90desertcab

Persusing the archives I've read that the 'breakaway characteristics' of tires vary greatly. As a non-professional driver, the car did get 'away' from me once in 2nd gear near WOT at about 4K rpm in a tight curve. I completely lost control and needless to say, felt like a real idiot - luckily no damage or injury. I desire a controllable, if not really hard cornering tire. Noise is an issue as well - the cab is noisey already.

Are there measurements or test results for street tires regarding the breakaway characteristics and noise levels for various brands and models?

Current tires are well worn Michelin Pilot SX on 16" wheels. I undesrtand these breakaway all at once - true? Kumhos have varied reviews and are supposedly noisey. The Bridgestone S02's? Eagles? TA's? Dunlops? Price is sort of an issue, but value is moreso.

Thanks in advance!

Colin 90 C2

Those Pilot SX's are pretty old now. I'm guessing at least 5-7 y.o.
I believe that almost any new tire will have better breakaway characteristics.

From what I've read, ozone takes a pretty good toll on tires, even ones with low mileage.

Bill Gregory

Porsche says not to use tires older than 6 years old.

Kismet

When I bought my C4 cabriolet it had 16" Avons and I managed to lose control once. My 17" wheels came with Falkens and I felt I was about to have an accident at any time, but luckily didn't. I'm now on Continental Sport Contact 2s, and find them a good all round tyre and a lot cheaper than Michelin or Bridgestone. I guess wet grip isn't such a big issue for you, but they are really good in the wet. I'm on my third set of rears and get between 11k and 15k miles per set. The fronts do about double that mileage.

Adrian

To answer your question the answer is no.
The number of variables involved are without end, infinite.
Porsche have their own N rated tyres (not tested on the 964 anymore though).
These tyres meet European noise level regulations on European roads under European conditions.
The standards set are those required by the Swiss government because they are the toughest in Europe.
Breakaway characteristics depends almost 100% on the driver.
Loss of traction or grip is rarely the fault of the tyre.
If it is worn down too far that is your fault not the tyres.
If you push the tyre past its limits that is your fault not the tyres.
The best advice is to get personal test results from this forum and elsewhere.
How your cabriolet is set up? What is the current weight distribution? Have you had a recent wheel alignment? What size wheels are you using? Carrera 2 or Carrera 4? Have you had a corner balance recently? What tyre pressures are you using? I could go on and on.
One of the best tyres I have found in 17 inch sizes is the Toyo T1S.
However the Toyo 19 and 22 inch tyres currently on the market are too noisy.
There are no black and white answers or choices just an infinite number of shades of grey.
Ciao,
Adrian.

JoeW

Of course people certainly have their favorites, but to add my .02 to Adrian's experience -- I found the Toyo T1/S to be quite forgiving ... I autoX'd them last year and while they certainly do break away, the seem to do so later than many other street tires, give lots of warning, and are gradual in their loss of traction. They are espcially good in the wet. I don't notice the noise with them, but it's really not an issue for me I guess.

A suggestion, whatever you get, take it to an autoX or two to learn what it feels like and sounds like at the limits. It will be good for your confidence with it.

Joe

90desertcab

I realize that regardless of the tire (or vehicle, for that matter), the driver has responsibility for all end results. The set up and weight distribution are, I believe, as delivered in the stock configuration. The car is a C2 with stock 16 inch rims. The car has not been aligned recently, but shows no clear need of this but I could be wrong. Could you please explain what a 'corner balance' is? I've been running the tires at 45 lbs cold. The objective of my post was to get the personal test results you suggest, as well as any links or sources of definitive information. Thanks.

BGLeduc

I'll second that suggestion.

While I am sure many will disagree, I take any tire performance report with total skepticism unless you either track the car, or autocross it.

I do both, and I can say with complete confidence that when I am driving on the street, I do not come anywhere close to getting near the edge of my tire's capability. If you are frequently encountering understeer or oversteer on the street, I'd say that your a menace to society

Adrian nailed it.....if you are pushing the tire past its limits, thats your fault, not the tires. Unless Derek Bell or the like is secretly contributing to this thread, I think its safe to say the majority of us will run out of talent long before the tire runs out of grip.

OK, flame suit is now on...have at it!

BGL

90desertcab

No flames from this corner. I tried to convey humility in my original post. The 964 has shown me how little I know about performance driving, despite having logged hundreds of thousands of miles both accident and ticket free. Most of the challenging driving I've encountered involved snow, ice, blizzards, etc. I do not frequently encounter under/oversteer. C'mon you guys, sheesh, do I have to tattoo 'NOVICE' on my forehead? The 964 and variants seem to handle differently than the vehicles I'm accustomed to. I simply wanted recommendations regarding a controllable tire. If I can find an autocross within 300 miles, I'll go. Similarly I'd love the opportunity for driving lessons ... I'm neither reckless or an idiot.

BGLeduc

Sorry about my tone there, Desertcab....no offense intended at all.

I was taking a little pre-emptive aim at suggestions that may pop up for this tire or that tire, from anyone that has not tracked it or autocrossed it. I harbor the view that no matter how hard you drive on the street, you really need to take them to a track environment to really know what happens at the limit.

While I run the Kumho Ecsta Supra 712's on the street, about all I can tell you about them is they are black, round, and do a mighty fine job of keeping the chassis from scraping the pavement...oh, and they are dirt cheap, and look pretty good too!

Seriously, I have not tracked 'em, so I don't really know what they feel like at the limit, and I don't normally drive on public roads where it would be safe to find out.

Now, if you ever want to know about Victoracers, I can bend your ear about those since thats what I run for Autocross and Time Trials.

You can spend a little or a lot for a set of tires, but as Adrian pointed out, you can get yourself into situations where even the best tire won't help you. I think pretty much any tire that you might find at Tire Rack that fits our cars would work well in most situations on the street.....but on the track, real differences will appear.

OK, someone once said that when your in a hole, rule #1 is "stop digging", so I am going to shut-up now!

Cheers and good luck finding some rubber for your ride.

Brian

joey bagadonuts

Sorry if you didn't get the response you were hoping for, Desertcab, but I don't believe anyone was being intentionally condescending. This board is well-known as the friendly forum and you can always expect helpful, honest feedback.

Can you expand on some of these challenges?

What are you used to driving? I'm sure someone, here, has experienced a similar transition and can offer pointers.

I think if you provide just a bit more information about your driving conditions and the type of problems you're experiencing, others might be able to offer some guidance. For example, I don't drive my car with snow or ice on the ground but I'm certain someone, here, can recommend a better choice than the Z-rated, max performance, summer tires that our cars normally sport.

Lastly, I noticed your cold pressure was 45 psi all around. For 16's, the Factory recommendation is 36f/44r and 36 all around for 17's. Many of us choose 36 psi cold all around, regardless of tire size, and feel that provides a nice balance of comfort, grip and neutral handling. You might want to start there and see how it goes.

joey bagadonuts

BTW, corner balancing refers to the weight distribution at all four corners, specifically, the difference between weight carried by right and left wheel at each axle. The Factory spec is a difference of no greater than 20kg with driver seated. If one side carries a disproportionate amount of weight, you could experience excessive lean in one direction or worse at higher speeds.

To check corner balance, your Porsche specialist will put your car on scales (one for each wheel) and determine if the weight has been properly distributed. Corrections are made by adjusting the ride height at each corner until the proper distribution is achieved. Depending on the state of your setup, this process could take 2-4 hours and cost a few hundred dollars, depending on your shop's hourly rate.

90desertcab

Sorry if I came off as overly sensitive. I guess I had hoped for more response with a consensus on the tires I should get.

I'm used to driving an .... uhm ... er ... Ford F150 4WD ... amidst the snickers here I'd offer that it's a GREAT vehicle for where I live. I've put half a million miles on Ford trucks ... the current truck (98blu4by on the F150 forum) has 105K miles since new with one ding. It serves every role from garbage scow to grocery hauler to tow-truck to mobile home (NM the blood in the bed - that was an antelope). The F150 is front heavy without a load - I usually balance it accordingly with logs. Logging roads with a foot of snow on them or US 191 between Bozeman, MT and Ashton, ID in January provide plenty of challenge for drivers - narrow, slick as snot and limited visibility - plenty of knuckleheads in the ditch as well. I'm quite accustomed to powersliding (luv the limited slip here) the F150 on gravel, mud or snow ... but pavement seems to be an entirely different matter, especially in the 964 - it all happens so much faster.

Despite living in the boondocks, the roads are GREAT for sports cars when the weather is decent. Ya know those car ads with empty twisty two lane asphalt stretching to the horizon with mountains in the distance? That's where I live and drive. It's perfect, save the fact that no one will be around to help you if you make a mistake ... so don't.

Is there a 964 manual on line? My car did not come with one. I had no idea the front and rear should be different pressures. This and the age of the tires on the car could account for part of my 'mishap'. Make no mistake, I understand operator error was the primary culprit.

garrett376

You're reading it - the 964 RennList forum!!!
Just search, or ask questions, and we'll help ya' figure it out!

Adrian

Rule number 1: Never purchase a car without an owners manual.
Rule number 2: Read rule number 1.
The Porsche you have purchased is rather sensitive to being set up correctly. It is a finely tuned sports car. The owners manual contains the basic information which will help you at least get the basics right.
It provides the tyre recommendations in sizes for summer and winter and the tyre pressures.
Sadly none of the tyres that were designed for the 964 are available anymore. 10 years ago the answer was easy. Now it is a compromise because Porsche have moved on and so have the tyre manufacturers. The compounds have completely changed.
One thing you NEVER install on a 964 is general all weather tyres. You have a set of summer tyres for summer and winter tyres for winter.
I am using Conti VMax IIs on the 964 for summer but these are a 19 inch tyre and I do not believe they are available in less than 18 inch and I do not even know if the 360kph versions that I have are even available in the USA.
This is why making recommendations is also difficult.
If you do a seach on the forums you will find this subject coverted to death. You just type in tyres (tires) and see what comes up.
One last point. The 964 is very sensitive to incorrect weight distribution. At DIN 70020 curb weight you should have 40% of the curb weight over the front axles and 60% over the rear axles.
Using a figure of 1500kg (nice round number) this means 600kg on the front and 900kg on the rear (you can easily convert this to pounds).
When you corner balance you are checking to see if you 300kg over each front wheel and 450kg over each rear wheel.
You set this distribution using the adjustable spring perches on the struts and shocks. The loading is done diagonally.
So if you have 320kg on the right front you will lower the left rear which in theory will have 430kg on it. You transfer the 20kg back the left rear wheel bring in it up to 450kg and front down to 300kg.
Now in reality it is never this easy so you are allowed a 20kg differential between the weight over each front wheel and the same across the rear wheels.
Now there is load limit across the front and rear axles as well. If you have the distribution correct at curb weight technically you should look at what you are carrying and distribute it evenly, some in the front (luggage compartment) and some in the rear behind the front seats.
Believe me before driving at high speed on the autobahn this needs to be done properly.
Anyway the point I was trying to make is that life with aPorsche just ain't that simple and we have all learned that the old saying "One man's meat is another man's poison" when it comes to tyres.
Key issues you look at with tyres are;
"Speed rating".
"Load rating".
"Size" (obviously).
"Overall diameter" (not an issue if you are using standard sizes).
Experiences with these tyres for your local conditions.
If you are on a budget then it just got a little harder.
If you are using 16 inch wheels it also got hard because the choices are limited and are reducing weekly.
Value for money again I recommend the Toyo T1S.
Ciao,
Adrian.