Run Flat Tires

[catman85]

I am new here and have a new Fusion Hybrid in the garage with 11 miles on it. I have seen a couple of threads about donut spares but my thinking is run flat tires. While my tires are still basically new I am talking to a couple of tire dealers about trading for run flats. My questions:

 

1. Should run flats be standard equipment or an option?

2. Is anybody doing this?

 

 

I use to own a C5 Corvette and run flats came standard on the car. Investing in a Hybrid means reducing the weight of a jack, spare, air compressor, etc. Run flat tires are not that much more money for the security benefits.

 

Any thoughts?

 

[murphy]

Run flat tires are likely to have much higher rolling resistance which will result in lower mpg.

[Waldo]

Run flat tires will add more rolling resistance and weight than is saved by eliminating the jack and spare. For best fuel economy, stick with the stock tires and throw in a spare and jack if you want.

[catman85]

What you both say is true. My stock Michelins green X weight 22 pounds each and the #1 rated "run flat" at tire rack, the same size, weight 28 pounds each. Is there other differences? The #1 rated run flat is also less money than a Michelin Green X. Don't think I could have a jack,spare, etc for the 24 pounds increase in rolling resistance.

 

What am I leaving out of this puzzle?

[Waldo]

Rolling resistance isn't about the weight of the tire, it's about the friction it creates between the rubber and the road. Even tires of the same weight can reduce your mileage by 1-2mpg just from the change in rolling resistance. The increased weight is a second factor that will also hurt.

 

Also keep in mind that rotating weight has a different effect than "stationary" weight. It takes more energy to get those extra 6 pounds rotating than it does to get 6 pounds in your trunk moving.

 

But the biggest reason to avoid run flats is because it will make the ride terrible.

[catman85]

Run flats do have stiffer side walls which will result in a stiffer ride, agreed. Is there a chart or formula to determine rolling resistance for tires?

[Waldo]

Every tire is different, it's extremely dependent on tire construction and rubber compound. Here's a bit of info, though it still won't answer your question:

 

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=175

[lolder]

Run flat tires would probably have to be standard on the coming autonomous cars.

[Texasota]

Run flat tires would probably have to be standard on the coming autonomous cars.

Can you elaborate? Why would they have to be standard?

[machoman1337]

Can you elaborate? Why would they have to be standard?

 

Perhaps autonomous cars aren't smart enough yet to properly respond to blowouts on normal tires? Just a guess, since a blowout's effect is one of the more unpredictable things in driving.

 

Anyway, BMW has been making runflats standard for years now and lots of people complained to no avail. I personally would avoid them too if I can, unless I was driving an armoured car into a dangerous area.

[vangonebuy]

2 thoughts on the run flats.

 

1) the handling on my Pirelli's P7 tested better then the same tires with a run flat option.

 

2) the ability of the tire to go 50 miles on a flat, Doesn't mean that the same tire can ever be repaired after you stop.

[devinron]

Run flats have softer compound which can result to shorter tread life.

[stlouisgeorge]

I seriously doubt a run flat can be repaired.

 

I would love run flats. They will be my next tire. I drive 55 per day one way to work. I go through North St. Louis (highest crime rate according to analysis of FBI data from a few years ago). Then I go through East St. Louis. Right now I would have to stop and wait for assistance on a cold night on the side of busy urban I-70. I have them priced in a another thread from Bridgestone (their best tire) for about $900 out the door.