19 inch wheels on the GT4 for track use?
08-04-2015, 06:39 PM
#16
Rennlist Member
This has been discussed ad-nauseam. 19" wheels are the smallest that will fit over the brakes.
Also, unfortunately, no one makes an 11" wide rear wheel for the Cayman other than Porsche- which is the factory GT4 wheel. All of the sets on tire rack use a 10" wheel
Also, unfortunately, no one makes an 11" wide rear wheel for the Cayman other than Porsche- which is the factory GT4 wheel. All of the sets on tire rack use a 10" wheel
08-04-2015, 06:42 PM
#17
Rennlist Member
Why would you put a 235 on a 9" wide wheel up front? The GT4 comes from the factory with a 245 on an 8.5...?
08-04-2015, 08:15 PM
#19
Not true. There are fitments available. You have to stop looking at the tirerack under 981 fitment and broaden your horizons.
08-04-2015, 08:26 PM
#20
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Yesterday i wrote: "you guys need to be very careful given that the rear GT4 tire has an 88" rollout which you are not going to achieve on your typical 19" or 18" R7." That is wrong. The rear tire rollout is actually 84.7" tall. Therefore the long winded rant i went into about tire rollouts affecting ABS math and having to run 5% taller rear tires applies ONLY to older cars OR cars that have 5% taller rear tires from the factory. The GT4 rear tire is only .7" taller in the rear so all you need to do is to keep that relationship equal if you move around from 18" to 20". This is way easier than in years past. I apologize for giving out information that was 100% wrong.
Last edited by BGB Motorsports; 08-05-2015 at 02:14 PM.
08-04-2015, 09:00 PM
#21
Has that rear fitment been verified on an actual car? From a German forum, where pics were shown, even 305/30-20s seem to be a stretch on the rear with OEM 20" wheels.
Last edited by ExMB; 08-04-2015 at 09:44 PM.
08-04-2015, 09:50 PM
#22
Rennlist Member
Thread Starter
I'd be careful with that front fitment as flush as they sit OEM. There is no way I'd have that tire stick outside of the fender.
Has that rear fitment been verified on an actual car? From a German forum, where pics were shown, even 305/30-20s seem to be a stretch on the rear with OEM 20" wheels.
Has that rear fitment been verified on an actual car? From a German forum, where pics were shown, even 305/30-20s seem to be a stretch on the rear with OEM 20" wheels.
08-05-2015, 12:22 AM
#23
You guys need to be very careful given that the rear GT4 tire has an 88" rollout which you are not going to achieve on your typical 19" or 18" R7.
I have run everything from GA1R to GA3R in 18", 19" and 20" on the 981 on and off track. Picking tires and wheels is not easy. Usually Forgeline calls us when they have questions. Put your inquiries in this thread or in a PM to me. If we have enough people we wouldn't be opposed to your wanting a group buy.
Truth be told, I know it says 11" rear here but that sounds too big to me. I know I know...factory documentation but an 11" wheel for a 295 street tire?!
Hoosier's new 295/40/18 rear is a godsend and an answer to the PSM/ABS woes that many of you experience and it's the tallest 295 they've made BUT it's still a few inches less rollout than stock. Email is even better but just list your desires and I can point you in the right direction AND confirm with Forgeline as I speak the the owners weekly. If we need to do a mass Rennlist purchase I would rather see the business go to Forgeline.
I have run everything from GA1R to GA3R in 18", 19" and 20" on the 981 on and off track. Picking tires and wheels is not easy. Usually Forgeline calls us when they have questions. Put your inquiries in this thread or in a PM to me. If we have enough people we wouldn't be opposed to your wanting a group buy.
Truth be told, I know it says 11" rear here but that sounds too big to me. I know I know...factory documentation but an 11" wheel for a 295 street tire?!
Hoosier's new 295/40/18 rear is a godsend and an answer to the PSM/ABS woes that many of you experience and it's the tallest 295 they've made BUT it's still a few inches less rollout than stock. Email is even better but just list your desires and I can point you in the right direction AND confirm with Forgeline as I speak the the owners weekly. If we need to do a mass Rennlist purchase I would rather see the business go to Forgeline.
08-05-2015, 09:54 AM
#24
Rennlist Member
I'm interested in a setup from BGB/Forgeline myself in 18 or 19 depending on available tires.
Question for those that have run Caymans on track.. I have seen several track prepped Caymans running what looks like 18" forgelines with Hancook tires, does anybody know if these will fit a GT4?
I believe this is an elite racing development car..
Question for those that have run Caymans on track.. I have seen several track prepped Caymans running what looks like 18" forgelines with Hancook tires, does anybody know if these will fit a GT4?
I believe this is an elite racing development car..
Last edited by electron mike; 08-11-2015 at 10:14 AM.
08-05-2015, 10:13 AM
#25
08-05-2015, 10:20 AM
#26
Rennlist Member
08-05-2015, 10:32 AM
#27
Keep in mind that your second pic is an older model Cayman. Asking comparison of wheel/tire fitment to the newer model is like apples and oranges with all the changes over the years.
08-05-2015, 10:46 AM
#28
Me = driver
RL = team boss (apparently)
BGB + Forgeline = Race Engineers and Mechanics
When the race engineers and mechanics have a tested working setup that they 100% trust for the car (that's not going to interfere with PSM/ABS), please let us drivers know via a post here and we will buy into it.
All the rest of this is bench racing and speculation. Data is only good if it applies and solves the equation in real life.
RL = team boss (apparently)
BGB + Forgeline = Race Engineers and Mechanics
When the race engineers and mechanics have a tested working setup that they 100% trust for the car (that's not going to interfere with PSM/ABS), please let us drivers know via a post here and we will buy into it.
All the rest of this is bench racing and speculation. Data is only good if it applies and solves the equation in real life.
08-05-2015, 11:33 AM
#29
Rennlist Member
Tire size is listed in the first pic you attached. Compare that to OEM size and plug both numbers into the link. That will give you a rough idea to your question.
Keep in mind that your second pic is an older model Cayman. Asking comparison of wheel/tire fitment to the newer model is like apples and oranges with all the changes over the years.
Keep in mind that your second pic is an older model Cayman. Asking comparison of wheel/tire fitment to the newer model is like apples and oranges with all the changes over the years.
08-05-2015, 12:15 PM
#30
Rennlist Member
You guys need to be very careful given that the rear GT4 tire has an 88" rollout which you are not going to achieve on your typical 19" or 18" R7.
I have run everything from GA1R to GA3R in 18", 19" and 20" on the 981 on and off track. Picking tires and wheels is not easy. Usually Forgeline calls us when they have questions. Put your inquiries in this thread or in a PM to me. If we have enough people we wouldn't be opposed to your wanting a group buy.
Truth be told, I know it says 11" rear here but that sounds too big to me. I know I know...factory documentation but an 11" wheel for a 295 street tire?!
Hoosier's new 295/40/18 rear is a godsend and an answer to the PSM/ABS woes that many of you experience and it's the tallest 295 they've made BUT it's still a few inches less rollout than stock. Email is even better but just list your desires and I can point you in the right direction AND confirm with Forgeline as I speak the the owners weekly. If we need to do a mass Rennlist purchase I would rather see the business go to Forgeline.
I have run everything from GA1R to GA3R in 18", 19" and 20" on the 981 on and off track. Picking tires and wheels is not easy. Usually Forgeline calls us when they have questions. Put your inquiries in this thread or in a PM to me. If we have enough people we wouldn't be opposed to your wanting a group buy.
Truth be told, I know it says 11" rear here but that sounds too big to me. I know I know...factory documentation but an 11" wheel for a 295 street tire?!
Hoosier's new 295/40/18 rear is a godsend and an answer to the PSM/ABS woes that many of you experience and it's the tallest 295 they've made BUT it's still a few inches less rollout than stock. Email is even better but just list your desires and I can point you in the right direction AND confirm with Forgeline as I speak the the owners weekly. If we need to do a mass Rennlist purchase I would rather see the business go to Forgeline.
Also, it seems everybody is saying 18" won't fit over the brakes, however, the GT4-Cup will most certainly be running 18" wheels/tires utilizing what I assume with be a PFC brake package. Perhaps the track rats can simply upgrade to the PFC brake kit from PMNA, and then run 18" wheels. That's what I would do.
I'm test fitting an old 18" CCW C14 (that cleared my 380mm PCCB's) on a GT4 today, actually, just to confirm for myself.
