Broken Cord on Michelin Tire
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09-08-2008, 06:31
Post: #11
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Broken Cord on Michelin Tire
The heavy duty tires on your Blue Bird are likely to "time out"
before the tread wears out. Actually, the usual advice is to replace the tires at 5 to 7 years -- 10 years of sun, rain, etc. is VERY hard on the tires. Always inspect tires for cracking and checking -- a sure sign that ozone and sun have damaged the tires. As for tire covers -- well, there's always a lot of debate about how helpful they are. Personally, I haven't bothered with them -- but my coach, when not in use, is stored in a relatively benign location as far as sun exposure is concerned. Pete Masterson '95 Blue Bird Wanderlodge WBDA 42 aeonix1@... On the road at Idaho Springs, CO On Sep 8, 2008, at 10:57 AM, bubblerboy64 wrote: > Question. I know that it is recommended to not run tires older then 8 > to 10 years maximum. Approximately how many miles are these tires > good for? I haven't heard that mentioned. If a guy runs about 10K > per year can he expect to run out of tread long before the years add > up? I don't typically get more then 35k on car tires I have no idea > what to expect on the MH. I of course understand there are all kinds > of variables to consider but as compared to a car what do you figure > for tread life on the tires you run on your BB'ds? > John Heckman > central Pa > 1973 FC > > > > > >> >> you guys should find a trucker or trucking company to buy your > tires >> prior to 3 or 4 years of age. rotating out a set every year or so >> will put new one on the front of your bus and run the tread off > the >> used tires. its a green thing to do because the tread will be used > up >> and the casing will be good for a retread. Tire Jobbers, can set > you >> up with good credit for rotating out your used tires. I screw cords >> up jumping curbs and potholes, kinda doubt it is a Mfg prorate > thing. >> >> GregO'Connor >> 94ptRomolandCa >> >> --- In WanderlodgeForum@yahoogroups.com, "Ross" >> wrote: >>> >>> Hi, >>> Just a note about reporting the "failure". The request by the > NHTSA >>> (national highway traffic safety assoc.) is for all failures, not >> just >>> blow-outs. In the requested information, there is a line >>> "Nature of the reported failure (slow leak,blow-out, worn etc)" >> This >>> can be important for the safety of all BlueBirds and all RV's >>> (especially those using 315 tires) >>> Ross >>> 2006 450 LXi >>> Here is the information: >>> >> > http://nhthqnwws112.odi.nhtsa.dot.gov/ac...s/Public/P >> ursuits/2008/RQ/INIM-RQ08004-29624.pdf >>> >>> --- In WanderlodgeForum@yahoogroups.com, "Randy Merrill" >>> >>>> >>>> Hi Everyone, >>>> >>>> The left front tire on my coach has a broken cord. The tread is >> uneven. >>>> I am getting the tire replaced next week before I head out on a >> 1,500 >>>> mile trip. The tire only has 27,000 miles on it. Does anyone > know >> if >>>> Michelin has a warranty on tires? Has anyone else had a problem >> with >>>> cord breakage on Michelins? >>>> >>>> Thanks, >>>> >>>> Randy Merrill >>>> 2003 40' >>>> Ocala, FL >>>> >>> >> > > > > ------------------------------------ > > Yahoo! Groups Links > > > |
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09-08-2008, 06:34
Post: #12
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Broken Cord on Michelin Tire
I can't say for sure about max inflation. I know that when tires
'bottom out' and hit a very hard edge (like the edge of a large pot hole or a transition between gravel and pavement) that damage is likely to occur. Going over curbs, too, can damage tires, especially if the side wall is highly distorted during the incident. I'd have to ask a tire engineer about the relative merits of inflation -- on one hand, it would seem like fully inflated tires are less likely to crush to the wheel rim, possibly protecting the tire from pinching damage, but the high pressure would also place the tire under tension pressure ... so??? Any tire engineers out there? Pete Masterson '95 Blue Bird Wanderlodge WBDA 42 aeonix1@... On the road at Idaho Springs, CO On Sep 8, 2008, at 11:26 AM, David Brady wrote: > Are highly inflated tires more prone to these failures? The recall > for the 450LXi specifies running tires at 130 psi. If the tire is at > max inflation then it is less able to deflect to road discontinuities. > Seems like you'll likely have more "broken belt" issues at max > inflation??? > > David Brady > '02 LXi, NV > > Pete Masterson wrote: >> >> I agree that the 'broken belt' thing is likely a result of a road >> hazard. While I haven't had any problems with my Toyo tires on my >> coach, over the years, I've had a several tires on my automobile(s) >> ruined by construction -- Indeed, a few years ago, when BART was >> being built in the SF Bay Area, I lost several tires due to hitting >> pavement from a gravel stretch where a subway was being built using >> the cut-and-cover method. While I certainly tried to drive carefully >> through the extensive construction zones, at night there were times >> you just didn't see a transition until you hit it with that sickening >> thud. Often the tires don't actually display any problems until days >> (or weeks) after the damaging event. The damage occurs, then the >> flexing of the tire causes the damage to spread until the tire-cord >> is compromised. >> >> Michelin makes generally good, tough tires. It's always possible that >> a manufacturing defect was involved, but it's unlikely. More likely >> there was a road hazard event that let to the failure. In that case, >> most tire companies don't cover the damage (but some companies may >> cover road hazard damage), so you'll need to enquire with a Michelin >> dealer. >> >> Pete Masterson >> '95 Blue Bird Wanderlodge WBDA 42 >> aeonix1@mac. com >> On the road at Idaho Springs, CO >> >> On Sep 8, 2008, at 10:21 AM, Gregory OConnor wrote: >> >>> you guys should find a trucker or trucking company to buy your tires >>> prior to 3 or 4 years of age. rotating out a set every year or so >>> will put new one on the front of your bus and run the tread off the >>> used tires. its a green thing to do because the tread will be >>> used up >>> and the casing will be good for a retread. Tire Jobbers, can set you >>> up with good credit for rotating out your used tires. I screw cords >>> up jumping curbs and potholes, kinda doubt it is a Mfg prorate >>> thing. >>> >>> GregO'Connor >>> 94ptRomolandCa >>> >>> --- In WanderlodgeForum@ yahoogroups. com >> >> >>> wrote: >>>> >>>> Hi, >>>> Just a note about reporting the "failure". The request by the NHTSA >>>> (national highway traffic safety assoc.) is for all failures, not >>> just >>>> blow-outs. In the requested information, there is a line >>>> "Nature of the reported failure (slow leak,blow-out, worn etc)" >>> This >>>> can be important for the safety of all BlueBirds and all RV's >>>> (especially those using 315 tires) >>>> Ross >>>> 2006 450 LXi >>>> Here is the information: >>>> >>> http://nhthqnwws112 .odi.nhtsa. dot.gov/acms/ docservlet/ >> Artemis/Public/ P >> <http://nhthqnwws112.odi.nhtsa.dot.gov/ac...t/Artemis/ >> Public/P> >>> ursuits/2008/ RQ/INIM-RQ08004- 29624.pdf >>>> >>>> --- In WanderlodgeForum@ yahoogroups. com >> >>>> >>>>> >>>>> Hi Everyone, >>>>> >>>>> The left front tire on my coach has a broken cord. The tread is >>> uneven. >>>>> I am getting the tire replaced next week before I head out on a >>> 1,500 >>>>> mile trip. The tire only has 27,000 miles on it. Does anyone know >>> if >>>>> Michelin has a warranty on tires? Has anyone else had a problem >>> with >>>>> cord breakage on Michelins? >>>>> >>>>> Thanks, >>>>> >>>>> Randy Merrill >>>>> 2003 40' >>>>> Ocala, FL >>>>> >>>> >>> >>> >> >> >> --------------------------------------------------------------------- >> --- >> >> No virus found in this incoming message. >> Checked by AVG. >> Version: 7.5.524 / Virus Database: 270.6.17/1655 - Release Date: >> 9/5/2008 7:05 PM >> > > > > -- > No virus found in this outgoing message. > Checked by AVG. > Version: 7.5.524 / Virus Database: 270.6.17/1655 - Release Date: > 9/5/2008 7:05 PM > > > ------------------------------------ > > Yahoo! Groups Links > > > |
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09-08-2008, 16:09
Post: #13
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Broken Cord on Michelin Tire
I think cords get screwed on rv tires because drivers make
stationary turns with the steers and park with that stress between the plys for months. Owner operator pro drivers pull forward then back after final turn to set the drive axle tires inline and steer tires relaxed prior to parking. John, I just finished 12 months and aprox 20,000 miles with used (off my bus) 7 year old 12R's on my dump truck. I go off road and overload them often. they have 6 months to go. I think you gotta do the math and calc out a new set every 8 years. the advantage of rotating out a set is two fold. 1- you get about $200. to $300. for a set(2 tires) of 3,4 year old used tires @ 80% thread. 2- you will always run less than 2 year young tires on the steer. To replace all 6 every 8 years, 6 tires @$425 per =$2550. / 8years = $315 per the year. to replace a pair every 30 months 2 tires @425.per = $850 -credit for used 200.=650 / 2.5 years =$260 per year. GregoryO'Connor 94ptRomolandCa --- In WanderlodgeForum@yahoogroups.com, "bubblerboy64" wrote: > > Question. I know that it is recommended to not run tires older then 8 > to 10 years maximum. Approximately how many miles are these tires > good for? I haven't heard that mentioned. If a guy runs about 10K > per year can he expect to run out of tread long before the years add > up? I don't typically get more then 35k on car tires I have no idea > what to expect on the MH. I of course understand there are all kinds > of variables to consider but as compared to a car what do you figure > for tread life on the tires you run on your BB'ds? > John Heckman > central Pa > 1973 FC > > > > > > > > > you guys should find a trucker or trucking company to buy your > tires > > prior to 3 or 4 years of age. rotating out a set every year or so > > will put new one on the front of your bus and run the tread off > the > > used tires. its a green thing to do because the tread will be used > up > > and the casing will be good for a retread. Tire Jobbers, can set > you > > up with good credit for rotating out your used tires. I screw cords > > up jumping curbs and potholes, kinda doubt it is a Mfg prorate > thing. > > > > GregO'Connor > > 94ptRomolandCa > > > > --- In WanderlodgeForum@yahoogroups.com, "Ross" > > wrote: > > > > > > Hi, > > > Just a note about reporting the "failure". The request by the > NHTSA > > > (national highway traffic safety assoc.) is for all failures, not > > just > > > blow-outs. In the requested information, there is a line > > > "Nature of the reported failure (slow leak,blow-out, worn etc)" > > This > > > can be important for the safety of all BlueBirds and all RV's > > > (especially those using 315 tires) > > > Ross > > > 2006 450 LXi > > > Here is the information: > > > > > > http://nhthqnwws112.odi.nhtsa.dot.gov/ac...is/Public/ P > > ursuits/2008/RQ/INIM-RQ08004-29624.pdf > > > > > > --- In WanderlodgeForum@yahoogroups.com, "Randy Merrill" > > > > > > > > > > > Hi Everyone, > > > > > > > > The left front tire on my coach has a broken cord. The tread is > > uneven. > > > > I am getting the tire replaced next week before I head out on a > > 1,500 > > > > mile trip. The tire only has 27,000 miles on it. Does anyone > know > > if > > > > Michelin has a warranty on tires? Has anyone else had a problem > > with > > > > cord breakage on Michelins? > > > > > > > > Thanks, > > > > > > > > Randy Merrill > > > > 2003 40' > > > > Ocala, FL > > > > > > > > > > |
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09-08-2008, 16:36
Post: #14
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Broken Cord on Michelin Tire
Makes sense, but dumping air and lowering landing gear such that
the coach weight is removed from the axles goes a long way to relieving stresses in bound up tires. David Brady '02 LXi, NV Gregory OConnor wrote: > > I think cords get screwed on rv tires because drivers make > stationary turns with the steers and park with that stress between > the plys for months. Owner operator pro drivers pull forward then > back after final turn to set the drive axle tires inline and steer > tires relaxed prior to parking. > > John, I just finished 12 months and aprox 20,000 miles with used > (off my bus) 7 year old 12R's on my dump truck. I go off road and > overload them often. they have 6 months to go. I think you gotta do > the math and calc out a new set every 8 years. the advantage of > rotating out a set is two fold. 1- you get about $200. to $300. for > a set(2 tires) of 3,4 year old used tires @ 80% thread. 2- you will > always run less than 2 year young tires on the steer. > > To replace all 6 every 8 years, > 6 tires @$425 per =$2550. / 8years = $315 per the year. > > to replace a pair every 30 months > 2 tires @425.per = $850 -credit for used 200.=650 / 2.5 years =$260 > per year. > > GregoryO'Connor > 94ptRomolandCa > > --- In WanderlodgeForum@yahoogroups.com > > wrote: > > > > Question. I know that it is recommended to not run tires older > then 8 > > to 10 years maximum. Approximately how many miles are these tires > > good for? I haven't heard that mentioned. If a guy runs about > 10K > > per year can he expect to run out of tread long before the years > add > > up? I don't typically get more then 35k on car tires I have no > idea > > what to expect on the MH. I of course understand there are all > kinds > > of variables to consider but as compared to a car what do you > figure > > for tread life on the tires you run on your BB'ds? > > John Heckman > > central Pa > > 1973 FC > > > > > > > > > > > > > > > > you guys should find a trucker or trucking company to buy your > > tires > > > prior to 3 or 4 years of age. rotating out a set every year or > so > > > will put new one on the front of your bus and run the tread off > > the > > > used tires. its a green thing to do because the tread will be > used > > up > > > and the casing will be good for a retread. Tire Jobbers, can > set > > you > > > up with good credit for rotating out your used tires. I screw > cords > > > up jumping curbs and potholes, kinda doubt it is a Mfg prorate > > thing. > > > > > > GregO'Connor > > > 94ptRomolandCa > > > > > > --- In WanderlodgeForum@yahoogroups.com > > > > wrote: > > > > > > > > Hi, > > > > Just a note about reporting the "failure". The request by the > > NHTSA > > > > (national highway traffic safety assoc.) is for all failures, > not > > > just > > > > blow-outs. In the requested information, there is a line > > > > "Nature of the reported failure (slow leak,blow-out, worn > etc)" > > > This > > > > can be important for the safety of all BlueBirds and all RV's > > > > (especially those using 315 tires) > > > > Ross > > > > 2006 450 LXi > > > > Here is the information: > > > > > > > > > > http://nhthqnwws112.odi.nhtsa.dot.gov/ac...is/Public/ > <http://nhthqnwws112.odi.nhtsa.dot.gov/ac...is/Public/> > P > > > ursuits/2008/RQ/INIM-RQ08004-29624.pdf > > > > > > > > --- In WanderlodgeForum@yahoogroups.com > > > > > > > > > > > > > > > Hi Everyone, > > > > > > > > > > The left front tire on my coach has a broken cord. The tread > is > > > uneven. > > > > > I am getting the tire replaced next week before I head out > on a > > > 1,500 > > > > > mile trip. The tire only has 27,000 miles on it. Does anyone > > know > > > if > > > > > Michelin has a warranty on tires? Has anyone else had a > problem > > > with > > > > > cord breakage on Michelins? > > > > > > > > > > Thanks, > > > > > > > > > > Randy Merrill > > > > > 2003 40' > > > > > Ocala, FL > > > > > > > > > > > > > > > > > ------------------------------------------------------------------------ > > No virus found in this incoming message. > Checked by AVG. > Version: 7.5.524 / Virus Database: 270.6.17/1655 - Release Date: 9/5/2008 7:05 PM > -- No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 270.6.17/1655 - Release Date: 9/5/2008 7:05 PM |
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09-09-2008, 04:37
Post: #15
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Broken Cord on Michelin Tire
Hi Pete, David, Greg, Randy and all else who have been The original question was re: a broken belt (actually shifted) on a This is one of the major differences between truck tires and those used The above realities of life is the reason why the tire manufacturers, Always happy to be of assistance: Neil LeKander Author, The Rver’s Ultimate Survial less likely to crush to the wheel rim, possibly protecting the tire from pinching damage, but the high pressure would also place the tire under tension pressure ... so??? Any tire engineers out there? Pete Masterson |
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09-09-2008, 04:54
Post: #16
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Broken Cord on Michelin Tire
NEIL:
Aint it safest just to fill air to whatever MAX it says on the tire????? Anyway...that's what I've done on my BIRD and my car for umpteen years....... Regards, Hank 90SP36 PS I have 12R22.5 Bridgestones on the BIRD and Goodyears on the Honda toad. --- In WanderlodgeForum@yahoogroups.com, "Neil & Pat" wrote: > > Hi Pete, David, Greg, Randy and all else who have been following this > thread. You called for a tire engineer to make input into this subject; > well I have been doing that for 36 years now and also happen to own and > operate a Wanderlodge (PT-36 ) for the past 12 years and have written > extensively on the subject of RV safety in my book on the subject as well as > respond to many of the tire questions posed on this and other forums. > Perhaps I can help. > > The original question was re: a broken belt (actually shifted) on a Michelin > tire with the thought was this a problem on the Michelin tires and would it > be subject to warranty. At 27k miles the tire problem in question is > almost certainly the result of a "road hazard" either a rock, shoulder drop > off, hitting a curb or possibly even improper usage of "chocks" for leveling > or other purposes. Had it been a manufacturing problem it would have shown > up much before that time. You did receive proper advice in that this is not > a warrantable condition by the manufacturer but often dealers do provide > "road hazard" protection as a service to their customers. > > This is one of the major differences between truck tires and those used on > automobiles; in order to carry heavy loads much higher pressures are used > and the tire is normally operated at a lower deflection rating. On trucks > the deflection of the sidewall when normally inflated is on average 8% by > design when it is properly inflated for the load carried, in contrast on an > automobile tire the deflection is approximately 12%, thus, yielding a > smoother ride and a tire less susceptible to impact loads as mentioned > above. For your interest aviation tires actually operate at 32% deflection > to carry the immense loads involved but do so with a duty cycle limited to a > few seconds. The "hoop strength" of the belt package" is under immense > tension from the inflation of the tire becoming more and more rigid and > unyielding as pressure goes up making the tire much more critical to this > type of abuse. So for our RVs we have a quandary, RVs are the only vehicles > on the road, which operate at 100% of the capability 100% of the time making > their safe operation somewhat precarious. We must carry the correct (high) > amount of air pressure to carry the load (at the correct deflection rate) > but should not exceed that pressure or operate below the required amount. > Higher pressure than required will yield decreased steering power, braking > power, higher impact type damage as well as decrease life; too low a > pressure will result in over deflection, hotter running temperatures > (possibly destructive), poor handling, greatly reduced life and the > potential for catastrophic premature failure. Take your pick, but none of > these options are very appealing to me. > > The above realities of life is the reason why the tire manufacturers, the > RVSEF and myself all repeatedly attend and lecture at rallies and anywhere > RVers gather to spread the word that RVs are different and incur > considerably more operator responsibilities from the owner/operators. It is > absolutely essential that you have your RV weighed properly wheel by wheel > to assure that none are overloaded and then and only then determine the > correct pressure for your specific RV under the conditions you operate it. > Plain and simple there is no other way. > > Always happy to be of assistance: > > Neil LeKander > Author, The Rver's Ultimate Survial Guide > http://www.rvsafetyinfo.com > > less likely to crush to the wheel rim, possibly protecting the tire > from pinching damage, but the high pressure would also place the tire > under tension pressure ... so??? > > Any tire engineers out there? > > Pete Masterson > |
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09-09-2008, 05:39
Post: #17
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Broken Cord on Michelin Tire
Thanks Neil, that helps a great deal. Glad to see you here
on this list. Just a couple of questions: 1) can I measure "deflection"? 2) does "deflection" change as the tire rotates at speed? 3) sounds like the sole purpose of tire pressure is to maintain the correct deflection? 4) if I were able to dynamically adjust runtime tire pressures, would optimum tire life/performance be achieved by maintaining the correct deflection under all ambient operating conditions? Thanks, David Brady '02 LXi, LV Neil & Pat wrote: > > * Hi Pete, David, Greg, Randy and all else who have been following > this thread. * You called for a tire engineer to make input into this > subject; well I have been doing that for 36 years now and also happen > to own and operate a Wanderlodge (PT-36 ) for the past 12 years and > have written extensively on the subject of RV safety in my book on the > subject as well as respond to many of the tire questions posed on this > and other forums. Perhaps I can help. > > The original question was re: a broken belt (actually shifted) on a > Michelin tire with the thought was this a problem on the Michelin > tires and would it be subject to warranty. At 27k miles the tire > problem in question is almost certainly the result of a âroad hazardâ > either a rock, shoulder drop off, hitting a curb or possibly even > improper usage of âchocksâ for leveling or other purposes. Had it been > a manufacturing problem it would have shown up much before that time. > You did receive proper advice in that this is not a warrantable > condition by the manufacturer but often dealers do provide âroad > hazardâ protection as a service to their customers. > > This is one of the major differences between truck tires and those > used on automobiles; in order to carry heavy loads much higher > pressures are used and the tire is normally operated at a lower > deflection rating. On trucks the deflection of the sidewall when > normally inflated is on average 8% by design when it is properly > inflated for the load carried, in contrast on an automobile tire the > deflection is approximately 12%, thus, yielding a smoother ride and a > tire less susceptible to impact loads as mentioned above. For your > interest aviation tires actually operate at 32% deflection to carry > the immense loads involved but do so with a duty cycle limited to a > few seconds. The âhoop strengthâ of the belt packageâ is under immense > tension from the inflation of the tire becoming more and more rigid > and unyielding as pressure goes up making the tire much more critical > to this type of abuse. So for our RVs we have a quandary, RVs are the > only vehicles on the road, which operate at 100% of the capability > 100% of the time making their safe operation somewhat precarious. We > must carry the correct (high) amount of air pressure to carry the load > (at the correct deflection rate) but should not exceed that pressure > or operate below the required amount. Higher pressure than required > will yield decreased steering power, braking power, higher impact type > damage as well as decrease life; too low a pressure will result in > over deflection, hotter running temperatures (possibly destructive) , > poor handling, greatly reduced life and the potential for catastrophic > premature failure. Take your pick, but none of these options are very > appealing to me. > > The above realities of life is the reason why the tire manufacturers, > the RVSEF and myself all repeatedly attend and lecture at rallies and > anywhere RVers gather to spread the word that RVs are different and > incur considerably more operator responsibilities from the > owner/operators. It is absolutely essential that you have your RV > weighed properly wheel by wheel to assure that none are overloaded and > then and only then determine the correct pressure for your specific RV > under the conditions you operate it. Plain and simple there is no > other way. > > Always happy to be of assistance: > > */ Neil LeKander /* > > */ Author, The Rverâs Ultimate Survial Guide /* > > */ http://www.rvsafetyinfo. com /* > > less likely to crush to the wheel rim, possibly protecting the tire > from pinching damage, but the high pressure would also place the tire > under tension pressure ... so??? > > Any tire engineers out there? > > Pete Masterson > > > ------------------------------------------------------------------------ > > No virus found in this incoming message. > Checked by AVG. > Version: 7.5.524 / Virus Database: 270.6.17/1655 - Release Date: 9/5/2008 7:05 PM > -- No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 270.6.17/1655 - Release Date: 9/5/2008 7:05 PM |
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09-09-2008, 13:48
Post: #18
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Broken Cord on Michelin Tire
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09-09-2008, 13:48
Post: #19
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Broken Cord on Michelin Tire
Hank, there is no question that under inflation is Regards, Neil Author, The Rver’s Ultimate Survival -----Original Message----- NEIL: Aint it safest just to fill air to whatever MAX it says on the tire????? Anyway...that' umpteen years....... Regards, Hank 90SP36 PS I have 12R22.5 Bridgestones on the BIRD and Goodyears on the Honda toad. --- In "WanderlodgeForum%40yahoogroups.com", "Neil & Pat" wrote: > > Hi Pete, David, Greg, Randy and all else who have been following this > thread. You called for a tire engineer to make input into this subject; > well I have been doing that for 36 years now and also happen to own and > operate a Wanderlodge (PT-36 ) for the past 12 years and have written > extensively on the subject of RV safety in my book on the subject as well as > respond to many of the tire questions posed on this and other forums. > Perhaps I can help. > > The original question was re: a broken belt (actually shifted) on a Michelin > tire with the thought was this a problem on the Michelin tires and would it > be subject to warranty. At 27k miles the tire problem in question is > almost certainly the result of a "road hazard" either a rock, shoulder drop > off, hitting a curb or possibly even improper usage of "chocks" for leveling > or other purposes. Had it been a manufacturing problem it would have shown > up much before that time. You did receive proper advice in that this is not > a warrantable condition by the manufacturer but often dealers do provide > "road hazard" protection as a service to their customers. > > This is one of the major differences between truck tires and those used on > automobiles; in order to carry heavy loads much higher pressures are used > and the tire is normally operated at a lower deflection rating. On trucks > the deflection of the sidewall when normally inflated is on average 8% by > design when it is properly inflated for the load carried, in contrast on an > automobile tire the deflection is approximately 12%, thus, yielding a > smoother ride and a tire less susceptible to impact loads as mentioned > above. For your interest aviation tires actually operate at 32% deflection > to carry the immense loads involved but do so with a duty cycle limited to a > few seconds. The "hoop strength" of the belt package" is under immense > tension from the inflation of the tire becoming more and more rigid and > unyielding as pressure goes up making the tire much more critical to this > type of abuse. So for our RVs we have a quandary, RVs are the only vehicles > on the road, which operate at 100% of the capability 100% of the time making > their safe operation somewhat precarious. We must carry the correct (high) > amount of air pressure to carry the load (at the correct deflection rate) > but should not exceed that pressure or operate below the required amount. > Higher pressure than required will yield decreased steering power, braking > power, higher impact type damage as well as decrease life; too low a > pressure will result in over deflection, hotter running temperatures > (possibly destructive) > potential for catastrophic premature failure. Take your pick, but none of > these options are very appealing to me. > > The above realities of life is the reason why the tire manufacturers, the > RVSEF and myself all repeatedly attend and lecture at rallies and anywhere > RVers gather to spread the word that RVs are different and incur > considerably more operator responsibilities from the owner/operators. It is > absolutely essential that you have your RV weighed properly wheel by wheel > to assure that none are overloaded and then and only then determine the > correct pressure for your specific RV under the conditions you operate it. > Plain and simple there is no other way. > > Always happy to be of assistance: > > Neil LeKander > Author, The Rver's Ultimate Survial Guide > http://www.rvsafetyinfo. > > less likely to crush to the wheel rim, possibly protecting the tire > from pinching damage, but the high pressure would also place the tire > under tension pressure ... so??? > > Any tire engineers out there? > > Pete Masterson >
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09-10-2008, 05:42
Post: #20
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Broken Cord on Michelin Tire
Thanks Hisham,
That's great information. We're still working our way back home; currently in Las Vegas. Gonna be 95deg F today, better get the sweaters. Glad you had a great trip and hope to meet up one of these days. Best, David, Suzana, and Danny '02 LXi, NV Hisham Amaral wrote: > David > > I found this link to be very good at answering some of the question I > had about truck tires. I would like to share it with the group. Please > discard if it is an information overload. > Hope that your trip to the West Coast was good and enjoyable, our was > the best ever. We will meet at one of the riles some day soon. > > http://www.goodyear .com/truck/ pdf/radialretser v/Retread_ All_V.pdf > <http://www.goodyear.com/truck/pdf/radial..._All_V.pdf> > > Hisham & Sue Amaral > 97 WLWB 43 > W. Bloomfield, MI > > --- On *Tue, 9/9/08, David Brady / > > From: David Brady > Subject: Re: [WanderlodgeForum] Re: Broken Cord on Michelin Tire > To: WanderlodgeForum@ yahoogroups. com > Date: Tuesday, September 9, 2008, 1:39 PM > > Thanks Neil, that helps a great deal. Glad to see you here > on this list. Just a couple of questions: > > 1) can I measure "deflection" ? > 2) does "deflection" change as the tire rotates at speed? > 3) sounds like the sole purpose of tire pressure is to maintain > the correct deflection? > 4) if I were able to dynamically adjust runtime tire pressures, > would optimum tire life/performance be achieved by maintaining > the correct deflection under all ambient operating conditions? > > Thanks, > David Brady > '02 LXi, LV > > Neil & Pat wrote: > > > > * Hi Pete, David, Greg, Randy and all else who have been following > > this thread. * You called for a tire engineer to make input into this > > subject; well I have been doing that for 36 years now and also happen > > to own and operate a Wanderlodge (PT-36 ) for the past 12 years and > > have written extensively on the subject of RV safety in my book on the > > subject as well as respond to many of the tire questions posed on this > > and other forums. Perhaps I can help. > > > > The original question was re: a broken belt (actually shifted) on a > > Michelin tire with the thought was this a problem on the Michelin > > tires and would it be subject to warranty. At 27k miles the tire > > problem in question is almost certainly the result of a âroad hazardâ > > either a rock, shoulder drop off, hitting a curb or possibly even > > improper usage of âchocksâ for leveling or other purposes. Had it been > > > a manufacturing problem it would have shown up much before that time. > > You did receive proper advice in that this is not a warrantable > > condition by the manufacturer but often dealers do provide âroad > > hazardâ protection as a service to their customers. > > > > This is one of the major differences between truck tires and those > > used on automobiles; in order to carry heavy loads much higher > > pressures are used and the tire is normally operated at a lower > > deflection rating. On trucks the deflection of the sidewall when > > normally inflated is on average 8% by design when it is properly > > inflated for the load carried, in contrast on an automobile tire the > > deflection is approximately 12%, thus, yielding a smoother ride and a > > tire less susceptible to impact loads as mentioned above. For your > > interest aviation tires actually operate at 32% deflection to carry > > the immense loads involved but do so with a duty cycle limited to a > > few seconds. The âhoop strengthâ of the belt packageâ is under > immense > > tension from the inflation of the tire becoming more and more rigid > > and unyielding as pressure goes up making the tire much more critical > > to this type of abuse. So for our RVs we have a quandary, RVs are the > > only vehicles on the road, which operate at 100% of the capability > > 100% of the time making their safe operation somewhat precarious. We > > must carry the correct (high) amount of air pressure to carry the load > > (at the correct deflection rate) but should not exceed that pressure > > or operate below the required amount. Higher pressure than required > > will yield decreased steering power, braking power, higher impact type > > damage as well as decrease life; too low a pressure will result in > > over deflection, hotter running temperatures (possibly destructive) , > > poor handling, greatly reduced life and the potential for catastrophic > > premature failure. Take your pick, but none of these options are very > > appealing to me. > > > > The above realities of life is the reason why the tire manufacturers, > > the RVSEF and myself all repeatedly attend and lecture at rallies and > > anywhere RVers gather to spread the word that RVs are different and > > incur considerably more operator responsibilities from the > > owner/operators. It is absolutely essential that you have your RV > > weighed properly wheel by wheel to assure that none are overloaded and > > then and only then determine the correct pressure for your specific RV > > under the conditions you operate it. Plain and simple there is no > > other way. > > > > Always happy to be of assistance: > > > > */ Neil LeKander /* > > > > */ Author, The Rverâs Ultimate Survial Guide /* > > > > */ http://www.rvsafetyinfo. com /* > > > > less likely to crush to the wheel rim, possibly protecting the tire > > from pinching damage, but the high pressure would also place the tire > > under tension pressure ... so??? > > > > Any tire engineers out there? > > > > Pete Masterson > > > > > > ------------ --------- --------- --------- --------- --------- --------- ------ > > > > No virus found in this incoming message. > > Checked by AVG. > > Version: 7.5.524 / Virus Database: 270.6.17/1655 - Release Date: 9/5/2008 > 7:05 PM > > > > > > -- > No virus found in this outgoing message. > Checked by AVG. > Version: 7.5.524 / Virus Database: 270.6.17/1655 - Release Date: 9/5/2008 7:05 > PM > > > ------------ --------- --------- ------ > > Yahoo! Groups Links > > > > > > > ------------------------------------------------------------------------ > > No virus found in this incoming message. > Checked by AVG. > Version: 7.5.524 / Virus Database: 270.6.17/1655 - Release Date: 9/5/2008 7:05 PM > -- No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 270.6.19/1664 - Release Date: 9/10/2008 6:00 AM |
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