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Twitchy Steering on 91 Testarossa

Discussion in 'Technical Q&A' started by Shamile, Jun 18, 2004.

  1. Shamile

    Shamile F1 Veteran

    Dec 31, 2002
    6,563
    Lakeland FL
    Full Name:
    Shamile
    Dear Ferraristi,

    I have a 91 Testarossa (US). The steering seems way to twitchy and sensitive for my liking. My 308 was nice and dead even at highway speeds. I don't know how anyone could drive the TR near it's reported top speed of 185 since at 70 on a well-grooved interstate, it dances all over the place. Does anyone have any ideas to "tame" it. It really takes the fun out of the car.


    Shamile
     
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  3. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,399
    MO
    Check your tire pressures. They seem to be a slight bit high judging from what you are telling me.

    I had a similar problem with my BMW. I set the pressures to 40 front and rear when I upsized the wheels. Bad idea, I could barely keep the car under control at highway speed. I dropped it down to the 33 F and 38 R and it fixed the problem. I suggest you try and turn the settings to the OEM spec. If it is still too sensitive, then try droping it by one PSI front and driving it.
     
  4. Jerrari

    Jerrari F1 Veteran

    Jul 24, 2001
    5,458
    Michigan
    Full Name:
    Jerry Wiersma
    FYI: I do not have this problem at all in my '89.
     
  5. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    19,283
    Texas
    Full Name:
    Steve Magnusson
    No such problem for me either (really feels beautiful/precise between 60-90 MPH). You're always stuck with the possibilty that it's just a weird tire-road interaction (what tyre type?), but it's such a simple, direct system that you might have a mechanical problem somewhere. It's kind of a b*tch to inspect a front suspension (since it needs to be fully-loaded), but have you tried just lifting the front wheels and giving them a feel, rocking/feeling/comparing the wheel bearings and tie rod ends, a visual on the A-arms, etc. ?
     
  6. Tifoso1

    Tifoso1 F1 Rookie

    Nov 18, 2003
    2,571
    Pacific NW
    Full Name:
    Anthony C.
    What kind of tyres do you have on the car, are they still OEMs? If so, there is a chance that they have simply ran its course and needs to be replaced. Also, it is my understanding that certain tyres have a tendency to "dance" according to different road surfaces and if you are also running plus sizes, that can also complicate things. But I think the others are right, check you tyre pressure first and go from there.
     
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  8. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,149
    way north california
    Full Name:
    chris morse
    Is this a sudden problem or is it a forever problem. have the alignment or tires been changed. Has the alignment posible been knocked out of spec, particularly toe in or toe out? look at the tires to see if there is any feathering that would indicate toe in or out.
    HTH,
    chris
     
  9. tbakowsky

    tbakowsky F1 World Champ
    Professional Ferrari Technician Consultant

    Sep 18, 2002
    15,117
    The Cold North
    Full Name:
    Tom
    I agree with the tires being the problem. TR's are very sensitive to this. The tires can look o.k but the the compound is not longer able to do it's job. I have had a few come in with this complaint. I suggest new tires each time. And each time it has fixed the problem.
     
  10. colo348

    colo348 Karting

    Nov 1, 2003
    141
    Colorado
    Full Name:
    Jim
    I Have a '91 TR and the steering and handling on the open road is very stable. However, when I first got it I did have the wheels balanced. Before the wheels were balance the handling above 80mph was, well you could'nt go there. In addition the car had not been driven on a routine basis by the previous owner so the tires had minor flat spots, which added to the instability. With the wheels balanced and a few miles on the tires, to get rid of the flat spots, the TR is amazing at 130 to 150mph (my limit not the TR's).

    If your wheels are in bablance you might want to have the frontend bushings, steering mechanism and shocks checked. My 348 had to have the front bushings replaced to tighten up the steering. Good luck.
    Jim
     
  11. colo348

    colo348 Karting

    Nov 1, 2003
    141
    Colorado
    Full Name:
    Jim
    I Have a '91 TR and the steering and handling on the open road is very stable. However, when I first got it I did have the wheels balanced. Before the wheels were balance the handling above 80mph was, well you could'nt go there. In addition the car had not been driven on a routine basis by the previous owner so the tires had minor flat spots, which added to the instability. With the wheels balanced and a few miles on the tires, to get rid of the flat spots, the TR is amazing at 130 to 150mph (my limit not the TR).

    If your wheels are in bablance you might want to have the frontend bushings, steering mechanism and shocks checked. My 348 had to have the front bushings replaced to tighten up the steering. Good luck.
    Jim
     
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  13. sunburn

    sunburn Formula Junior

    Nov 2, 2003
    693
    Dawsonville, GA
    Full Name:
    Rick R.
    I have an 88 TR and it's very stable. However, I agree with the pervious posts . . watch out for the tires. I had a 348 Spider and put oversized width tires on it (275 instead of 255 rears) and it was freeky. It would track severly and I mean it was BAD. Even my wife noticed it tracking and asked what happened to the solid feel before the tire change. I swapped them for the normal size and like magic . . . knife edge precision!
     
  14. Shamile

    Shamile F1 Veteran

    Dec 31, 2002
    6,563
    Lakeland FL
    Full Name:
    Shamile
  15. Shamile

    Shamile F1 Veteran

    Dec 31, 2002
    6,563
    Lakeland FL
    Full Name:
    Shamile
    Dear Ferraristi,

    Thank you so much for your responces.

    The tires are yokohama ZRs 225/50ZR 16 F, 255/55 ZR 16 R. I keep the proper pressure at 38 all round. ( as per manual ). The steering feels solid, not loose or vague. The tires are balanced and there is no vibration through the seat or steering. It just seems to pull everywhere on slightly uneven or grooved interstate. It will twitch and pull to where I can feel the side to side. I never noticed this on my 308....which was very stable at normal HWY speeds. The TR is not scary...just.....um..TWITCHY ! Can I " Dull " it down? I did want to change to the 512 TR rims and tires. I would like a wider tire on the rear. 255's seem too narrow for a WIDE A** TR :)

    Thank you again.
     
  16. Shamile

    Shamile F1 Veteran

    Dec 31, 2002
    6,563
    Lakeland FL
    Full Name:
    Shamile
    Dear Ferraristi,

    I forgot to mention that the front tires do not show any abnormal signs or wear. They are even accross the face. The left rear does show wear on the extreme inside. It has worn away half the tread at about 2" wide. The right rear shows even wear accross the face. Can this be enough to create the side to side pull on groves and uneven pavement?
     
  17. thecarreaper

    thecarreaper F1 World Champ
    Silver Subscribed

    Sep 30, 2003
    15,978
    Savannah
    Full Name:
    I NEED A JOB
    having recently driven to and from florida several times in a few different cars, my .02 of input is the roads i was on including the long sections of 1-95 really suck if you drive ANYTHING with wide performance tires. i have been to winter park and Orlando a few times and i noticed the roads seemed to have " ruts" in them from large truck traffic. just an idea, find a newly paved wide road and go for a nice brisk drive, and smile really big for me , cause i love the TR. when i grow out of the 308 's, maybe i can get 12 cyl " something "!!
     
  18. Shamile

    Shamile F1 Veteran

    Dec 31, 2002
    6,563
    Lakeland FL
    Full Name:
    Shamile
    Dear Ferraristi,

    That's exactly where I live in Florida...the I-4 corridor. I'm mainly on I-4, 95 and 75...and exactly what you said....ruts. So it this a case of the roads I'm dealt and not the car?

    If so, any tricks to compensate? I'm going to drop the pressure all round to 37PSI.as per another Ferraristi. Or...should it only be the fronts?

    Please let me know !

    Shamile
     

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