718 as an Autocross Tool
09-17-2018, 04:17 PM
#166
Rennlist Member
roll centers front and rear maybe impacted with that size meat in the rear. The puzzle is how big of tire can match that on the front. I believe 265 is as large as can be mounted on a 8.5 wide wheel. 265 plus 30 equals 295. Creating more understeer by ignoring the 30 rule is putting a lot of faith on a single adjustable swaybar in front to compensate for balance difference. Maybe camber and air pressure will help.
Peter
09-17-2018, 07:09 PM
#170
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My experience so far tells me the places where understeer is really a problem, at least in autoX, for the 718 is in slow tight
stuff. My thinking is that if one had a PDK and could down shift to first in those areas than throttle oversteer is possible and therefore a 305 in back is more of a boon then hinderence. Then again I do not have a PDK so that last bit might be invalid.
09-17-2018, 08:37 PM
#171
Thanks!
Looking at the TireRack specs for the RE71R, the only 285 in an 18 diameter is the 285/30R18, which has an outer diameter of 24.8", while the lowest profile 255 is a 255/35R18 with an outer diameter of 25."
The the rears in the stock sizes are about an inch larger than the fronts.
Do you have any issues with traction control, etc, running the rears with a slightly smaller diameter than the fronts?
Looking at the TireRack specs for the RE71R, the only 285 in an 18 diameter is the 285/30R18, which has an outer diameter of 24.8", while the lowest profile 255 is a 255/35R18 with an outer diameter of 25."
The the rears in the stock sizes are about an inch larger than the fronts.
Do you have any issues with traction control, etc, running the rears with a slightly smaller diameter than the fronts?
09-18-2018, 02:56 AM
#173
Yury had been running 265/305 19” re71r almost all year but once tested back to back with the 255/285 18” setup he felt he was faster or at least more consistent on the 18” and that’s what he ran at nats. I was disappointed to hear this as with the short gearing of the pdk I had being able to run this tire size as a big plus for the 718 base. That said, everyone is different and setups can differ a lot to. His opinion might not be shared by all.
09-18-2018, 07:54 PM
#174
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Ya, I took some time to talk to Yury in grid about his set up. He ordered the car exactly as I would have minus the PCCB option. He mentioned to me that with the PDK down shifting to first was a non-penalty situation and that when on a 19" wheel the gearing still worked well for that low speed tight stuff that I really suffer with in my manual car. That said, he also mentioned that he felt the 18" set up was faster yet. I went directly to 18" so I can only speculate. What has me scratching my head right now is the wider 20" Carrera S wheel option in 2019 cars...11.5in rear! Hmm, could be a game changer.
09-18-2018, 08:10 PM
#175
Ya, I took some time to talk to Yury in grid about his set up. He ordered the car exactly as I would have minus the PCCB option. He mentioned to me that with the PDK down shifting to first was a non-penalty situation and that when on a 19" wheel the gearing still worked well for that low speed tight stuff that I really suffer with in my manual car. That said, he also mentioned that he felt the 18" set up was faster yet. I went directly to 18" so I can only speculate. What has me scratching my head right now is the wider 20" Carrera S wheel option in 2019 cars...11.5in rear! Hmm, could be a game changer.
