[Cloud9...68]

I ran my first track session with my new-to-me 17 x 9" Twist's on all four corners, shod with 245/40-17's BF Goodrich G-Force Rivals. My former setup had 8.5 x 18" Enkei NT-03's up front, and 10" in back, with 255/35-18 and 285/35-18 Hankook R-S3's. I have to say, I'm very pleased with how the setup performed on its maiden voyage. It was my first session on the longer, intermediate part of the track since taking the advanced class, and there are some areas where I'm still a little tentative, and I didn't want to cook my new tires (or worse, spin), but the car feels very well planted, with no loss of grip from the narrower tires. I think this speaks to the fact that the Rivals are just superior to the R-S3's, as Grassroots Motorsports found in their test. I was afraid the narrower tires on the rear would create a tail-happy attitude due to the reduced grip back there, but if anything, it just made the car feel a little more lively and tossable through the corners.



The new tires are 1.2" smaller in diameter than my old rears, which gives me an effective 4.6% lower (higher numerical) final drive ratio, and this really makes a difference in the car's acceleration througout the track. The car just feels plain fast. So, a big thumbs-up so far. And the fact that the tires are so much cheaper than 18-inchers, and that I can rotate them to squeeze a lot more life out of them, is a huge plus, as it will allow me to get the most important thing of all, which is more seat time.

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[bill3]

I can reinforce your experience. I have a square setup with 16x8's running Hoosier R6's. Same setup I used successfully for years on my 944S2 now working on my 968. (Yes, I know I could run bigger wheels and tires but there is that cost thing...). 944's were originally delivered with square setups (on 15's); when they went to 16's, the ones they had were from the 911: 7's and 8's. Same for the 17's that came on 968's.



Your setup sounds like an optimum way to go based on my experience--especially with the smaller diameter.



I do rotate my tires front to back and side to side and it makes a big difference since the wear patterns are quite different front to back (and side to side of course)



Keep us posted but I'm betting you've got the optimum configuration

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[Cloud9...68]

Thanks for the feedback - a square 17 x 9 set-up does seem pretty optimal for this car. I just wish there were lighter wheels available in the 17 x 9 size - my twists weigh 21 lbs apiece, which is the same as my 18 x 10" Enkei NT03's I had on the rear before. But I do understand it's the mass as the outer periphery that counts, and my Rivals are a whopping 6 lbs apiece lighter than the Hankooks I had in the back before, which probably explains a lot of the livelivier feeling the car has now.

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[flash]

there are, but you have to spend some big bucks. hre makes a 17# wheel in that size that is pretty bullet proof.

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[flash]

by the way, just in case somebody thought i wasn't paying attention - i am not surprised in the least about the results. i am happy to see that somebody else is also realizing that the conventional thinking was flawed. perhaps it will start people re-thinking about how they set up their cars. getting rid of ridiculously stiff springs and gas shocks will hopefully be next.



seriously though, hre will build you a wheel to your specs. they have some very light ones, and they are very strong. that's why i run them. they will set you back a pretty penny though, so you may need to locate a good jeweler in advance.

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[Cloud9...68]

Yeah, this is definitely an interesting process. Even though, at least compared to other students at Driveway Austin, I get around the track very well, I'm a long way from having established enough feel for what the car is communicating to be to start tweaking things like spring rates, alignments settings, shock settings, etc. I just went with what a very well known guy in the Porsche and BMW worlds recommended, and the results, based on the feedback from the various instructors, seem reasonable so far. I do appreciate the recommendation to go with a square set-up, as it will save me a lot of money in tires over time. Unfortunately, since I'm still (and will continue to be for some time) on the learning curve, it will be difficult to discern whether improvements in lap times (and no, I'm not focusing much on lap times - I just request the transponder from time to time as a spot check) are caused by a change is some setting on the car, or from improvements in my driving. So I plan to wait until my lap times hit a plateau before I start tweaking things. And judging by the experience of riding with that experienced racer I commented on in another thread, my driving has a long way to go to catch up with the current capability of the car.

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[chazie78]

Thoughts on a 17x7" square setup? 

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[bill3]

Depends on what tires and what level of driving you are doing. Perfect for the street and even for Autocross or track with sticky tires, like and RE71 R. As per this thread, square is the way these cars are supposed to be set up. 7" width is fine for a street tire; only need wider for track or, maybe, autocross. 

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[chazie78]

yeah, I found a sweet deal on some boxster twists' 17x7 with good condition contis on. plan to hoon around a bit then throw some all seasons for the winter..... 

 

TY 

 

chas 

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