Tire Pressure Max

[churp]

I agree with BailOut that tires last 85,000 miles if you drive like Grandma with a very light car....My Dad changed the tires on his 83 Mazda pickup at 109,000 not because of the tread but the sidewalls were ready to blow! And I also agree 60psi will help gas milage but it is unsafe as hell...probably manslaughter charge from the family of the person you kill (if they ever find out you hade 60 psi in your tires--total neglect of safety notices from tire and car manufacturers)

.5 to 2 mpg isn't worth it

Just because you're sober doesn't mean your not responsible!

[BailOut]

http://www.officer.com/article/artic...on=19&id=27281

[Black Yaris]

I think this will trump your source guy

http://www.betiresmart.ca/inflation/...n&loc2=placard
http://www.rma.org/tire_safety/tire_...afety/tpms.cfm
http://www.tiresafety.com/

[BailOut]

Umm, Black Yaris, what are you trying to show with those 3 links? I don't see what information they contain that you are trying to convey.

One just apes the old adage about following the vehicle manufacturer's recommendation, another says people don't check their tire pressure, and the last doesn't say anything except it provides a shamelss plug for Bridgestone who, of course, would much prefer you run your tires ragged in 20,000 - 30,000 miles rather than 85,000+.

If I missed anything there feel free to correct me.

[churp]

In the 3rd link under the 'MAINTENENCE' section....it states to NEVER inflate passenger car tires above the listed pressure on the tire.....as an engineer I can only assume this means the manufacturer has limits to his liability and states it clearly here....how clearer can it get? You may never have a blowout at 90psi...but just like drinking and driving, if you go beyond prescribed limits you are personally responsible for your actions if something goes wrong.

As for the driving instructor...I didn't see any credentials other than he has taught 'so&so many'. Butt dynos don't show failure point, strength of materials, dynamic loads, etc. so where does he base his knowledge on tire pressure science?

Max pressure listed on the tire is just that....it's there for a reason.

[PetersRedYaris]

Bailout- It's totally cool if you want to do this on your own car, but why would you recommend a possibly dangerous modification to other people who may or may not know better? Wouldn't you feel bad if they had a blowout and someone got hurt as a result? Gamble with your own life, and if YOU have a blow-out and harm another individual, I hope you take responsibility for your actions.

[BailOut]

We keep coming back to what I first said...

Pump up your tires to *at least" the max sidewall. If you are still uncomfortable with that statement then read it as "Pump up your tires to max sidewall."

If you want to go higher you can and there are many people that do and and have done so for quite a while.

However, as with all other things hypermiling you certainly don't *have* to do it if you don't wish to, whatever your reasons. Just take the information, assimilate it, and make your own decisions.

On a side note, for a bunch of folks that are willing to swap out engine, exhaust, suspension, tire size and width and just about any other components on a whim you sure are ultra conservative when it comes to tire pressure and oil change intervals. hehe


Edit: Peter, that is way over the top and totally uncalled for. Please do not make such unfounded alarmist statements. Hundreds of people between the Prius and general hypermiling communities representing over a million collective miles of driving on all kinds of roads and in every condition run at higher than max sidewall, and over a 5 or 6 year period not a single incident of a blown tire or this pressure contributing to an accident has come to light.

[eTiMaGo]

Well he's not forcing anyone to run 60PSI, just sharing his experience, observations and research.

It is entirely up to the individual to follow or not, but if you are interested, why not try a halfway point, like 45-50PSI? It's definitely safer than under-inflated tyres! (which reminds me, I gotta check my pressure...)

[eTiMaGo]

hahha jinx!

[SailDesign]

Originally Posted by CleanMPG website

Welcome to the CleanMPG forums.


Some posts may describe situations which may in some cases be unsafe or illegal in some jurisdictions. Please use common sense and consult your local laws to make sure you do not hurt yourself or others or break any laws.

Need I say much more? Oh, OK, then...

Originally Posted by Deeper into the "Advanced Hypermiling" section

I can discuss but cannot personally recommend upwards of 25% higher then MAX sidewall as there are legal constraints we all have to live with.

[BailOut]

I can discuss but cannot personally recommend upwards of 25% higher then MAX sidewall as there are legal constraints we all have to live with.

44 x .25 = 11
44 + 11 = 55

So go with 55 PSI instead of 60 if it makes you feel better.

[Black Yaris]

Originally Posted by BailOut

Umm, Black Yaris, what are you trying to show with those 3 links? I don't see what information they contain that you are trying to convey.

One just apes the old adage about following the vehicle manufacturer's recommendation, another says people don't check their tire pressure, and the last doesn't say anything except it provides a shamelss plug for Bridgestone who, of course, would much prefer you run your tires ragged in 20,000 - 30,000 miles rather than 85,000+.

If I missed anything there feel free to correct me.

do you know how to read? those links say use the tire pressure provided by your vehicles manifacture. Many Bridgestone tires are rated well above 80k miles BTW, same goes for Michelin. the one link was from the rubber manifactures accoc of america, mabe you should read into that site a bit and you could learn a thing ot two about tires. I ain't just pulling shit out of my ass I have gone to training coarses from most of the big tire companies, as well counpany training... I would just love for you to pick up a tire guide and read it, so you can learn how dangerous those high pressures realy are.

on a side note, have you ever seen a tire blow up at 60 psi? I have, it ain't pretty, had to rush the kid to the hospitol, and all he was doing was airing up a pass tire over the rec press cause the cust thought it was best, and he was new and did not know any better, and it blew up in his face... kid was fine... but gave us a scare.....

[SailDesign]

Whew! I'm really glad Ken Obenski read the December [above] issue of this newsletter (SPARE TIRE/TANK CAUTION!) and took the time to share his expertise. He's a registered engineer, works in failure analysis, and blew open my eyes regarding tire overinflation hazards. My original fear dates back to a 6-year-old Coyote blowing out a 24-inch bicycle tire. The December newsletter understatement, "The explosive force of compressed gasses (air) is incomprehensible to most of us," is only emphasized by what follows. I expect, if you're like me, by the time you finish his letter (salient points reprinted below), you'll even be afraid to inflate your tires to street pressure!

1. An 8x15 inch trailer tire, load range E, 85 psi rating, blew out a sidewall during inflation. Tire tech was on top of the tire because the safety equipment was not working right. It launched him first, and went through the shop roof. Compressor was set for 165 psi with no regulator between the tank and the tire but 150 feet of 1/2 inch pipe.

2. A 15-inch car tire, 32 psi rating, gas station had a locking air chuck (OS HA required). User did not realize that letting go of the chuck would not stop air flow. The hose blew out, knocked him down and lifted the tire over a retaining wall. Severe head injury.

3. Wheelbarrow tire, 4x8, 32 psi rating, aired up with unregulated hose connected to 100 psi. The rim split in half and decapitated owner.

4. Nearly new bicycle tire, mine, 90 psi rating, blew off rim at 70 psi. Stress in bead wires is 300,000 psi! Tire manufacturer says, "Tires blow off the rim all the time," like it was no big deal. Tell that to my knee.

5. Bike tires are thin-walled but also very small cross section. Thin-wall pressure-vessel design is just a ratio of diameter to wall. Bicycle tires are bias ply, so the cords don't separate as the tire swells, like a radial. (Bill Fragale, Phoenix area, also nailed me on this one.)

6. My tire engineer warns against exceeding sidewall rating by more than 10 percent. Orris says the first thing to fail should be the sidewall. Steel rims are formed from one piece of sheet and will not fail, but some aluminum rims might fail by the flange breaking off. The rim fragment will be a bullet.

7. Air at about 125 psi behaves like pure oxygen! Organic materials can spontaneously com- bust in it. When this happens the gasses expand even more and what you have is a one-cylinder engine with no crankshaft and no exhaust valve.

8. Navy has one serious accident a day from high-pressure air. See 7.

9. Desert temperatures and high altitude can raise tire pressure another 20 percent (pvnrt = pvnrt). See 7.

10. Tires have a warning on the sidewall not to exceed a certain pressure to seat beads. Usually it is less than 125 percent.

11. Most of the tire-explosion problems we have seen are from putting tires on the wrong size rims. There are 15.5- and 16.5- inch tires and rims, that almost interchange with 15, or 16, but will release without warning, at or near rated pressure.

12.Just because you get away with something does not mean it's safe. Safety factor is not there for us to use, it's a safety margin to deal with the unpredictable, like: Suppose your gauge is off, or the tire has latent defects, or they overstressed it in mounting, or in your case, you high center on a rock.

13.The energy stored in your 32- inch diameter tire at 100 psi is 13,000 foot pounds, enough to lift the entire truck 4 feet, or launch tire and wheel at 146 feet per second. That's 12 times the muzzle energy of a .44 magnum! How securely is that tire attached to your truck?

Not sure how else to say this, but... If "Hypermiling" is your sport, don't play it on roads I have to drive onPlease!

[BailOut]

Then stay off my roads, SailDesign, because I call on your repost. The original writer apparently failed his advanced math classes and has a paparazzi-style penchant for focusing on and embellishing the one-offs.


On a side note it is best to provide a link to your content source.

[SailDesign]

Originally Posted by BailOut

On a side note it is best to provide a link to your content source.

'Pologies for that. Here she is.
http://www.4x4now.com/sf1296.htm
I have to admit that the "Ecological 4x4" title is a bit of an oxymoron, though

Looking again at thet "Hows and Whys" section of the CleanMPG site, I note a great many of the things that really really annoy me in other drivers being listed as good. Amongst them:
1) Speeding up and slowing down repeatedly (Pulse&Glide). So frikkin dangerous as no-one else on the road knows what you are about to do next.
2) Speeding up on the downhills and slowing down on the ups. I know, everyone does it, but it's another PITA.
3) Drafting. Stay off my tail and I won't practice brake-stands. Honest!
4) Surfing - aka staying in my blind spot when I would like to pass the other idiot on the road.
5) High-lining or whatever (running with your lefthand wheel on the white line and your righthand wheel on the "hump" between normal wheel paths). This si actually described as helping keep others awake! If you expect me to pull out further and sooner to pass you, better wear some ear-plugs. If you are not in your travel lane, then I will let you know. Look up Rhode Island General Law Title 31, Chapter 15, Section 4. OTOH, I'll save you the trouble. Here it is:

§ 31-15-4 Overtaking on left. – The following rules shall govern the overtaking and passing of vehicles proceeding in the same direction, subject to those limitations, exceptions, and special rules stated in this section:
(1) The driver of a vehicle overtaking another vehicle proceeding in the same direction shall give a timely, audible signal and shall pass to the left at a safe distance and shall not again drive to the right side of the roadway until safely clear of the overtaken vehicle.
(2) Except when overtaking and passing on the right is permitted, the driver of the front vehicle on the audible signal of the overtaking vehicle shall give way to the right, and shall not increase speed until completely passed by the overtaking vehicle.

So, if you are hogging the middle of the lanes, and I honk at you, you are required to move out of the way and not speed up until I'm past. I have only tried this on cops I know

Steve "doesn't need to drive badly to use less gas"

[PetersRedYaris]

Originally Posted by BailOut

Then stay off my roads, SailDesign, because I call on your repost. The original writer apparently failed his advanced math classes and has a paparazzi-style penchant for focusing on and embellishing the one-offs.


On a side note it is best to provide a link to your content source.

Angry, angry, angry! Why are you so angry? The consensus is, it's just plain dangerous. You don't need to be upset we're not all jumping on your band-wagon.

Question- Is +.5-2 MPG really hypermiling? Maybe call is Goodmiling. I think you need to double your mileage before the word hyper can be correctly used.

[SailDesign]

Originally Posted by PetersRedYaris

Question- Is +.5-2 MPG really hypermiling? Maybe call is Goodmiling. I think you need to double your mileage before the word hyper can be correctly used.

I think at the +5 mpg stage, it could be called "supermiling", which would bring +0.5 to +2 into the s'miling range.

Certainly makes me smile

[BailOut]

The term "hypermiling" refers to continually beating the EPA's combined estimate for your vehicle and can involve combining driving techniques with some changes to your vehicle (including tire pressure). Every additional change you make to your driving style and vehicle nets better MPG, and it all adds up.

The original combined EPA estimate for the Yaris is 37 MPG (it's only 32 under the cheesy new system). My last tank was 49.74 MPG (click my signature for more information) and I commute over a mountain 5 days a week.

By the way, Peter, I'm not angry. Disappointed at the lack of understanding and exasperated with some of the attitudes perhaps, but not angry.