m3irish

I may have improperly expressed that the data from the TR is poor and I don't meant that. What I meant to say is that the data is not a measure of correctness or safety.

Great link to a good baseline to run on. Going beyond you need to put different tires on different width wheels to see what feels good and whats fast knowing the two might be mutually exclusive or one in the same.

orthojoe

Adjusted the front sway bars stiff on the GT3 today for Laguna Seca. The car ran 1:37.5, which is the fastest the car has gone at this track, but there is still a bit of midcorner oversteer. I think adjusting the rear bar to full soft will fix remaining oversteer. I'm feeling pretty good that I can get this rear 295 RE71R to work.

There are some setup issues that still I need to work through. The 1:37.5 was with Ben at the wheel of the car. Later in the day I got in the car and I could only get 1:39.0. I then hopped in someone else's GT3 with full stiff front and soft rear and the car felt much better to me and I ended up with 1:38.1 in someone else's car while having to lift for sound since this car didnt have the GPS device. Meanwhile Ben was chasing me in our own car and could only get 1:38.8.

stuntman

Without spending weeks worth of testing and tens of thousands of dollars on tires, coming from someone who has, I think the "general rule of thumb" (in the article) for choosing a tread width that's the same, to 0.5" narrower than the wheel width almost always will yield the best feel, response, and performance for that tire width.

Manifold

Here's Tire Rack info for three variants of the Cup 2 in 305/30-20. Note the large range in tread width, and based on Stuntman's guideline, the 12" wheel is fine, whereas an 11.5" wheel may be too narrow.

Manifold

Anyone here tried the ContiForce Contact? There's a favorable review of it on Tire Rack from a 991 GT3 owner:

http://www.tirerack.com/tires/tires....RatingsReviews

orthojoe

I haven't, but a friend has. Says they were ok. Pricing is similar, from what I remember to cup2.

We may be seeing more things from continental since they recently purchased Hoosier tire

mqandil

Joe this is impressive time. The only reason I asked you about your setting on the front bar because I too had some issues with exit oversteer and did discover stiffing the front bar helps but it did increase the understeer on the car which is why I asked you. However in my case I went back to the middle bar sitting on front, and instead increased the rear camber by an additional 0.5 degree so now it is slightly higher than the front. This really helped settle the back under power during corner exit. I did not notice big change to the understeer. It seems everyone is doing the opposite of that but for some reason in my car it worked great to settle the back. It could be just my driving style. Again thanks for the info. Mark

orthojoe

Thanks. Yes, it really is interesting how some people have totally opposite sway bar settings, which is why I always try to tell people not to copy what someone else is doing until you figure out what your own car is doing with you behind the wheel and adjust for yourself. The GT3 that I drove which wasn't mine had near stock alignment settings too, which makes me wonder...

Macca

You know the views I've started to form on this car Joe. It's pretty much as quick as it going to be out of the box on factory recommended settings. Everything else is for tyre wear/longevity only, and to be honest the 991 GT3 isn't bad in this respect - even on factory settings the front shoulders give up at about the time the heat cycles have affected the MPSC2 in any case (unless you are running the same track not flipping to even out wear).

To be honest if MPSC2 were made in USA instead of France and didn't carry the "N0" Porsche "tax" rating then they might be 40% cheaper than they are today - if that was the case I don't think id bother recommending anyone did anything with the settings out of the box, save your money for some headers and "just drive it".

Hopefully a few more mania furred will come to the fray and deliver s tyre that will work on this car at a lower price in 2017. Surely the Koreans see an opportunity here. Nitto, toyo or Hankook could really win some mind space with a fast R Comp in 20" sizes etc

Macca

"Mania furred" as above is not done kinky new Brazilian but "manufactured" corrected by silly Apple spell check. Editing it via the RL app on IPhone is painful as others have noted...

orthojoe

Oh yes. I'm a believer and agree with you, my friend

MaxLTV

So are you saying RE71 is a go?

orthojoe

In think so. However, be prepared to make adjustments to your sway bars in order to make it work.
For Ben, it's proven to be equally fast. I'm close to approving it, but I'm still not totally happy with midcorner and the car didn't feel nearly as good as Don's car. Ben could not keep up with me when I was driving don's car. Give me one more day to adjust the sway bar one more setting and I'll put out the verdict then. 11/5.

Manifold

Seems like the narrower rear tire is reducing rear grip, so the sway bars adjustments are restoring balance, but the net result is still less overall grip?

orthojoe

That is the question, but the car did run it's fastest lap ever even with the sway bar/setup not optimized yet.