CapriRacer wrote: If you live in a hot climate (AZ, CA, NV, TX, and FL) then the limit is six years. If you live in a cold climate (MN, ND, WI, MT, etc), then the limit is 10 years. States in between are ..... ah ........ in between.
Do you recommend using any tire treatment chemicals if so what and why, if not why? The obvious would be to keep the tires covered, and not park on dirt or wet ground. Anything else to prolong tire life?
Thanks in advance!
Nathan
The best thing to do to prolong the life and performance of your tires is to keep them cool. You can see the results of my test on Tire Covers for specifics here.
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.
ExRocketScientist wrote: You mention monitoring the rise in air pressure. Based on my knowledge of the ideal gas law, what you are in effect measuring is the increase in temperature. For me, twisting the valve caps off an on that often is a real pain, plus, the guages available that will handle my 80 psi tires are not exactly high fidelity.
I know you have said you are not an RVer, so I will let you in on what some of us do. We carry these infrared non contact thermometers that are available from Home Depot, Lowes, Harbor Freight, or an auto parts store. Whenever we stop, we check the temperatures of our tires, our hubs, and our brakes. It is real quick and convenient. If we knew the air temperature outside the tires (i.e. have a wireless thermometer stashed somewhere where the sun doesn't shine underneath the trailer), shouldn't there be a maximum temperature above that for the tire?
First, you are exactly right about the ideal gas law thing.
What I have is lots of experience with passenger car tires and I know it works there. I've expanded the recommendation to accommodate tires with starting pressure higher than 35 psi.
As far as surface temperature goes. This is where I don't have experience. The passenger car thing goes back to the days before the IR devices - and I'm quite comfortable with that. What I am not comfortable with is making recommendations without that kind of research. Perhaps those of you who have these devices can get a correlation going between what we know works for inflation pressure buildup and surface temperature.
I do have some experience with using a $10k IR camera on tires running on a test drum. The Harbor Freight units are probably fine on metal parts that have a more uniform temperature due to reasonable conductivity but rubber is a very poor conductor so there are in reality vast temperature ranges that can be seen on actual tires. I have seen delta T of over 50°F over a distance of 0.07". The HF units will only give you an average.
Remember on average over the last 50 years gas costs less than $1 a gal.
ausie607 wrote: Thanks CapriRacer for the great info.
Unfortunately much has been said about the poor quality of Chinese (bombs) manufactured tires widely used on many RV brands. The tires in question, to the average consumer appear to have the same ratings as the domestic products and I assume must meed the mandated industry standards. If that is the case, why does it appear that these imported tires appear to have a much higher rate of catastrophic failures compared to some domestic brands.
What is it that makes these offshore tires more prone to failure or is this just another myth?
ExRocketScientist wrote: One of our long term members points out that trailer tires on a multiaxle trailer experience lateral forces that are not experienced by any other application. This is due to the fact that the tire must slide sideways in order for the trailer to turn. In fact, if you stop in a sharp turn, get out and glance at your tires real quick, your first impression is that either your axles are bent or your wheels are bent. On a tandem axle, one tire will be sticking out where it contacts the road, while the other is pushed back under the trailer. Now I know a tire used in a steering position will experience lateral forces, but not to this degree. Is this why they use larger cords in the carcass of ST tires?
Several days ago, you mentioned the ST tire design is an older design. You have also mentioned changes in the design of passenger car tires (and I am assuming corresponding changes in the design of light truck tires) since the Ford/Firestone issue in 2000. Can you explain how the design of the ST differs from that of the P and LT?
This correct. Using software from CarSim with a specific set-up for multi axle trailers we can see the internal strain can be 25% higher during cornering than is seen on a vehicle with tires at the four corners.
If there are doubts watch the video on "Lug nut torque" at the Keystone site. Specifically look at the very significant sidewall deflection seen between 45 sec and 1:06.
This is why trailer tires need to run the max sidewall inflation all the time. Increased inflation will decrease the slip angle needed to generate the cornering force so increasing the inflation will also decrease the shear internal to the tire at the interface between the belt edges and should also decrease the tendancy to peal the belts off the carcass.
But unless we know the actual weight on the axles, we do not know the pressure required for you mythical trailer! However installing any tire on a rim or axle that is below tires max rating is wrong. Chris
The recommended cold pressure was already set by the Vehicle Manufacturer. And you made a valid point. With load capacities set at max to provide 3420# of load capacity the axles could have a 6750# GAWR. And mine was, by setting the replacement tires to 80 psi they only provided 3042# of load capacity.
Chris, read this reference carefully. Without a vaild recommended placard tire pressure the reference cannot be applied.
FE your post has some confusion that maybe you can clarify. Your trailer came with LRD ST tires rated to 3000 lbs each. I believe you have stated and tires would indicate 6k axles! Yet above you seem to indicate 6750 axles. In realty 6750 axles do not exist. Keystone uses 7k axles on newer trailers (remember I provided axle labels) and set GAWR at 6750 on placard to send them out with Marathon's rated to 3420.
Are you still on tract to end your ST failures with new 17.5 rims and LRF tires?
Chris
My Rig
2001.5 2500 STD CAB AUTO SLT 4x4, CTD 4:10's, Bomb'd to Tow
2005 Cardinal 29WBLX.
Chris wrote: Capriracer, you talked about we consumers banding together to share info on what works! We have been trying to do that here for a good number of years! However tire threads often get closed when posters show up with a stack of documents and start saying "you can not do that"! And some flat do not like the brand/model that works better than any other. That leads to more back and forth that gets threads closed. SAD!
In reading your posts over the last week it does not seem to be as black and white as they claim!
So keep the info flowing.
Thanks - Chris
Chris IMO the main reason that there might be sub standard tires on the highway and why there may be some RVs made with undersized tires is that few if any RV owners complain to the proper sources about the quality of our products. I cover the needed actions in my post on why "bad" tires are on the road. BUT given the fact that the RV community accepts quality in the RV industry that is more like what we got from "Detroit" in the 60's we only have ourselves to blane.
FastEagle wrote: The vehicle manufacturer doesn’t seem to have a problem setting recommended tire pressures on RV trailers. They build the trailer around an axle selection and then hypothetically load the axles to the max with an estimated cargo capacity. Most will have tires that are just a little above the axles requirement so all the vehicle manufacturer has to do is set the recommended tire pressure to the maximum allowed by the tire manufacturer and that will cover their six. I just went to a rather large RV showing in Jacksonville, FL and every RV trailer’s tire placard I checked - ALL - from single axles to dual and triple axles up to 7000# had maximum sidewall pressures depicted.
The problem lies with the owner wanting to adjust tire pressures to actual axle loads. It really looks like fooling around with tire pressures today will cause them to be under inflated (overloaded) tomorrow. NOBODY goes to the scales for every trip. Most don’t even check their tire pressures after an overnight stay on the road. The ST tire manufacturers say “OK” we’ll build the ST tires to withstand max sidewall pressures all the time. Just air them to the max and don’t overload the axles and they will work. But, they are not consistent. Some will allow pressure manipulations by the vehicle manufacturer or their recommendations with replacement tires of their brand. POP! Goes the tires. They want full sidewall pressure.
FE
I think you summed up the problem pretty well FE. We are just not getting that 15% margin, and if we did lighten the load and get it, we are letting it out by pressing in on that little thing in the end of the valve stem.
. . . snip . . .
This is why trailer tires need to run the max sidewall inflation all the time. Increased inflation will decrease the slip angle needed to generate the cornering force so increasing the inflation will also decrease the shear internal to the tire at the interface between the belt edges and should also decrease the tendancy to peal the belts off the carcass.
This is another excellent piece of information from this thread, given the number of people who have peeled their tread right off. More new information brought to the table.
Chris wrote: Capriracer, you talked about we consumers banding together to share info on what works! We have been trying to do that here for a good number of years! However tire threads often get closed when posters show up with a stack of documents and start saying "you can not do that"! And some flat do not like the brand/model that works better than any other. That leads to more back and forth that gets threads closed. SAD!
In reading your posts over the last week it does not seem to be as black and white as they claim!
So keep the info flowing.
Thanks - Chris
Chris IMO the main reason that there might be sub standard tires on the highway and why there may be some RVs made with undersized tires is that few if any RV owners complain to the proper sources about the quality of our products. I cover the needed actions in my post on why "bad" tires are on the road. BUT given the fact that the RV community accepts quality in the RV industry that is more like what we got from "Detroit" in the 60's we only have ourselves to blane.
This is the bottom line. We are getting only what we accept.
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