Help Me Pick my DE Tire Size!
09-06-2007, 12:53 PM
#46
Moderator
Rennlist Member
Rennlist Member
This is all very interesting and I have to assume that John has recently changed his opinion about proper fitment for the 997S because just this past spring he suggested and quoted 8.5x18 and 11x18 for me on PSCs and RA1s. If he believes that during the past 6 months evidence has suggested he change his suggestion from 11" to 12" wide, then so be it. It remains curious to me that all other tire and wheel makers are suggesting the 11" wide wheel for the 295 PSC and 305 RA1. I'm genuinely interested in John's findings that the tires run cooler and wear much better -- that's something I'm sure we all would like to know more about.
I wish I could find that diagram that showed the relationship and the pros / cons of wheel and tire fitment. It showed a wheel in section with a tire that was too wide and then one that was too narrow. The one where the rim was not wide enough showed the tire bowing out because the tire was "pinched" . In the other diagram it showed the tire cupped because it was stretched. When 11" was suggested to me by John and all other wheel makers, it made sense to me because I didn't want the uneven grip and wear of say a 12" wheel with my tires that were designed for 11" wheels.
Perhaps John will share with us his information in how he makes the 12" wheel work so well. Is it different pressures to push the center of the tire out to create even grip and wear? Is there something "different" about the 997S platform that works better with an oversized rear wheel?
Guys, I don't think anyone of us is closed minded. It's just that after years of having all wheel and tire makers match 295/305 with 11" for the 997S (including John / CCW until recently), we are genuinely interested to know why. If it makes sense, maybe we will all switch to wider rear wheels if the industry moves that way.
I wish I could find that diagram that showed the relationship and the pros / cons of wheel and tire fitment. It showed a wheel in section with a tire that was too wide and then one that was too narrow. The one where the rim was not wide enough showed the tire bowing out because the tire was "pinched" . In the other diagram it showed the tire cupped because it was stretched. When 11" was suggested to me by John and all other wheel makers, it made sense to me because I didn't want the uneven grip and wear of say a 12" wheel with my tires that were designed for 11" wheels.
Perhaps John will share with us his information in how he makes the 12" wheel work so well. Is it different pressures to push the center of the tire out to create even grip and wear? Is there something "different" about the 997S platform that works better with an oversized rear wheel?
Guys, I don't think anyone of us is closed minded. It's just that after years of having all wheel and tire makers match 295/305 with 11" for the 997S (including John / CCW until recently), we are genuinely interested to know why. If it makes sense, maybe we will all switch to wider rear wheels if the industry moves that way.
09-06-2007, 01:06 PM
#47
Rennlist Member
horse of a slightly different color but the 996TT GT2 runs a 12 inch rear with a 315 tire from the factory.
that is the size I run on my TT at the track and have had good results with a hoosier and a cup tire.
that is the size I run on my TT at the track and have had good results with a hoosier and a cup tire.
09-06-2007, 10:41 PM
#48
Race Director
Thread Starter
Relax everyone, I am going with what John at CCW is building me. If it does not work he will take them back and CCW come with a super great reputation. Things change and John feels this is the size to go with and price was not any different from one size to the other being discussed here.
