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10-18-2017, 04:16 PM
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#1
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Who Dares, Wins
Join Date: May 2012
Location: Chester County, PA
Posts: 7,063
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A thought I had on exploding tires
So I am sitting through a class to become an accident re-constructionists... I have not seen so many numbers and math formulas since high school trig! (THAT I FAILED BTW!! )
But any ways to me point! We are talking about skidding tires and yaw marks (roadway marks from and leading up to vehicles loosing control and crashing). The idea (more of a fact) comes up of the tires in an over steer or yaw situation (back end trying to pass the front in a spin out) of the front outer tire basically getting super loaded up with the weight of the vehicle due to its inertia and other forces.. Often well enough to cause the tire to fail, flex or even blow the bead from the rim.
So it got me thinking, taking the crappy tires aside, I wonder if the marginal load ratings (barely above the weights of the trailer) of these tires traveling down the road or questionable quality... Low speed ratings and such. I wonder what kind of forces these tires incure even into a gradual turn in the road. Even if not speeding those outside tire would be put under a ton more load than the inner wheels (of the turn) and with them, sometimes, being barely over the GVW of the trailer could this lead to the bursting?
I guess I maybe read to much into all this e= mc 2 stuff...
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Pat, Jen, Heather & Sapphire, the head mouser.
2015 Chevy HD D-Max
2022 Impression 315MB
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10-18-2017, 04:35 PM
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#2
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Senior Member
Join Date: Jul 2013
Location: BoCoMo
Posts: 2,784
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Stress on tires comes from many variables.
I just shake my head when I see a fifth wheel and the roof line in the front is 6-10 inches higher in the front than the back.... My thoughts are the massive amount of stress being placed on the back tires and axle assembly and the lifting up of the front tires and assembly.
I saw one like this a couple of weeks ago that was way more tilted and pointed it out to the wife. and said... foolish and way unsafe.
We look at tire rating and 'think' that all four tires are carrying the same amount of load weight... they are not and can not, due to the way RVs are laid out and how they are set up to tow. A weight distribution system should force the tongue weight up and lift the back to the tow unit and RV and push weight to the front of the tow unit and to the back of the RV. ie. more weight on the front tires of the truck and rear tires of the RV. Tire weight carrying is never the same from tire to tire and should be thought of when figuring 'carrying' capacity.
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Brother Les
2013 Forest River Salem Hemisphere SBT312QBUD
2001 CrewCab F-250 7.3 PowerStroke Diesel
SuperChip, BTS transmission, 6.0 Trans Cooler
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10-18-2017, 04:54 PM
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#3
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Senior Member
Join Date: Feb 2015
Location: Southern, IL
Posts: 3,272
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Doc73,
I hear ya on the dynamics needed to be considered part. Just chuckled to myself after reading your entire post and wondered, how well would an rv do in a flat spin?
Sorry for being off-topic
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Bob & Michelle
2016 Ford F-250 Lariat 4x4
2017 Flagstaff Super Lite 526RLWS
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10-18-2017, 05:17 PM
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#4
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Just as confused as you
Join Date: Aug 2013
Location: south central Wisconsin
Posts: 5,108
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Quote:
Originally Posted by doc73
So I am sitting through a class to become an accident re-constructionists... I have not seen so many numbers and math formulas since high school trig! (THAT I FAILED BTW!! )
I guess I maybe read to much into all this e= mc 2 stuff...
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I see your problem, the confusion lies in the way your understanding the formula, it's e=mc2, not e= mc 2.
Yea, I had to look it up to be certain.
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Richard & Jill
2014 Flagstaff 832IKBS Classic Super Lite
2018 Silverado 1500 Crew Cab Z71 4WD All Star Edition
Camping since 1989, Seasonal since 2000.
Car Shredder Op/Tech, Scrap Metal Recycling - retired
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10-18-2017, 05:24 PM
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#5
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Senior Member
Join Date: Jul 2017
Location: California
Posts: 7,616
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Quote:
Originally Posted by Scrapper
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or actually maybe e=mc˛
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10-18-2017, 05:35 PM
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#6
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Who Dares, Wins
Join Date: May 2012
Location: Chester County, PA
Posts: 7,063
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Quote:
Originally Posted by babock
or actually maybe e=mc˛
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Yeah, I was not smart enough to figure out how to make the 2 littlererer..... Haha.
__________________
Pat, Jen, Heather & Sapphire, the head mouser.
2015 Chevy HD D-Max
2022 Impression 315MB
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10-18-2017, 05:37 PM
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#7
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Who Dares, Wins
Join Date: May 2012
Location: Chester County, PA
Posts: 7,063
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Quote:
Originally Posted by Wobbles
Doc73,
I hear ya on the dynamics needed to be considered part. Just chuckled to myself after reading your entire post and wondered, how well would an rv do in a flat spin?
Sorry for being off-topic
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Considering they can't even seem to hold up while parked sometimes... It would be good to WATCH!! We get to crash cars friday to test our skid marks, to speed being driven calculation and impact damage!
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Pat, Jen, Heather & Sapphire, the head mouser.
2015 Chevy HD D-Max
2022 Impression 315MB
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10-18-2017, 05:54 PM
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#8
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Senior Member
Join Date: May 2017
Location: Edgar Springs Mo.
Posts: 289
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Quote:
Originally Posted by doc73
Considering they can't even seem to hold up while parked sometimes... It would be good to WATCH!! We get to crash cars friday to test our skid marks, to speed being driven calculation and impact damage!
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Speaking of crashing cars, here at Fort Leonard Wood we have a few tracks with the towers to watch. The MP's get in the Crown royals and other cars and do cop chasing scenario's, reverse spins and they crash them up. If we can repair them by putting band-aids ( Metal) on them we do. We put brand new Tires on them every week because they run the rubber right off them. The Secret Service will train on it also....very realistic and fun to watch
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Not Camping enough Need therapy
2013 Forest River Salem/Sport Fifth WHL
2017 GMC Sierra 2500 Duramax/Allison
Curt Q20 Fifth wheel, Champion Inverter3500
US Army Retired
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10-18-2017, 06:16 PM
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#9
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Senior Member
Join Date: Jul 2017
Location: California
Posts: 7,616
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Quote:
Originally Posted by doc73
Yeah, I was not smart enough to figure out how to make the 2 littlererer..... Haha.
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Look up alt codes.
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10-18-2017, 06:52 PM
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#10
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Senior Member
Join Date: Nov 2012
Location: Mount Laurel, New Jersey
Posts: 9,230
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Watching how some get into a spot and just about push the trailer sideways to get in, can't be good on any tire. I try to back as evenly as I can in little increments greater then one hard push. I could be wrong. Just a thought.
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2012 SunSeeker 3100SS Toad-1962 Futura Average 100 + days camping
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10-18-2017, 07:42 PM
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#11
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Senior Member
Join Date: Feb 2015
Location: Southern, IL
Posts: 3,272
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Quote:
Originally Posted by A32Deuce
Watching how some get into a spot and just about push the trailer sideways to get in, can't be good on any tire. I try to back as evenly as I can in little increments greater then one hard push. I could be wrong. Just a thought.
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Ace, I was thinking of a worst case scenario, myself. Like a spin on the interstate. As far as what I can control, I try not to “scuff” the tires.
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10-18-2017, 09:39 PM
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#12
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Site Team
Join Date: Nov 2011
Posts: 4,499
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Bikersarge...
Its Fun to do too. Back in 1978 My instructor offered $100 to anyone who could flip the crown Vic by turning too sharp during pursuit training on a airport runway. It always spun out of control before going up on two wheels. That was until one driver blew the front outside tire in a turn and the rim dig in the asphalt and almost flipped the car. The instructor immediately said "all bets are off if you blow a tire."
We had a blast in that training.
I think SUV's changed the no-flip rule for police vehicles.
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2018 Forester 3011 DS
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10-18-2017, 10:21 PM
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#13
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Senior Member
Join Date: Jun 2016
Posts: 5,033
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You folks are getting way too technical for me. I'm just happy that when RVSEF weighed my rig at the International Rally, my 4 trailer tires were within 50 lbs of each other. Oddly, the front tire on one side was heavy and the rear on the other side was heavy. The axle weights were identical. Go figure....
BTW I'm under my axle limits by 500 lbs each and have 900+ lbs available per tire. FR did good by me.
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Al
I am starting to think, that I will never be old enough--------to know better.
Tolerance will reach such a level that intelligent people will be banned from thinking so as not to offend the imbeciles. Fyodor Mikhailovich Dostoevsky, Russian Novelist
S.E. Mich. Flagstaff 26FKWS / 2022 F-150 3.5 EcoBoost SCrew Propride
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10-19-2017, 12:16 PM
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#14
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Junior Member
Join Date: Jan 2017
Posts: 9
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e=mc˛
Einstein. Yes, this would be correct.
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10-19-2017, 12:36 PM
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#15
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Senior Member
Join Date: Feb 2017
Location: Wherever my heart takes me.
Posts: 274
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I am a retired police officer and Traffic accident investigator. Chicago NW has a very good set of data on this topic -VS- inertia, Type of rubber used, tread depth etc. All manufactures submit fail data or did as of a few years back when I retired.
If you want to look deep and cannot find the data you seek. You may email me @ tonyshope@gmail.com and I will seek current data from friends still on the force.
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10-19-2017, 12:43 PM
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#16
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Who Dares, Wins
Join Date: May 2012
Location: Chester County, PA
Posts: 7,063
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While we have not, or might not cover it.. I'd be curious to know when going into a corner at x speed on a y superelevation what weight increase the outside tires incurred. I'd bet that 900 extra pounds get sucked up real quick.
__________________
Pat, Jen, Heather & Sapphire, the head mouser.
2015 Chevy HD D-Max
2022 Impression 315MB
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10-19-2017, 02:12 PM
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#17
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Senior Member
Join Date: Feb 2017
Location: Wherever my heart takes me.
Posts: 274
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Quote:
Originally Posted by doc73
While we have not, or might not cover it.. I'd be curious to know when going into a corner at x speed on a y superelevation what weight increase the outside tires incurred. I'd bet that 900 extra pounds get sucked up real quick.
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So with your statement I am wondering. (Are you thinking high elevation from low elevation?
If so there is a cure for that as we ran on squads. It is a pressure relief tire cap.
If you enter (for sake of argument) the mountains and your tow vehicle/RV/TT have a rating of 60 lbs/80 lbs etc type E as you travel uphill you reduce your (Pop of rim load exponentially) In other words as you ascend the mountain your likely hood of blowing or most likely rolling a tire off the rim in a sharp curve increase and does in fact reduce you unit weight by (Memory here again I can point you to the experts) an average of 50% above 5k sea level. You will notice if you have an air mattress and begin at 600Ft or below as you increse in elevation the mattress might burst a a few K higher in elevation.
Now we ad Yaw/Wgt depending on suspension type and you could easily have a decrease of up to 1k weight as your tires are now over inflated.
The biggest failure I have seen with the pressure relief caps is they do not fill back at the same rate upon decent, unless you have a very expensive righ with pumps to refill on the roll.
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10-19-2017, 02:29 PM
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#18
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Senior Member
Join Date: Jul 2013
Location: BoCoMo
Posts: 2,784
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Quote:
Originally Posted by TonyShope
So with your statement I am wondering. (Are you thinking high elevation from low elevation?
If so there is a cure for that as we ran on squads. It is a pressure relief tire cap.
If you enter (for sake of argument) the mountains and your tow vehicle/RV/TT have a rating of 60 lbs/80 lbs etc type E as you travel uphill you reduce your (Pop of rim load exponentially) In other words as you ascend the mountain your likely hood of blowing or most likely rolling a tire off the rim in a sharp curve increase and does in fact reduce you unit weight by (Memory here again I can point you to the experts) an average of 50% above 5k sea level. You will notice if you have an air mattress and begin at 600Ft or below as you increse in elevation the mattress might burst a a few K higher in elevation.
Now we ad Yaw/Wgt depending on suspension type and you could easily have a decrease of up to 1k weight as your tires are now over inflated.
The biggest failure I have seen with the pressure relief caps is they do not fill back at the same rate upon decent, unless you have a very expensive righ with pumps to refill on the roll.
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It may help more if the refill air pumps used nitrogen to smooth out the rate of decent of the unit.........
__________________
Brother Les
2013 Forest River Salem Hemisphere SBT312QBUD
2001 CrewCab F-250 7.3 PowerStroke Diesel
SuperChip, BTS transmission, 6.0 Trans Cooler
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10-19-2017, 03:06 PM
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#19
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Senior Member
Join Date: Mar 2017
Location: Stockdale Texas
Posts: 448
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Quote:
Originally Posted by doc73
Yeah, I was not smart enough to figure out how to make the 2 littlererer..... Haha.
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X2 on that. How did you make it littlererererer and so on
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10-19-2017, 03:23 PM
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#20
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Senior Member
Join Date: Dec 2015
Location: Eastern NC
Posts: 3,963
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Quote:
Originally Posted by A32Deuce
Watching how some get into a spot and just about push the trailer sideways to get in, can't be good on any tire. I try to back as evenly as I can in little increments greater then one hard push. I could be wrong. Just a thought.
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True! I had a concrete storage lot that was 38' with 19' between where the 5er cap was to end. Not a problem with a 32' 5er but when a 43'er had to be maneuvered often 1 of the front LR G tires would leak around the wheel. It took 2 trips to figure out. 1 more and I moved to a 45' storage lot on gravel with over 50' to pull forward and back straight in. Don't know if it made a difference but tires were always cold when wiggling in those times and never a problem leaving.
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