Ultra tires

Discussion in 'General Harley Davidson Topic' started by alto, Apr 3, 2011.

  1. alto

    alto Active Member

    237
    28
    3
    First..I'm ignorant of tires/thread. I'd like to understand why some tires , like Dunlop , have deep thread across the entire tire, like the tires I've always known over my many years..Car tire type thread ...Yet others, like the Avon Venom I have on my ultra, seem to be solid rubber at contact with road and have the outward grooves. I understand the grooves channeling the water out and away from center. What I don't understand is the center of the tire being just solid rubber with no thread. I look at my fairly new ( maybe 2000 miles) Avon rear tire and see, what to my old-school mind, is a 'bald tire' in the center.
    Maybe I'm not explaining my thoughts on these Avon tires vs a more 'conventional ' thread over the entire tire. I'm told ( had dealer look at the tires) that they are fine. Am I just too old and old-school to want to see 'conventional' tire thread?
     
  2. alto

    alto Active Member

    237
    28
    3
    I appreciate your thoughts. When talking with the service manager about my tires, I said I didn't want high mileage/cold type tires...that I prefer a soft compound/sticky/warm tire that was great in rain....that I'd rather change tires more often if necessary ( I'm not an aggressive driver at all and, I put on just a few thousand miles per year)....He said..." That's what you have with those Avon tires". It's not that I didn't believe him. I just want to educate myself to be comfortable with what I have.
    Again, thanks for your thoughts.
     
  3. Mad Dog Jim

    Mad Dog Jim Banned

    605
    0
    5
    I have been told many things by dealers and its probably all true but very generalized. Such as; Dunlop tires are the best all around, Metzelers run the longest, and Avon is the stickiest. The problem is that they all make different types of tires. Not all Metzelers are long lasting, not all Avons are stickiest, etc. You may have the sticky Avons... Tread pattern often reveals what type of rubber they are made of. If there is a solid foot print in the center, most likely they are soft compound there.
     
  4. Hoople

    Hoople Account Removed

    7,198
    0
    34
    I am not a tire guru by a long shot, so just passing info along. How I understand it, the single most important characteristic for both dry & wet adhesion is the Silica content of the tire. I was told, one of the highest silica content tires around is the Pirelli Dragon. Short life but do grip. Another high on the silica list is the Metzeler 880. Ran at high pressures,,they handle nice and mileage so far is good.

    As far as thread goes. Yes, having no thread (water channel) on a flat surface tire (automotive) would be the kiss of death. But I believe since a bike tire is really a curved riding surface (riding surface is more of a line than a flat surface), thread may not play that big a role. (pounds of weight per square inch of contact area)

    Since the contact patch of our tires is very narrow, having grooves directly in the narrow contact patch area to reduce hydroplaning is just not practical. Lets say your riding on a 1/8" sheet of water going 50 MPH. The narrow contact area is more of a knife edge than a riding surface. The edge forces the water to the sides instead of riding directly on the surface as a car tire would. Now lets say you hit a 1/2" deep puddle going 60 MPH. As long as the bike was vertical when it entered the puddle, the bike could never fall over due to the gyro effect of the wheels. Thread or no thread, you could not turn or stop and would just glide over the puddle in a hydroplane state. On the other hand, if the bike went into that same puddle leaning to the side, grooves would be more important in channeling away as much water as possible. Still don't think your going to make it through a turn with a 1/2" puddle, but if you were on that 1/8" sheet of water, grooves would help. I therefore believe tire thread really does not even enter the picture unless your leaning in the wet.

    Also having tire grooves in the narrow contact area would make the tires "darty" in my opinion. (tar snakes, steel bridges etc)

    Just my view, nothing more. It's a complex topic for sure.
     
  5. Mad Dog Jim

    Mad Dog Jim Banned

    605
    0
    5
    Hoop - It's a multiple factor equation for sure! That's why being over generalized could be a problem. Like believing that one brand is the best, and taking that to mean all that brand's tires are the best for any and all applications.

    Maybe there is a tire physics guru in our midst that could shine some light on this subject...
     
  6. Hoople

    Hoople Account Removed

    7,198
    0
    34
    So true. I actually worry more about sand than water. I can see rain and adjust for it. Sand can come out of nowhere on a picture perfect day. I have never heard of one tire being better in the "sand".:)
     
  7. alto

    alto Active Member

    237
    28
    3
    Thanks to all. Lots of info here. I try to learn a new thing every day..Unfortunately, at my age, I'm forgetting two things every day.
     
  8. Mad Dog Jim

    Mad Dog Jim Banned

    605
    0
    5
    Which leads us to the heart of the matter. "IF" you can find the technical data on tires, such as the coefficient of force, coefficient of rolling force, coefficient of drag etc, my guess is that those figures are discovered in a lab setting under perfect conditions. Then you have to consider that even a proffesional race track isn't "perfect". And the open road is FAR from perfect! can we expect to find a perfect tire for 40 degree weather with rain, that also works well in 100 degree temps? and sand, and potholes, and gravel, and...

    In my opinion we ought to be only concerned with using tires from a reputable manufacturer, with the proper load rating, and a compound and tread patern that best suits our individual riding style and typical conditions. For me, I like an all weather tire with a heavy load rating, high mileage, and that tracks straight in groves. I have found that the Metz ME880 works great for that. But so do many others. If I were going to do a lot of high speed cornering on a race track I would use a different tire. Different bike too:s
     
  9. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    4,633
    83
    100
    There are about 5 significant manufacturers that make tires for the HDs. Here is the list:
    • Avon
    • Dunlop
    • Metzeler
    • Michelin
    • Pirelli
    Some folks might add Continental to the list, and the crotch-rocket crowd might want to add some of the Japanese brands to the list.

    Each manufacturer has one or more "models" that may fit your bike. Check their "fitment" page. Research these on their sites and then on the net. Make an informed decision based on your bike and how you ride it.

    On my bagger ('03 UC), I have tried the Dunlops D402s (gone away from them because of the problems with cracks in the water channels), and Avon Venoms (good grip with pretty soft compound so they wear quickly). Next I am going to try the Pirelli Night Dragons. I wanted to try the Michelin Commanders, but they have discontinued those. Supposed to come out with the Commander IIs. We'll see.

    On my little bike ('91 Dyna), I run Avon Venoms. I want the grip there.

    TQ