18" or 19" rims on GT4
#212
When tracking cars....NEVER add the numbers up. Just enjoy the experiences.
#213
Pro
Thread Starter
Why?
To the original poster, why would you change Porsche's engineered and uber-tested tires and wheels for 18" or 19" wheels?
It cost more, not less.
Did not the invention of the street-able Race tire makes the switch back and forth obsolete?
Here is how I figure...
19" tires in and of themselves are not substantially less expensive, but I do understand there are sticky tires which are (currently) only offered in 19" tires which are substantially less expensive.
The 20" OEM Cup 2s are about $2,000, whereas good street-able 19" tires or slicks could cost only $1,300 for set.
But, the track rims cost too. New 19” rims will cost about $4,000 for custom forged wheels. Or, about $2,000 for decent off-the-shelf rims (with some compromise in quality/weight/and diameter).
Assuming I’m running 4 or 5 track weekends & 2,500 street miles per year, I’ll be changing my expensive Cup 2s every year. Here is how the math works out:
If I stay with OEM:
Year 1………………….$2.500
Year 2………………… $2,500
Year 3 …………………$2,500
Year 4 ……………… $2,500
Total Outflow………….$10,000 This is an expensive option.
Vs.
Buy a set of track tires and Wheels:
Year 1
Change my OEM 20" to street Michelin Sport Pilot…..... $1,300
Buy track rims and slicks…………………………………………. $4,000
Total Year 1………………………………………………………………… $5,300
Year 2 …………………………………………………………………….. $1,300
Year 3 …………………………………………………………………….. $1,300
Year 4 …………………………………………………………………….. $1,300
Plus, replace the 20” street MSPs…………………………….. $1,300
Total Outflow…………………………………………………………….. $10,500
This is an even more expensive option.
Of course, in terms of absolute performance, slicks on 19” wheels would be quicker than street-able 20” tires. But, how much quicker? Is it worth the hassle of buying / storing / transporting /and changing wheels every time. And what about the fact that slicks specifically are not allowed under the Porsche’s operating manual and warranty?
I think the math makes a very good case for staying with the extreme performance multi-purpose street/race OEM 20" wheels and tires.
Flame suit on, what say you?
To the original poster, why would you change Porsche's engineered and uber-tested tires and wheels for 18" or 19" wheels?
It cost more, not less.
Did not the invention of the street-able Race tire makes the switch back and forth obsolete?
Here is how I figure...
19" tires in and of themselves are not substantially less expensive, but I do understand there are sticky tires which are (currently) only offered in 19" tires which are substantially less expensive.
The 20" OEM Cup 2s are about $2,000, whereas good street-able 19" tires or slicks could cost only $1,300 for set.
But, the track rims cost too. New 19” rims will cost about $4,000 for custom forged wheels. Or, about $2,000 for decent off-the-shelf rims (with some compromise in quality/weight/and diameter).
Assuming I’m running 4 or 5 track weekends & 2,500 street miles per year, I’ll be changing my expensive Cup 2s every year. Here is how the math works out:
If I stay with OEM:
Year 1………………….$2.500
Year 2………………… $2,500
Year 3 …………………$2,500
Year 4 ……………… $2,500
Total Outflow………….$10,000 This is an expensive option.
Vs.
Buy a set of track tires and Wheels:
Year 1
Change my OEM 20" to street Michelin Sport Pilot…..... $1,300
Buy track rims and slicks…………………………………………. $4,000
Total Year 1………………………………………………………………… $5,300
Year 2 …………………………………………………………………….. $1,300
Year 3 …………………………………………………………………….. $1,300
Year 4 …………………………………………………………………….. $1,300
Plus, replace the 20” street MSPs…………………………….. $1,300
Total Outflow…………………………………………………………….. $10,500
This is an even more expensive option.
Of course, in terms of absolute performance, slicks on 19” wheels would be quicker than street-able 20” tires. But, how much quicker? Is it worth the hassle of buying / storing / transporting /and changing wheels every time. And what about the fact that slicks specifically are not allowed under the Porsche’s operating manual and warranty?
I think the math makes a very good case for staying with the extreme performance multi-purpose street/race OEM 20" wheels and tires.
Flame suit on, what say you?
Currently on my 987.2S I swap to 18" rims for each event and the ultra sticky tyres are only available in 18". The A050 tyres cost US$3600 per set which barely last 7 events and one year, so its not about the cost, within reason. A050 is a time attack tyre and can heat up after 3 corners, but you can also easy overcook them.
The 19" or 20" MPSC2 or Maxx Race are far from R-Spec tyres and are all a LOT slower than these. Even full slicks are slower.
I wont be breaking no Porche track records again in the GT4 with road tyres on.
#214
Instructor
Has anyone seen the Deman Motorsports Facebook page? It looks like they have a street gt4 converted to run Conti GS class and it appears to be running 18" forgelines with the porsche red calipers.
#215
I don't think that's a GT4. Those are 997 calipers, those are not GT4 lights, and not GT4 uprights on the rear. I think it's a hacked together to fit a GT4 class.
#216
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Conti GS
And by NO means Hacked together
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2016 GT4-R
Rick DeMan
DeMan Motorsport
Upper Nyack, NY
845 727 3070
Porsche Sales & Service
Porsche Race services and parts
www.DeManMotorsport.com
2016 GT4-R
Rick DeMan
DeMan Motorsport
Upper Nyack, NY
845 727 3070
Porsche Sales & Service
Porsche Race services and parts
www.DeManMotorsport.com
#217
#219
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Very cool to see you build a GT4 for CSCT vs the Clubsports....you get to run the old school H Pattern....will be fun to watch and compare your cars vs the CJ Willson/Bodymotion/Etc Clubsport versions.......good luck to you and the team!
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James F. Sofronas | President & Owner
Global Motorsports Group ™
E: james@gmgracing.com
P: +1 (714) 432-1582
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#220
Rennlist Member
How do the piston sizes vary from the stock calipers? I'm wondering how it affects bias.
Cool stuff!
#221
How did you get an 18" wheel to fit on the rear is basically what everyone is asking. I don't see how it could be done with a factory street upright in the rear.
#222
Rennlist Member
My apologies - hacked was a bad choice of words. I mean parted together - it's not a factory GT4. Given that the factory GT4 is a parts bin car...what you did seems logical.
How did you get an 18" wheel to fit on the rear is basically what everyone is asking. I don't see how it could be done with a factory street upright in the rear.
How did you get an 18" wheel to fit on the rear is basically what everyone is asking. I don't see how it could be done with a factory street upright in the rear.
No modification is needed. I can bolt a 18x10.5" wheel now to mine if I wanted. I don't get why everyone has such a hard-on for cramming an 11" wheel on the car for track purposes. The fact that the factory RACE car is using 10.5" tells you all you need to know people.
The overly large, mono-block stock front caliper is the only real hurdle/problem for 18" wheels.
#224
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Rear wheels
The rear an 18" wheel fits over the caliper without issue. The problem is the rear toe link will hit anything wider than a 10.5" wheel and the offset has to be just right.
The front a 997 CUP caliper is a complete and direct bolt on and piston sizes are the same. 18" wheel fits right over the 997 Cup without issue.
The rotor is the same fitment as the 997 Turbo PCCB 380mm so all steel replacements for that application are a bolt on.
The front a 997 CUP caliper is a complete and direct bolt on and piston sizes are the same. 18" wheel fits right over the 997 Cup without issue.
The rotor is the same fitment as the 997 Turbo PCCB 380mm so all steel replacements for that application are a bolt on.
#225
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GT4-R
Thanks James! I'm sure there will be a few interesting discussions!