The vast majority of gators are cold cap retreads.
I’ve personally read varying opinions from respected sources on the cause of truck tires’ treads separating from the casing. Most blame retreading, however I admit to never having seen an authoritative study with actual data. Unless I do, I’ll continue to believe that recapping is the cause. If such a study exists, I for one would like to see it.
A cold cap will almost always seperate from the carcass as a somewhat clean complete tread while the tread on a tire that has never been capped will usually seperate with a great deal of shoulder rubber and cord material. I haven’t watched the linked video of the recapping but I imagine that it would show the fully cured tread being attached to an old carcass and that tread is what becomes a gator. The weak link in a recap is the bonding of a cured tread to a cured carvass. The original tire was cured with the tread being formed in a mold and in the vast majority of failures, usually from under inflation and/or overloading they begin to disintegrate from the body plies (radial plies) outward.
If anyone is curious enough and feels they can safely pick up a few gators they will likely see the complete tread section with serialized IDs molded into the shoulder and a soft layer of bonding rubber that has failed to remain stuck to the old tire.
I think I’ll take your word on that one Rod… {
In response to do tires always have to be black
Figures.
I bet they all would meet DOT specs, too.
I’m going to modify what Rod Knox said (meaning I disagree with his conclusion, but he was on the right path).
There are several weak links in retreads - the most prominent one is the interface between the old casing and the new tread (regardless of the retread method).
Where I strongly disagree with him is that the majority of truck tire failures are in the casing itself and NOT the retread itself. Evidence? If you look at the stuff that litters the side of the interstate, you will not find smooth detachments of the retreads. What you will find is chunks of the casing. (If you can see wire, it isn’t the retread failing - the casing is failing!)
Yes, most of the failures are from retreads, but that is because most of the tires being used are retreads - ergo, most of the failures ought to be from retreads, but the cause of the failure is not the retread materials, nor the retread process.
Capri, with great respect (and I mean that sincerely), the road gators I see typically look like separations of the tread from the carcass. Unfortunately, there doesn’t seem to be any publically available analysis to determine causes road gators. I’ve searched unsuccessfully for one in the past. As a result, all of the available data is anecdotal.
My experience is that industries do these kinds of analysis (I’ve done a few myself in my industries) but if the results aren’t beneficial to them, the studies remain confidential. I would be surprised if studies by the recapping industry hasn’t been done and the results not been beneficial to the industry. But I’m guessing. I have no actual knowledge to support my suspicion.
I’d like to see an organization like NHTSA do a study. If the difference is as great as I suspect, 100 OEM tires and 100 recaps all tested under load to failure in a laboratory should show a big difference. My money says the recaps would create road gators and the OEMs would not.
Again, I have no real data, only my gut feel to go by. But it strikes me as odd that there’s no study available showing recaps to be no more likely to gator than OEMs.
On the subject of those gators, I saw an interesting sight a while back on Rt 95 N above Boston, that I don’t understand.
I was driving in the left lane and happened to glance to my right and saw a tire (no wheel) rolling down the road by itself, a few feet to the left of a car. The car was heading to the breakdown lane and the tire seemed to go in that direction also. The car had all 4 tires on it.
My only guess is that what I saw was the tread (plus belts?) only, it had separated from the tire and continued rolling… Could that happen and the tire still hold pressure?
Any comments or ideas?
b
Yeah, they can do that.
I’ve personally seen and had to avoid a truck tread unwrapping itself from a still-inflated carcass on the highway and rolling a bit before falling over. In that case I know is was a cap separation, but that’s only a sample of one, not significant to confirm my belief that the overwhelming majority of gators are from recaps.
Most of the gators I see are strips or partial tread. These seem to lay down on the road flat and while scary, do not do any real damage. The ones where the tread comes off as a complete circle are bad as the lay over and still stick up 10-12 inches or more. My parents hit one of these and did several thousand dollars worth of damage. They were in traffic and it was on them before they could do anything about it.
I hit one once in a rental car and it didn’t do any serious damage. I was in the right lane and there was a tread between the two lanes. Some car with out of state plates blew by me and hit the gator, sending it right in my direction. All I could do was slow down and hold on. There was a highway rest area like 5 miles down the road so I just took it easy until I got there. I inspected underneath for anything leaking and made sure the tires weren’t damaged. All was OK and I went about 2000 more miles on that rental without incident.
What colored tires are for:
LOL, he must be going through his “blue period”.
This road gator found some pork for dinner . . .
mountain bike,
Try googling “Commercial Tire Debris Study”. You’ll get this:
www.nhtsa.gov/.../COMVEC%202009%20Tire%20Debris%20Svenson%20(2).pdf
It’s a study conducted by NHTSA.
Summary:
Retreads were not overrepresented in the tire debris items collected.
Results indicate the majority of tire debris collected was not a result of manufacturing or retreading process deficiencies.
Is that good enough? If not, there are more studies, if you google for them.
And from personal experience: Just yesterday, I traveled over 100 miles, and cataloged the pieces along the Interstate (Full disclosure, I was traveling 65 mph) - and 90% had wires visible even at 65 mph. Those are casing failures, not failures of the retread itself. That seems to line up pretty well with the NHTSA study. I suggest you do the same to satisfy yourself that the NHTSA study reflects reality.
Capri, that’s exactly the kind of analysis I was looking for and I absolutely accept its conclusions.
When all the categories are aggregated, the study showed that the majority of tire debris collected was not a result of manufacturing or retreading process deficiencies, however it also confirms that the significant majority of tire failures of all types that resulted in debris are from recaps.
o Approximately 68% of tire fragments were from
retread tires and 18% were from original tread
tires. The remaining 14% could not be determined.
In conclusion, while my perception that cap separation is the cause of most road gators appears to be incorrect, my belief that recaps on tractor-trailer trucks have a much higher failure rate than OEM tires is supported. The failure rate of recaps is significant enough IMHO to see them banned.
Actually, the data supports the fact that there are much more failures on recaps. However, the failure RATE depends on the ratio of recaps to original tires, which @CapriRacer has indicated is quite high. If so, the failure rates may not be much different.
That is an excellent point. I just went looking for the relevant data unsuccessfully, but I accept that the percentage of recaps on semi rigs in very high, which might make the actual rate no greater than that of OEMs. I also know that airplanes have very high percentages of recaps vs. OEMs, and while those tires are not subject to the sort of long distance use that would generate great heat, they are upon touchdown subject to very high deflection and very high shear loads between the carcass and the cap.
This subject has been debated and studies from various angles by many organizations and for many years. I appreciate that Capri has link in a comprehensive study by a highly respected organization that has no ulterior motive. While I still have reservations, that level of integrity is what makes for a truly intelligent debate. I admittedly cannot justify my reservations based on the data.
I do think the failure rate is higher, just because the retread carcasses have seen more miles, and the QC before recapping isn’t perfect (far from, I’d bet in some cases).
“they are upon touchdown subject to very high deflection and very high shear loads between the carcass and the cap”
I wonder if there would be a cost gain if airplane wheels had small motors to spin them up just before touchdown instead of the shock and losing rubber to marks on the runway.