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Wooba-wooba-wooba

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by hobbit, May 11, 2008.

  1. hobbit

    hobbit Senior Member

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    A perfect Sunday afternoon is a perfect time to do a little
    car maintenance, so today I decided to combine a bunch of things
    including an oil change, what I hope will continue being a
    yearly cleanout/inspection of the brakes, and tire rotation.
    The scene at one point looked like this:
    [​IMG]
    .
    The front disks needed a little de-dusting and regreasing of
    the backing plates and pad end clips, and a quick spin and
    limbering-up of the slide pins as excruciatingly detailed here.
    The rears were pretty much pristine and needed only a superficial
    wipe. The donut is being used to allow both wheels on a side
    to be off at the same time, and if you haven't looked at your
    own spare tire, yes, it really is that hideous yellow. In fact
    if you haven't ever seen it now is a good time to unearth it,
    gaze upon its blatant ugliness, and make sure it's pumped up
    to 60 PSI which is what it wants before hiding its wretched
    countenance in the oubliette of the lower cargo well again.
    .
    Anyway, the Hydroedges are a directional tread and can thus
    only be rotated front-to-back, so having a side's worth of
    wheels off allows comparison between fore and aft treads. I
    had rotated them once about 5K after getting them, but now
    they'd been in the same positions for about 15K or more since
    wear had been completely imperceptible back then. Now, it's
    still more or less imperceptible by eye but perhaps discernible
    by electronic measurement. Here are the left-side treads
    matched up together [front is above]:
    [​IMG]
    .
    And the right-side ones:
    [​IMG]
    .
    There isn't really any obvious delta -- maybe half a pixel's
    worth of tread depth in the pictures included here, if that.
    However, something about the right rear *felt* funny as I ran my
    hand over the tread to brush off sand, and closer observation shows
    that it's got a little bit of sideways feathering in the tread, with
    one edge of the lugs feeling higher and sharper than the other:
    [​IMG]
    .
    Hmmm. If the road had been scrubbing the tire very slightly
    to the left, that means the right rear spindle is toed in just
    a tiny tad. After 15K the tire is not particularly bad, but is
    definitely different from the front. Now, I had been starting
    to notice a very slight delta on the wheel speed display of
    late, concerning the rear tires, and observing that the LED blink
    rate on very gentle right or left turning was telling me that the
    right rear's radius had become very slightly smaller than it used
    to be. Mysterious, given that I re-checked and had identical
    pressure and temperature in both right and left. So now I guess
    I've got my answer, after many miles. Never noticed anything
    with the old Integrities.
    .
    I also had been noticing a mild sort of "wooba-wooba" sound,
    especially while gliding sans engine at low/mid speed, like
    the first hints of a wheel bearing going bad, except that as far
    as I can tell the wheel bearings are all fine and tight. That
    sound has pretty much always been there, and didn't seem to change
    with turning side stress in either direction which would also help
    indicate bad bearings. Maybe it was something about this tire.
    .
    So I swapped everything front-to-rear in the process of working
    around all four wheels, and went out for a little test loop to
    reseat all the brake parts. It was there that I had a profound
    demonstration of the purpose for tire rotation. The wooba-wooba
    feeling is much more noticeable now, hits some weird resonance
    around 18 MPH, and runs considerably louder on the highway
    than it used to! And regen braking makes a positively awful
    grinding noise as it comes down through low speeds. Definitely
    seems to mostly be coming from the right front, but the left-
    side swap could also be having an effect too. There's no
    pulling or drift, just this horrible racket like I was driving
    your typical beat-up green Maxima hoopdie with the faded gold
    trim, one spray-painted fender, and all mismatched tires.
    .
    This is kind of annoying, and I hope it resolves itself back
    to quieter operation really soon as the tires adapt to their
    new positions. Trying to match a nice straight board against
    the rear sidewalls and out along the rocker panel doesn't show
    any obvious toe, so it must be really subtle. Maybe time to
    visit an alignment shop and get the numbers...
    .
    _H*
     
  2. Neicy

    Neicy Member

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    Interesting that such a small visible difference should make such noise after rotating.

    I haven't even checked the ugly donut since I got the car. Who knows what the pressure is - good reminder for us all.

    Been waiting for the maintainance light to start blinking. It should go on soon. I really want to try doing it myself this time if I can muster up the courage... we'll see.
     
  3. alanh

    alanh Active Member

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    Absolutely check the spare. I checked it a few months after I bought the car, and it was only 30 psi. I suspect a lot of dealers forget to top off the spare before delivering the car.
     
  4. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Interesting. I had my tires rotated a couple of weeks ago and hear a little of the same sound. I can see that the edge wear of the former front tires is higher than I like even though "Firestone" failed to report the metrics.

    Here are my numbers and comments:

    1. Front Lt: camber -0.5, caster 2.0, toe 0.10, depth 5/32
    2. Front Rt: camber -1.0, caster 1.4, toe 0.10, depth 4/32
    3. Rear Lt: camber -1.1, toe -0.03, depth 6/32
    4. Rear Rt: camber -1.0, toe -0.03, depth 5/32
    The toe is OK although I would like to see the front toe cut in half. The theory is when power is applied the front wheels will tend to pull-in and achieve an optimum toe. But my front edge wear suggests less toe may make a significant improvement.

    Caster is something I've not really looked at and my understanding is this is difficult to adjust without touching the front struts. I figured when I replace the front struts I'll work on getting this right but it difficult to tell exactly what it needs to be. When I turn around in the driveway, I hear 'tire noise' that I don't like but I can't tell which way to go and how to really understand the optimum values.

    I would like to reduce the rear camber but there are limits to what I can achieve with the metal tabs. However, the "Specialty Products" EZ Shim, 75800 looks to be a much better solution. I should be able to dial in perfect toe and camber.

    I would like to get all cambers down to 0.5, front and rear. The front right is a bolt adjustment and the rear wheels will be handled by the EZ Shims, or that is my story and I'm sticking with it. <grins>

    Bob Wilson
     
  5. jayman

    jayman Senior Member

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    H

    I have to admit I clicked on your post expecting an entirely different sort of report. But I digress .... does changing the tire pressure effect the resonance intensity? That is, temporarily lower the pressures to stock, see if the noise is still there

    I had a fleet pickup make a similar noise a few years back and it drove me insane, as it occurred at around 55 km/h. I finally arranged to have somebody else drive the cursed thing while I followed

    The right rear tire appeared to be mounted improperly, it had a pronounced "wobble" to it. Oddly enough, I didn't feel this while driving

    These sort of NVH (Noise, Vibration, Harshness) issues can be hard to resolve. Is it possible a dragging caliper or loose brake part is amplifying the noise?

    I'm leaving tomorrow for a business trip, should be back in a week. If you wish I can look into this when I get back

    jay
     
  6. sendconroymail

    sendconroymail One Mean SOB

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    When I rotate my tires I use 2 floor jacks (one in the front and one in the back). I can rotate all 4 tires in no time doing that.
     
  7. dogfriend

    dogfriend Human - Animal Hybrid

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    I want to subscribe to see what Hobbit's alignment readings are. So I will make a couple of comments:

    1. Just want to say this is a great title for the thread.

    2. I had a wooba-wooba-wooba with my Explorer/ Goodyear RT/S tires that got progressively louder and louder so that I finally retired (a pun) them at 52k miles even though they could have gone another 10k based on tread depth. Full time 4wd is hard on tires, especially the front ones. And they don't get much of a break in the rear.

    3. Be sure to ask for the alignment reading in degrees, not in inches. This was a big problem around the Sacramento area where no one seems to understand that there is any other way of expressing the toe except for fractional inches. You need to know the angles in degrees, not in 32nds of an inch.
     
  8. SparrowHawk60

    SparrowHawk60 Happy to be green!

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    It that a 4 by 8 you're using for a Jack Stand??

    Come on, spend a few bucks to get some real ones!

    Guy used a cinder block once, the Caddy fell and crushed him dead!
    Guy used nothing but a three ton bottle jack to lift the front end of his car, car fell and cost him both of his legs.
    Kids were playing around a car up on four jacks stands, no tires on it, car twisted and fell off the jack stands, killing to of the kids hiding under neath it.
     
  9. richard schumacher

    richard schumacher shortbus driver

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    Ditto SparrowHawk60! Using a 2x8 *on edge* (!) as a backup for the jackstand is foolishly dangerous. If the stand fails it's much too likely that the 2x8 will simply fall over. Yes, I see the wheel chocks: do you want to bet life and limb that the tires have so little compliance that the chocks won't allow the car to move a half-inch? Please use something appropriate to the purpose, we want to keep your expertise available.


    To create an annoying wooba-wooba sound? No, thanks :_>

    On a FWD car it's safer to rotate tires only as needed to keep the two less-worn tires at the rear. This reduces the chances of fishtailing. See for example the bottom of this Michelin page at
    How to Buy: Tire Care & Buying Guide: Michelin Tires

    Doing this also means that *on average* you will have more tread on your tires. Consider: if you rotate the tires perfectly, just before you replace all four of them, all four of them will be worn out. Whereas, using the best-at-rear method, when the two front tires (which wear out faster on a FWD drive car) are worn out and at the point of replacement, the two rear tires still have considerable tread. It also means that the front wheels never have new tread on them, but that is a safer compromise.
     
  10. Syclone

    Syclone Member

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    Talking about unsafe practices....
     

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  11. Tchou

    Tchou Member

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    What's bothers me in the picture is that the part of the tire in contact with the road is not flat, it seems like the tire is over inflated, are those tires radial ?
    if they are the should be flat, not like these...
     
  12. bbald123

    bbald123 Thermodynamics Law Enforcement

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    Pretty much sure that tires with no load on them have a round aspect.
     
  13. PIOUSPRIUS

    PIOUSPRIUS New Member

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    Hobbit ! You are not alone ! I slid on ice this winter and hit a curb hard enough to bend a rim. I replaced it and had the front end aligned at a Toyota dealer. It was after that I noticed around 22 mph I heard a wooba sound too. It lasts up to around 55 mph. The weird thing is it doesn't seem to keep pace with how fast the tires are spinning. I took it back but the dealer said what sound. Let me know if you find anything. I'm going back to the dealer one more time.
     
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hmm, this sounds like a bad wheel bearing; except that you say the sound does not correlate with vehicle speed.
     
  15. PIOUSPRIUS

    PIOUSPRIUS New Member

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    A bad bearing is what I thought too but it just doesn't seem to keep pace with how fast the wheels are spinning. Since I whacked the curb pretty good I thought maybe drive train, bearing, damaged tire.....not sure. I'm going to take it back in a few days for service so I think I'm going to make them go with me for a little drive.
     
  16. hobbit

    hobbit Senior Member

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    A few points.
    .
    The wood wasn't actually needed or under any significant pressure;
    a halfass backup for vertical lift, NOT any pretense of lateral
    stability. Lateral stability was handled by the park lock and
    the chocks and the fact that the other side of the car was still
    on the ground, so spare me the "up on blocks" hysteria. And at no
    point during this operation, which I realize I will never convince
    some people of general non-sketchiness, was I actually underneath
    parts of the car. I was also careful to shake the car around on the
    way up to make sure it wasn't going to settle into some undesireable
    position. No more risk than doing a tire change at roadside with
    the stock jack, and that's the best I can say about it.
    .
    There's another thread going about jack stands, and hints at how one
    might be LESS safe using them indiscriminately.
    .
    When I spin the wheels I notice no lateral run-out or wiggling, so
    I don't think the rims themselves have any problem. The noise
    wasn't there before I rotated fore-and-aft, and I didn't take a
    sledgehammer to my wheels in the meantime. I'm going to assume for
    the moment that the noise is due to the wheels being somewhat
    differently oriented and weighted at front and rear, most likely
    from different camber. Bet that if I swapped them back right now,
    the noise would be gone again but the different wear patterns would
    then continue.
    .
    All tire treads look rounded under no load. Including the one
    in my infamous treadwear.jpg shot -- but if the center is so rounded
    like it is on top, you ask, how can all the wear be at the edges?
    Because as the tread hits the road, all bets are off under insufficient
    inflation pressure and the outer parts are taking all the weight.
    The Hydroedges in general look a bit flatter across the tread than
    the Integrities did, even at 44 psi or better.
    .
    .
    Any recommendations on types of shops which will do alignment
    CHECKS and just give me an accurate report, without trying to
    hard-upsell monkeying with same? Preferably while I wait? It
    isn't a service I've ever really shopped for.
    .
    _H*
     
  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Hobbit,


    I suggest that you find wheel alignment shops in your local Yellow Pages. Then call them up & ask:
    1. what they would charge to read the current alignment settings
    2. what is the charge to set the front and rear suspension to spec, and
    3. for an appt so that you can wait while the work is being done.
    I had done this with my 2001 last summer after replacing the struts/shocks, and the alignment shop charged me $20 for the alignment report. They would have charged me ~$85 for a four wheel alignment including shims on the rear axle. As it turned out, no adjustment was recommended and I was satisfied with that finding.
     
  18. dogfriend

    dogfriend Human - Animal Hybrid

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    I would just talk to the shop to find out if they can give you the info (measurements in degrees) that you need. Galaxee recommended finding a shop with a Hunter DSP 600 machine. I found that the local Goodyear shop had this kind of machine, but were unable to give me the measurements in the proper units. Maybe look for a younger, computer competent tech who knows how to use the software.

    Also, you probably want a shop that will let you watch if you are the least bit paranoid. I add this because the Toyota dealer takes the car to the back of the facility where you have no idea what they are doing. They gave me a printout that showed me that all alignment specs were perfect, but could not explain to me how they corrected the toe on the rear axle. A subsequent check at an independent shop showed that they did not correct anything; they just manipulated the readings to get what they wanted.