Some Hypermiling techniques denounced by AAA

[euromodder]

What a shipload of rubbish.
RU sure it isn't some advertorial ?

Originally Posted by htvfd460

With in the response to: "AAA opposes all of those methods, noting that cutting off a car's engine may negatively affect power steering and power brakes;

It's known and taken care of by those who use this technique.

overinflating tires leads to uneven tire wear;

Depends on your definition of overinflation.

Going above the manufacturer's suggested inflation, which is ridiculously low, has helped to EVEN out my tyre wear and cured some vagueness around the dead ahead position.
(Yes, wheel geometry was set up according to the manufacturer's specifications.)
At the tyre's max. rated sidewall inflation it's a bit less comfortable, but absolutely bearable.

Going above the tyre manufacturer's , well, that's overinflation to me as I'm not really willing to go that way.

rolling through stop signs puts drivers at risk.

It doesn't when there is no crossing traffic.

The typical US 4-way STOP is without any doubt the most retarded way of controlling a crossing I've ever come across. It's also the most wasteful.

If these were to be removed entirely from US soil, it'd most definitely show up as reduced fuel usage.
There's no need for them, so they aren't used anywhere in Europe.
Get your politicians to remove them, the sooner the better.

tailgating trucks puts drivers at risk.

I agree to that.
You can't see much beyond a suitable truck, if at all.
When trying it out, I needed to get in way too close before getting any serious results.
Keeping pace next to a truck isn't a good idea either.

But there are ways to use the truck to shield your own car from the wind.

With electric steering, having the ignition off shuts off the computer or tells the computer that the vehicle as a whole isnt being used for roadly purposes.

The ignition isn't off, it's in II, the very same position it's in when driving.

Over inflating tires {The one thing that urks me the most out of anything automotive} leads to serious concerning problems.

I've yet to come across the first serious concerning problem with going to sidewall spec.
It has cured at least one serious concerning problem though.

Overinflating still increases tire temperature as much as underinflation.

My tyres @ max sidewall are definitely colder than they used to be.

Yes I know.
It's a habit I carry over from my motorcycling days

The tire wears unevenly and affects breaking

I haven't yet found any braking deficiency due to inflating the tyres to (near) sidewall spec.

The brakes have to work harder and burn faster and glaze up

Hypermilers try to brake as little and as lightly as possible, and that's what may glaze the pads, not braking hard.

Over and under inflation reduces that to 1/3 that wear milage.

I've replaced tyres because he shoulders were mostly gone.
That was back when they were set at placard inflation during servicing, and all too infrequently checked. As most car tyres are.

The other part is that the ride becomes stiff and can bounce on a bumpy road resulting in less controll.

Stiff suspension is OK.
But it shouldn't become bouncy, that means the tyres are really overinflated.

Or rather that the manufacturer decided to use the tyre as your suspension.
Ride a Lotus to experience stiff, efficient, but not bouncy suspension.
It's a hoot !

[Frank Lee]

I said I'd look at your evidence and I did.

"A" = Put a bit of time into proper spelling and be rewarded with more instant credibility.

"B" = A non event occurring only in your head, not worthy of further comment.

"C" = Recall for a hose defect spraying oil at presumably high pressure and/or significant quantity onto hot parts, as a preventative CYA measure as no actual fires occurring are noted. Quite different from a dribble dripping down from a cap.

"D" = That is a nice chart; too bad for you it says nothing about overinflating leading to higher temps. The ehow link wouldn't load and wasn't even searchable.

"E" = The only place tire overinflation leads to increased tire mass, increased tire diameter enough to matter, and those leading to effects on braking enough to measure are in your head. The brake bias link wouldn't load but it matters not anyway.

"F" = Just about everyone here has experimented with higher tire pressure- I know I have been doing it since the mid '70s. Nobody has reported anything similar to your claims. You have presented nothing to refute that.

"G" = If anyone has gone into the ditch, crashed, caught air, blown a tire, bent a rim, or had an otherwise adverse experience with tire pressures over sidewall max, please speak up. I don't recall any such complaints.

"H" = Here we are, I've spent time reviewing what you've presented. You have failed on all counts. Thanks for the waste of time.

[htvfd460]

FRANK LEE-
A- I realy dont care about grammer or spelling. I am one of those Texting people. I rarely use my phone to talk to any one. I have just adjusted to having 160 characters to supply my ideas with.

B- Intermittent concerns were my specialty at my dealership. The first to come to mind was an Escape with a malfuntioning starter. After it would warm up the starter would stop working untill it cooled off enough. Before saying this is in my head {It is in my head and thats where my memeory comes from so you are right about that} Take into concideration that I havent just worked on Fords, But they are what i focus mostly on. I have seen and experienced interesting and what seemed odd things happen to vehicles. For instance if the brake light bulbs in a 2008 f-150 are replaced with a set of LEDs the cruise controll will no longer work. The remedy is regular bulbs that a low voltage can be transfered threw for the abs module to monitor.

C-Ford's o9s09 recall did cause fires. I am using this as an example to express the danger in such a little amount of fluid can cause severe damage, so it is something to just keep an eye out for. The crysler example was to show that even new stuff can fail, As well it shows that its not just from the fill cap {My Ranger has a seperate resivoir connected to the pum via 2 hoses with clamps. clamps after time can fail from rust and stresses, i dont trust them 100%} Gm also had a liquid fire problem "GM said it was aware of five fires" And this was with the Washer fluid, from the fluid heating feature.

D- From Michelin "Most of the increase in temperature is in the tread area. There can also be some increase in the bead area since this is a flex point of the tire but more in the tread area.

We appreciate your business and thank you for choosing Michelin."

No matter what there is always friction between the road surface and tires when they meet. Low pressure creates most of the heat at the side wall since that is the part of the tire that is flexing. On a tire that is filled to Factory spec, the flex is mostly at the tread and that is where the temperature increases. With a tire that is over inflated {My definition is: beyond optimum traction, and dynamics for steering handeling and comfort} But we can go with over the tires rating on the side wall for this one, What happens is the energy is tranfered from the center treads straight to the rim. The bead temperature increases and CAN {Not always} warp the mating surface, later creating a leak from that sealing point. The other place that the temp increased is in the center treads. This creates an uneven hot spot and can lead to other malformations like a split belt in the tire. I have seen these happen from normal driving conditions, so its a good thing to take into concideration.

E- I was focusing on the required energy to beable to stop the vehicle when it comes to an increased diameter of the tire. The location of the force changes when contact is placed further out. It can be compared to installing a larger radius tire on to a vehilce. Such as lifting a truck and installing 35s on it. The braking distance is significantly increased and brake fade comes about faster. Glazing of the rotors if from the surface of the rotor at contact with the pads creating enough heat to make the metal in the rotor maliable enough to essentially smooth it out. Similarly to heating plastic and putting a thumb print into the surface. None the less placing the position of the surface of where the resistive energy is located increases the amount of torque required to slow down or stop it.

F- it seems as if you arent taking what i typed in previously into concideration. The spectrum that i see runs from stock to Seriously modified to an extreme. There are alot of people looking to find ways to increase fuel economy, Even Jim Bob with his 2009 Dualy Superduty with the diesel engine and a 12" suspension lift and 35" tires. We all know a little adds up to a bigger picture.

G- From my experence people that end up having that problem end up buying a new car. Especiall if the vehicle is worth $3000 or less, Insurance companys total them out if the cost for repair is over 1/2 the value of the vehicle. Curbs take out rims just as much as our potholes arround here, especially the curbs that are 12" tall. If any one is getting air their arent on a flat surface and it may indicate unsafe driving.

H- I have come to appreciate you reponses. I do enjoy a good debate. And I know i have responded with little maturity in response. For being rude, I do appolgize.

EUROMODDER
My truck rides bumpstops, i have to have a bit of give in my tyres. Ford says 30psi and 28 psi seems best for even tire wear for my specific application. I do understand that each vehicle is different.

There is a place that the locals arround here call 5 corners. 5 stop signs for each road for the intersection. It is always a big debate for students who are taking drivers ed in this county. {Sussex NJ} The signs were place there in responce to the ammount of accidents. There is also an intersection where someone ran a stop sign and T-boned a State trooper. After the Officer died they put up a stop lamp there. {This is what i reference to with rolling stops}

With the Ignition off, I think of a 2010 Tarus SHO. Push button start. So electronicaly reliant that it becomes 3 times the effort to program the new "Wireless key". The vehical sometimes requires disassembaly to start the process. I also think of an automatic and a bad battery. Plus its like an autostart in an automatic with the MYkey {Not a fan of those keys and remote starts}. The car shuts off when the key is placed in the ignition switch. It negates the puropse of the RMST, And doubles starter wear on those occasions.

Tire wear is also different from manufaturer to manufacturer. Even the sizes too. A 205/75/15 From michelin will have different dimentions from a cooper 205/75/15. It can be a balancing act from one to another. I am focusing on the OEM tires though. Some vehicles can handle it and others like a Ford Explorer with RSC will not. The explorers monitor the radius of the tire, from going straight to turning. The sensors are sensitive enough to detect mismatched tires and will cause transfercase engagement issues while going straight.

The glazing has always been a larger Ford vehicle with cheaper rotors than oem issue from what i have seen. From what i have seeni have concluded people get what they pay for. But times are tough and alot of people are having brake issues when they go to a local garage by what i hear arround here.

My 1/3 wear was at an extreme as indicated in that part of the post. On my truck setting the tires to 30 psi yielded me new tires at 14,000 miles. Adjusting to 28 psi in the front has helped me keep my tires till now {over 75,000 miles}I need to change them though since my wheel bearing went.

Riding Bumpstop is what i am doin and it is not a comfy ride. I deal though.

I do have to say you have taken the time to check your vehicles parameters and been responsible with it.

[Frank Lee]

FYI weight of air in car tires:

Re: how much does the air in a basic car tire weigh?

or about what 20-30 pennies weigh.

None of your points apply. What are you doing?

[htvfd460]

I never implied that adding air pressure adds mass. Simply changing the shape of the tire (adding air pushes the center tread out further from the rim)alters the placement of the outer treads further away from the center.

[Frank Lee]

By how much?

[htvfd460]

Oh I must suggest that tires being balanced that are "over inflated" be balanced to the center of the rim instead of a dynamic balance. It will help keep a uniform balance.

[htvfd460]

It will increase by the diameter's difference. My tires are about 27.5" at 28 psi. Setting the pressure to 35psi expands my (center tread) diameter to 29". My tires change by 1.5".

[gone-ot]

Originally Posted by htvfd460

It will increase by the diameter's difference. My tires are about 27.5" at 28 psi. Setting the pressure to 35psi expands my (center tread) diameter to 29". My tires change by 1.5".

...I'll bet that was an "unloaded" diameter change, not the "actual" change (which is much smaller) when loaded, ie: the tires' "flattened" foot print.

...typically, there's a 3% reduction in diameter between unloaded and loaded conditions.

[htvfd460]

I can't check ride height if the wheels aren't attached to the truck on a flat surface. I wanted to see the correlation between the tire height versus ride height.