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new 550ix: run-flats vs summer/winter tires

Discussion in 'Wheels & Tires' started by ggarai, Sep 21, 2010.

    ggarai guest

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    The new 550ix has runflat all-seasons. Dealer says they won't even sell me summer tires instead. I'm used to having summer/ winter tires, each on own rim. Is that old-fashioned? Have run-flats gotten better? How are they in snow with x-drive?
    • Member


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    Ride comfort is, as always, a matter of opinion.

    What may be hard as a rock to one person, maybe just right, or pillow soft to someone else.

    Opinions are split pretty evenly on this. Some say run-flats ride and handle like bricks. Others say they're just fine. Only you and your posterior will be able to say one way or another for sure.

    Your question might as well be "what's the best color on a BMW."

    By law, all new cars starting with 2008 models have a TPMS, indicated by a light with the cross section of a tire and an exclamation point. It looks like the illustration below.

    Despite what the dealers will tell you, runflats CAN be swapped with conventional tires and wheels. You can even put OTHER runflats on the wheels in most cases. If you decide to go with conventional tires:

    a) be prepared to pay for a full set of tires and wheels
    b) the TPMS warning light will remain ON forever (you might be able to just pull the bulb from the cluster)
    c) a conventional spare tire and wheel will certainly eat up trunk space, as BMW has been eliminating the spare tire wheel and reclaiming the trunk space for a "mobility kit" instead. You're also going to need a jack and a lug wrench. Those will eat trunk space too.

    You can also go to http://www.tirerack.com to compare tires against others.
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    It is not necessary to purchase new wheels to mount conventional tires. Self-supporting run-flat tires (the type used by BMW) do not require special wheels. Also, the TPMS does not know nor care whether the tires are of run-flat or conventional construction. It simply monitors pressure.

    However, if one buys a second set of wheels for winter use, aesthetics or whatever, it is necessary to also buy pressure sensors for them to maintain TPMS function. These are sold separately (can't find a price online but if memory serves they are ~$50-$100 apiece).

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