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Thread: Bridgestone Potenza

  1. #1

    Thumbs up Bridgestone Potenza

    July 2002, 12 months running on the original Potenza's.

    The first 1500 miles with the stock suspension I had a few hairly front end pushes and 'plows', which I thought might be loss of grip, but upon making several enquiries both in the US and Europe, I discovered that the main cause of this lies in the suspension set, so I eplaced the suspension with the AC SCHNITZER kit. This gives a much more track and sport camber which totally eliminated the front end push, or 'plow' effect.

    After this change I have no complaints about the tires grip, the ride on the road is fine, and on the track days I've taken the car to the tires have performed very well, with little howl, and no loss of grip. These tires have been harshly critisized, but I think unfairly, any issues with them vanish by changing the suspension.

    With around 6000 street and 450 track miles they are nearing the end of thier cycle. (2 days Willow Springs, big loop, 1 day Button Willow and 1 day Vegas Speedway road course, all in hot CA summer weather ie; mid 90's & up).

    10 Aug 2002 - replaced with Michelin Pilot Sports......after 6 months on these I can say the Potenzas give better and more consistant grip in the mid summer heat at the track, while the MPS have an edge in cooler weather, but when it gets really hot they loose some thier grip.
    Last edited by macfly; February 16th 2003 at 04:30.
    Andrew Macpherson

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

  2. #2

    Run flats are less sticky, aren't they?

    I hear lots of gripes about the "run craps". I don't drive my Z8 above 8 tenths (intentionally) so I also think the Bridgestones are just fine. If this was my track car, I'd feel differently. Mainly I like not worrying about being stranded somewhere with a flat.

  3. #3

    Arrow Depends......

    On a casual drive they don't seem to get up to 'temperature' as well, and don't 'feel' as grippy as the Pilot Sports.

    On hot track days when the Pilot Sports are overheating and getting sloppy, the Run Flats are hanging on strong, with just a little howling, but remaining very predictable.

    I would almost venture to say they are better at the most extreme end of the spectrum, and the seem to love heat. I would dearly love to see a scientific test of all the tires we might consider using on our Z8's to know which was definitively the best tire.

    I have no experience with SO3's, Goodyears, Pirellis, Dunlops, Khumos, Hoosiers, or Toyos, all of which have ardent fans at the track.
    Andrew Macpherson

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

  4. #4
    Z8 Ate My Homework! Norcal's Avatar
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    Nov 2002
    Thanks for the write-up.

    With the stock suspension, did you get much tire howl on track? I do, but most is at the front I think.

  5. #5

    Arrow Indeed...

    Both tires do howl, but the Potenzas are a bit more vocal. After the change of suspension they got a lot quieter. The car is sitting on them in a more evenly balanced manner, giving a more evenly demanding weight distribution than the fairly soft standard set up, which tends to pitch the whole weight of the car onto the front left or right corner of the car at turn in.

    Front end 'plowing', pushing out or understeering was my biggest disappointment with the car, thus I changed my suspension over to the ACS kit first, as I had not heard any criticism of the Bridgestones at that point.

    I found the car's tendency to plow really didn't suit my comfort level at speed, so it made sense to swap for a more sport orientated setup. The lowering and stiffening of the suspension and the change in camber makes the car feel completely neutral at the track.

    The change of tires made a very small difference, I would say that the Potenzas are better in hot weather, while the Pilot's fare better when cooler, and tend to show more signs of 'going off' when the SoCal mid afternoon heat really starts to cook the track surface, and the air temp is in the high 80's or above.

    It was always just past the apex that the inherent understeer threatened to have me in the bushes. As you are starting to power out of a turn the weight would 'sit back', lighten up the front, and presto, you'd be nose to dirt. Not a 'good look' as they say! Once I changed the suspension this never happened again, so I feel a lot of the criticism that the 'Run Craps' have had may really be unfairly leveled at them, when it is the suspension set up that is at fault.

    If you are considering changing anything I'd do the suspension first, I think the slighter better when cool Pilot Sports help hide the cars understeering nature, but it will always return at speed, and eventually you'll be looking at the 'wide side' approcahing fast!

    Hope that helps.
    Andrew Macpherson

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

  6. #6
    Z8 Ate My Homework! Norcal's Avatar
    Join Date
    Nov 2002
    Funny, most of my understeer occures at turn in, and building (perhaps too much throttle) to the apex. Heavy throtle and unwind toward track out is always very neutral. Maybe a bit more trail braking would throw more weight to the front and help that. I'll have to work with my instructors on that. For all I know im doing it all wrong, but it sure feels right. I might also try different rubber, perhaps even a tad more up front to help with the plow. No time soon though.

    Thanks for the input


  7. #7

    Turn in...

    I had an instructor earlier in the year who showed me a set up and turn in technique he learned from Steve Dinan, who is apparently really great driver.

    As you are just beginning to let off the brakes you squeeze the steering wheel just a couple of degrees into the upcoming turn. This neutralizes the weight transfer before the actual turn in. This only lasts a half second or so, but it really makes the car feel as if it's on rails once you do turn in.

    Once I had it mastered I found it one of the best techniques for achieving total balance, consistency, placement etc. You may well be doing this already, but I realized that I was waiting to turn in, then just turning in, so it was making the weight transfer quite abrupt, and no doubt contributing to the understeer feeling, which is now completely gone. (Of course the ACS kit & the Pilot Sports play their part.)

    I am very aware that after a year of track days the tires and suspension have probably not made as big a difference as me learning how to drive properly! I am doing things at this end of the year I just didn?t know about when I first went to the track. I am really enjoying it as an evolving learning process, I love tracking the Zee, I don?t want a track car, or a race car, I just really enjoy driving mine at a track, it feels so at home there.
    Andrew Macpherson

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