage more people to get their real corner loads or at a minimum to stop estimation on equal distribution. The above is a strong smoking gun for the probable root cause for the 18% tire failure rate seen in RV applications. I find it interesting that FMCA people seem to feel this is not something they need to worry about.

dbik86i Before you can increase the load capacity you will need to increase the inflation. Your wheels may not be rated for the higher inflation. They should be marked with a statement of max load and max inflation. It also sounds like you are assuming your tire failure was due to overload and not some other cause such as impact or puncture. Did you have the failed tire inspected by a Company Store, not an independent tire dealer? Did you ask for an adjustment from the Manufacturer? Manufacturers will only accept or turn down an adjustment AFTER an experienced engineer does a complete inspection. Note I said Engineer and not just a tire tech. I also wonder if the new G rated tire is a good match based on actual size of it's companion dual. If you had much more than 5,000 miles then there is a chance the worn F rated tire is smaller so you are asking the G rated tire to carry more load but probably don't have increased inflation for the increased load. If you have to I would suggest you move the fronts to the rear dual positions and put the mixed load tires F & G on the front to avoid the potential dual lading issue.

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.

Some answers: IR Thermometer - Harbor Freight $26 - $30 when on sale. Be careful. It is doing some averaging over a 1" to 3" diameter circle so it will NOT give accurate max temp of a tire tread. This is based on my experience with $20k Thermograph video camera which shows that different areas of a tread can have a temperature range of over 50 degrees for over small distances. I have seen this range over as little as 0.10". This hand held unit is OK for approximate temperatures but you need to have a consistent surface temp over the entire area being scanned. Looks vs Results. Ya, I understand that the nice flat black mesh covers that hang down from the side of a Class-A might look better than a white vinyl "bag" over the tires. But if you want to get longer life from your tires while parked you may have to make the choice of "Looking Marvelous" as Billy Chrystal said or or actually maximizing the protection of your tires. Maybe if people started asking for a White or Light Grey or possibly even a IR reflective material for their tire cover then some manufacturer might start making such. Color along does not dictate a material's ability to reflect IR or to insulate. Dirt vs Concrete vs Asphalt You want to not park on a surface that can "wick" oil or moisture to the tire. So Concrete would be first choice but you can also just park on the plastic pads they sell at RV stores or you could get some pieces of 2x12 or plywood and cut to a little larger than the contact patch of your tires. These could be covered with some sheet aluminum or plastic that you can get from local home supply store. You might even look at using floor tile to cover the wood. The aluminum or plastic sheet doesn't need to be thick as the wood will distribute the load. Cheaper than concrete and you can move around as needed. Cheep enough to be replaced every couple of years if needed. Opinion or Science? Well the science of rubber chemistry indicates that tires are always "curing" it is just the rate that changes with temperature. See the link on Chemical Reaction rate vs Temperature in my post. The longer tires "cure" the harder they become, which can lead to microscopic cracks which once started can grow. Rubber does not "heal" like your skin so once cracks start, they just get bigger. So given that "curing effect is cumulative and not reversible, every day your tire spends at 135 degrees is about like two days at 115 or four days at 95. You can think of a tire as having a finite amount of "life". It is always leaking "life" out. Once the "life" is gone the tire is not able to resist serious damage as well as it can when full of "life". So the question is, Do you think it is worth the effort to keep your tire "full of life" as long as possible? The question of operating warm is related to the migration of wax and UV protectant chemicals that are part of the tire's compound. These chemicals are "consumed" by exposure to UV and flexing a tire allows these chemicals to migrate to the surface easier than when parked. It is not just the tire temperature that allows the protectants to migrate. Normal vehicle operation is in the 10,000 to 50,000 miles a year depending on type of tire and application. With tires good for 30,000 to 100,000 miles total, you can see that "normal" tire life is five years or less with most tires coming out of service at four years. RV applications might see only 5,000 to 10,000 miles a year. Class-A tires are basically the same as used on Heavy truck tires. Heavy truck tires are generally worn out in two to four years and then replaced but RV owners want their tires to last two to five times as long as "normal" tires do so RV owners need to make extra effort to maximize the life of their tires.

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.