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996 race tires???

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Old 02-03-2011, 02:09 PM
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jrgordonsenior
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Originally Posted by Glen
Taller = bigger contact patch with equal width...
Glenn I can't visualize how that works for equal width tires. Can you please explain it to me in so I can understand please....

Thanks, JRG
Old 02-03-2011, 02:16 PM
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Glen
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Yes the contact patch is longer since the tire is taller. Width of patch is the same, length of patch is longer. Make sense?
Old 02-03-2011, 04:10 PM
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jrgordonsenior
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Originally Posted by Glen
Yes the contact patch is longer since the tire is taller. Width of patch is the same, length of patch is longer. Make sense?
OK, now I get it. It's the length. Thanks Glen.....
Old 02-03-2011, 05:22 PM
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IPguy
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Longer is better....
Old 02-03-2011, 05:47 PM
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onefastviking
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I always thought it was the girth that was important, but what do I know.


Originally Posted by jrgordonsenior
OK, now I get it. It's the length. Thanks Glen.....
Old 11-17-2015, 12:41 AM
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HiWind
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Bump ... So how much rolling for a 265/275 up front?
Will paint crack?
Old 11-17-2015, 09:45 AM
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kk2
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Rad went crazy trying every combination imaginable. Here's one of the posts by him:

Originally Posted by NJ-GT
I ran the 285/30R18 A6 that is as tall as the 255/35R18 A6 (which is really a 275/30R18), combined with the 335/30R18 A6 in my 996 GT3. No ABS issues at track days, time trials or autocrosses.

The 315 and 335 Hoosiers on 18" have the same overall diameter.

At the 2009 SCCA Nationals, a good friend was running 255/315 in his stock 996 GT3, no ABS issues either.

The 255/315 Hoosiers are within the tolerance of the F/R diameters for the ABS computer. No problems at all.
Old 11-17-2015, 12:32 PM
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onefastviking
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Originally Posted by HiWind
Bump ... So how much rolling for a 265/275 up front?
Will paint crack?

A fair amount of rolling no doubt for the 275's, as well as key suspension pieces, proper alignment, a little adjustment of front rads, and some work with the inner shields if you choose to run them. It's not an easy throw some tires on type of thing as everything must be just right to make it all fit. Although I have done this on a non gt3 narrow body 996, so you too can do it.

If you rush the fender roll and have never done it before then you might crack the paint, if you are experienced at it then you know what to do to lessen the chance of cracking. I'll add that the factory paint usually cracks less than if it's been repainted at some time in its life. I think the factory paint is just done better with regards to primer and body prep so it literally sticks better, but that's just my best guess as to why. Hints to prevent cracking ......1) take it very slowly. 2) use heat, as in a heat gun.

Hope that helps,
Viking
Old 11-17-2015, 01:14 PM
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HiWind
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thanks for diggin that up KK ...
and cheers for coming back onto topic Viking ... the detail helps as I had little idea it involved repos of the rads etc...

Seeing as I'm just trying out a few ideas and given what you've said I think I'm going to try a 265 first off with the (heatgunned) fender roll and add a bigger front splitter ... maybe some more rake too ... but first off wider/longer (per Glen's post above) contact patch tires before I drop into the setup rabbit hole
Old 11-17-2015, 01:17 PM
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kk2
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What's wrong with your current setup? Too much understeer? My car is setup similarly and with a proper setup I don't have any issues.
Old 11-17-2015, 02:52 PM
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HiWind
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not sure .. working on it

but if I slow down the understeer goes away
Old 11-17-2015, 03:03 PM
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FWIW I ended up with 265 and 305 Hoosiers on my old 996. Now running 280'$ and 330'$.
Old 11-17-2015, 03:13 PM
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HiWind
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yes I saw that elsewhere Ritter ... how did you fit the 265s on front?
just alignment & fender massage?
change wheel outer lips?
Old 11-17-2015, 03:19 PM
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It seems so long ago, best ask JRG and OFV but I recall combination of wheel (rim) size, camber, fender roll and liner trim. We ended up with a balanced car with very good and even tire wear front and rear.
Old 11-18-2015, 11:23 AM
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HiWind
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looks like i need to change my front 3 piece BBS outer rim ... do I need a 3.5" piece?


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