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-   -   How do our RFT's really work? You actually should drive on em if a flat occurs? (

K-A 02-26-2013 04:15 AM

How do our RFT's really work? You actually should drive on em if a flat occurs?
I've been imagining just how much smoother this already super smooth car can be with a proper set of tires. To be honest, I can't notice any downfalls to my RFT's since the car does ride so smoothly especially being on 19" wheels with a low suspension in stock form, but again I have no comparison points with non-RFT's on this particular car to compare to.

So figuring that for using such an apparently crappy set of tires on our cars, there has to be SOMETHING good about it, are they *really* safe to drive on if we blow a tire? And for how long? It seems like something that should get anyone paranoid, driving on 19" expensive rims with a blown tire, RFT's or not.... but again, if RFT's are NOT capable of truly being driven on during a flat, then what's their point? I.e you don't get any benefits from such a rough tire.

If there's anything that paranoias me about the RFT's deterring from ride comfort and shock-absorbsion it would be accelerating or being the reason to any interior rattles. I'd hate if RFT's would even rough things up to cost me even one interior rattle due to it.

BTW, my car has Pirelli P-Zero Nero RFT's, which I've heard is a new offering on just 2013 cars. Not sure if that's true, but if so, would there be a possibility that it's a superior RFT, which is why I don't have too many complaints toward it yet?

mryakanisachoad 02-26-2013 04:34 AM

I have no basis for this claim other than my general knowledge of tires: I'm certain the Pirellis are far superior to the Goodyears.

mryakanisachoad 02-26-2013 04:44 AM

Not a large enough sample of reviews on TireRack to be definitive but the good thing is that there were no outliers (best tire ever! / worst tire ever!).

Seemed like average to above average responses which is really good for run-flats.

jjsC6 02-26-2013 04:50 AM

I have not driven on a flat run-flat despite having had several cars with them (my current BMW and several Corvettes). But I know people who have and they say you cannot even tell they are flat. I will tell you this though, if you think your car rides well with them you are wrong. If you switched to non-runflats you would notice the difference within a couple of miles. I know that because I've switched several times on my Corvettes, and I can tell that my BMW has runflats. You must have awfully good roads where you live if you can't tell.

K-A 02-26-2013 04:59 AM

I actually didn't mean that I can't tell because the RFT's are so good. I said I can't tell because the car is so inherently smooth that I can't tell what the RFT's are hurting, since I have nothing to compare them to on this exact car. I'm sure they're regressive since everyone says they are. Like I said, my biggest concern other than not being able to experience just how smooth this car is with smooth tires (the thought of this car on proper tires now just makes me geek out in excitement yet then despair since I now feel like my cars comfort engineering is being held back by subpar riding tires), but that if they're THAT rough, they'd potentially "loosen up" the car and interior prematurely.... I guess you can call that a paranoia, hopefully too dramatic to be realistic (though rougher tires will transmit more harshness to the chassis and interior).

mryakanisachoad: Thanks for the info. That's kinda hopeful since people seem at least moderate toward the Pirelli RFT's, which as you pointed out, in RFT world seems to be a great response.

qadhi79 02-26-2013 05:08 AM

My goodyear RFT was busted with literally a hole in the sidewall on my old E60 530i..RFTs do not go flat (duh) so I only came to know about the hole from the tyre pressure sensor and a loud noise of air escaping the tyre..even with no air the tyre looked almost round!

Called my BMW SA and was told that I can easily drive it around and come to dealership for a change but I had a flight the same day and drove on the busted RFT for around 60kms before leaving it with BMW for a replacement

To tell you the truth, I did not even feel that I am driving with a flat tyre..before this incident I was skeptical of the RFTs but now I really think they are a must in a family car

Sent from my GT-I9300 using Bimmer App

mryakanisachoad 02-26-2013 05:12 AM

I'm not sure where you live but if you're not having any issues with the Pirelli's and you're not in the mood to spend 1500 bucks right now to grab some Michelins I say stick with them.

Run-flats have come a long way since 7 or 8 years ago , especially depending on the manufacturer.

I literally cannot use those Goodyear run flats where I live. And, you do make a good point about what cost does this convience come at? Suspension parts on these cars ain't cheap. I remember horror stories from guys back in 2006 who literally had strut towers getting blown up because of those OEM run-flats. It's great if you can drive around on a flat tire: not so great if your stut towers have shot through your hood.

Another problem was with these delicate active headlight rigs. Remember all the sad eyes?

MoldCAD 02-26-2013 05:19 AM

What do you guys think about the Continental ContiSportContact RFTs?

I have them on the M 18" wheels (my car came with them), but didn't drive on them yet as I replaced them with my set of winter wheels before even leaving the dealer...

radarguy 02-26-2013 05:34 AM

My experience on the 19" LS2 is that it is very obvious when the tire goes flat. I had a sidewall blowout. They tell you not to drive over 50 MPH and believe me you won't want to. You can feel it in the steering and there is some vibration and I suppose the braking suffers also. I suspect that there would be less vibration with a simple puncture flat. But, you can definitely drive it unlike a blowout on a conventional tire. I drove it for 60 miles without any drama and the rim was not damaged. They definitely "run flat" and do a good job on that count.

The X Men 02-26-2013 05:36 AM


Originally Posted by MoldCAD (Post 7405309)
What do you guys think about the Continental ContiSportContact RFTs?

I have them on the M 18" wheels (my car came with them), but didn't drive on them yet as I replaced them with my set of winter wheels before even leaving the dealer...

I have those on my F10, nice tires, smoother than the GY and better in the foul weather.
Run flat will ride a bit stiffer when compare to the non-runflats, The gap is closing though, I remember my 1st set of runflats from 6 years ago, the ride was much worst. Personally, I think BMW did a great job designing the F10's suspesnion to ride the way it does with the runflats. I had the same Conti tires on my last A6 but in a non-runflat version and it did ride a bit smoother. It really comes down to risk vs benefit. Personally, I think the F10's ride is smooth enough with my 18" Conti runflat that I will not compromise safety for a little bit of comfort.

MoldCAD 02-26-2013 05:46 AM

Thanks, X Men - cannot wait for spring even more now :)

mjsbmw 02-26-2013 06:15 AM

Our F10 suspension has been designed to accept the stiffer sidewall of runflats and the safety factor of having to avoid changing a flat tire on the side of a busy road or in the rain is worth the compromise.

From what I have read, the experience of those who have 19 inch wheels is significantly more problematic than those with 18s and even less so with 17s. No surprises right?

As to the Goodyear LS2 runflats, I have them on my 18s and they are just fine. They do not handle like Michelin Super Sports (non runflats) but no runflats that I can think of equal that kind of tire performance as of now. My only complaint is that they cost $300 a piece from Tirerack. $

As to durability, I hit a fairly significant pothole three weeks ago and the Goodyear tires were not damaged although the inside wheels on the right side developed a slight bend which caused vibrations. That was easily repaired.

RambleJ 02-26-2013 07:13 AM

I had rft's on my 07 & 08 335s and on my 08 535. On those cars the stiffness of the rft's was horrible. They made every bump, road crack jolt the car with some violence, granted those cars suspension was a lot better and lower to the ground.
The benefit of the rft's is that you can drive on them in the case of a blowout or flat. You will know the car has a flat obviously thanks to the tpms. I have since changed out my front two tires due to the known rft bubbling and have not had any issues since.

Stonehauler 02-26-2013 08:36 AM

You can drive in it, but if the bead unseats, you will be stuck. My wife's 3 had a flat, the bead unseated and we ended up having to flatbed it to a tire place. I am just thankful it happened near home (subdivision) and not someplace in the middle of nowhere on a day the stores are closed.

Gilgorm 02-26-2013 11:24 AM

I have 18" Dunlop SP Winter Sport 3D runflats. Last weekend, I (and a passenger) were headed to the airport when the FTM went off. Canadian cars don't have TPMS but they have the almost useless FTM. They do their job but only when the tire has no pressure.

Anyway, I was on the highway in heavy snow when it went off. I had no idea the tire was flat other than the back end was 'squirmy'. I continued to the airport, picked up two passengers and their luggage and drove home. The tire was definitely flat. There was no air pressure.

After the holiday weekend, I pumped up the car in my driveway but could hear air escaping. I drove to my trusted independent. The FTM did not go off because there was a small amount of air left by the time I got there. They were able to source a new, exact tire, replaced my dead one and sent me on my way. More than $410 + tax.
I was able to see the damage and three installers had a look at the inside. The inside looked the same as the new one but the more I drove on the old one I had noticed the car was getting lower and lower as the sidewalls were slowly bowing out. The actual hole was from a 3.5 inch tapcon screw right through the centre groove of the tire. It took two guys with pliers to remove it. The belts were showing on the inside. The tire was not repairable. I doubt a regular tire would have survived.

I drove about 60km (37mi) but was very careful and watched my speed. I do wonder what would happen if I had been on a road trip with no spare and a long way from home. The tire definitely did its job. Until the end of the trips I could not tell visually if the tire was totally flat. Snow on the tire and the road didn't help. Kicking it doesn't help either. LOL I had to test it with a gauge.

alewifebp 02-26-2013 08:37 PM

I knew right away when my OEM RFT went flat after I hit a pothole. Besides TPMS informing me, the car was harder to drive and was also very loud. It did allow me to get home and to the dealer the next day. Of course, they didn't have a replacement in stock, but that's a whole other story. So it was usable, but not very.

By comparison, I reported in this forum when I hit another pothole. This one was hit at a much higher rate of speed, and was with my then new Michelin Pilot Sport A/S Plus tires. Wouldn't you know it, besides some additional vibrations, the car was still plenty drivable at high speeds, but developed a bubble. I shortly got that replaced as well. Long story short, the conventional tire had a better degradation than the run flat. YMMV.

whitby 02-26-2013 09:12 PM

I have had several BMW models with run flats that I have had the 'opportunity' to drive while actually flat.

2006 Z4 Coupe E86 Sport Package: Terrible tires, noisy and made the handling and ride awful. Had two occasions when the tires got nails (both in the rear). Could not tell the difference on normal roads. Noise etc. did not change at max allowable speeds. Bridgestone. Replaced with Michelin Pilot Super Sport RFT which helped dramatically with noise and ride but handling became suspect.

2007 530i E60 Sport Package: Excellent experience. Quiet with no issues for handling or ride quality. Two punctures. Again the car rode and handled on normal roads without a problem at max allowable speed. Drove safely to dealership in one case and Discount Tire the other time. Repaired once, replaced the second time since they were also worn. Continental

2012 528i F10 MSPort Package: Tires are noisy. Handling fine. Ride slightly uncomfortable (not smooth) but improve as they warm up. Puncture in rear right tire. Replaced under tire warranty/protection by dealer. Drove safely to dealership no issues. Noise and handling changes undetectable at max allowable speed on normal roads. Continental.

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