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Terminology... Posted by Larry West [Email] (#1140) [Profile/Gallery] (more from Larry West) on Sat, 28 Feb 2009 20:35:59 In Reply to: Because......., John Nuttall, Sat, 28 Feb 2009 15:03:31 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I think, as Stephen said, you're not so much worried about directional, but let's go over the tire types first:
1) Standard - these tires don't care which side of he car they're on, which direction they rotate, or which face is outboard on the car. They can be moved about while mounted to any corner.
2) Directional - these tires should only be rotated in one direction, usually because of the tread pattern (but not always). The tread pattern was usually similar to a Champ Car or F1 rain tire, designed to move water away from the center of the tread. Goodyear "Gatorbacks" were an example, as were Bridgestone Potenza RE-71s, as I used to use on my Classic 900s. The same tire is used all around. Moving a mounted tire from one side to another requires the tire be dismounted, flipped and re-mounted to the wheel.
3) Symmetrical - These tires should be run with one face outboard. Again, this is usually due to tread design and/or compound. Back in the late 80s, early 90s, the tire to get was the Yokohama A008, which featured tread like this. These can be moved, mounted to the wheels, from side to side on the car.
4) Directional AND Symmetrical - These tires must be run on a specific side of the car. There are two part numbers for each tire size, one for the left side, and one for the right. These cannot be run on the other side, even if flipped. I had a set of Nokian NR-Vs that were like this.
Years ago, I used to buy Bridgestone RE-71 tires, These were directional. After so many miles went by, I'd have them "flipped" on the wheels to even the wear (I also had an alignment for a Classic 900 that evened the wear, and handled better...).
So, the only type that cannot move from one side to the other is the directional and symmetrical. Standard tires don't care, the directionals need only be flipped on the wheel, and the Symmetricals can move about freely.
However, "they" say that once you run a radial in one direction, you're not supposed to run in rotating the opposite way. But I neither know who "they" are, nor how this conclusion was reached...
Personally, I like the directionals, as their tread pattern usually is better in the wet than any others. And the minor inconvenience of flipping them doesn't bother me.
My 2002 9-5 Sedan really likes the Bridgestone Potenza G019 Grid tires I put on last year. And my 1990 900 likes the Bridgestone Potenza G009 tires it got a year before that. Both of these have directional tread patterns, and neither car has demonstrated anything untoward regarding handling...
YMMV...
_______________________________________ Current: 2002 9-5 Aero Kombi Cosmic Blue 2000 9-5 SE sedan, Imola Red 1990 900S Rose Quartz, Auto Past: 1999 9-5 LPT Combi 1999 9-5 LPT sedan 2002 9-5 Arc 1990 900 5-speed 1986 900 turbo Convertible 1991 9000 turbo 1980 99 GLi 1986 900 turbo 1986 900 S 1991 900 turbo 1984 900 turbo 1976 99 GL
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