slickest1 wrote: There seems to be a difference of opinion on under inflation. As far as I am concerned if a tire is not inflated to the number on the sidewall it is under inflated. 35 years of running trucks, most failures other than road hazards were caused by under inflation. I am sure lots will disagree.
According to every major tire manufacturer, that is incorrect. You should inflate to the PSI recommended for the load you are carrying. Having too much pressure can reduce your contact patch and cause bad handling, not to mention a worse ride.
Get a four corner weigh with your RV loaded to the max with fuel, full tanks and passengers. Consult the manufacturers charts and put the recommended PSI based on the heaviest side for each axle. Some like to add a 5 psi cushion.
Use a TPMS to monitor pressure while on the road. A leak caused by a road hazard can go undetected until too late.
What amazes me about these "opinions", and everyone of the posts in this session except for the one's that stuck to the original subject is opinions, none have a attachment or reference to a manufactures site with creditible info. Everyone, just like me has read all this BS for years and I believe about 1% of it.
* This post was
edited 01/14/12 03:02pm by peaches&cream *
Two blowouts one deflated and tore apart at 70 mph. Seond one the same thing. Another one was to the point of destruction when the valve stem let go. Fourth was ready to let go when all two others were replaced. Chinese valve stems with no uv protection in the rubber. It was on the F 150. We safely came to a stop each time. A car; I dunno.
All the air was out of the tires on the Edge. Another Driver helped wife air them up. One developed a blister, from it and would have let go just anytime when we found it. Replaced two. Other two are now suspect and will be replaced.
Saw several at the Tire Dealer destroyed by hard ware on the road. One new, wheel and tire had a four inch long 1/2 bolt and nut through the tire protruding through the wheel. One hit a ratchet from a tie down strap off a semi trailer. through the tire and protruded through the inside of the wheel. Cars with large brake disc would have had a real problem.
Daveinet wrote: PARKMANAA Help me understand the logic behind your comment. You state that "over inflation causes undue stresses on the tire". So I am trying to picture just how those stresses occur. My tire max pressure is 80 psi and rated for 3000 lbs at that pressure. If my coach loads the tire at 3000 lbs everyone is happy. The tire must contain 80 pounds per square inch of force in all directions including the road. If I have 3000 lbs pushing against the tire, the contact patch will be ~37.5 square inches. If I have 2500 lbs pushing against the tire, the contact patch will be 31.25 square inches. In either case, the force outward from the air pushing on the tire is 80 PSI. This means regardless of the load, the outward force against the belts in the tire is the SAME 80 PSI. Either the tire is designed to be able to take 80 PSI or it is not. If the sidewall says it is designed to take 80 PSI, doggone it, it will not stress the tire to have 80 psi in it. As long as the load is less than the rating, the stress will also be less than the rating.
So what about tire wear in the center from over inflation compared to load. Same principle applies. You have 80 psi pushing out on the tire. If you have a narrower contact patch, that means that some of the tire does not wear. The inside of the tire wears as if it has a 3000 lbs load. The outside of the tire wears as if it has less load, because it does. So the inside of the tire wears faster than the outside, but the inside wear rate is the same is if the tire was running with full 3000 lbs load.
As far as stress is concerned, the tire only has 80 psi pushing out. So hitting an impact or road debris can not put more stress on the tire, if there is less load on the tire, because the air in the tire can only push out at 80 psi. Less load can not create more impact.
The only theoretical negative effect that running higher than recommended pressure for the load can have, is that the tire will not flex as much, and the emulsifiers in the sidewalls will not flow to the outside of the tire as much. Since the tire still flexes quite a bit, I have a hard time thinking this difference would be a measurable amount.
Simple...inflate the tires to max pressure (usually about 50psi) on an empty boat trailer and run 65MPH over a couple expansion joints. The trailer bouncing a foot into the air and then banging down is pretty hard on the tires & the hubs (not to mention the rest of the trailer).
Offhand, running max pressure (80psi) in my truck while empty is intolerable. It makes for a pounding, kidney hammering, bone-shaking ride that is literally painful. Drop to 45 in front & 35-40 in back...MUCH better!
John and Elizabeth (Liz), with 3 nutty cats
My beloved St. Bernard, Marm, lost him 1/2/12
Current rig:
1992 International Genesis school bus conversion
Two flats on my B700. Right front (Goodyear G149) picked up a drill bit (removed & repaired), left rear outside (Bridgestone, capped by Bandag) picked up a large nail (too close to edge to patch, replaced).
Two blowouts:
LF on Liz's Cherokee, a 30x9.50R15 BFG Long Trail about 2 months old, hit a chunk of exhaust pipe.
Right front on a 1972 Ford F-800 rollback, a 10.00R20 I think was a Michelin, no idea on the cause.
peaches&cream wrote: What amazes me about these "opinions", and everyone of the posts in this session except for the one's that stuck to the original subject is opinions, none have a attachment or reference to a manufactures site with creditible info. Everyone, just like me has read all this BS for years and I believe about 1% of it.
peaches&cream wrote: What amazes me about these "opinions", and everyone of the posts in this session except for the one's that stuck to the original subject is opinions, none have a attachment or reference to a manufactures site with creditible info. Everyone, just like me has read all this BS for years and I believe about 1% of it.
All three of these manufacturers recommend determining your tire pressure by weighing your RV and consulting their charts.
Thank you. I have Goodyear tires and have used their recommendations since I have owned my MH. I had much rather use the Manf. reccomedations than the opinions of the posters. It's good to see someone can backup their statements. Have a great day.
BRIDGSTONE brochure wrote: Remember, these are minimum
pressures for each of these loads. In
other words, you can increase your
inflation pressure above what the
chart shows, so long as you don’t
exceed the maximum pressure
specified for that tire.
Don't you people read what you post?
* This post was
edited 01/15/12 02:57pm by Daveinet *
Dave
The Flying Fortress
FMCA F298817
'83 Revcon Prince 31' FWD
502 w/Howell/GM 16197427 ECM/Edelbrock MPFI,Thorley's & Magnaflows,
4L85E 4 speed, KoniFSD,
6% grade = wanna drag? MISC photos Revconeers Forum
"BTW: There is a difference between an opinion and physics"
Now, Dave we wouldn't want to confuse any one by using facts or would we?
David Just rolling along enjoying life w/F53 Southwind towing a 87 Samurai or 01 Grand Vitara looking to golf or fish Simply Despicable Any errors are a result of CRS.
Y'know, I'm sitting here trying to remember the last time I had a tire actually blow out for no apparent reason...
I can't remember that ever happening!
I had a Kumho tire on the truck develop a bump in the tread from a broken belt, but it didn't lose any air...
DW hit a curb and cut a tire on the '06 Liberty, but it was very obvious what happened there...
Nope, I can't remember ever having a tire just suddenly explode while driving down the road. If it ever happened, it was so long ago that I just can't remember it.
CM1, USN (RET)
2002 Fleetwood Southwind 32V, Ford V10
Toad: 2006 Jeep Rubicon LJ
Other toad: '06 PT Cruiser, Kar Kaddy dolly
Toy: 1977 Dodge W100 CC SWB, 3/4 ton axles & springs
"When seconds count, help is only minutes away!"
Offline
