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Thread: Z8 Tires

  1. #1
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    Z8 Tires

    Just bought a Z8 and would like to replace the run flats. I see a several posts trying various tires over time; any thoughts/recommendations after some mileage?

    Bridgestone R 11
    Continental Extreme DW
    BF Goodrich gForce Sport Comp.

    Love to hear some feedback!

    THANKS!!

  2. #2
    Z8 Guru 2112's Avatar
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    Don't forget Michelin.

    2000 Red over black
    heavily modified for performance. Although, not to the level of GM's car

  3. #3
    Team Z8 KenZ8's Avatar
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    2K dry miles on the gForce tires. It finally rained here so I just did 50 wet miles. Really wet miles. Still love the tires. The rain is already gone, so now washing the Z8 and getting ready to put the top down again.

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    I heard the Michelin Pilots are no longer available. No web sites or tire dealer carry the 275 sizes that I saw...

  5. #5
    Administrator thegunguy's Avatar
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    What size are you needing? Options vary widely by size.
    thegunguy

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    Thanks. I was looking to keep stock sizes: 245/45/18 and 275/40/18. I have heard good things about the Michelin Pilot SS tires. I would like to stay away fom run-flats. Input is appreciated!
    Thanks!

  7. #7
    Team Z8 Charles's Avatar
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    I think I got one of the last sets of Michelin PS2's which were the "go to" tire here for stock wheels. The last time I saw a thread, the new SS's did not come in both front and rear sizes for the 18's, but that may change over time. Ken's BF Goodrich's seem a great choice while we wait, particularly if you are going to drive the car some.

    Your profile says you have an Alpina, which has stock 20" rims rather than the 18's, and I believe the SS's are available for them.
    Charles Guerin
    AH61406 - Titanium Silver/ /Black

  8. #8
    Administrator thegunguy's Avatar
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    The BFGoodrich and RE11s are the best options options on the OE wheel right now.
    thegunguy

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    Whoops - Need to change my profile! Just bought a Z8 yesterday, not an Alpina. I am looking for 18 inch tires. It currently has the factory run flats which I will keep. The G-Force tires are very reasonably priced also.

  10. #10
    Z8 Madness
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    Congrats on the new Z8. Please share pics and info when you get a chance.

    I have Michelin PS2s (purchased about 3 years ago).
    2016 Porsche GTS/MT

  11. #11
    Z8Mania
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    Congratulations!!

  12. #12
    Team Z8 Charles's Avatar
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    I know I just posted this but beware of searching for the perfect tire and delaying the PP. If budget is a concern, a better choice is to get the PP and less expensive tires, rather than better tires and no PP. You will hit the proverbial 'pothole at 50 mph' and regret it. Get a PP and drive fearlessly.
    Charles Guerin
    AH61406 - Titanium Silver/ /Black

  13. #13
    Z8Mania
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    ^^^^ I agree with Charles. Get the PP and get the tires on there.

  14. #14
    Administrator thegunguy's Avatar
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    Charles has a great point, but I'd suggest getting RFTs off ASAP. 1) they're probably anciently old and even more rigid than new. 2) They're ridiculously heavy, and many of us suspect that their mass and rigidity increase the chance of damage, even on PP cars. 3) their interior sidewalls have been known to break off in chunks, which won't be discovered until you change tires.

    It's scary that many cars are still running around with the original tires equipped. Yikes!
    thegunguy

  15. #15
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    I again appreciate the input! Have had 3 cars with run flats and I ended up taking them all off. On my 335i if you ran over a dime you could tell if it was heads or tails. My wife drove her X5 80 miles on a flat without knowing it, until it blew up in chunks at 70 mph. (Yes, the TPM light went on, but it always does on the first real cold days of the year) The X5 even came with a run flat spare!?

    I will be installing the PP right away as I do intend to drive the Z8, but like most, only on special occasions. But when I do, I don't want to worry about damage!

    Really leaning towards the g-Force tires. Tread looks good also...

    Tom

  16. #16
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    I'm not sure I understand why you are all so keen to ditch the RFT's. The US sourced car I recently bought from 2001 with 4000 miles had its original run flats. BMW over here in England recommended I change them. As I am a stickler for originality I chose to replace them with new original spec Bridgestone RFT's. The old ones showed no signs of deterioration inside or out. I have however noted that the new ones do seem to give a smoother ride but that may just be a question of tyre pressure. I have however had the PP installed for peace of mind. Chris

  17. #17
    Administrator thegunguy's Avatar
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    Three reasons:

    1) they ride horribly due to their stiff sidewalls. On our rough CA roads, the experience is miserable.

    2) they're VERY heavy, and they have been linked to shock tower doming on several BMW models the, Z8 and 3 series in particular. The suspensions that were used with RFTs when they were introduced to the industry were not optimized or prepared for the additional unsprung weight and stiffness, including the Z8. They were an afterthought. RFT technology has gotten a lot better, but to be tolerable they require specific suspension calibration and reinforcement (go look at the difference in the towers on a E46 and an E90).

    3) they don't provide as much safety as the marketing for them might suggest. They require constant pressure monitoring with a gauge as they show now sign pressure change, and if you have a quick leak on the go, you get no feedback until they blow, as mentioned by Z8LVR. BMW's differenced based TPMS is a horrible fit for RFTs. It's entirely possible to lose pressure without a warning light - right up to the point of full RFT failure.

    So, with the increased potential for damage, horrible ride, and vapor-ware safety, many of us are MUCH more comfortable with traditional tires and a can of flat-fix or road-services in emergencies. RFTs have no benefits and a bunch of negatives.

    If you want to stay true to the way the car came from the factory, the RE040s are the only choice (for as long as the supply lasts), but your frame won't be "original" for long.

    Don't get me wrong, the availability of PP is great, and we're all thankful to BMW for providing it. However, the super heavy and stiff RFTs are very much a part of the potential for damage. I don't think you'll find anyone that was close to the issue in the past with RFTs on their car. To each their own, but I don't have a problem saying that you don't want RFTs on your car, and it's something that I'd factor in to the value of vehicles going forward.
    thegunguy

  18. #18
    Z8 Guru 2112's Avatar
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    Well said Rifle.

    I swapped the Runflats long before any frame issues were known and was amazed at how much better the car was all around.

    .
    2000 Red over black
    heavily modified for performance. Although, not to the level of GM's car

  19. #19
    Team Z8 Charles's Avatar
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    Quote Originally Posted by mrcjackson View Post
    I'm not sure I understand why you are all so keen to ditch the RFT's. The US sourced car I recently bought from 2001 with 4000 miles had its original run flats. BMW over here in England recommended I change them. As I am a stickler for originality I chose to replace them with new original spec Bridgestone RFT's. The old ones showed no signs of deterioration inside or out. I have however noted that the new ones do seem to give a smoother ride but that may just be a question of tyre pressure. I have however had the PP installed for peace of mind. Chris
    You have to watch the dealers, as they don't all know about Z8's and just follow original factory protocol. There are a few board members that have stuck with run flats, but what convinced me was the fact that the strut towers are aluminum (not steel.....are any other bmw's aluminum now?), so I opted for non-rf's. Another item is the oil. Knowledgable dealers will use Castrol TWS 10-60 rather than what the sticker on the engine says, while others just follow the sticker.
    Charles Guerin
    AH61406 - Titanium Silver/ /Black

  20. #20
    Z8Mania
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    I think if you want to keep the car original to show it every now and then, keep the original tires and you can always use them for display purposes but for actual driving, I echo what everyone said.

  21. #21
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    I replaced the RFTs with BF Goodrich tires on the car and they are super! Kudos to Discount Tires for an outstanding install job and great price. These guys put on new gloves every time before getting close to the vehicle. Tires are super nice riding and handling. The run flats had 6.8K miles on them and were shot. The manager mentioned that when you store cars they MUST be at the correct vehicle specified pressure, especially RFTs, or cracking of the inside sidewall occurs, leaks, then comes apart. Mine had all kinds of cracks on all four tires, only visible on the inside. Said he sees it a lot on older low mileage vehicles. Figure I'd post it as a lot of Z8 owners may store it a while between drives.
    Thanks to KenZ8 on the BF Goodrich advice - love 'em!

    Tom

  22. #22
    Administrator thegunguy's Avatar
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    The cracks and chunks are VERY common as RFTs age. As you note, they are critical about pressure, yet they have no visual indication of change, which isn't always practical. Also, BMW's rotational difference based tire monitoring system isn't well suited to alert issues with RFTs.

    Besides the ride, weight, etc., these are some of the reasons that many of us have ditched the RFTs.

    I cannot recommend enough that every owner get rid of them. Simply, they're not good for the Z8.
    thegunguy

  23. #23
    Z8Mania
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    The cracking is not due to tire pressure- though it is critical to check on any tire, but especially so on RFT as Rifle says. The cracking comes from heat cycles. The heat cycles dries them out and then you get the cracking. All tires will experience this over time. Even if you never drive on them they will become brittle. Thats why its recommended to replace them every 5-7 years depending on your situation. Best case scenario is with a 2003 Z8, if it has original RFTs on it, those tires could be 9 years old- and thats with a 2003. Bottom line- its plain dangerous to drive a Z8 with original tires on it.

    As to specified pressure- for storage purposes you can pump them up to a drop under the max pressure thats specified on the tire sidewall. This is overinflation with the goal of avoiding flat spotting. I also like to use tire cradles for this purpose. www.tirecradle.com You can lower the pressure to the specified 32/32 (from my memory so maybe Im wrong).

  24. #24
    Z8 Guru 2112's Avatar
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    Quote Originally Posted by Z8Mania View Post
    I also like to use tire cradles for this purpose. www.tirecradle.com .
    Another option;

    http://flatstoppers.com/

    http://www.ebay.com/itm/New-Flatstop..._Tools&vxp=mtr

    .
    2000 Red over black
    heavily modified for performance. Although, not to the level of GM's car

  25. #25
    Z8Mania
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    Those look good too. I think I prefer the softer tire cradles but these look to be considerably less expensive.

  26. #26
    Those price are insane, thats a $2 moulded item!!
    Andrew Macpherson

    Expert Z8 Inspections, with full support for both Z8 sale and purchases.

  27. #27
    Z8Mania
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    The TCs are a very high quality product that I couldn't reproduce if I tried but these do look like that but I guess when you're one of the only games in town..............