OK, a couple of fine points to nitpick.
First, that indentation is the overlap of the PLIES (not the belts). It is indeed stronger there than the rest of the tire.
Why don't you see indentations in passenger car tires? You do, but a passenger car tire is inflated in the 30 psi range, not the 70 to 80 psi range. If you look carefully, you will find at least one indentation for every ply (not belt ply) a tire has.
Also, notice in the photo a circumferential indentation 360 degrees around the tire in the mid sidewall area - where the lettering is. That is where the ends of the plies are. The plies are turned up around the bead - a hoop of steel wires - and they end in the mid sidewall area. Because of differences in the amount of material, you get bulges and indentations, and that is one of those areas.
I used to travel on business to many, many states - and the one common thing I picked up was that there is a difference between city drivers and country drivers.
No I don't mean the roads and the amount of traffic. I mean the characteristics individual drivers generally have.
Country drivers will wait at a stop sign until they can not see anyone at all before crossing. City driver gauge how much room there is in traffic and if they can cross without getting hit.
For City drivers, the speed limit is kind of a suggested lower limit, but Country drivers see it as an absolute and it would be better if you left some room for error.
Country drivers aren't worried about the time it takes to get where they are going. City drivers want to spend the minimum amount of time traveling. "They got stuff to do!"
Me Again and GMW Photos (and anyone else who is interested in following this conversation),
First, there are 2 different situations being discussed:
1) What is called a "Property Damage Claim" - that is a claim where the tire failure caused damage to a vehicle. AKA, a "PDC".
Normally the tire manufacturer bypasses the dealer and handles the claim directly with the consumer - but there are some variations where the tire dealer might be involved.
Also, normally the tire manufacturer will want the tire back - along with documentation about the incident and the amount of damage. Regardless of what the determination is (that is, manufacturer at fault or not), it is required by the Federal Government that this be reported to them. But without the tire being returned, there isn't anything to report.
Usually the consumer can negotiate a settlement - even on a road hazard claim - so it is always worth the trouble to do so.
And just so you know, at one point in time, I was the guy who examined those tires.
2) A tire failure without damage to the vehicle. This is covered by the warranty. Please note that EVERY tire has a "materials and workmanship" portion of the warranty and even though there may be a time limit, the warranty period is usually long enough to make this issue of value to the consumer.
In this case, the tire dealer is directly involved. The tire dealer's incentive to do this is the money (credit) the tire manufacturer will give the dealer when the tire is returned. So, "No!", the dealer has a good reason NOT to throw the tire away.
And there is a reporting requirement for those tires as well - just like the PDC's. They are reported separately, in different formats, but they both have to be reported. Most people take this very seriously - and the folks that don't are risking some severe penalties.
But let's look at this from the tire manufacturer's point of view (and here I'm going to address the "Beta testing" remark).
I'm sure everyone is aware that there are minimal testing requirements for tires sold in the US - commonly called "DOT Tests". Those tests were based on standard industry tests - one of which is called a "Step Load" or Step-up Load".
This test consists of a tire mounted on a wheel and loaded against a test wheel at a certain load. The wheel turns at a certain speed for a certain length of time, then the load is increased and run for another increment of time. This is repeated until the tire reaches the rated load - at which point the tire passes the test.
But the industry tests continued increasing the load (in steps) until the tire failed - AND - (an important point) it is common for tire manufacturers to require their tires to meet some elevated level to assure that ALL their tires pass the test. While the government only does spot checks on compliance, there are severe penalties if the tire is found not to comply. (A recall at the very least, but there can be more penalties if needed.)
And another important point - it would not take very long for anyone observing tire performance to realize that passing the government minimums does NOT insure good tire performance. - AND - that the Step Load test can be indicator of the level of performance in the real world. This is where returning the failed tire to the manufacturer comes in.
Testing is great if it correlates to the real world. Returning the tire to the tire manufacturer not only gives the manufacturer a way to describe how the tire is performing, but it gives him a way to determine if his testing is producing the same kind of failures. If not, then the test needs to be modified.
I'll give you an example: In the process of trying to comply with the TREAD Act (the law that came out of the Ford/Firestone incident a few years back), the company I worked for developed a test which was faster to do. Unfortunately, it produced a failure mode that no one had ever seen - and more importantly, it did not produce the typical "belt leaving belt failure". Quick test, but of little value.
Further, improving the performance of a tire on the Step Load test results in an incremental improvement in field performance - as measured by the rate of return. Without these returns, the tire manufacturer will not know what the problem areas are and whether improvements actually worked.
And just so you know, at one point in time, I was the guy who analyzed the rate of returns and whether the improvements worked.
What I just described above was specific to tires, but the general system is applicable to virtually anyone offering a product or service. In other words, you won't know how you're doing if you don't get feedback. Even Starbucks offers a free coffee if you fill in an on-line form. It's their way of gauging things.
Now let's talk practical matters: Do tire dealers actually return failed tires to the manufacturer? For the most part, they do. They have contacts either directly with the manufacturer or through a distributor. Everyone involved is actively returning tires to the manufacturer. It's just part of the business.
Tread separations don't just happen overnight. They are most often caused by some form of tire damage - inflicted or built-in - that will eventually cause the tire to fail completely.....
I'm going to disagree with that.
While in service damage to a tire can cause a "belt leaving belt separation" (what is commonly called a "tread separation"), the most common cause is a deficiency in design - meaning the type and placement of materials in a tire (per the specification) and the material specifications. Manufacturing issues (commonly called defects) are hardly ever the cause.
......A professional tire expert can determine the exact cause of the damage to the tires shown in the pictures.......
I'm going to disagree with that as well.
If there is in service tire damage or an actual defect, then, yes, a tire expert would be able to pinpoint the cause. But because most tire failures (and I'm excluding road hazard related "failures" here) are design deficiencies, there is an absence of evidence and therefore any "cause" is speculation about the design.
And lastly, tire experts of the caliber to be able to examine a tire failure and at least have something intelligent to say about it, do NOT reside at tire dealerships.
But tire manufacturers have such experts and returning a failed tire to them is a good idea. But do NOT expect any honest assessment in response to you, the consumer. There are legal liabilities in play and anything written down can be used in a court of law. Any expert who can do such an examination would be aware of those legal liabilities and would be very careful about what he said.
There are 2 kinds of "sipes".
1) The kind put in the mold by the tire manufacturer. Those are obvious by looking at the tread pattern. They are blade like, but they have a clear gap.
2) The kind cut into the tire at the tire dealership. Those are the result of a knife cut and have no gap.
What siping does is cut a block of otherwise continuous rubber into smaller pieces. That allows the blocks of rubber to be more flexible, but it also creates edges so it enhances the "paddle wheel affect".
But more movement generates heat, and wear.
Benefits of siping?
Better snow traction.
Better wet traction.
Some wear loss
Some dry traction loss
Some fuel economy loss (very small)
Increased running temperature (very small)
Yes, some of the above contradicts advertised claims. I would caution people about listening to anyone trying to sell a product or service. They may not be entirely accurate.
Personally, I would only sipe a tire near the end of its life - to offset the loss of wet traction and snow traction as a tire wears. The loss of wear and the F/E hit are offset by the increased life I can get out before the traction drops to unsafe levels.
I'm a pro - that is they pay me ....... wait, they don't any more. Does that make me a pro or not???
I'm of the opinion that a) I want to take a closer look, and b) they are likely separated.
If I were in your shoes, I would schedule a weighing of the trailer. Tire by tire. You really want to look at that side of the trailer.
Not sure what the "original" factory tire size was other than a 15 inch tire. This RV was ordered new from the factory with the "optional" 16 inch wheels and has 235/80 R16s on it.
There is a Kitchen slide over one set of tires (with associated wiring and such). So I do not want to increase the overall diameter too much. so I am looking at these two options:
I don't think it matters - unless the 1/2" difference in ride height is an issue.
Here are the options:
I'm thinking that if you are going from an ST225/75R15. then the easy choice is LT225/75R16. Only the diameter is an issue - and it will need 1/2" more clearance in the vertical direction.
Made the decision to go LT....after tons of research I decided on Bridgestone Duravis R250. So now the tire size question...
I have a 28 foot 5th wheel with dual 4400 pound axles (trailer GAWR rating is 8800 pounds. Unloaded weight is about 7500 pounds and max loaded is about 10K pounds. Pin weight unloaded is 1350, I suspect about 1800 laoded. Trailer usually comes with 15 inch wheels, this one has the optional 16 inch rims. Currently has 235/80/R16.
Looking at replacing with Bridgestone Duravis R250 225/75/R16. Load Range Index 116 (2496 Pounds).
1) Do you think I am good to go with this load range/size? Seems to me they should work just fine given the weights I am working with.
2) Wally World now has them for $214 a piece with free shipping to store (pretty great price). Will not be using the trailer for the next 5 months. Should I wait till spring or go for the good price that Wally World has on them? Will being installed and sitting for 5 months affect life of tires?
That would be a good choice. But you need to verify that the weights listed are accurate. Some trailer manufacturers don't do a good job in this area. I'd recommend getting the trailer weighed BEFORE you buy tires.
Weighing the trailer? Fully loaded with everything you've ever put in there, including full water tanks.
Tire by tire, please. If not, you need to account for side to side and front to rear variation. I recommend using a 10% value for axle by axle measurements, and 15% if all 4 are weighed as a unit.
Yes there has. The govt. does the tests.....
Sorry, the government does not conduct the tests. The tire manufacturer does the tests.
The government might test a tire or 2 to verify compliance, but they do NOT conduct the certification test for each and every tire on the market. They can't. Way, way too many.
- AND MOST IMPOTANT -
When the government does test a tire, it will do so according to the test procedure applicable to each type of tire. They will NOT test an ST tire to LT tire conditions and vice versa.
.....The so called weight advantage of the ST is very slight.. The speed superiority of the LT is signifignant....
Sorry, but the math says they are in line with each other.
Note: Please be aware you can't compare a 10% load carrying capacity with a 10% speed difference. It doesn't work that way. It's an exponential curve.
LTs were around before STs came into existence.. In fact they were the original trailer tire.....
Sorry, but ST tires came into existence the same year LT tires did. Go find the Tire and Rim Association Yearbooks, Oh, about 1968, and look it up yourself. Prior to that there weren't LT tires (or ST tires). They used a different system. and they didn't use letters.
In fact, prior to the introduction of LT metric and ST tires (and P metric, for that matter) the difference between tires used on trailers and tires used on pickup trucks was the notes on the tables involved. Tires on trailers were allowed to have more load carrying capacity BECAUSE they were operated at slower speeds.
Oh, and LT tires back in those days didn't perform very well. Certainly not up to the standards of today.
......The ONLY thing stricter for the ST tire tests is the 3% tougher load requirement........
Ah, that is part of the problem.
An LT235/85R16 LR E has a load carrying capacity of 3042# at 80 psi.
An ST235/85R16 LR E has a load carrying capacity of 3640# at 80 psi.
So it's more like 20%.
...... But the rest of the LT tires testing is so severe, that I would wager a tidy sum that the LT tire is easily capable of meeting that test requirement as well........
Ordinarily, I would point to your other factual errors and take you up on your bet, but I happen to agree with you - but for a different reason.
......I would wager a whole LOT of money that the STs cannot pass the LTs tests.......
And not only is it here we disagree, but you have proved my point.
You do not KNOW of anyone who has done the testing.
........Every LT tire meets the standard for ST ratings .
ST tires do not meet the LT standards ......
Sorry, but while the standards are different between ST tires and LT tires, there hasn't been anyone who has done the testing to verify that.
ST tires are designated to have a larger load carrying capacity, but have a speed restriction of 65 mph. LT tires have a lower load carrying capacity, but have a higher speed capability.
You can argue that ST tires aren't built as well as LT tires - either because of the quality of the design or the quality of the manufacturing material and/or processes - but ST tires are designated for a certain task and LT tires are designated for a different task.
Nevertheless, there isn't any evidence that either will pass the other's testing requirements.
So, how does one drive 70 MPH, and hit something with the back tire but not the front tire with a SRW truck?
Because the front tire will roll over the object and kick it up and send it tumbling towards the rear tire where is gets trapped as it is tumbling.
Too bad you can't remember the actual numbers, but I still think the opposite of what you think might be true. One real issue with using things like race car or similar scales is that they are fine for things like cars where the weights on the tires are distributed at for separate corners, but on tandem axle trailers putting a scale under one tire on a side will give you erronous numbers...........
I'm not going to quote the entire posting - takes up too much space.
Larry, it's obvious you've never seen race car scales. There are 4 pads and part of the set up is to make sure they are level. I am sure that anyone who would use them would be aware of this.
Second, EVERY time I have seen published results from a weighing of trailer where they did individual tires, there has been variation. I have seen enough of these to feel comfortable making this statement:
Because I want to give conservative advice (that is, one that is certain to produce good results) I recommend that if the trailer is weighed axle by axle, that people use a 10% factor to get the max load - and 15% if the weigh all 4 tires at once.
I'd like to see more individual weighings to further refining the number, but it doesn't appear to be very far off. - keeping in mind that I am looking for the maximum variation.
tires are ST235/80/R16
That 92 was fairly constant but just one one tire - occasionally would drop to 91 for a while. Rest of the tires ran 89-90. No braking, running at speed on the road. I tow at 65.
I did not get that scientific on the cold pressure. That one 92 degree tire could have been 1-2 lbs higher when cold. I have not been using a digital pressure gauge for cold airing up.
OK, so it does sound like the tires need to be adjusted in some way.
As a start, I'd recommend you get scientific - and I's also recommend using 90 psi and see how much build up you get.
But I think the real answer is using a larger tire size.
Word of caution:
The load on tires varies front to rear and side to side. If you are doing reserve capacity calculations you have to account for this. If you've weighed the trailer, tire by tire, then you know what the variation is.
But if you weighed your trailer axle by axle, I'd recommend to use a 10% figure for the worst case - and if you weighed your trailer as a whole (that is, not axle by axle, or tire by tire), then I'd recommend using 15%.
To put this in perspective, RVUSA quoted some figures, but didn't account for the variation - and at 12.7%, he just might have an overloaded tire. But we can't be sure without individual tire weights.
Just got my TST system cranked up and also just came off the road from a 920 mile run. Have 16's on the fifth wheel so I always start at 80 psi cold. It was generally around 56 degrees or cooler outside. One morning it was 40 outside and I noticed the tires generally had dropped from 80 to 78. The highest pressure indicated was 92 psi. Temp ran about 12 degrees higher than ambient.
I been wondering on this subject also so this was a good read.
I did not time it but sure was surprised how the tire temp and pressure quickly climbed close to the final running numbers when initially starting out.
The rule of thumb is that you'd like no more than a 10% pressure build up - and if you get 15% or more, you need to take action.
You are AT 15%, so you need to take some action to improve the load carrying capacity of the tires - which means a larger size or more inflation pressure.
You said you were using 16" tires at 80 psi, but you didn't say what size. If they are ST235/80R16 Load Range E's, I'd recommend you move up to the larger LT235/85R16's Load Range E's.
Hi all, got my new tires ST225/75r15d. they are rated for 65psi for weight of 2540 per tire x4. Now all I read is never fill to max. Mr Big-o tells me the tire is make for 65 psi max.(cold) so going down the heated highway my tires go to 72psi. I really don't know. now on my 2004 Lincoln Navigator they want P275/65R18 and the tire is 44psi max, so fill to 35. is suv tires not like the st tires? they make room for heat, but not the trailer. what is the thinking here?
thanks and happy camping.
Cars, pickup trucks and SUV's are done differently than trailers. Those vehicles (meaning not trailers) have a tire placard that can be trusted, so use the pressure listed there - assuming you are towing within the limitations published by the vehicle manufacturer.
Trailers on the other hand have demonstrated that the manufacturers aren't consistent and frequently under-tire the vehicle - which is why the standard answer is to inflate the tires to the max.
A better answer can be obtained by actually weighing the vehicle (in its worst possible configuration). What you are looking for is the worst possible tire load any tire will see, so that also means weighing it tire by tire (or compensating for the fact that you didn't).
If you put max PSI in the tire but load it very lightly won't the tire wear in the center improperly?
The problem here is that tire wear is complex and while tire pressure is important to get even wear, there are other factors that have a greater effect.
Put another way, it is quite possible to get uneven tire wear in spite of the tire being properly inflated - and it is quite possible to get even wear on a improperly inflated tire.
And one last thought: Tire load tables are MAXIMUMS, not recommendations.
A couple of thoughts:
First, I can't vouch for the availability of an ST205/75R14 out in the hinterlands. Someone else will have to chime in on that.
It should be pretty easy to tell if the ST205/75R14 will fit. It is just a tick over 2" larger in diameter - so you will need an inch more clearance. And since we are talking a pretty simple suspension, it should be easy to estimate how much movement the suspension would make when fully collapsed.
And lastly, an ST205/75R14 Load Range C is rated at 1760 pounds @ 50 psi.