Michelin_Sidewall_Crack_Chart November 13, 2014, 03:31:54 pm Yahoo Message Number: 149501Hi All,I just uploaded a picture called "Michelin_Sidewall_Crack_Chart". I don't agree with the cracks that are acceptable in the picture. I guess I'm being overly cautious, but I was surprised to see what Michelin thought was acceptable.San Diego Bob
Re: Michelin_Sidewall_Crack_Chart Reply #1 – November 13, 2014, 05:12:41 pm Yahoo Message Number: 149502At least I think it's a Michelin tire chart. It was posted on iRV2 Forums in 2010 and referenced as a Michelin tire chart. I can't find it anywhere on the present Michelin website. This is probably understandable considering their recent recall for cracking and other problems.San Diego Bob
Re: Michelin_Sidewall_Crack_Chart Reply #2 – November 13, 2014, 06:17:26 pm Yahoo Message Number: 149503Bob, these are the photos that I think you're referring to:http://www.irv2.com/photopost/showphoto.php?photo=13769Going only from the photos, if any of my tires showed cracking to the extent of even the *first* set of "acceptable cracking" (an oxymoron for sure!) in those photos, I'd be at the tire shop in a heartbeat!Joan
Re: Michelin_Sidewall_Crack_Chart Reply #3 – November 13, 2014, 09:36:22 pm Yahoo Message Number: 149505I'm not so sure. Does any of us know why a little cracking is dangerous? What is the failure mode of a cracked sidewall? I suggest that the strength of the tire comes from the fibre, not the visible rubber surface of the tire. I wouldn't like to drive for long on the suspect tires, but maybe some cracking is acceptable.John
Re: Michelin_Sidewall_Crack_Chart Reply #4 – November 13, 2014, 10:32:33 pm Yahoo Message Number: 149507I don't know if that is a Michelin tire chart, but I can tell you Goodyear is quite lenient about cracks in the sidewalls of the tires they sell for airplanes, at least in the size I own; basically, if it doesn't go down to the fabric plies, and is shorter than 2" or so, it's safe. My understanding is the rubber does not provide any strength, but is protection for the plies. So, as long as the plies aren't visible, the plies are protected. And cracks can be in the tread, too, not just the sidewall, but the tread cracks they illustrated were isolated cracks. 20 years ago, I had a tire dealer in Canada tell me exactly the same thing about the Michelins on my Class B motorhome (same size the ones on the E450). I'm sure the numbers for my aircraft tire don't apply to our truck tires - it's st an illustration that cracking is not enough to make a tire unsafe.Eric Greenwell [lifewithalazydazerv] wrote, On 11/13/2014 4:17 PM:
Re: Michelin_Sidewall_Crack_Chart Reply #5 – November 14, 2014, 08:03:51 am Yahoo Message Number: 149511No, "cracking" is not necessarily enough by itself to make a tire unsafe; it's the number, type, extent, and depth of the "cracks" that can determine whether the tire is going to fail. Tires that develop shallow *cosmetic* surface cracks and/or alligatoring may be safe, but deeper cracks, even if the fabric or steel ply is not visible, compromise the overall integrity of the tire sidewall and make it more prone to blowout. According to this information from Goodyear, a tire should be replaced if a sidewall crack is 2/32" (1/16") or deeper. A crack of that depth in a tire sidewall, particularly an RV tire sidewall, is *way* beyond my acceptance level; YMMV.http://www.goodyearrvtires.com/tire-replacement-guidelines.aspxJoan
Re: Michelin_Sidewall_Crack_Chart Reply #6 – November 14, 2014, 10:19:38 am Yahoo Message Number: 149512Michelin's chart was developed from their experience with million of tires, used over billion of miles. In fleet usage, auto shop managers must have guidelines to follow when inspecting tires. The chart shows what Michelin has determined to be acceptable cracking, while still having safe, servable tires. Everyone has an opinion, sometimes based on facts, sometimes on emotions. Choosing an opinion based upon the manufacturer's recommendations has served me well for over 40 years. The manufacturer knows the product much better than any of us armchair engineers.Larry
Re: Michelin_Sidewall_Crack_Chart Reply #7 – November 14, 2014, 11:48:59 am Yahoo Message Number: 149517Choosing an opinion based upon the manufacturer's recommendations has served me well for over 40 years.--- Larry, I certainly don't disagree with this statement; it's the corollary to "RTFM!" However, I would sure like to *see* how closely Michelin's (photos of) "acceptable" levels of sidewall cracking compare to the *actual conditions* of recalled tires; IOW, what were the specific sidewall "cracking" issues that prompted the recalls and to what extent was "CYA"mode in play?Joan
Re: Michelin_Sidewall_Crack_Chart Reply #8 – November 14, 2014, 07:30:41 pm Yahoo Message Number: 149534Hi All,What prompted my original post of the Michelin cracking chart was I had my first (hopefully last) shredded tire failure (driver side rear) on the freeway going to Albuquerque (65 MPH). My tires were 4 years old and didn't show any cracking. After this event, I've gone into the "super conservative" camp on tires. As the way life goes, I doubt if conservative keeps me from having another event, because sometimes life sucks . The best I can possibly hope for is reducing the chances of another problem.My old tires were Continental, which were purchased by the prior owner 3 months before I bought the LD. The tires had about 14,000 miles on them since new. I wasn't keen on the original tires, but I thought Continental didn't make a crummy tire and they should be good enough to get me through the 5 year mark. Upon hindsight, I definitely need to revise that thought.After the tire failure, I switched all the tires to Michelins. It's a Larry endorsed tire so that makes it good enough for me. Events have shown that even Michelin can have failure problems as shown by their recent recall, but I expect the failure problems are behind them (if not I'll yell at Larry ).Very surprisingly the tire that failed never lost pressure. There were large hunks of loose rubber tread and lotsa steel cord showing. The failure was not in sidewall, but in the tread area. Ever wonder where all those loose tread pieces on the freeway come from . . . people like me. I have a tire monitor system and checking it before I got out of the cab showed all tires had pressure. Looking at the failed tire was a jaw dropping experience because it was really tore up badly. Maintaining pressure seemed highly unlikely considering its appearance. So occasionally a tire can fall apart and maintain pressure, as long you stop quick enough.Since this event, I bought larger traffic cones (18") and a high visibility vest. My previous cones were short and light weight. The old traffic cones could blow over if someone came close. I did pull off of the shoulder and was as far away from the traffic lane as possible. Naturally the tire failure was on the traffic side of the LD. An AZ highway patrol officer stopped and helped me. When he saw I had everything under control, he took off after someone that buzzed past us too fast. I was thinking about calling Coachnet, but thought I could change it before they arrived.I had the LD weighed today and the results were a little surprising. I'll post the weights later.San Diego Bob
Re: Michelin_Sidewall_Crack_Chart Reply #9 – November 15, 2014, 05:28:56 pm Yahoo Message Number: 149545Bob. " It's a Larry endorsed tire so that makes it good enough for me. Events have shown that even Michelin can have failure problems as shown by their recent recall, but I expect the failure problems are behind them (if not I'll yell at Larry)." I do not know which type of Michelin tires you purchased, but I would second Larry's endorsement of Michelins. I have owned 5 sets of their LTX-MS tires and an now on my second set of their LTX-MS/2 tires. I have found them to be very reliable although I know that others have had the opposite experience. My rule is to replace the tires after 40K miles, which for me is less than 4 years. The only time that I broke this rule, I had a problem and blew two of them. In both cases I developed a lateral break across the inner casing. A Michelin factory rep told me that "in motorhome service you will damage a casing long before you wear out the tread." He thought that a "replace @ 40K" was a good conservative practice. (We didn't discuss sidewall cracking as I have never had it happen.) I believe that the recall of interest was for "tread separation problems" and only applied to a specific set of LT-MX tires built in their Nova Scotia plant. Unfortunately many of the problem tires were delivered to Ford for use on E-Series vehicles. To my understanding it did not include any "second generation" LTX-MS/2 tires. Fortunately I had no tires in the recall."Since this event, I bought larger traffic cones (18") and a high visibility vest. My previous cones were short and light weight." Instead of traffic cones, why not carry a set of the "folding triangle reflector units" like most truck drivers use? The good ones are steel, about 14-inches high & wide when unfolded. They are heavy and not sensitive to wind. Typically a set of three comes in a plastic storage box about 15-inches long with a cross section of about 6-inches by 6-inches. I have set of three in a box and the box weighs about 17 pounds. I suspect that the triangles take less storage space than cones. I have never used the triangles, but carry them "just in case." I also carry a few "road flares" (or railroad fusies). Have never used them either, but have given away some at accidents. "I had the LD weighed today and the results were a little surprising. I'll post the weights later." Please do this and include the details on the "state of the coach." (LD model, amount of on-board fluids, cargo, passengers, etc.). I am very interested in this subject. I now own an SOB but previously had a 2005 MB. I am not satisfied with the SOB and am looking at acquiring a used LD. Unfortunately I never weighed my LD when I had it but am interested in how it might compare to my SOB.Doug Baker
Re: Michelin_Sidewall_Crack_Chart Reply #10 – November 16, 2014, 02:08:39 pm Yahoo Message Number: 149558The Michelins I bought were the type Larry recommended, the LTX M/S 2. I listen closely to what Larry says as he has most likely been there, done that and that's one of many reasons why I started going to his Morro Bay GTG last year (going again this year too).I do have an exact set of the large fold up triangles that you described. I prefer cones and now the vest in the daytime and in addition triangles plus flares at night. I wouldn't have attempted to fix the flat at night, I would have called Coach Net and made it their problem. I debated about making it their problem on the recent incident, but figured I would be underway before they arrived.When the cars are going past you at 75-85 mph, when the speed limit is 75 mph, you need all the visibility help you can get when stopped on the shoulder and working on the side of the RV nearest the traffic. I was never comfortable doing that even though I was off the paved shoulder. It was nice to see the highway patrol stop and turn on his lights too. He was there for several minutes while I worked. But somebody didn't pay much attention to his lights and got a ticket for not moving over one lane and going too fast. And that's a good example of visibility and a few yahoos (not the search engine) that just don't slow down or move over and jeopardize the worker on the side of the road. I'm sure we've all seen the videos of what can happen while stopped on the side of the road.I just posted a picture of my old and new cones (stack of 4 new cones and one old cone in the photo section of our forum). It should be the first picture in photo stream or album. My new stackable cones cost $7.10 each, 13" tall and weigh 2.5 lbs. They are heavier and taller than the old cones. I got my new cones from the following link, but you can find other stores with Google. The Traffic Safety Store had different size cones to pick from and I selected the size that I thought was a compromise for storing in my tire compartment and visibility. I also bought my vest from them. My tire compartment is filled with a lot of crap, tool box, tire chucks, boards, etc, etc. Mostly stored stuff that I will never need or use, but it's there when necessary.12 inch Traffic Cones | Traffic Safety StoreI will post the results of my 2000 MB weigh soon. Hopefully tomorrow.San Diego Bob
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