Adrian

Dear Riccardo,
C2 are less affected by this than C4s. I also feel if you had driven your C2 with a good set of tyres first and then mixed them like you purchased it, you would have noticed it more. One thing with 964 handling or any sports car handling is what you drive normally and your previous experience. For many 964 owners this is their first Porsche. For many more it is not their daily driver. If you jump from a Toyota Camry to a 964 even on flat tyres it would still feel like it handles better.
One day maybe I will run some lectures covering all of this. It takes far more time to explain such things in detail than can be afforded to bulletin boards. Tyres in themselves are a science. They are not just something you have fitted to a car just to keep it off the ground,
Ciao,
Adrian
911C4

Christer

Johnfm

The 'nose-up'attitude as you call it is quite normal on stock astronaut suspension - see this picture of mine:



Again, if you are going to upgrade the suspension I would recommend doing the springs and shocks together.

johnfm

Just spoke to my mechanics - they confirmed that it is 99% likely the tyre mismatch. I believe you all on this point & will immediately be changing the fronts - BUT I would still love to read/hear some theory behind it!!

Re: lowering, my garage wants £175 + vat for fitting the springs - assuming no problems are discovered during the job (the oldest caveat in the Porsche mechanics handbook!!!)

Anyway, will assess costs of spring & shocks (though opinion is slighyly divided depending on application). I won't be tracking the car much if at all (hey, its a 'tip and you guys thinhk they suck!!! )

Richard 92 C2

johnfm

<img src="graemlins/soapbox.gif" border="0" alt="[soapbox]" />

I too am the proud owner of a 92 C2 Tip. Hear this !..... Dont ever let me hear them say the Tip sucks . I read a Prosche technical report somewhere that alledged that a tip was faster around a track than a manual.

Notwithstanding the fact that you have loads of things you could be doing with your hands instead of shifting gear ..... ummmm Girls love Porsches

Ok, I'll get my coat ..

johnfm

After driving both I bought the Tip. Notwithstanding the cost issues of clutch & flywheel, I was blown away with the performance of both cars, but the option of not shifting in traffic was fantastic.

Ideally, an extra ratio would be great, but for 99% of the time the 4 speeds are fine.

I would really like for us to have a track day (maybe with Christer & Roygarth!!) and have some Tip vs 5-speed fun!!!

Christer

Roygarth is coming nowhere near my car - how many stories has he posted here saying I raced this Maranello and managed to beat him to the next lights by jumping over the roundabout instead of going round it.... - sounds like a complete nutter. And would probably beat us all on the track in a 2CV Tiptronic

Now you come to mention track days again - I tell you what I really must get going on this. Perhaps we can get together for some synchronised lift-off oversteer...?

I don't know whether 5 gears against 4 is fair. How about I get rid of my 1st gear and Roygarth dumps his 3rd?

Adrian

Dear John,
It is very hard to try and explain in a few words to answer your question. However let me try and put it this way.
A Porsche is a sports car engineered with the tyres as an integral part of the basic engineering. The 964 (as will all Porsches) is balanced and tuned (suspension tuning that is) in a particular way. The tyres originally used for the 964 were just one brand and type, the Bridgestone RE71. Some 964s inthe USA were delivered to customers with a different tyre. Option M231 (not customer selectable though). Anyway I digress. The suspension tuning includes a calculated amount of grip. If you used different tyres front and back these tyres will not grip in the same manner as four tyres which are the same tread pattern, same rubber compound etc etc. The mixes tyres will throw the 964 out of balance. When you do to your 964 what some of us have done to ours then you really see this. If you align to more aggressive settings it gets even worse.
Grip Balance would be the 2 words I would use to explain this issue in simple terms. Mix tyres and you have uneven grip which is outside of the original design specifications. This unbalanced situation adversely affects handling.
Ciao,
Adrian
911C4

Randall G.

[quote]Originally posted by jonfkaminsky:
<strong>***snip***

Weiner pulled some pretty dicey stuff on my car...I think the "pro" label is hardly warranted. He doesn't even have a shop, although he likes to pretend he does.</strong><hr></blockquote>

Hi Jon,

Are we talking the same Steve Weiner here? I haven't done a archive search to verify, but I thought people have sent their cars to him in the past for big mods (e.g., suspension). If what you're saying is true, Steve is pulling off one hell of a sham.

Steve has made tremendous contributions to this board (though he makes most of his posts to the 993 forum), and has helped me personally via e-mail. I know he has spent (too?) much time on the phone helping fellow 911 owners through tricky problems/mods. Steve's knowledge has always struck me as legitimate, unlike some people that have posted on this board in the past, bringing airs of expert status without (true) deep understanding.

We sometimes think Bruce A. is "out to lunch," but there's no denying that he is--overall--a 911 expert (and his book is fantastic, some passages not withstanding). Perhaps what you're experiencing with Steve is similar. That is, is it possible for one product that doesn't deliver as promised to taint the whole perception?

(Along these lines--and as I alluded to above--I think replacing all four tires, regardless of tread depth or if the tire is the same model--is a waste of $$.)

I'm not doubting your words, Jon. They just aren't consistent with my own perceptions.

<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Anyway, back on topic .....

I was on the Tirerack's website last night, looking to order my new front RE-730's. Check out the message that pops up when you try to order only the front tires:



So ... I called the Tirerack this morning. I asked Dan how close a match the RE-730 is for the RE-71. He told me that it's the closest match you can find, based on the tire's specs, but you might still experience some "Dr. Jekyll/Mr. Hyde" handling with the mixed model tires.

Randall G.

***oops***

jonfkaminsky

Randall-
we are talking about the same person. Yes he does help out in the forums. Yes he does have a business called Rennsport Systems. However, that business is nothing more than a website and a home address. He has no shop, no personnel other than himself. When you get services from Rennsport Systems you get the work done at somebody else's shop. How do I know this? Because I was a Rennsport Systems customer. But the work was crap, and "they" did not perform work they charged me lots of money for. Problem is, who do you go after? Weiner who has no shop, or the shop doing the work who can simply say "you made the deal with Weiner, don't talk to us." Now compound that problem with being from out of state and you're really screwed. I'm not the only one, BTW.

There are a lot of people who are simply afraid to say anything because of his status on the web board. There are also a lot of people who just parrot his stuff and put him on a pedestal...But they don't know him, haven't dealt with him, never bought anything from him, don't know that he is little more than a website.

This isn't to say that some people have had had good experiences with Weiner. I'm sure some have. But the real test of professionalism is how you are treated when things go wrong. So no sweat Randall- if your experiences are different from mine, that is totally cool with me, and certainly legitimate.

Adrian helps a lot of people too. But at least his motives are altruistic...i.e. this isn't his business.

Randall G.

[quote]Originally posted by jonfkaminsky:
<strong>***snip***

So no sweat Randall- if your experiences are different from mine, that is totally cool with me, and certainly legitimate.

***snip***</strong><hr></blockquote>

Actually, I've never actually purchased anything from Steve. I don't even know anyone personally that has. I just know him from his posts and the e-mails we've traded. I would say you have more tangible experience than myself.

Doesn't even own a shop ... that's tough to fathom--and defend.