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Directional tire found mounted wrong direction...6 months later!

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by efusco, Oct 6, 2008.

  1. efusco

    efusco Moderator Emeritus
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    Around 6-8 months ago or so I had a slow leak in a tire that couldn't be repaired and required replacement under my tire warranty. At that time there was maybe 45k miles on my tires.

    So Sam's Club replaced my bad tire w/a new Michelin HydroEdge. I have happily been driving on that since it was replaced...maybe 10k miles or so. Getting some of my highest MPG tanks ever and great handling and performance esp. since adding the BT strut support.

    Well, today I took the car in for my state inspection to renew my tags...passed w/o trouble but they pointed out that that tire had be mounted backward...it's a directional tire and should be mounted the other way....well crap.

    I had it fixed (the Sam's club is 20 miles away and it takes forever to get anything done so it was worth the $14 to just be done w/ it). Now, driving home, it seems like there is a louder tire whine than I'm used to.

    Is this my imagination? Why do directional tires need to face the right direction...is it a wet traction thing only? Is/was it a bigger deal than I realize? Learn me something.
     
  2. Boo

    Boo Boola Boola Member

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    By appearances, it aids in moving rain and snow away from the tire. If you mount it backwards, it would seem to move rain and snow toward the center of the tire.
     
  3. EZW1

    EZW1 Active Member

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    Directional tires are directional because of the way the treat is moulded. The concern is, if they'e mounted wrong, they stand a greater chance of failure. This doesn't mean they WILL fail.
     
  4. bedrock8x

    bedrock8x Senior Member

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    The spec does not mention it is directional.

    HydroEdge: Browse Tires in Passenger Car/Minivan: MICHELIN® Tires: Michelin Tires

    The tread pattern looks directional, but IMHO it doesn't matter as the slanted treads are not deep grooved, wet traction is not going to make a big difference.




     
  5. efusco

    efusco Moderator Emeritus
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    They're definately directional tires...there's an arrow on the sidewall and the tread clearly is designed that way.

    I realize that it will affect, to some degree, wet traction (though I hadn't noticed any issues despite the tremendous amount of rain this Spring).

    My concerns were more about wear and failure or any other issues I had not considered.
     
  6. Boo

    Boo Boola Boola Member

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    Here's what TireRack says:

    Hydroplaning: The Role Tires Play

    Hydroplaning happens when one or more tires is lifted from the road by a wedge of water that gets trapped in front of and under a tire as the vehicle drives through water. Hydroplaning most frequently occurs during heavy rainstorms when water creates puddles on the highway or expressway. In addition to the accompanying splash and scaring the heck out of the driver, hydroplaning typically causes the steering wheel to jerk and the vehicle to abruptly pull towards the puddle.

    The speed at which a tire hydroplanes is a function of water depth, vehicle speed, vehicle weight, tire width, tread depth and tread design. It depends on how much water has to be removed, how much weight is pressing down on the tires and how efficient the tread design is at evacuating water. While deeper water, higher speeds, lighter vehicles, wider tires, less tread depth and less efficient tread designs will cause tires to hydroplane at lower speeds; all tires will be forced to hydroplane at some speed.

    As a rule, tread design affects hydroplaning resistance at high speeds and in deep water. Tread compound affects wet traction at lower speeds or in shallow water.

    Directional tread designs (sometimes called Unidirectional tread designs) are frequently used on tires intended to better resist hydroplaning. Their multiple tread grooves are aligned in a repeating "V" shape to increase the tire’s ability to channel water from between the tire’s footprint and the road. Somewhat like the vanes of a water pump continually pushing water in one direction through the engine, the grooves of a directional tire are designed to push water in one direction through the tire (forward on an angle to the sides). Directional tread designs are especially helpful in increasing hydroplaning resistance when relatively wide Plus Two, Plus Three or Plus Four tire and wheel applications result in fitting a much wider tire to a vehicle than its Original Equipment size.
     
  7. PriuStorm

    PriuStorm Senior Member

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    I'm just wondering if you've been feeling an urge to drive around in circles for the past 6 months... :D
     
  8. efusco

    efusco Moderator Emeritus
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    LOL...I pulse from 0-180 degrees, and glide from 181-360!
     
  9. efusco

    efusco Moderator Emeritus
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    Again Boo, I understand what directional treads do. And I understand that having them backward will make them do that job less well. I'm interested in other potential consequences of having ONE tire mounted the wrong way for 6 months.
     
  10. Boo

    Boo Boola Boola Member

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    Yep. We cross-posted. I think the "consequence" for that one tire is an inconsequential, de minimus amount of unnatural wear pattern. Like being a little more tanned on your front than on your back.
     
  11. Rokeby

    Rokeby Member

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    First off, I'm not alleging anything is wrong with the tire -- I don't know
    enough about tires to be so bold.

    Was the backwards run tire on the front (driven wheel) or the back?

    Maybe there's an opportunity to learn something here. You have a once in a
    lifetime chance to compare the tread of the backwards run tire against one or
    more that ran correctly. I would find it interesting to see if you could detect
    any uneven wear comparing the front edge of a tread block to the after edge
    of that block. At this point, if there is any difference, comparing the two tires
    it should show up as twice normal.
     
  12. efusco

    efusco Moderator Emeritus
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    It was the front driver's side...but it was a new tire and my others had about 40-45k miles on them, so a comparison would not be possible.