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  1. #1
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    Directional tread on tires?

    I installed some Panaracer TGs on my commuter bike a couple of weeks ago but removed them after two days because my bike felt so much slower. Actually, it wasn't just a feeling -- my average speed those two days was about 2 mph slower than usual.

    I got to looking at the Panaracers over the weekend and realized that they have a directional arrow on the sidewalls. They actually are supposed to be mounted with the tread facing a certain direction -- the opposite of how I had installed them. I always install my tires so the decal lines up with the valve on the quick release side of my bike, so I can more easily locate holes in tubes when I get a flat. Turns out that the tread was facing backwards when I mounted the tires my usual way.

    I've never used bike tires before than had directional treads. Is this common? I've always used Michelins and other tires without much tread and no directional requirements. BTW, my bike definitely rolled a lot smoother and faster with the tires turned the right way.

  2. #2
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    Tread patterns are non-directional because they are also non-functional

    Quote Originally Posted by tarwheel2
    I've never used bike tires before than had directional treads. Is this common? I've always used Michelins and other tires without much tread and no directional requirements. BTW, my bike definitely rolled a lot smoother and faster with the tires turned the right way.
    Tread patterns on bicycle tires meant for pavement are primarily cosmetic. Unlike relatively wide, low pressure tires found on motor vehicles, the narrow high pressure tires found on bicycles can not hydroplane (well, at least not at speeds you are ever likely to see on a bike), and therefore the tread patterns on bicycle tires serve no function. Therefore, bicycle treads are not directional.

  3. #3
    DragonFly rider
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    Question Not directional

    Most higher end bycle tires are directional and there are a variety of tread patterns and rubber compounds for different road surfaces and weather conditions.
    As for hydroplaneing,no but slideout due to wet road,ice patch or loose road surface is
    where tread,compound and direction of rotation do make a difference.
    This of cource is just my 2cents take it or leave it.

  4. #4
    RoadBikeReview Member
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    All I can say is the sidewalls of my Pasellas say to mount them facing a certain direction. When I inadvertently mounted them the opposite way, they had significantly more rolling resistance. I notice the resistance without even realizing the tires were mounted wrong.

    I always used Michelins and other brands with no tread patterns, so I never encountered this issue before. For instance, there is no right or wrong way to mount a Michelin ProRace with regard to the tread because they have no tread pattern. The Paselas, in contrast, do have a tread pattern.

  5. #5
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    Leavit

    Quote Originally Posted by Pelon2
    Most higher end bycle tires are directional and there are a variety of tread patterns and rubber compounds for different road surfaces and weather conditions.
    As for hydroplaneing,no but slideout due to wet road,ice patch or loose road surface is
    where tread,compound and direction of rotation do make a difference.
    This of cource is just my 2cents take it or leave it.
    Hmmm. Take it. Or leave it. Hmmmm. Well, since it is based on no data and no engineering principles, I guess I will vote for "leave it." Modern road tires do NOT change ride characteristics in any way because of mounting direction. Deep cut tread? Sure. But those aren't what we're talking about here.

  6. #6
    Two wheels=freedom!
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    Tradition is to have the tire label on the drive side of the bike, on the opposite side of the rim from the valve hole. But with some modern tires having multiple labels on both sides of the tire...

  7. #7
    wim
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    Tradition is to have the tire label on the drive side of the bike, on the opposite side of the rim from the valve hole
    Must be a new tradition. The old tradition was to have the tire label(s) centered over the valve. Gosh durn, nothin ever stays the same any more . . .

  8. #8
    Unapologetic bike wh*re
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    The Pasela is a touring tire with a deeper tread that is designed to roll better when it's installed with a proper orientation.

    Many tires are direction specific and when you get into off road tires you also get front / rear specific tires that optimize traction and handling.

  9. #9
    Unapologetic bike wh*re
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    My tire labels are centered over the valve hole... I guess I'm a luddite.

  10. #10
    Two wheels=freedom!
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    Take a look at a set of tubulars, tire labes are opposite the valve, have been for as long as I've used em (over 25yrs). Clinchers if you care to follow with that, go ahead, just keep the label on the drive side of the bike.

  11. #11
    Unapologetic bike wh*re
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    The Schwalbes I just out on my Rocky are directional so it's impossible to have the label on the rear tire facing the drive side unless you mount it backwards.

  12. #12
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    Bicycle tire tread is non-functional, and therefore inherently non-directional

    Quote Originally Posted by tarwheel2
    All I can say is the sidewalls of my Pasellas say to mount them facing a certain direction. When I inadvertently mounted them the opposite way, they had significantly more rolling resistance. I notice the resistance without even realizing the tires were mounted wrong.
    There was either something else going on, or you were imagining things. Tread patterns on narrow road tires is too shallow to have any significant affect, let alone have some kind of directional affect.

    Tread patterns are put on bicycle tires for cosmetic and marketing reasons, not performance reasons. Many consumers see that automobile tires have tread, and therefore make the assumption that bicycle tires should too. These consumers then shy away from smooth treaded road tires, assuming that these "bald" tires have poor traction, and instead want to buy tires with a tread pattern. Thus, in order to stay in business, tire manucturers make what the consumers want - regardless of whether it really is a better product.

    Motorized racers have long figured out that on dry pavement, smooth treaded tires always have better traction and lower rolling resistance. That is why all dry road racing tires (stock cars, sports cars, formula 1, Indy cars, dragsters, etc.) use smooth tires. Similarly, bicycles also perform best on smooth treaded tires.

    On wet roads, the wide, low pressure tires used on motor vehicles tend to hydroplane, so grooves and sipes are added to prevent hydroplaning. But because bicycle tires are much narrower and under higher pressure, the speeds at which they can hydroplane are much higher than for motor vehicles. Even for wet roads, smooth treaded bicycle tires perform better. (Also notice that the contact patch of a bicycle tire is smaller than a single tread block of a grooved and siped motor vehicle tire).

    Because tread pattern on a bicycle tire is non-functional, they are inherently non-directional.

  13. #13
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    Gp4000

    my GP4000 tyres have arrows on sidewalls indicating they are directional even though they practically have no tread.

    I send e-mail to Conti with a question and (surprise) heard nothing back from them.

    There must be a reason for those arrows, beyond pure marketing.

    I *think* the internal fibres/threads/etc are laid out internally in certain way/direction as to influence tyre handling/cornering/wet-road behaviour. I dont this rollling on a straight and dry road you will notice any difference if they are mounted "incorrectly" wrt directional arrows.

  14. #14
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    Why should a slick tire be directional?

    Quote Originally Posted by acid_rider
    my GP4000 tyres have arrows on sidewalls indicating they are directional even though they practically have no tread.

    I send e-mail to Conti with a question and (surprise) heard nothing back from them.

    There must be a reason for those arrows, beyond pure marketing.

    I *think* the internal fibres/threads/etc are laid out internally in certain way/direction as to influence tyre handling/cornering/wet-road behaviour. I dont this rollling on a straight and dry road you will notice any difference if they are mounted "incorrectly" wrt directional arrows.
    Are you just speculating about the casing threads making the casing directional? Why should bicycle tires be directional, when no other slick tires (automobile, motorcycle, airplane etc.) are directional? It is even questionable about whether some tires with deeply patterned treads are at all directional. Motocross tires used to be made with assymmetrical (directional treads), but they are no longer made this way, primarily because they figured out it served no function. And if deeply knobbed tires made for very soft conditions aren't directional, why should slick treads made for hard surfaces be directional.

    Directional arrows are placed on road bike tires for the same reason that patterned treads are - to enhance their perceived value (but not their actual performance).

  15. #15
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    yes

    Quote Originally Posted by Mark McM
    Are you just speculating about the casing threads making the casing directional?
    Directional arrows are placed on road bike tires for the same reason that patterned treads are - to enhance their perceived value (but not their actual performance).
    I agree, yes, we are *both* speculating here. I have yet to hear anything official from Continental, after 1 week since my question was e-mailed to them. They clearly do care about their customer questions! NOT!

    I dont think having directional arrows on tyres enhances anything. There is a tiny bit of side-wall tread on GP4000 so perhaps this is the reason for arrows. Or total BS. 8^)

  16. #16
    RoadBikeReview Member
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    Quote Originally Posted by acid_rider
    I agree, yes, we are *both* speculating here.
    I'm not so sure about that. There is no speculation that all bicycle tires use 45 degree bias plies, and that they are rotationally symmetric (non-directional). There is also no speculation that the tread does not penetrate the pavement, and that the tire at the contact point is essentially stationary (i.e. the bottom of the wheel is not moving forward with the respect to the ground.

  17. #17
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    Quote Originally Posted by Mark McM
    Why should bicycle tires be directional, when no other slick tires (automobile, motorcycle, airplane etc.) are directional?
    F1 tires (grooved slicks) are directional through the casing construction.

  18. #18
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    I watched a documentary on legendary motorcycle road racing champion Kenny Roberts. He raced in the States on slicks as they did not race in the rain in the U.S.. Once he was racing in Europe and it started to rain. To Kenny's surprise the race was not cancelled. He had no motorcycle tires with treads. He asked the other teams if he could borrow a set of rain tires (with grooves/treads); however, no team would lend him tires. He was able to get ahold of a tread cutter and cut his own treads in his slicks and won the race. I know bicycle tires aren't quite the same as motorcycle tires but they seem fairly similar. One would think that if you need motorcycle tires with treads to ride/race in the wet, then you would need the same for bicycle tires, as 50-60 mph downhills in cycling is not uncommon. As far as tread pattern goes, I thought the idea was to channel any water away from the center of the tire. If you flipped the tire around it would channel the water toward the center of the tire.

  19. #19
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    Hydroplaning

    Quote Originally Posted by Fivethumbs
    One would think that if you need motorcycle tires with treads to ride/race in the wet, then you would need the same for bicycle tires, as 50-60 mph downhills in cycling is not uncommon.
    Bicycle tires require nearly 100 mph to hydroplane, given the high pressure. Motocycle tires have much lower pressure and will, therefore, hydroplane at much lower speeds. Knowing these facts is the difference between what "one would think" and reality

  20. #20
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    Are you saying that at speeds less than 100 mph a slick bicycle tire offers the exact same traction as a grooved bicycle tire in the wet? I have no experience other than a typical layman's but that doesn't sound right to me.

  21. #21
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    Quote Originally Posted by Fivethumbs
    Are you saying that at speeds less than 100 mph a slick bicycle tire offers the exact same traction as a grooved bicycle tire in the wet? I have no experience other than a typical layman's but that doesn't sound right to me.
    Yup. That's what he's saying, and that's what is true. It's a fact, no matter what you think.

    Also, the Continental "directional arrow" is not there for any important reason. Hell, Dunlop got an intermediate rain tire for GP motorcycles approved by the DOT so they could use it in supersport motorcycle racing, here in the US, where tires had to be DOT tires. And, it so happened that some folks chose to run the front tires, on those tire sets, counter to their directional arrow. And they wuz going a lot faster than anyone here will go on their bikes.

  22. #22
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    I was skeptical but I found something that backs up what you say.

    "Benefits of smooth tread are not easily demonstrated because most
    bicycle riders seldom ride near the limit of traction in either curves
    or braking. There is no simple measure of elapsed time or lean angle
    that clearly demonstrates any advantage, partly because skill among
    riders varies greatly. However, machines that measure traction show
    that smooth tires corner better on both wet and dry pavement. In such
    tests, other things being equal, smooth tires achieve greater lean
    angles while having lower rolling resistance.

    Tread patterns have no effect on surfaces in which they leave no
    impression. That is to say, if the road is harder than the tire, a
    tread pattern does not improve traction. That smooth tires have
    better dry traction is probably accepted by most bicyclists, but wet
    pavement still appears to raise doubts even though motorcycles have
    shown that tread patterns do not improve wet traction.

    A window-cleaning squeegee demonstrates this effect well. Even with a
    new sharp edge, it glides effortlessly over wet glass leaving a
    microscopic layer of water behind to evaporate. On a second swipe,
    the squeegee sticks to the dry glass. This example should make
    apparent that the lubricating water layer cannot be removed by tire
    tread, and that only the micro-grit of the road surface can penetrate
    this layer to give traction. For this reason, metal plates, paint
    stripes, and railway tracks are incorrigibly slippery.

    Besides having better wet and dry traction, smooth tread also has
    lower rolling resistance, because its rubber does not deform into
    tread voids. Rubber being essentially incompressible, deforms like a
    water filled balloon, changing shape, but not volume. For a tire with
    tread voids, its rubber bulges under load and rebounds with less force
    than the deforming force. This internal damping causes the energy
    losses of rolling resistance. In contrast the smooth tread transmits
    the load to the loss-free pneumatic compliance of the tire.

    In curves, tread features squirm to allow walking and ultimately,
    early breakout. This is best demonstrated on knobby MTB tires, some
    of which track so poorly that they are difficult to ride no-hands.

    Although knobby wheelbarrow tires serves only to trap dirt, smooth
    tires may yet be accepted there sooner than for bicycles."

  23. #23
    Unapologetic bike wh*re
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    Tread patterns have no effect on surfaces in which they leave no
    impression. That is to say, if the road is harder than the tire, a
    tread pattern does not improve traction.


    That is fine for road bikes but for mountain bikes and motorcycles the type of rubber compounds used, the characteristics of the tyre, and the tread make a huge difference in how the machine performs.

    I rode a motorcycle for many years and did find a marked improvement in wet performance when I set my bike up with Avon Super Venoms which are / were regarded as one of the best wet performance tires. In riding through torrential rains the bike handled nearly as well as it did on dry pavement whereas other tires I ran felt sketchy at speed in the rain.

    I just changed the tyres on my mb from aggressive knobbies to much slicker offroad tyres and on the hardpacked trails I ride the slicker tyres roll faster and actually climb better than the tires that look like they should be able to climb walls. When it gets wet I have another mb set up with tyres better suited for muddy conditions.

    The most telling thing about slick tyres and their traction abilities is that many fixed gear riders here run the same slicks in the winter as they do in the summer and we get a good share of snow and ice.

  24. #24
    al0
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    Compounds - yes, theymake difference (but not always intended by manufacturer), threads - pure cosmetic.

    BTW, it was shown by tests (German TOUR magazine) that "wet-road" tires serve on wet roads by no means better then general-purpose tires.

    Quote Originally Posted by Pelon2
    Most higher end bycle tires are directional and there are a variety of tread patterns and rubber compounds for different road surfaces and weather conditions.
    As for hydroplaneing,no but slideout due to wet road,ice patch or loose road surface is
    where tread,compound and direction of rotation do make a difference.
    This of cource is just my 2cents take it or leave it.

  25. #25
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    Quote Originally Posted by Fivethumbs
    I was skeptical but I found something that backs up what you say.

    Of course, without the source or a link, there's no way of knowing whether this author has any more of a clue than others here. All I can tell is he (she?) tells a pretty story.

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