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E85 / E86 Z4 (2003-2008)
E85 Z4 convertible and E86 Z4 coupe talk with our BMW gurus here.

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  #1  
Old 02-06-2013, 07:12 AM
psfz4 psfz4 is offline
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Location: Cincinnati, Ohio
 
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Mein Auto: 2004 2.5i Z4
Z4 run flat tires

I bought a 2004 with 19,000 miles that has the original run flats on it. The tread is OK but they are pushing 10 years old, so I am planning to put on new tires. I am new to run flats and have read a zillion threads, which are often conflicting. I don't even understand the concept behind run flats, except that they are an excuse for leaving a spare and jack out of the car. As an engineer, I can't get my mind around a tire that:

1. allows you to drive 50 miles to somewhere when you get a flat.
2.once you get there the tire can not be repaired and must be replaced
3. when you get there, no one is likely to have a replacement or the equiptment to install run flats
4.If the tires have more than slight wear, they should be replaced as a full set?
5. some owners claim that run flats are more likely to get flats than conventional tires?

Am I missing something here?

Thanks in advance for explaing the logic to me.

PS If you put a spare and jack or a slime repair kit in the trunk, how do you tie it down so it doesn't fly around. Is your AAA card a better solution?
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  #2  
Old 02-06-2013, 07:46 AM
Solarus Solarus is offline
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Location: Pennsylvania, USA
 
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Mein Auto: BMW Z4 3.0i 2006
I swapped mine nearly immediately after buying my car for a $400 set of Sumitomos from Tirerack. Should I blow one - that's what my insurance policy roadside assistance is for. I honestly don't see many benefits from runflats, in case of severe damage they will explode like any other tire, while replacing or otherwise purchasing them is at least twice the cost of regular rubber.
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  #3  
Old 02-06-2013, 07:50 AM
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GeorgeT GeorgeT is online now
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What you really miss without runflats is a harsher ride and mediocre handling. Get a set of good, non-runflats and you will be amazed at the ride difference, plus they are less expensive.
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  #4  
Old 02-06-2013, 08:29 AM
Teacher Blind Teacher Blind is offline
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Location: Red Bluff, California
 
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Mein Auto: BMW Z4 3.0si
I had run flats.
Tramlining.
Harsh Ride.
Expensive to replace.
Wife did not like to drive the car.

I got go flats.
Tracks straight.
Smooth.
Quiet.
All of a sudden, my town had great roads to ride on.
My wife loves to drive the Bimmer now.

I miss the run flats.

Not.
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  #5  
Old 02-06-2013, 09:06 AM
ItalFigaro ItalFigaro is offline
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Mein Auto: 2006 Z4
Glad to see this thread... I have run flats and can't stand the ride. My other car has always had Bridgestone Potenza Pole Position tires... fantastic tires and I'm pretty sure that I'm going to swap these out.
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  #6  
Old 02-06-2013, 10:54 AM
Solarus Solarus is offline
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Not to push Sumis, but I'll be honest with you all - for the measly price Tirerack charges for them, Sumitomo are incredible. Quiet, great grip, take highway ramps at 65mph without a squeal. Had Potenza run-flats fresh out of the dealership - thought my front wheel bearings were shot.

Keep in mind: Front and Rear sizes are different, at least for the 17" sport package wheels.
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  #7  
Old 02-07-2013, 06:29 AM
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Pinecone Pinecone is offline
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1. Very stiff and thick sidewall to support the tread off the rim without air.

2. Because the sidewall folds and to the two parts rub against each other, it damages the sidewalls, thus they need to be replaced.

3. Oh well.

4. This is always a good idea. As a tire ages and wears, the traction characteristics change. And in doing so, you can change the vehicle dynamics to cause issues when you need the performance.

5. No idea.

BTW a number of BMWs and other cars did/do not have spares, even without run flats. Our M Roadster, E46 M3, and Fiat Abarth all are spareless, without run flats.
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  #8  
Old 02-07-2013, 08:07 AM
gaijin gaijin is offline
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Mein Auto: 2003 Z4 3.0i
+1. High performance tires are a much better alternative over run flats. With that said, Sumi's are great value performance tires to consider. Towing service, mobile phone and a credit card are good substitutes as spare tire in the event of the unthinkable.
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  #9  
Old 02-07-2013, 08:25 AM
STIHLBOLTS STIHLBOLTS is offline
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Mein Auto: 2008 Z4MR
06-08 - M Roadsters and Coupes came with regular tires and a fix a flat kit and air compressor. I had a 04 prior to this M and I stayed with Run Flats but went with a softer tire. Bridgestone vs Kumho. Kumho's were less expensive and had a better ride. You will never get the ride of a regular tire with a run flat. They have come a long way since their creation and I am sure that they will get better still. But if given the choice between a run flat vs regular, give me regular any day. It just boils down to your risk factor.

You are correct, there are thousands of threads comparing RFT vs Regular and you won't get but two answers, go or no go.

Best of luck.
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  #10  
Old 02-09-2013, 10:54 PM
Redflea Redflea is offline
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Quote:
Originally Posted by Teacher Blind View Post
I had run flats.
Tramlining.
Harsh Ride.
Expensive to replace.
Wife did not like to drive the car.

I got go flats.
Tracks straight.
Smooth.
Quiet.
All of a sudden, my town had great roads to ride on.
My wife loves to drive the Bimmer now.

I miss the run flats.

Not.
So far, truest, funniest post of 2013...

Sent from my Galaxy Nexus using Bimmer App
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  #11  
Old 02-10-2013, 06:08 AM
psfz4 psfz4 is offline
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So the only problem with go flats is that my wife will want to drive the car?

Last edited by psfz4; 02-10-2013 at 09:48 AM.
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  #12  
Old 04-16-2013, 06:44 PM
RMeter RMeter is offline
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Mein Auto: 2003 Z4 3.0
Michelin pilot sport ps2 with a $75 tire inflator/backup battery kept in trunk just in case. You will notice the smoother ride right away.
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  #13  
Old 04-18-2013, 12:30 AM
LRuano LRuano is offline
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Mein Auto: 04 530i, 04 Z4
Aaa card is a better bet, A+ gives you up to 100 mile tow, I got some conti for about $80 a piece, car runs great, run flats and expensive high performance are all over rated, unless you are driving on a race track, get some affordable tires, you will be fine
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  #14  
Old 04-19-2013, 11:24 AM
Deros50 Deros50 is offline
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Z4 run flat tires

Tried to get regular tires on run flat rims. Shops here would not install because they said make up of rim specialized to run flat tires. They say that tire might seperate from rim at high speed. Bought new rims and Bridgestone's 760 RE sports.


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  #15  
Old 04-19-2013, 11:01 PM
Bucko521 Bucko521 is offline
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Quote:
Originally Posted by Deros50 View Post
Tried to get regular tires on run flat rims. Shops here would not install because they said make up of rim specialized to run flat tires. They say that tire might separate from rim at high speed. Bought new rims and Bridgestone's 760 RE sports.
There is no such thing as a run-flat rim. The shop just wanted to sell you a more expensive tire I suspect.

I'd love to hear how they think non-run flats would separate!!

I just replaced my tires with RFT, but I made the choice to do that...no a tire shop.
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  #16  
Old 04-20-2013, 05:44 AM
psfz4 psfz4 is offline
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Mein Auto: 2004 2.5i Z4
As I understand it, there are two run flat systems out there. One type has a supporting rib in the center of the wheel to support the tread in the case of a flat. These wheels are most definately different than conventional wheels. The more common type (used on BMW) has thick, stiff sidewalls on the tires which can support the tread in the event of a flat. The wheels for this type are also different, but I am not sure how. I suspect that the wheel bead is stronger/deeper/ heavier, but I am not sure which. What I do know is that there is no problem putting non run flats on this type of wheel, but not all tire changing equiptment can handle run flat wheels. I recently switched to non run flats and had to check around to see which shops had the right equiptment to remove the old run flats from my wheels, and some did not. I will say that in all the bazillion posts about run flats on this and other forums, this is the first time I have ever heard of someone putting run flats on a car that originally had conventional tires. I sure hope you car has a tire pressure monitoring system, because diving on run flats that have less than 15 psi in them results in a non repairable tire.

Last edited by psfz4; 04-20-2013 at 12:26 PM.
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  #17  
Old 04-23-2013, 01:15 PM
jman1975 jman1975 is offline
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Quote:
Originally Posted by Deros50 View Post
Tried to get regular tires on run flat rims. Shops here would not install because they said make up of rim specialized to run flat tires. They say that tire might seperate from rim at high speed. Bought new rims and Bridgestone's 760 RE sports.
interesting...

I put Hankook V12s on my OEM wheels, no problems
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  #18  
Old 04-20-2013, 08:29 AM
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Zedfor Zedfor is offline
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Mein Auto: 2003 Z4, 2007 X3
Z4 run flat tires

Best thing I ever did was to ditch the run flats for Conti Extremes.


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  #19  
Old 04-23-2013, 09:22 PM
Daego Daego is offline
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I fitted 4 Goodyear F1 Asymmetric 2 non-runflats on my factory Z4 108-style wheels last summer and never looked back. It's a great improvement, as Teacher Blind discusses above. Anyone that tells you need special wheels in order to install non-RFTs is full of equine dung.
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  #20  
Old 04-24-2013, 10:01 AM
STIHLBOLTS STIHLBOLTS is offline
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Mein Auto: 2008 Z4MR
I did the same, on 2004 3.0, took run flats off and put Kumho tires on with no issues from local tire dealer. Wonderful difference in the ride.
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  #21  
Old 04-24-2013, 12:02 PM
deuce32 deuce32 is offline
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Mein Auto: 2007 BMW Z4 si3.0
Ditched the runflats

I got rid of the Bridgestone runflats and bought a set of Coopers for my '07 3.0si. Have been amazed at the difference in the ride, handling, quiet, etc. Put a scissors jack, plugger, and small compressor in trunk just in case. Can't remember the last time I ever had to actually change a flat on one of my cars.
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  #22  
Old 04-24-2013, 01:10 PM
Z3Papa Z3Papa is offline
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I've been driving my Z3 without spare or run flats for going on six years. The spare which sits in my garage is virtually useless. Get a mobility kit if it makes you feel more secure.
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  #23  
Old 04-24-2013, 01:26 PM
ItalFigaro ItalFigaro is offline
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You know, I think I can call for roadside assistance with 1) BMW or 2) my insurance company. Either way, I would be covered, I would think. Given that our tends to not go too too far (not yet, anyway) I can't find a good excuse to keep the run flats.
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