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Thread: Run Flat Tires

  1. #1
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    Run Flat Tires

    I have 8900 miles on my run flat tires.
    I have seen comments about changing these run flats, with no detail about their faults.


    What are the negatives, so I can make a decision.

    Thanks,
    I Squared

  2. #2
    Sport Button On - DSC Off jpklecker's Avatar
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    I used to have them, the car comes with them, and I noticed a squeeking sound when backing into the garrage after about 15,000 miles. After changing out the tires, the mechanic showed me that the inside sidewall, that is the support once the air is out due to a puncture, was all cracked and several pieces had broken off. This caused my squeeking sound.

    Another consideration is the weight and stiffness of these type of tires. I don't know if you've read the frame forum, but this car can have frame damage if driven over potholes or other items that would jar the front shock towers. By keeping the run flats, the stress on the frame is greater with each sharp bump; both due to the stiffness (the hard sidewalls) and the extra weight of this type of tire. Almost all the owners of these wonderfull cars have switched to regular tires both due to the lighter weight on the frame and the greater give (or flexibility) of the regular tires, thus reducing the chance of frame damage. A large majority have also added the performance package, which adds a brace between the front shock towers, to further strengthen and stiffen the front frame.

    If you switch to the regular tires be sure to get a inflation kit which includes a bottle of sealant to help you drive to a place to service the tires in case of a puncture. Most have purchased Michelin PS2 tires, I myself have Bridgestone Pole Positions on my Z8.

    Hope this helps...
    John Klecker - 2002 Topaz / Crema (61782)

  3. #3
    Z8Mania
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    Thats spot on. In general the run flats are superior in terms of working with low or no air in them. In every other measure, sportiness, comfort, and even grip because tire tech has improved more with tires like the PS2, the regular tires are superior. I think if you drove through bad areas regularly maybe the run flats are worth the trade offs but otherwise Id switch them.

  4. #4
    Administrator thegunguy's Avatar
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    In addition to the other comments, my original runflats had large chunks separated from the interior of the sidewalls when I ditched them after only 7k miles. Not very confidence expiring.

    This was likely due to the original owner (who had the car for 4yrs and 1,600 miles) not monitoring the pressure and then driving the car without enough air. However, that's one of the issues I have with runflats - no visual indication of pressure status. Sure I check my tires somewhat regularly, but it's also nice to be able to a quick walk-around to eye-ball that everything is okay when filling the tank.

    To me, the single advantage of runflats is non-existent. They might save a wheel, but in the end, the car's going home on a flat-bed. So, it's a bad day no matter what. However, the tradeoffs are many compared to a quality standard tire.
    thegunguy

  5. #5
    Z8Mania
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    I agree with everything except the flatbed. You can drive on run flats- they are restricted for range and max speed, but you can drive on them. The lack of visual indicator is a reason you really do have to check them and really need a TPMS. I have to say that all low profile tires suffer from a certain lack of visual distinction- they could be at half pressure and still look good to most people. Theres no substitute for checking and also a good TPMS.

  6. #6
    Administrator thegunguy's Avatar
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    Sure you can drive on them. I seem to remember a claim of around a 100 miles, but that's not something I'd ever want to do unless I was in a place where I wouldn't or couldn't pull over. I just see ruflats as having the ability survive blowout type damage, allowing me to stop the car as soon as possible.

    Too bad the indirect TPMS in the Z8 is a joke.

    Regularly checking pressure is critical with our cars that often sit for extended periods.
    thegunguy

  7. #7
    Z8Mania
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    Agreed. FWIW I had RFTs other cars and I had a nail in one and I was able to drive about 70 miles home at 60 with no problems. Of course I didnt lose all air, it was just a slow leak. In the end I just cant stand the trade offs, most of all is the lack of road imperfection absorption- RFTs just don't "feel" right to me.