Tips about switching to Hoosier R7
#16
Rennlist Member
Good timing on the thread, I was about to initiate one on with exactly same title...
Any comments on how to maximize the Hoho experience for first timers is very very welcome!
Any comments on how to maximize the Hoho experience for first timers is very very welcome!
#17
15-20 HC's....Are you kidding me...!!!!...you're not driving hard enough!!!! ; ) I have to sit out two or three sessions on a two day weekend just to make sure I have enough tire left for the main on Sunday. I typically see 8 HC's, every once in a blue moon, I see 10-12, but that requires flipping the tires on the rims, insides to outsides, and minimizing quali laps to 2-3 max.
As FJ said, "once you go Hoo Hoos you never go back"
(sidebar: FJ & I know each other, therefore, I'm not being a jerk....just giving a buddy a hard time while armchair racing).
Hoo Hoos are fun....they just increase your operating costs. To sum things up, my season is dictated by my rubber expense. I look at the events I'd like to run and then calculate the rubber needed to do so, then I have to adjust the number of events accordingly to what I can stomach.
R7 burn rate is approximately $225-275+ per session (HC).
As FJ said, "once you go Hoo Hoos you never go back"
(sidebar: FJ & I know each other, therefore, I'm not being a jerk....just giving a buddy a hard time while armchair racing).
Hoo Hoos are fun....they just increase your operating costs. To sum things up, my season is dictated by my rubber expense. I look at the events I'd like to run and then calculate the rubber needed to do so, then I have to adjust the number of events accordingly to what I can stomach.
R7 burn rate is approximately $225-275+ per session (HC).
Maximum attack!
#18
#21
Rennlist Member
In my opinion the first 3 heat cycles I feel like superman. Then 4-8 is around 90% as good. 9-12 grip falls off some more but still just a tad better than say Nt01's. 13-20 is still okay but driver need to adjust to reduced grip (and perfectly fine driving in a HPDE in traffic where slower cars/drivers won't gave a pass. ). Also keep in mind that how the tires hold up to the heat cycles is relative to vehicle setup.
In regard to tire pressure I have experienced the best grip at 32/34psi but the tire manufacturer recommends closer to 40psi for a 3000+ lb rear engine car, I think for tire wall durability reason. Its a trade off between grip and durability, driver decides which to favor or just split the difference. At track swith high speed + high banking angle such as Watkins Glen or Daytona I'd run the higher pressure.
In regard to tire pressure I have experienced the best grip at 32/34psi but the tire manufacturer recommends closer to 40psi for a 3000+ lb rear engine car, I think for tire wall durability reason. Its a trade off between grip and durability, driver decides which to favor or just split the difference. At track swith high speed + high banking angle such as Watkins Glen or Daytona I'd run the higher pressure.
What suspension setup do you have, in terms of camber, etc? My personal experience, I have killed (canvas exposed) the rears of my R7's in 8 sessions (more on the inside). I wonder if it's setup related or just being a bit too aggressive on the driving... Track is COTA, 8 25 min sessions, car is 997.2 GT3 ~ -2.4 camber on rears, fronts still ok.
JC
#22
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Hi Tom
What suspension setup do you have, in terms of camber, etc? My personal experience, I have killed (canvas exposed) the rears of my R7's in 8 sessions (more on the inside). I wonder if it's setup related or just being a bit too aggressive on the driving... Track is COTA, 8 25 min sessions, car is 997.2 GT3 ~ -2.4 camber on rears, fronts still ok.
JC
What suspension setup do you have, in terms of camber, etc? My personal experience, I have killed (canvas exposed) the rears of my R7's in 8 sessions (more on the inside). I wonder if it's setup related or just being a bit too aggressive on the driving... Track is COTA, 8 25 min sessions, car is 997.2 GT3 ~ -2.4 camber on rears, fronts still ok.
JC
I have the following suspension/setup:
Tractive coilovers (had 560/840 lb springs, then switched to 672/1008 lb springs) controlled by DSC
TPC front sway bar(28.9mm OD) set at middle hole (sometime I go one hole softer)
OEM GT2 rear sway bar(25.5mm OD) set at middle hole
Porsche Motorsport 997.1 Cup front LCA's (rubber bushings) +18mm length per arm
Porsche Motorsport 997.1 Cup rear LCA's (metal bushings) +2mm length per arm
TPC rear toe links (less than 0.5mm bump steer @ 1" compression from ride height)
Guard LSD, 40/60 ramps, ~70 lbs of breakaway torque
Front camber -3.1
Front toe -1.5mm per side
Rear camber -2.3
Rear toe +2.0mm per side
I listed the suspension hardware because they have a direct affect on the rate of compression(velocity and amount of camber and toe change during the suspension travel). The alignment numbers are just a set of static values with prediction for the peak suspension travel velocity and peak stroke. The springs, shocks, and sway bars help manage the rate of change, and total stroke or stroke vs. time. The LSD effectiveness dictates the base balance of the car and adjustable sway bars are used to fine tune that balance, while the stiffer bars sort of balance each other out to provide what we call platform. With a stiffer suspension the dynamic camber gain is reduced relative to a given load making the wear easier on the tires(but that does't change the fact that they heat cycle out long before they wear out, at least for me they do).
Looks like we both run almost the same amount of static rear camber. If your alignment is holding fine then check the shocks- a blown shock can cause odd tire wear in short amount of time. Or the rear tires might be spinning too much from a loose setup or worn LSD or a lot of throttle induced rotation or all of the above. If you have a data system you can see the wheel speed difference. I do like my car to be slight tight rather than loose so that could make up for some of the difference as well.
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2023 Porsche Sprint Challenge 992 Cup Am Champion
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2022 Porsche Sprint Challenge 992 Cup & 991 Cup Champion
2020 IMSA GT3 Cup Challenge 2nd Championship
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PCA National Instructor
TPC Racing stats:
2023 Porsche Sprint Challenge 992 Cup Am Champion
2023 Porsche Sprint Challenge GT4 Pro-Am Team Champion
2022 Porsche Sprint Challenge 992 Cup & 991 Cup Champion
2020 IMSA GT3 Cup Challenge 2nd Championship
2018 IMSA GT3 Cup Challenge 2nd Championship
2016 IMSA GT3 Cup Challenge Champion
2013 IMSA GT3 Cup Challenge Champion
2006 Rolex-24 @ Daytona GT Champion
2004 Grand-Am SGS Class Champion
#23
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That is very useful, very complete and of course there are lots of other setup factors to consider.
I know I had the LSD killed back when I run them, and the setup was definitely loose when compared with street tires (MPSC2), which I believe it could be related to the difference in diameter which affect the ride height (larger diameter on rears in comparison with the baseline)
The follow up question is, what is your ride height? I may need to lower my rear to get some add weight on the back?
I know I had the LSD killed back when I run them, and the setup was definitely loose when compared with street tires (MPSC2), which I believe it could be related to the difference in diameter which affect the ride height (larger diameter on rears in comparison with the baseline)
The follow up question is, what is your ride height? I may need to lower my rear to get some add weight on the back?
#24
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That is very useful, very complete and of course there are lots of other setup factors to consider.
I know I had the LSD killed back when I run them, and the setup was definitely loose when compared with street tires (MPSC2), which I believe it could be related to the difference in diameter which affect the ride height (larger diameter on rears in comparison with the baseline)
The follow up question is, what is your ride height? I may need to lower my rear to get some add weight on the back?
I know I had the LSD killed back when I run them, and the setup was definitely loose when compared with street tires (MPSC2), which I believe it could be related to the difference in diameter which affect the ride height (larger diameter on rears in comparison with the baseline)
The follow up question is, what is your ride height? I may need to lower my rear to get some add weight on the back?
Ride height numbers are only relevant if you and I are both using the same size(height) tires.
On 235/315-19"s I run pretty close to factory spec GT3 ride height.
On 265/325-19"s I run pretty close to factory spec GT2 ride height, because of the much taller tires I had to lower the suspension quite a bit and then still ended up at taller height then what I started with.
I am a fan of the Hoosier R7 tires, but I'm not thrilled about the available sizes in 18"s for our cars. The 18" R7's are rather short compared to OEM height tires. My personal preference goes to taller or at least match OEM height tires. I really really wished that 18" R7's come in ~25.5" front, 26.3" to 26.8"rears.
#25
Rennlist Member
Reviving to get some Hoosier input from those using them on the track with 997.1 GT3 (not RS). What sizes are you using with R7 and 18” wheels? I have a set of 18” CCW’s with R6’s (ancient) that are 245/35/18 and 315/30/18. I have stock suspension with camber maxed out. Thanks for any assistance in getting the right sizes. I’m also open to other track tires that would work with these 18’s.
#26
Drifting
Reviving to get some Hoosier input from those using them on the track with 997.1 GT3 (not RS). What sizes are you using with R7 and 18” wheels? I have a set of 18” CCW’s with R6’s (ancient) that are 245/35/18 and 315/30/18. I have stock suspension with camber maxed out. Thanks for any assistance in getting the right sizes. I’m also open to other track tires that would work with these 18’s.
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cbracerx (10-03-2021)
#28
Reviving to get some Hoosier input from those using them on the track with 997.1 GT3 (not RS). What sizes are you using with R7 and 18” wheels? I have a set of 18” CCW’s with R6’s (ancient) that are 245/35/18 and 315/30/18. I have stock suspension with camber maxed out. Thanks for any assistance in getting the right sizes. I’m also open to other track tires that would work with these 18’s.
If you are going to spend the money looking for tires that don't fall off after a few laps, go with slicks. About 30-40% more expensive, but they give you a substantially better mile/$ value and you have the proper sizes to run on a 7.1 (245/645-18 and 305 or 315/680-18 for a Pirelli, Yokos a 240/640-18 and 280/680-18 or 250/300). If don't care about times, NT01s are still the tire to beat as they give you about 12 cycles of use. On a non RS 7.1, I'd run a 245/40/18 and 305/35/18.
Last edited by powdrhound; 10-03-2021 at 02:07 PM.
#29
Rennlist Member
Thanks for the helpful responses. I don't care about times, this is just for DE, so the 18" Nitto is a fine option for my use case.
However, seems that NT01 in the sizes required is a special order right now (end of season in NE I guess). Pricing with shipping from Summit Racing has these at about the same level as Cup2's, which are readily available. So I bought a set of Cup2;s as a stopgap and will see how long the existing tires on my car will last for a two day event this 10/14-15. My fronts are like new but the rears are at 50% or so...
Those should hold me until springtime, and I'll do more advance planning on the 18" tires well before then.
However, seems that NT01 in the sizes required is a special order right now (end of season in NE I guess). Pricing with shipping from Summit Racing has these at about the same level as Cup2's, which are readily available. So I bought a set of Cup2;s as a stopgap and will see how long the existing tires on my car will last for a two day event this 10/14-15. My fronts are like new but the rears are at 50% or so...
Those should hold me until springtime, and I'll do more advance planning on the 18" tires well before then.
#30
Rennlist Member
Thanks for the helpful responses. I don't care about times, this is just for DE, so the 18" Nitto is a fine option for my use case.
However, seems that NT01 in the sizes required is a special order right now (end of season in NE I guess). Pricing with shipping from Summit Racing has these at about the same level as Cup2's, which are readily available. So I bought a set of Cup2;s as a stopgap and will see how long the existing tires on my car will last for a two day event this 10/14-15. My fronts are like new but the rears are at 50% or so...
Those should hold me until springtime, and I'll do more advance planning on the 18" tires well before then.
However, seems that NT01 in the sizes required is a special order right now (end of season in NE I guess). Pricing with shipping from Summit Racing has these at about the same level as Cup2's, which are readily available. So I bought a set of Cup2;s as a stopgap and will see how long the existing tires on my car will last for a two day event this 10/14-15. My fronts are like new but the rears are at 50% or so...
Those should hold me until springtime, and I'll do more advance planning on the 18" tires well before then.