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Thread: away with the runflats

  1. #1
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    away with the runflats

    I finally put my new stock 18" wheels with MPS2 tires on my 900 mile 60109.
    The change is absolutely remarkable.
    During a short run, the tire pressure light came on. I have 35 lbs. in all four tires.
    Does anyone know how to reset this warning light. Dana tells me that there is no sending unit on the wheel itself.
    LarryG

  2. #2
    Administrator thegunguy's Avatar
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    Follow the procedure on page 67 of the manual. It's pretty simple.

    As I recall, the system is based on differential wheel speeds. So if all four tires go at an equal rate, no problem will be reported.
    thegunguy

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    thanks very much. Actually the shop that mounted the tires, put 40 lbs in the front tires and 35 lbs in the rear. Perhaps that is why the tire pressure warning light appeared. I have adjusted the air pressure in the front tires and all seems well.
    As mentioned above, the ride with the new Michelins rather than 10 year old runflats is just incredible. The ride with the runflats is just so jarring even with the correct pressures.
    LarryG

  4. #4
    Z8Mania
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    All tires should be 35 PSI cold- meaning 65F- it will be hard to do if you just drove the car. The system does work by comparing rotational differences between the tires using the ABS sensors to do it. To reset, I believe you need to have the car on, be stationary, hold the tire pressure button down (I think its near the radio cluster- it looks like a cross section of a tire that has gone flat with an "!" in it). Hold the button until a red light in the gauges which is the tire pressure light- lights up- then go drive and the system will calibrate. This kind of system is better than nothing but it can be falsed if you go over a rut in the road so if you do, and the system comes on and the car feels fine, there is a good chance it was faked out.

  5. #5
    Mine has been faked out so many times I barely take any notice of it any more, especially if you're at the track, or doing spirited back road stuff. It actually makes sense that it is off the ABS sensors, because since adding the LSD I do seem to get this light coming on a lot more. I was initially thinking it was something to do with the wider 20" rims, but the equation of LSD + twisty back road + ABS sensor = fake out makes much more sense.
    Possibly another reason not to have an LSD?
    Andrew Macpherson

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

  6. #6
    Z8Mania
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    Could be. When we were in the heat of the LSD issue we were told (I forget by whom) that the LSD would work fine with our cars but I am seriously considering taking the LSD out when I do the Alpina suspension. Its nice to have the 3.64 gears but they expose the play in the drive train. I believe this was the best system of the time but TPS tech has moved on. My scud tells me the pressure-in tenths of PSI- and also temperature of each tire. I like getting all the data. But this is not the Z8s reason for being- her reason is just the romance of the open road. If you get the light and the car is pulling you know its for real but if you get the light and shes driving right, then I would keep going but to each their own.

  7. #7
    Z8 Addict Z8doc's Avatar
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    I dumped the run flats at 24K miles and went to Bridgestone Pole position S03s with the Dinan Stage 3 suspension and liked the ride with adding the LSD with Quaife and 3,64 gears shortly thereafter. I have never had problems with excessive tire pressure warnings. Michelin PS2s at around 40K miles when I added the Brembo Big Brake and the 20" Beyern Type 5. I now have 52K miles and never have the tire pressure problems so either I am just lucky (and I do the LSD + Twisty spirited driving too ) or the combo does not seriously impact the ABS sensors / tire pressure monitoring system. I do know that since the LSD, I certainly have much less of the DSC warning light going off, and is well worth keeping in my opinion.
    Best Regards,

    Jeff
    61995 Silver /// Rot - Original Owner
    Z8 Club of Germany e.V. #102

  8. #8
    Administrator thegunguy's Avatar
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    I'm not sure how the LSD would have any impact on the TPMS as it's really just altering which wheel gets power versus the open diff. Plus, I'd have to bet that the TPMS faults are based on longer observed measurements than anything that the LSD might impact the relative speed of the wheels. I also kind of doubt that it would detect a blowout. Unlike the other systems with sensors in the wheels, it's quite a dumb system.

    I've had no warning lights post the install of the Quaife with OE wheels and tires or Quaife plus 19s.

    If they're what I believe they are, the ABS sensors as are rather exposed from below (one front right, one back left). They're somewhere around the sway bar or drop links, I think - it's been a while since I've been under the car. I thought them oddly placed and open for interference from below. Perhaps sensor issues could lead to TPMS over-excitement?
    thegunguy

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    After adjusting the tire pressures, I took my car out yesterday for a spirited drive. The tire pressure monitoring system behaved itself.
    Those runflats won't be missed.
    LarryG

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    Smile

    Did you get a kit to handle flats?

  11. #11
    Z8Mania
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    Eldred, How have you been?! You are missed! I hope life has been good to you. Shoot me an email if you like jerry at levyhouse dot com. I have the m mobility kit in my trunk. One under the floor board there is a spot that was designed for the kit I believe. Also those cans of "goo" are only good for so long and I am sure mine has long since expired. My limited experience with these is they are pretty useless.

  12. #12
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    Jerry, I have been well. I will send you an email. It is great to reconnect with the Z8Family.
    Eldred Nims
    AH60642- Original Owner
    2001 Silver - Red / Black Interior

  13. #13
    Z8Mania
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    Got it- will respond soon. The whole Z8 family is coming together!