Carmakers increasingly under fire for using run-flat tires

[Zafiro]

As the number of cars being equipped with run-flat tires increases car buyers are quickly learning that the new design is not all that it's cracked up to be. One automaker adamant in its decision to equip its cars with run-flats instead of installing a proper spare in the trunk is BMW, and it's now starting to experience a consumer backlash from that decision. Many of its customers are frustrated, not only at the shortcomings of the tire itself but also because of the exorbitant bill they face once the tires need to be replaced. Note that many service centers are unable to fix run-flats, and you can forget about re-treads (though that's probably a good thing).

Apart from the high cost of replacing the tires, run-flats are harder to come by and they don't last as long as regular tires either. Though the idea of not having to worry about changing the tire if it gets punctured sounds great, run-flats only have a range of about 50 to 100 miles once the rubber is damaged. Not much solace if you happen to hit a spike in the middle of nowhere.

Along with BMW, Corvette also has run-flats, and Toyota and Honda put them on some minivans.

Apparently, run-flats were introduced because consumers want "the smallest amount of hassle in their lives," according to an engineer from Bridgestone. Perhaps it's time drivers were forced to learn how to change a tire as part of their licensing tests.

[Source: MSN]

 

[PanterroR]

I know i won't have them on my car anymore...

 

[martinbo]

The idea behind run-flats in the urban environment is spot on; I'd rather have my wife limp home on a run-flat than have to attempt changing a tyre in the dark of night on the side of the road.

That said, run-flats cannot be seen as a replacement for a full-sized spare wheel in countries with vast open spaces such as Southern Africa and Australia. One must appreciate that run-flat mileage is further limited to the load borne by the vehicle, so typically, when you're on your way to your holiday destination you've got the kid(s) in the car and a trunk full of luggage. Immediately your range on the run-flat is drastically reduced. This is obvious because the reiforced tyre walls have more load to bear and thus lose their form more rapidly.

What I want to see in the future is that all tyres offered are run-flat capable but the car itself has a full sized spare located in the trunk. The pricing and availability of run-flat tyres over here is ludicrous. I have two mates with E90s and 17" rims and when the go away they pack a full-size rim with tyre into a trailer!!!

Run-flats absolutely have merit but they must not be used as an engineering cop-out to increase boot space by virtue of the omission of a full size spare. The new Merc C-Class has one over the E90 in this respect.

 

[Merc1]

Perhaps it's time drivers were forced to learn how to change a tire as part of their licensing tests.

Amen! Most people have no clue and for a man this is a shame IMO.

M

 

[PanterroR]

Amen! Most people have no clue and for a man this is a shame IMO.

M

Exactly!

Even my wife knows how to change it in few minutes, no kidding.

 

[Merc1]

That said, Mercedes' jacks are lousy as hell. At least they were on the W208 CLK I have!

M

 

[martinbo]

In SA where the risk of crime is high, my wife is instructed to drive to the safest location (even if that means getting home) on a flat tyre. If the rim gets damaged, tough sh!t. That's what insurance is for.

 

[Zafiro]

I know I will change my runflats for real tires when they've been worn out.

Runflats are heavy compared to normal tires so I understand why the M5 isnt using runflats.

 

[martinbo]

Also, with their stiffer sidewalls, run-flats give engineers less scope to fine tune the suspension for the optimum ride / handling compromise. This and the higher unsprung mass you mention above is the reason that M uses conventional tyres.

 

[Anisc]

Agreed. If I have a flat at 11 p.m on a sunday night, I rather limp back home than sit by the road side changing tires. Still at 80 kms/hr max with run flats that's pretty fast limping.

In SA where the risk of crime is high, my wife is instructed to drive to the safest location (even if that means getting home) on a flat tyre. If the rim gets damaged, tough sh!t. That's what insurance is for.