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-   997 GT2/GT3 Forum (https://rennlist.com/forums/997-gt2-gt3-forum-141/)
-   -   Tips about switching to Hoosier R7 (https://rennlist.com/forums/997-gt2-gt3-forum/972799-tips-about-switching-to-hoosier-r7.html)

AGO 02-08-2017 05:33 PM

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!

FJSeattle 02-08-2017 06:11 PM


Originally Posted by VID997 (Post 13936492)
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).


Maximum attack!




Originally Posted by mooty (Post 13938730)
time off? you work?

:typing:

FJSeattle 02-08-2017 06:12 PM


Originally Posted by AGO (Post 13945277)
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!

Warm them up slowly and cool them down.

acalayag 11-13-2018 06:23 AM

Hi Tom,

What air temps are too low to run R7’s on? Just ordered my first set but now worried it might be too cold (Bay Area mid 50-60’s)

oldskews4 11-13-2018 04:08 PM

You are fine. If it gets into the 40's then you have to be mindful to carefully warm them up. They can crack if you push on them cold.

Don't use below 40F.

AGO 11-20-2018 02:03 PM


Originally Posted by Tom-TPC Racing (Post 13917314)
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. :grr:). 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.

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

Tom@TPC Racing 11-20-2018 07:22 PM


Originally Posted by AGO (Post 15443990)
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

Hi 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.

AGO 11-21-2018 03:17 PM

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?

Tom@TPC Racing 11-21-2018 05:18 PM


Originally Posted by AGO (Post 15446728)
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?

If your LSD is worn then lowering the rear is only a temporary solution. Think of the chassis as seesaw, lower the rear will reduce oversteer but as the rear improves the front will understeer... let's say a drivers lowers the rear to make the car less loose, then the car becomes pushy on entry, then this driver does a popular thing of stiffening the rear sway bar and/or soften the front bar, then the car may become loose again.
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.

cbracerx 10-03-2021 12:03 AM

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.

ngng 10-03-2021 02:41 AM


Originally Posted by cbracerx (Post 17702494)
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.

Hoosiers are like crack, but they fall off pretty dramatically. Would personally run the proven NT01, or untested RRs in 255/35/18 + 315/30/18.

cbracerx 10-03-2021 09:27 AM

Thanks, I’ve used the NT01 as my go to track tire for the past 10 years. If those sizes will fit with the stock bodywork that could work for me.

powdrhound 10-03-2021 01:47 PM


Originally Posted by cbracerx (Post 17702494)
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.

I tried several sets of Hoosier R7s about 4 years ago. Ran the 255/35/18 and 335/30/18. The tires were good for a warm up lap followed by 2 hot laps before sharply falling off the cliff. I would get about 4 sessions on these before they were worse than NT01s. After 6 sessions, they were utter garbage. Overall, I thought they sucked with a very narrow window of acceptable perfomance. Granted, I ran them in the summer with OAT +80F, but they simply could not handle the heat.

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.

cbracerx 10-03-2021 03:38 PM

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.


joejenie 10-04-2021 01:09 AM


Originally Posted by cbracerx (Post 17703419)
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.

Don't know if they are still hard to get, but I like the Nankang AR-1s better than the NT01 and they last just as long. Hate them on the roads though. Very loud.


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