You know it's time to turn in your EcoModder membership when...

[ksa8907]

Originally Posted by gumby79

Many of the car manufacturers have gone to run flat technology tires. The reason for running the ultra stiff sidewall run-flat style Tire is to delete the weight of a spare tire. Unfortunately the downside is the tire doesn't deform until it has consumed itself due to the extra heat of the air not supporting the weight the sidewall is doing it insted. Every Tire I have stopped on the side of the highway to help someone stranded that has been one of these run-flat Technologies has disintegrated before the driver was aware that they had a low tire and then there's no spare tire I ruined rim and they're still stuck on the side of the highway. The only ones I've seen survive a picking up a nail have had the air monitoring systems that have become A DOT safety item, when the air pressure monitoring systems gained safety item status the aftermarket air pressure monitoring systems were pulled off the market unless they can pass the DOT testing procedures making them unavailable to vehicles like mine that don't have factory installed safety equipment.
On the bright side it only cost you 11 MPG instead of that plus a tire.

I recommend everyone I know NOT to buy run-flat tires. If you do get a nail, how are you going to know so you can make effective use of those 50 miles of running with a puncture? You won't know, and you'll be stranded just the same.

[freebeard]

I remember that when I was in high school, once —for two weeks— I was down at the shop patching tires for my car or my parents every night after school.

The last time I had a tire problem, I'd oversteered into a curb in a traffic circle at about 35mph. Oops!

[Piwoslaw]

Originally Posted by gumby79

The reason for running the ultra stiff sidewall run-flat style Tire is to delete the weight of a spare tire.

Sorry to go OT, but this got me thinking: For the sidewall to be stronger it also becomes heavier, right?

If yes, then this adds rotational mass to the wheel, increasing fuel consumption during each acceleration. When multiplied by 4 and added up over the life of the tire, or the car, does this still justify the saved mass of the spare tire?

Also, heavier tires add unsprung weight, which reduces comfort.

[gumby79]

^^^
This extra mass is also offset by stiffness reducing rolling resistance.
Suspension can be tuned for the new ride quality to acheve no change.
Also on the delete list were the jack, lug wrench, associated mounting hardwere/brackets, cubby , concealment/ false floor(hidden compartment common in station wagons, sedans, and coupes) .
The manufacturers figure there's a high enough percentage of people that have no clue how to change a spare tire so there's really no point in having a spare (say thank you to budget cuts removing most shop related classes from schools). Most of today's younger drivers (<40) will drive it till the tire comes apart and then they'll call a tow truck. Because of this lack of knowledge tire pressure monitoring systems became a safety feature.
I'm sure there is some white papers describing the change of run-flat tires Vs spare tires and non run-flat tires

[freebeard]

They can have their white papers. I want to think about tweels made from densified wood.

[Daschicken]

Been there, done that. The difference is that the tire was visibly flat(other side of car, so I didn't see it), and I ignored several warnings before I thought I felt the car rolling differently and pulled over to change it to the spare. By that time it was too late, I had already killed it. For the first few miles of that trip, the car(dad's G35x) felt like it rolled the same, despite having one flat tire....

Originally Posted by MetroMPG

I've never lost a sidewall! (Touch wood.)

Lots of screws/nails through the treads though. I've used up a whole pack of those puncture patch gummy worms.

I hate those gummy plugs! Use the mushroom plugs or take it to a shop that will dismount the tire and patch+plug from the inside. The gummy plugs have a tendency to not do their ONE JOB and seal the tire. When I worked at Goodyear I had plenty of people come in one day after having their tire plugged with a gummy plug. They leak! Plus they are no fun at all to remove and patch properly. I would recommend taking that tire to a shop and making sure that the tire didn't start deteriorating internally and producing dust on the inside of the tire. You MAY(?) be able to look inside the tire through the valve stem with the valve core removed, but have never tried that before.

Originally Posted by ksa8907

I recommend everyone I know NOT to buy run-flat tires. If you do get a nail, how are you going to know so you can make effective use of those 50 miles of running with a puncture? You won't know, and you'll be stranded just the same.

Yep, it always surprises me when a car with run flats comes in with a flat tire that has no visible deformation, and I go and take the valve core out and no air comes out!

[Daox]

My turn.

So, I recently did something member-turn-in worthy too. I still have my 2004 Civic. My cousin wants it, but he has to sell his car first. So, its been sitting in my driveway. I haven't fired it up in a while, so I figured I would do that, let the battery top off, etc. So, I did. I went out, it fired right up with no issues. I sat a while in the car and then went inside to take care of a few things while it ran. Well, I got busy and totally forgot about it. The next morning I went out to plug the block heater in on my Mirage and I hear something running... At first I thought the neighbor was already up to something really early in the morning. Then, I saw little puffs coming from the Civic exhaust... *sigh* I went over and shut it off. I think I had a full tank when I parked it. The gas gauge showed I burned about 1/4 tank, or around 3 gallons! Doh!

[Xist]

You did not calculate the exact idle consumption?!

[MetroMPG]

Originally Posted by Daox

My turn.

Ooo! This is getting good.

Who will get voted off the island THIS WEEK?!

I think I had a full tank when I parked it. The gas gauge showed I burned about 1/4 tank, or around 3 gallons! Doh!

You win! Or lose! I wonder how much extra fuel I burned rolling around on my flat tire.

The funny thing is: I remember this being a call on Car Talk once. VERY similar story. The guys laughed their keisters off!

[Piwoslaw]

Originally Posted by Daox

I sat a while in the car and then went inside to take care of a few things while it ran.

Here there is a law which states that you cannot leave your vehicle while the engine is running.
Just sayin'...