CapriRacer -
(thank you again for your feedback)
Quote:
Originally Posted by CapriRacer
If I have this right, the concern is the car following the grooves in the pavement. We tire engineers call that "groove wander" - although the term "tramlining" is also used (I prefer the former - a bit more descriptive, I think.)
What is happening is that the grooves in the tire are lining up with the grooves in the pavement and when edge meets edge, the tire tends to be follow the edge in the pavement. This phenomenon is going to be affected by the number of grooves in the tire (and the number of grooves in the pavement) and the amount of footprint pressure for each groove.
Obviously over inflating the tires is going to put more pressure on the center grooves - and those grooves will dominate the way the tire behaves. Less pressure will tend to engage the rest of the grooves and decrease the effect.
2 problems: While there are standards about pavement grooving - spacing, width - there are so many non-standard pavement grooving, it is difficult for a tire manufacturer to space the grooves in a tire to account for all of them.
Grooves in a tire are necessary to allow a pathway for the water when the tire rolls through the water - which is what the grooves in the pavement are also doing. In designing a tire, well defined grooves work better that grooves that are interrupted by the tread pattern. Plus the edges of a tread element are areas were the wear will be more rapid that in the center of the element. "Heel and toe" wear is a good examples of this at work. Well defined grooves tend to be more resistant to irregular wear, especially diagonal wear.
In your case, I would try decreasing the pressure and see if that doesn't help.
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I was experiencing the groove wander when the tires were set to 42 PSI, so I don't think it will make a difference. I predicted this behavior before I bought the tire when I looked at the tread :
The Continental tread reminded me
a lot of my old motorcycle tires (circa 1980's), which also had the "clean/flat" tread grooves and suffered from massive groove wander. On the new Continentals, I think the tread grooves are also very wide. If I had known this in my motorcycle daze, I would have gotten a tire with the diagonal grooves you describe :
I agree that the tire behavior is dependent on the groove of the road. There are some "groove zones" on the freeway that do not effect me. It always depends. It's like a "harmonic frequency" thing. In the back of my mind I wonder if these tires were designed for "European Highways" that may not have the same kind of "groovy" freeway design patterns that we do.
Part of being a Hypermiler is "driving the road ahead". This means following the 3+ second rule and looking for escape routes from possible accident scenarios. Despite the bad traffic my LA driving conditions are very mild. I don't have to deal with snow, mud, or torrential rain the way the rest of the country does.
Overall I am very happy with the tires. The GPS correction means I always get a 2% bonus whenever I fill-in my gaslog. That's happy stuff for me,
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CarloSW2