O.T. Run Flat Tires

[duke]

I am in the process of shopping for a new vehicle. While looking at a BMW X3 I saw they come stock with run flat tires and no spare. In fact most of the new BMWs come this way. What are the opinions and real life experience with this type of tire. Any feedback is appreciated.
duke

[zap]

Never had run flats and never will.

I know folks who do (MB and BMW owners) and none like the ride of run flats.

Get the dealer to swap tires and put a can of fix a flat or whatever in the trunk.

[AngryScientist]

had run-flats. they sucked. heavy, loud, UBER expensive.

mostly wore them out, put standard high performance tires on the car, and a spare wheel/tire in the trunk. bliss.

[witcombusa]

Yep, they suck

Heavy, less responsive, stiff ride, overpriced and simply not needed. BMW used to pride themselves on having full sized spares.....those were the days.

[crownjewelwl]

they ride like bricks, but are convenient...

you don't appreciate them until you actually get a flat

[pjm]

They are awful things. Mine felt like they were made of concrete and were noisy as heck. Ditched them a couple of years ago. Replaced with 17" BBS wheels with Michelin Pilot Super Sports for the summer and the 16" stock wheels with Dunlop Winter Sport 3D for the crappy season. Bought a spare tire kit from Bavauto.com which takes up a little trunk space, but it works for me. Runflats are by no means failsafe - a sidewall gash will leave you stranded....

[Ken Robb]

Run-flats and suspensions designed for them have improved a lot since they were introduced so comments from early users should be taken with a grain of salt. Most drivers now can't tell their performance from regular tires.

They do cost more than average tires but not much more than ultra-performance tires. I think a big reason auto manufacturers use them is to save the weight of a fifth wheel/tire in the quest to meet CAFE requirements.

One drawback may be that a full range of sizes/designs won't be available in many tire shops. You can drive 50 miles at reduced speeds with a puncture. This is fine in Chicago but you may be stranded in the middle of Montana. I have heard of drivers having to wait a day or two while a replacement tire was shipped to a BMW dealer when they didn't have the correct tire in stock. In that situation I might buy the cheapest regular in my size to drive to the nearest place with the correct tire in stock. Usually big tire stores have decent used tires for sale so I might be able to buy one as a stop-gap. If I had to buy a new tire I could probably sell it as slightly used to the shop where I buy my new run-flat.

My 2007 MINI Cooper S came with run-flats. The ride was firm but all MINIs ride hard and mine has sport suspension so there is no way it will ride soft. Seeking to improve the car's handling on the track I replaced them with Bridgestone High Perfomance non-run-flats in a plus-one size. The original tires still had tread at 26,000 miles.

The new tires do stick a little better and ride with slightly less impact harshness at the cost of a slight reduction in fuel economy. I am now relying on AAA to tow me to a tire store or MINI dealer if I get a flat. I could add a "mobility kit" of sealant/compressor if I planned to drive where I might be stranded far from a tire store.

Given a choice I still prefer high performance regular tires but I think average drivers will be happy/better off with run flats and pressure monitors because so few drivers EVER check their tire pressures so many cars are a blow-out-in-waiting.

[witcombusa]

Run-flats and suspensions designed for them have improved a lot since they were introduced so comments from early users should be taken with a grain of salt. Most drivers now can't tell their performance from regular tires.

They do cost more than average tires but not much more than ultra-performance tires. I think a big reason auto manufacturers use them is to save the weight of a fifth wheel/tire in the quest to meet CAFE requirements.

One drawback may be that a full range of sizes/designs won't be available in many tire shops. You can drive 50 miles at reduced speeds with a puncture. This is fine in Chicago but you may be stranded in the middle of Montana. I have heard of drivers having to wait a day or two while a replacement tire was shipped to a BMW dealer when they didn't have the correct tire in stock. In that situation I might buy the cheapest regular in my size to drive to the nearest place with the correct tire in stock. Usually big tire stores have decent used tires for sale so I might be able to buy one as a stop-gap. If I had to buy a new tire I could probably sell it as slightly used to the shop where I buy my new run-flat.

My 2007 MINI Cooper S came with run-flats. The ride was firm but all MINIs ride hard and mine has sport suspension so there is no way it will ride soft. Seeking to improve the car's handling on the track I replaced them with Bridgestone High Perfomance non-run-flats in a plus-one size. The original tires still had tread at 26,000 miles.

The new tires do stick a little better and ride with slightly less impact harshness at the cost of a slight reduction in fuel economy. I am now relying on AAA to tow me to a tire store or MINI dealer if I get a flat. I could add a "mobility kit" of sealant/compressor if I planned to drive where I might be stranded far from a tire store.

Given a choice I still prefer high performance regular tires but I think average drivers will be happy/better off with run flats and pressure monitors because so few drivers EVER check their tire pressures so many cars are a blow-out-in-waiting.

The price alone (roughly double) is enough to nix the deal.

I'll be lucky to get 20k out of the factory RF tires on a '11 Cooper S. Fact is the rear "seat" in a Cooper is worthless for anything other than up to a medium sized dog w/real sized adults up front. So make room for a full sized spare and give me some proper tires!!!

[crownjewelwl]

They are awful things. Mine felt like they were made of concrete and were noisy as heck. Ditched them a couple of years ago. Replaced with 17" BBS wheels with Michelin Pilot Super Sports for the summer and the 16" stock wheels with Dunlop Winter Sport 3D for the crappy season. Bought a spare tire kit from Bavauto.com which takes up a little trunk space, but it works for me. Runflats are by no means failsafe - a sidewall gash will leave you stranded....

i'll take a run flat over a road tubeless any day of the week

[pjm]

To the guys in warm weather climes - spend a winter (and well into the spring)
here in the NE, aka pothole country, and then tell me runflats aren't so bad.:rolleyes: I also believe the runflats stiffer sidewalls contribute to more bent rims especially with wheels 18" and larger.

[19wisconsin64]

i've noticed a large difference in ride quality between different run flat tire manufacturers. my bmw 335 sedan rides on run flats. the original tires were final until they needed to be replaced, at which point the ride became harsh..the sidewalls lost whatever minimal elasticity they had after 4 years.

there are now michelin run flats, and the ride is compliant as can be expected for sport tuned car, with sport suspension, a low ride height, and short sidewall height. i like them, but the older tires (can't remember the brand) were terrible.

they have re-calibrated suspensions to accommodate run flats as original equipment, and if you get an X3 consider only advice on that specific model year.

i got bad advice from tire-rack on tires ordered from there, so your BMW dealer would be a good source of advice.

good luck!

ps, look for a post 2007 mid-year X3, they have a much better ride than the first versions of that small SUV. larger, better ride, better everything.

[esldude]

I have used them on a C5 Corvette which also come with them and are designed for them. They are stiffer. They also seem to communicate road feel better when driving in a sporting manner. I would think that good also in the BMW.

However, they ride a bit stiffer, mainly though they are so loud. Only a little loud when new, but as the tread wears down they get louder and louder. You might end up thinking of replacing them before fully worn out just due to noise. BMW may have that insulated somewhat better, but you will notice it. Also, Michelin run flats are less stiff and less loud than say Goodyears, but it all still applies.

I ended up with conventional tires. Carry some good tire sealant like Green Slim, and a small electric air pump. That would deal with most flats you get. Many cheaper tire sealants can cause trouble with the sensor that reports air pressure. One can also find small space saver spares and likely find a place for it in the trunk. Just make sure it clears your brake discs when you choose one.

For further peace of mind one can take the money saved and spend it on a AAA membership with money left over. That would be a last ditch fall back plan.

[Ken Robb]

I don't think tires get loud so much because they are run-flats. I think it is mostly due to the tread pattern on high performance tires. Their tread blocks tend to be larger than general purpose tires to minimize tread squirm when subjected to high G-forces. Fewer larger blocks generate a bit more noise and most of it is in a lower frequency that we can hear better.

When a tire is designed less for "performance" driving it will have more blocks of smaller and varied sizes. The size variation varies the natural harmonic resonance frequencies of the blocks so there is less noise generated and the noises different frequencies tend to cancel each other out somewhat.

[esldude]

I don't think tires get loud so much because they are run-flats. I think it is mostly due to the tread pattern on high performance tires. Their tread blocks tend to be larger than general purpose tires to minimize tread squirm when subjected to high G-forces. Fewer larger blocks generate a bit more noise and most of it is in a lower frequency that we can hear better.

When a tire is designed less for "performance" driving it will have more blocks of smaller and varied sizes. The size variation varies the natural harmonic resonance frequencies of the blocks so there is less noise generated and the noises different frequencies tend to cancel each other out somewhat.

Good try, but that isn't it. Very high performance tires with blockier tread and capable of even greater G-forces are quieter than run flats. I do think it is the stiff sidewall necessary for run-flat capability that makes them transmit more road vibration as noise versus a compliant tire. Pretty obvious really.

[djg21]

Run-flats and suspensions designed for them have improved a lot since they were introduced so comments from early users should be taken with a grain of salt. Most drivers now can't tell their performance from regular tires.


I agree with this. I have high performance runflats on my BMW 335xi, and they feel fine. I am in the market to replace my snows, and runflats are more expensive.

[Ken Robb]

Good try, but that isn't it. Very high performance tires with blockier tread and capable of even greater G-forces are quieter than run flats. I do think it is the stiff sidewall necessary for run-flat capability that makes them transmit more road vibration as noise versus a compliant tire. Pretty obvious really.

I'll be sure to pass this on to the engineers at Toyo Tire for whom I did test drives.

[jamesau]

I have 2 3-series with run-flats and I loathe those tires; they're the only reason I'd consider going to another brand of car when time comes due for another.
The impact harshness makes me cringe and swear out loud at NJ/PA potholes, the 50mph/50 mile range is a joke, my experienced and trusted repair shop won't patch them, they're expensive, and their availability is a concern (especially if you need a new one unexpectedly while on a trip).

I'd suspect the higher profile tires on the X3 would lessen the harshness concern, but then there are the other concerns. Plan out your test drive beforehand and aim right for your targeted sharp-edged NH pothole at speed and make up your own mind.

BMW makes great cars though.

[djg21]

I have used them on a C5 Corvette which also come with them and are designed for them. They are stiffer. They also seem to communicate road feel better when driving in a sporting manner. I would think that good also in the BMW.

If you would use larger diameter wheels on sports cars to increase performace while cornering, wouldn't it make sense to use tires with stiffer sidewalls too? While I might get a plusher ride with regular tubeless, the suspension in my BMW is designed to use with run flats and they perform fine. I also don't want to lose trunkspace to a spare.

[AngryScientist]

another of my gripes with run flats: i'm a roadtrip kinda guy. hit the road with a half baked plan. have fun.

puncture a runflat, and that pretty much kills the trip, or adds major inconvenience. with regular tires, you throw on the spare, and keep on chugging.

[esldude]

If you would use larger diameter wheels on sports cars to increase performace while cornering, wouldn't it make sense to use tires with stiffer sidewalls too? While I might get a plusher ride with regular tubeless, the suspension in my BMW is designed to use with run flats and they perform fine. I also don't want to lose trunkspace to a spare.

Yeah, to a point. Seems run flats have stiffer sidewalls than even stiff regular tires. Is that better? Depends. Everything is a trade off. A full race suspension setup is pretty stiff for daily road use. Can be done.

The point is run flats don't seem to offer any cornering advantage vs non-run flats while still riding harsher. They do have a different feel of directional stability which I like, but not with all the other baggage. The C5 wasn't setup for a comfortable ride exactly so maybe a car leaning a bit more toward compliance would tip things in the other direction.

[kestrel]

My Z06 came with conventional tires and no spare. Chevy engineers wouldn't compromise the ride and handling with runflats. I have a mini compressor, flat fix kit, etc. in the trunk area. 45,000 miles, never an issue.

[don compton]

I'll be sure to pass this on to the engineers at Toyo Tire for whom I did test drives.
I currently own my second Mini Cooper. My first ( an '08 S with 17" runflats ) was a nightmare on curves with ruts or grooves in the roads. The rear end would hope all over the road. After 12,000 miles of that bull****, I switched to conventional tires in the same size. The runflats had slightly better on center steering feel ( brutally stiff sidewalls ) but had far less adhesion. The non runflats transformed the car into a wonderful driving car.
My second Mini is equipped with 16" tires and rides better than the 17's. But as soon as these tires wear out, I will ditch the runflats. The runflats are about 200-250 dollars per tire. A high quality non runflat can be had for 90-125 dollars.
Runflats are no less prone to flats than regular tires. After you drive them flat, you have to replace the tire( $250 flat ). Extremely bad economics.
A no-brainer!!!!!!!

[pcxmbfj]

Didn't know my wifes BMW had runflats until they need replacement last year.

Replaced with regular tires and AAA membership, still saved money.

[djdj]

I could add a "mobility kit" of sealant/compressor if I planned to drive where I might be stranded far from a tire store.

.

I got a flat on my MINI with run-flats, so I tried an old can of fix-a-flat. It somehow leaked a bit on the wheel; I rinsed it off right away but the sealant ate away some of the paint on the wheel. I won't use it ever again. And it turns out I didn't need it becuase the flat run-flat got me 25 miles to the dealer with no issues.

[witcombusa]

I got a flat on my MINI with run-flats, so I tried an old can of fix-a-flat. It somehow leaked a bit on the wheel; I rinsed it off right away but the sealant ate away some of the paint on the wheel. I won't use it ever again. And it turns out I didn't need it becuase the flat run-flat got me 25 miles to the dealer with no issues.

Who wants to have to run to a tire store and waste a few hours at best just because they got a flat? Not me. Throw on a full sized spare and continue a few minutes later...

Run flats and tire pressure monitors answer a question no one was asking

[Ken Robb]

I guess I have to restate what I posted earlier: I replaced my OEM run-flats with regular high-performance Bridgestones.

[MerckxMad]

I've had RFTs on my last two BMW 328's over the past six years. The set of Bridgestones that came on my 2006 sedan were crap. At 20K, they cupped, and sounded like a truck driving on a flat. Horrible things. The Continentals on my 2010 seem to be a bit better due to a redesign in the suspension and better sidewall design. They still stink, but less so. The only time I appreciated the RFT was when my wife flatted on the highway at night.

[duke]

Great feedback. Thanks everyone.
duke

[djdj]

Who wants to have to run to a tire store and waste a few hours at best just because they got a flat? Not me. Throw on a full sized spare and continue a few minutes later...

Run flats and tire pressure monitors answer a question no one was asking

Full-sized spare? Ha. No room for one in a 2002 S. And only 1 flat in over 10 years ownership, btw.