by Jon11582 » Wed Jul 25, 2007 3:22 pm
The OEM potenzas are crap in rain and snow. And not too good in dry cornering either.
Speed rating is specifically a rating of the speed at which a tire has been tested to keep together after running for 10 minutes. It does not say anything about the cornering ability or traction of the tire, it just says if you ran it for 10 minutes in a straight line at X speed, it wont shred on you. You could theoretically have a really hard tire that keeps together at Y-rated speeds, but cant grip in corners at all.
Traction rating is another rating thats part of the UTQG (Uniform tire quality grading) given to tires to try and objectively rate their wet grip. This rating isn't too useful either because it rates the tires when they are new. It doesn't say anything about how well the wet traction will hold later on in the tread life. (The RE92s scored an "A" for traction, but any of us who have had their RE92s for a while know that they suck in the wet.)
Also, one note on tire pressure. Bad wet traction would more likely be worse if you were low on air pressure, than high. Loss of traction in rain is caused by the channels in the tread not being able to push the rain to the edge of the tire, and instead forcing it under the tread, causing a loss in traction. Low pressure causes the tire to have a wider footprint, and causes less pressure pushing the tire to the road . The wider footprint increases the distance that water has to travel to get out of the way of the tread, and the lower pressure pushing the tire to the road causes water to more easily get under the tread.
See this for an article for an excellent illustration:
http://www.tirerack.com/tires/tiretech/ ... p?techid=3
Theoretically, being too high on air pressure would cause better wet traction (to a point), but worse dry traction.
Speed rating is specifically a rating of the speed at which a tire has been tested to keep together after running for 10 minutes. It does not say anything about the cornering ability or traction of the tire, it just says if you ran it for 10 minutes in a straight line at X speed, it wont shred on you. You could theoretically have a really hard tire that keeps together at Y-rated speeds, but cant grip in corners at all.
Traction rating is another rating thats part of the UTQG (Uniform tire quality grading) given to tires to try and objectively rate their wet grip. This rating isn't too useful either because it rates the tires when they are new. It doesn't say anything about how well the wet traction will hold later on in the tread life. (The RE92s scored an "A" for traction, but any of us who have had their RE92s for a while know that they suck in the wet.)
Also, one note on tire pressure. Bad wet traction would more likely be worse if you were low on air pressure, than high. Loss of traction in rain is caused by the channels in the tread not being able to push the rain to the edge of the tire, and instead forcing it under the tread, causing a loss in traction. Low pressure causes the tire to have a wider footprint, and causes less pressure pushing the tire to the road . The wider footprint increases the distance that water has to travel to get out of the way of the tread, and the lower pressure pushing the tire to the road causes water to more easily get under the tread.
See this for an article for an excellent illustration:
http://www.tirerack.com/tires/tiretech/ ... p?techid=3
Theoretically, being too high on air pressure would cause better wet traction (to a point), but worse dry traction.
2000 Black Solara SE
- Jon11582
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