: Run Flat Tires...



Peyton
06-27-13, 08:18 PM
Hey all,

BMW used run flats on their 3 series and no one liked them, loud, uncomfortable etc. But Cadillac decided to copy them so they can be as much like the 3 series as possible and I think it was a bad choice, I'd rather have summer or all season tires but question is, how long should they last? I've heard they last about 7,500 miles... which would be terrible. Also can I replace them with all-seasons when these wear out or am I kinda stuck with buying more expensive runflats that are noisy and I don't prefer?

I have the 3.6 premium and with the bose noise cancellation I can hear the engine faintly but the tires are what generates most of the noise IMO.

Felton10
06-27-13, 08:45 PM
I was told the tires cost about $ 350 each to replace, but that I could also replace them regular all season tires when they wore out. Didn't tell me what the mileage life on them was. But with no spare-would be tempted to get them again.

MASCAD
06-27-13, 09:16 PM
Hey all,

BMW used run flats on their 3 series and no one liked them, loud, uncomfortable etc. But Cadillac decided to copy them so they can be as much like the 3 series as possible and I think it was a bad choice, I'd rather have summer or all season tires but question is, how long should they last? I've heard they last about 7,500 miles... which would be terrible. Also can I replace them with all-seasons when these wear out or am I kinda stuck with buying more expensive runflats that are noisy and I don't prefer?

I have the 3.6 premium and with the bose noise cancellation I can hear the engine faintly but the tires are what generates most of the noise IMO.


I suspect that the reason the ATS uses run flats has nothing to do with BMW at all but rather is more of a weight & space saving measure. Cadillac has used them for this very reason on previous models as early as 2004. Other manufactures likewise have and do use them for the same reason.

Hoosier Daddy
06-27-13, 09:43 PM
I think the main reason for the run flat tires is to improve fuel mileage (i.e. reduce weight). Basically they let them eliminate a heavy spare tire. Some manufacturers just replaced the spare with a can of stop leak and a small air compressor. Ford's version weighs around 5 lbs, MUCH less than a spare tire. Both solutions have resulted in some angry customers. I didn't much like it the first time I had a car without a spare. Now I appreciate the weight reduction, not just for mileage but for improvements in acceleration, handling and braking too.

The run-flats can be replaced with regular tires which is what I plan to do when these wear out. Of course they will leave you stranded in case of a puncture unless you keep something in the car to stop a leak and re-inflate the tire.

Run flats do not have to make for a stiff ride. Some of the initial complaints were due to the springs and shocks not being softened enough to compensate. The other side of that coin is that switching from run-flats to regular will soften the ride at some expense to handling.

bluecrayon
06-27-13, 10:12 PM
I was told that "you shouldn't have to replace the tires for the 36 month lease" which is obviously a bunch of bs.....however I was also told that if I need to I can replace them with whatever I want.

RonboATS
06-27-13, 10:19 PM
I traded in a 2011 Camaro 2SS/RS with 11,000 miles on the ATS. The Camaro had the stop leak/air compressor method for replacing the spare tire. I don't want to jinx myself but in 32 years of driving I've had two flat tires. I'll dump the run flats for regular all-seasons when the time comes.

ben.gators
06-27-13, 10:49 PM
I was told that "you shouldn't have to replace the tires for the 36 month lease" which is obviously a bunch of bs.....however I was also told that if I need to I can replace them with whatever I want.

It is a common practice, especially among BMW owners, that they replace the run flat tires with regular, high performance tires and at the end of lease term they simply mount the run flat tires back and return the car.

I am not sure what exactly your dealer mean by "you shouldn't have to replace the tires for the 36 month lease"?
1- Because this is a leased car, you don't have the authority to change the tires.
OR
2- At the end of lease, you are not required to replace the tires with new one.

I believe 1 is definitely wrong. You can do it.
And 2 may or may not be true. If the tires are completely worn out, or damaged, they may (and I think will) force you to replace the tire or may charge you for the tires.

Any idea?

73JPS
06-27-13, 11:17 PM
It is a common practice, especially among BMW owners, that they replace the run flat tires with regular, high performance tires and at the end of lease term they simply mount the run flat tires back and return the car.

I am not sure what exactly your dealer mean by "you shouldn't have to replace the tires for the 36 month lease"?
1- Because this is a leased car, you don't have the authority to change the tires.
OR
2- At the end of lease, you are not required to replace the tires with new one.

I believe 1 is definitely wrong. You can do it.
And 2 may or may not be true. If the tires are completely worn out, or damaged, they may (and I think will) force you to replace the tire or may charge you for the tires.

Any idea?

Those are not the only two options... Option '3', and probably the most logical, is "Based on the number of miles included in a standard 36 month lease, you will not have worn the tires enough to require replacement".

KXAM
06-27-13, 11:20 PM
NOTE: All Corvettes have come with runflats for a long time. Mostly Goodyears and very frankly, they are C R A P! I replaced mine at 17,000 miles because they were far too noisy and the traction was getting worse and worse.. Our ATS at least has the Michelin ZP tires which are much better than Goodyear. I replaced my runflats with Hankook tires all around. Even with the 'vettes big sizes they only ran me $800, all-in and out the door. The Goodyears would have been closer to $1400. Michelin even more, like $1800! GM is doing the runflats to keep weight down and save a few bucks no doubt. For sure they are not trying to copy BMW.
I keep a small compressor in the back and a can of Slime, plus I have the best AAA program. I am also a risk taker and have only had one or two flats in 50 some year of driving. Runflats are either you love them or you hate them kind of deal.
Conservative folks tend to really like them as do most folks that wear tin foil hats. each to his own....

Fraggy
06-27-13, 11:23 PM
I have no desire to switch to conventional tires. The ride us waaay smooth enough.

Everyte I switched in BMWs I always regretted it as it lead to suspension mods to take up the slop of the softer tires coupled with the mushy soft bushings they used to compensate for the stiff RFTs.

ben.gators
06-27-13, 11:26 PM
Those are not the only two options... Option '3', and probably the most logical, is "Based on the number of miles included in a standard 36 month lease, you will not have worn the tires enough to require replacement".
I agree, that makes sense, and that's why I haven't replaced the run flat tires, yet!
Do you know in average, how many miles will these run flat tires last?

GJB
06-28-13, 12:16 AM
According to the Michelin web site The summer tires that can't be rotated due to front/rear width difference have a tread wear warrantee at half that of the all season ZP which are 30K for tread wear and 45k for workmanship. So summer ZP on the ATS 15K and the all season 30 K.

bungee91
06-28-13, 10:05 AM
I have no complaints with the Bridgestone Potenza REO5A's that the premium RWD's come with. They handle exceptionally well, and aren't noticeably noisy. These are summer tires, so I switch to a dedicated set for winter and that helps save some miles on them.

I previously had Michelin Pilot Super Sports (these are non run flats) on my Z4 M and even though they may have been a tad bit better I'd be lying if I said I really noticed the difference.

M5eater
06-28-13, 10:19 AM
Hey all,

BMW used run flats on their 3 series and no one liked them, loud, uncomfortable etc. But Cadillac decided to copy them so they can be as much like the 3 series as possible and I think it was a bad choice, I'd rather have summer or all season tires but question is, how long should they last? I've heard they last about 7,500 miles... which would be terrible. Also can I replace them with all-seasons when these wear out or am I kinda stuck with buying more expensive runflats that are noisy and I don't prefer?

I have the 3.6 premium and with the bose noise cancellation I can hear the engine faintly but the tires are what generates most of the noise IMO.

They last 7,500 miles because you bought a car with summer tires which have 140 tread wear.

7.5-10K is about right for a 140 Treadwear tire.

Personally I'm glad they're RFT's it frees up space in the already microsopic trunk that would otherwise be occupied by a spare or a canister.

if you would still rather not have them, get AAA or equivilent.

mikesul
06-28-13, 10:33 AM
I took the 18" RFT set of wheels and tires off at 230 miles. Replaced them with 18"x9" rims and 255.35.18 tires by Kumho. Much better roadhandling and traction in the rain. Have the original set for sale, if anyone is interested PM me.

Fraggy
06-28-13, 10:47 AM
They last way more than 7500 miles, I'm almost at 8000 and they are nearly new still.

MASCAD
06-28-13, 11:39 AM
I was told the tires cost about $ 350 each to replace, but that I could also replace them regular all season tires when they wore out. Didn't tell me what the mileage life on them was. But with no spare-would be tempted to get them again.

Looking at Tirerack the OEM Michelins for a AWD w/ 18" wheels are more like $200 each

KXAM
06-28-13, 12:26 PM
Just one further comment: runflats in general do not get noisy and loud till they have worn down by 40% to 60%! On the drive wheels, traction starts dropping off much sooner. The harder the tire [i.e. higher tread wear #] the faster you will see a traction loss. On a Corvette, that means rear wheels will spin extremely easy with only 30 or 40% tread wear with runcraps! Do not kid yourselves, right now you may love your runflats but visit back here in a year or two and provide your comments after you have put 12,000 to 18,000 miles on them.! I have never heard of a Corvette owner having to do some sort of suspension adjustment after putting on non-runflats! That must be some BMW spun wives tale! Or, a way for them to make more $$$. And don't tell me a BMW's suspension is superior to a Corvettes suspension!!! Oh yes, and do be careful in the rain with 40%+ wear....do you like ice skating?!

bravnik
06-28-13, 12:52 PM
All I know is that I got a nail in mine the other day and Wheel Works and Firestone would not touch it. I had to take it to Cadillac and they were able to patch it. I had a quote for $342 (if I remember right) after taxes for the tire from Firestone (with insurance).

I plan on replacing them with summer tires when the time comes. I have free towing with both Cadi and my insurance so I might be inconvenienced but who cares. Unless the summer tires are really close to the cost of the RF's, then the RF's are out.

RxATS
06-28-13, 01:39 PM
I'm about to reach 10k and still have plenty of tread remaining.

bluecrayon
06-28-13, 11:45 PM
It is a common practice, especially among BMW owners, that they replace the run flat tires with regular, high performance tires and at the end of lease term they simply mount the run flat tires back and return the car.

I am not sure what exactly your dealer mean by "you shouldn't have to replace the tires for the 36 month lease"?
1- Because this is a leased car, you don't have the authority to change the tires.
OR
2- At the end of lease, you are not required to replace the tires with new one.

I believe 1 is definitely wrong. You can do it.
And 2 may or may not be true. If the tires are completely worn out, or damaged, they may (and I think will) force you to replace the tire or may charge you for the tires.

Any idea?

I think they were just trying to tell me that normally the tires don't need replacing after 36,000 miles, which I doubt since I've never gotten that many miles out of a tire. I'm not sure if you'd be charged if after the lease is up the tires were about shot. I'd say after about 36k miles they'd either be about ready to replace or already replaced. I personally am not yet sure if I'd replace with factory tires or go with something else.

Stevo Supremo
06-29-13, 12:34 AM
I have the run flats and they performed AMAZINGLY at the track, wayyyy better than the Pirellie P0's my cobalt had. Other than them weighing a bit more than the average tires I absolutely LOVE them.

David
06-29-13, 04:41 PM
I was dubious about my ATS having run-flats, as I've never had a car with them before (my last two cars were a '08 CTS and a '10 CTS); so far, I can't tell much difference in ride quality/noise compared with these... will see how it goes over the next 24 months.

Hoosier Daddy
06-29-13, 05:14 PM
I was dubious about my ATS having run-flats, as I've never had a car with them before (my last two cars were a '08 CTS and a '10 CTS); so far, I can't tell much difference in ride quality/noise compared with these... will see how it goes over the next 24 months.
Ride quality can be identical IF the springs and shocks are properly designed for them. Most complaints stem from cases where run flats were substituted on a system designed for softer sidewalls. Tire sidewalls act as springs. To keep the same effective overall spring rate, you have to soften the springs when you stiffen the sidewall and vice versa.

M5eater
06-29-13, 07:23 PM
Ride quality can be identical IF the springs and shocks are properly designed for them. Most complaints stem from cases where run flats were substituted on a system designed for softer sidewalls. Tire sidewalls act as springs. To keep the same effective overall spring rate, you have to soften the springs when you stiffen the sidewall and vice versa.

typically going harsher with RFT yields poorer results in that spring rates are not compensated for, and RFTs are generally horrible for traction.

Going backwards (from a RFT designed suspension to normal tires) is typically more favorable just by nature that you can get into a much better tire.

investor74
06-29-13, 11:53 PM
Hey all,

BMW used run flats on their 3 series and no one liked them, loud, uncomfortable etc. But Cadillac decided to copy them so they can be as much like the 3 series as possible and I think it was a bad choice, I'd rather have summer or all season tires but question is, how long should they last? I've heard they last about 7,500 miles... which would be terrible. Also can I replace them with all-seasons when these wear out or am I kinda stuck with buying more expensive runflats that are noisy and I don't prefer?

I have the 3.6 premium and with the bose noise cancellation I can hear the engine faintly but the tires are what generates most of the noise IMO.

Many tire stores refuse to mount regular tires in place of OEM run-flats. You might have to shop around a bit.

Fraggy
06-30-13, 01:15 AM
Just one further comment: runflats in general do not get noisy and loud till they have worn down by 40% to 60%! On the drive wheels, traction starts dropping off much sooner. The harder the tire [i.e. higher tread wear #] the faster you will see a traction loss. On a Corvette, that means rear wheels will spin extremely easy with only 30 or 40% tread wear with runcraps! Do not kid yourselves, right now you may love your runflats but visit back here in a year or two and provide your comments after you have put 12,000 to 18,000 miles on them.! I have never heard of a Corvette owner having to do some sort of suspension adjustment after putting on non-runflats! That must be some BMW spun wives tale! Or, a way for them to make more $$$. And don't tell me a BMW's suspension is superior to a Corvettes suspension!!! Oh yes, and do be careful in the rain with 40%+ wear....do you like ice skating?!

My god you're a genius. Lets all bow....

My point was that BMW suspension COULD NOT tolerate regular tires.

KXAM
06-30-13, 01:57 PM
My god you're a genius. Lets all bow....

My point was that BMW suspension COULD NOT tolerate regular tires.

Then why don't you state what you mean! And, there is no call for being a wise ass! I was just providing meaningful experience. Why does everybody on the net have to try to put someone down no matter the subject. I still do not understand your statement: "cannot tolerate regular tires"?! Sounds like BMW or German BS...."tolerate"....!!!

Fraggy
06-30-13, 05:47 PM
Let me try to help. The soft suspension and soft bushing meant to compensate for the stiff RFTs lead to too much mush when paired with soft conventional tires.

Then to compensate and get crisp handling back, we started to tighten up the suspension with aftermarket parts or M3 parts or a combination of both.

If you don't get it now I'm done.

M5eater
06-30-13, 06:07 PM
Let me try to help. The soft suspension and soft bushing meant to compensate for the stiff RFTs lead to too much mush when paired with soft conventional tires.

Then to compensate and get crisp handling back, we started to tighten up the suspension with aftermarket parts or M3 parts or a combination of both.

If you don't get it now I'm done.

The worst part?

Pilot Sport PS2 RFT: $1400 220 Treadware
Pilot Super Sport Non-RFT- $934 300 Treadware.

flycaster
07-01-13, 09:40 AM
Now I have to admit that I am no expert on how tires match to the car's suspension; but I have swapped out the RFTs on both my BMWs (2002 325i w/sport and 2005 BMW Z4) and have driven with regular M/S tires for the last 5-7 years. All I can say is that the rides have been great: Quiet and responsive, not mushy. Couldn't have asked for anything more. I do carry a small portable pump and tire-plugging tools. however, I must also say that for the ATS, I did take out tire/wheel insurance - around $300 for 4 years (getting a little older and not wanting to care about anything).

M5eater
07-01-13, 10:16 AM
Now I have to admit that I am no expert on how tires match to the car's suspension; but I have swapped out the RFTs on both my BMWs (2002 325i w/sport and 2005 BMW Z4) and have driven with regular M/S tires for the last 5-7 years. All I can say is that the rides have been great: Quiet and responsive, not mushy. Couldn't have asked for anything more. I do carry a small portable pump and tire-plugging tools. however, I must also say that for the ATS, I did take out tire/wheel insurance - around $300 for 4 years (getting a little older and not wanting to care about anything).

It's not as dramatic driving normally as we're making it out to be.

Most of this has to do with guys in 335i's having squirmy suspension on their 400whp N54's, or when you want to track the car.