Tire Sizing - need sanity check
03-30-2002, 01:34 AM
#16
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[quote]Originally posted by Greg Fishman:
<strong>
Of course remember that this suggestion is coming from a guy that thinks Hoosier's are great rain tires.
</strong><hr></blockquote>
Rain? Hoosiers work well in the snow, too.
<strong>
Of course remember that this suggestion is coming from a guy that thinks Hoosier's are great rain tires.
</strong><hr></blockquote>
Rain? Hoosiers work well in the snow, too.
03-30-2002, 09:57 AM
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[quote]Originally posted by DJ:
<strong>
Rain? Hoosiers work well in the snow, too.</strong><hr></blockquote>
That's because you have a 4S, you know those cars can make it through anything and are impossible to spin. Right Anir?
<strong>
Rain? Hoosiers work well in the snow, too.</strong><hr></blockquote>
That's because you have a 4S, you know those cars can make it through anything and are impossible to spin. Right Anir?
03-30-2002, 10:49 AM
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[quote]Originally posted by Tito:
<strong>are SO3's N rated yet or not?</strong><hr></blockquote>
No.
[quote]<strong>Are people just using them regardless?
Tito</strong><hr></blockquote>
Yes.
<strong>are SO3's N rated yet or not?</strong><hr></blockquote>
No.
[quote]<strong>Are people just using them regardless?
Tito</strong><hr></blockquote>
Yes.
03-30-2002, 11:59 AM
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About the 'N' rating, for the 993 some tires are rated N0, N1 or N2 or a combination of these: e.g for S01 it's N1 or N2, for Michelin Mxx3 Pilot it's N1 or N0, for P Zero N1, for Dunlop SP Sport: N0...if the S03 have no rating what are we supposed to do when the S02's are not in production anymore? does it mean we use unrated tires (S03's) and why do new tires not get a rating for older models? anybody knows the answer? I am asking because S02's are hard to get by in Holland now..
03-30-2002, 12:17 PM
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If you feel that the N specification tires are important for you, get the newest Porsche approved tire of your size. Otherwise, there are plenty non-N tires that will perform as good as or better than the N-spec tires. Porsche publishes their approved tires on a yearly basis in Technical Service Bulletins and Christophorus. Some of them are also listed in Robin's P-car.com site.
FWIW, here in the US, we are still able to find some of the N-spec tires from the late nineties. Check <a href="http://www.tirerack.com" target="_blank">Tire Rack</a> if you are interested.
FWIW, here in the US, we are still able to find some of the N-spec tires from the late nineties. Check <a href="http://www.tirerack.com" target="_blank">Tire Rack</a> if you are interested.
03-30-2002, 12:27 PM
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I had a chat with Mike Schatz the other day about N tires - here is a summary.
Pre 993, they are very important. The appropriate N designation assures you that the sidewall stiffness is correct and this can have a major effect on handling. Also somewhat important on 993's, but with the improved rear suspension, it is not as critical. On a 964, Mike says you can really upset the handling with a non N tire, or N of a different generation.
Track - does not matter as 1) there are no R tires with N designation 2) You are tuning all sorts of other things.
My takeaway is that on a 993, it is not that big a deal, but you may find that the handling characteristics are different, so be prepared.
Pre 993, they are very important. The appropriate N designation assures you that the sidewall stiffness is correct and this can have a major effect on handling. Also somewhat important on 993's, but with the improved rear suspension, it is not as critical. On a 964, Mike says you can really upset the handling with a non N tire, or N of a different generation.
Track - does not matter as 1) there are no R tires with N designation 2) You are tuning all sorts of other things.
My takeaway is that on a 993, it is not that big a deal, but you may find that the handling characteristics are different, so be prepared.
03-30-2002, 02:37 PM
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[quote]Originally posted by Mark D - TT Alumni:
<strong>Pre 993, they are very important. The appropriate N designation assures you that the sidewall stiffness is correct and this can have a major effect on handling. Also somewhat important on 993's, but with the improved rear suspension, it is not as critical. On a 964, Mike says you can really upset the handling with a non N tire, or N of a different generation.</strong><hr></blockquote>
I am not sure I totally agree with this but even if it were true, where would one get an N-spec tire for a pre-993? The ones that were approved for each of the older models are no longer in production and those approved for today's cars cannot possibly satisfy the needs of the older cars. Back when the 964 was introduced, the BFG Comp T/A was one of the N-spec tires installed at the factory. At the time, it was a killer performance tire but was noisy, so-so in the wet and didn't last too long. People complained and the Comp T/A was removed from the approved list. All of a sudden, mediocre tires like Dunlop's SP8000 appeared because they were much better in the wet, quieter and lasted longer.
Today's N-spec tires are approved by Porsche to satisfy fuel economy, noise and tread life requirements and NOT necessarily ultimate performance. For instance, some of today's N-spec tires do not make it to countries like Switzerland because they have the most stringent noise regulations. IMO, none of today's N-spec tires provides the levels of grip needed for the older cars. They are fine for the modern chassis and suspension setups, however.
The bottom line is that N-spec tires are largely there for Porsche to ensure their cars meet certain government requirements and customer needs. There are plenty non-N tires that will perform equally as good or better than these.
<strong>Pre 993, they are very important. The appropriate N designation assures you that the sidewall stiffness is correct and this can have a major effect on handling. Also somewhat important on 993's, but with the improved rear suspension, it is not as critical. On a 964, Mike says you can really upset the handling with a non N tire, or N of a different generation.</strong><hr></blockquote>
I am not sure I totally agree with this but even if it were true, where would one get an N-spec tire for a pre-993? The ones that were approved for each of the older models are no longer in production and those approved for today's cars cannot possibly satisfy the needs of the older cars. Back when the 964 was introduced, the BFG Comp T/A was one of the N-spec tires installed at the factory. At the time, it was a killer performance tire but was noisy, so-so in the wet and didn't last too long. People complained and the Comp T/A was removed from the approved list. All of a sudden, mediocre tires like Dunlop's SP8000 appeared because they were much better in the wet, quieter and lasted longer.
Today's N-spec tires are approved by Porsche to satisfy fuel economy, noise and tread life requirements and NOT necessarily ultimate performance. For instance, some of today's N-spec tires do not make it to countries like Switzerland because they have the most stringent noise regulations. IMO, none of today's N-spec tires provides the levels of grip needed for the older cars. They are fine for the modern chassis and suspension setups, however.
The bottom line is that N-spec tires are largely there for Porsche to ensure their cars meet certain government requirements and customer needs. There are plenty non-N tires that will perform equally as good or better than these.
03-30-2002, 02:47 PM
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Im Glad you said that Viken. My 993 had New Sumitomo rotational tyres when I bought it and was wondering what to do.
Since I have not noticed any tyre related problems, I decided that I would keep them until I needed to replace them. They look pretty good too. Same or Similar tread to Good Year.
Since I have not noticed any tyre related problems, I decided that I would keep them until I needed to replace them. They look pretty good too. Same or Similar tread to Good Year.
03-31-2002, 07:07 AM
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Thanks for the response,
I tend to agree that the N rating doesn't make much difference. I used some SO2s that were not N rated and honestly I couldn't feel a difference.
Two related issues.
Has anyone else been heard that your insurance company may refuse to cough up in the event of an accident if you are using non-N rated tyres. Or is this the figment of somes' imagination.
Secondly is the N rating system and the reasons for the choice of tyre include (as detailed above eg noise / fuel comsumption) another example of Porsche loosing the plot.
<img src="graemlins/icon107.gif" border="0" alt="[icon107]" /> <img src="graemlins/icon107.gif" border="0" alt="[icon107]" /> <img src="graemlins/c.gif" border="0" alt="[ouch]" />
Tito
I tend to agree that the N rating doesn't make much difference. I used some SO2s that were not N rated and honestly I couldn't feel a difference.
Two related issues.
Has anyone else been heard that your insurance company may refuse to cough up in the event of an accident if you are using non-N rated tyres. Or is this the figment of somes' imagination.
Secondly is the N rating system and the reasons for the choice of tyre include (as detailed above eg noise / fuel comsumption) another example of Porsche loosing the plot.
<img src="graemlins/icon107.gif" border="0" alt="[icon107]" /> <img src="graemlins/icon107.gif" border="0" alt="[icon107]" /> <img src="graemlins/c.gif" border="0" alt="[ouch]" />
Tito
03-31-2002, 11:26 AM
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[quote]Originally posted by Tito:
<strong>Has anyone else been heard that your insurance company may refuse to cough up in the event of an accident if you are using non-N rated tyres. Or is this the figment of somes' imagination.</strong><hr></blockquote>
Not in the US. However, some people from Europe have indicated that this indeed is the case. I find it hard to believe, if true.
[quote]<strong>Secondly is the N rating system and the reasons for the choice of tyre include (as detailed above eg noise / fuel comsumption) another example of Porsche loosing the plot.</strong><hr></blockquote>
I don't think Porsche should be blamed for doing this. After all, they are mostly complying with regulations and "demands."
<strong>Has anyone else been heard that your insurance company may refuse to cough up in the event of an accident if you are using non-N rated tyres. Or is this the figment of somes' imagination.</strong><hr></blockquote>
Not in the US. However, some people from Europe have indicated that this indeed is the case. I find it hard to believe, if true.
[quote]<strong>Secondly is the N rating system and the reasons for the choice of tyre include (as detailed above eg noise / fuel comsumption) another example of Porsche loosing the plot.</strong><hr></blockquote>
I don't think Porsche should be blamed for doing this. After all, they are mostly complying with regulations and "demands."
03-31-2002, 01:00 PM
#27
Not to roil the waters here but...
Why the 225/40 front? Too skinny and too tall (given the fact that you're planning on running a 285/30 rear). Why not find a 245/35 for the front?
That's what I ran when I had 8s & 10s. I also think a 245/285 split will give you a little better balance.
Re the SO3s-- they're pretty great tires, but I understand the new compound is significantly harder than the old SO2s (or is this more urban myth?).
If you want to save some dough, consider the Toyo T1S (street only, not much good on the track except as a rain tire). Very reasonable and very well engineered. If you're planning on using Bridgestones for the street plus track days, I guess my question is--why? This is an awfully expensive tire to grind down in a weekend of track fun.
Lee in D.C.
Why the 225/40 front? Too skinny and too tall (given the fact that you're planning on running a 285/30 rear). Why not find a 245/35 for the front?
That's what I ran when I had 8s & 10s. I also think a 245/285 split will give you a little better balance.
Re the SO3s-- they're pretty great tires, but I understand the new compound is significantly harder than the old SO2s (or is this more urban myth?).
If you want to save some dough, consider the Toyo T1S (street only, not much good on the track except as a rain tire). Very reasonable and very well engineered. If you're planning on using Bridgestones for the street plus track days, I guess my question is--why? This is an awfully expensive tire to grind down in a weekend of track fun.
Lee in D.C.
03-31-2002, 01:29 PM
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[quote]Originally posted by DCLee:
<strong>Why the 225/40 front? Too skinny and too tall (given the fact that you're planning on running a 285/30 rear). Why not find a 245/35 for the front? That's what I ran when I had 8s & 10s. I also think a 245/285 split will give you a little better balance.</strong><hr></blockquote>
You are quite right. But, the 245/35 works best on an 8.5" wheel and not many companies offer that size.
[quote]<strong>Re the SO3s-- they're pretty great tires, but I understand the new compound is significantly harder than the old SO2s (or is this more urban myth?).</strong><hr></blockquote>
No it's not. Another issue is the fact that the newer tires have bigger grooves to dissipate water. This usually means less rubber on the road or a smaller contact patch.
<strong>Why the 225/40 front? Too skinny and too tall (given the fact that you're planning on running a 285/30 rear). Why not find a 245/35 for the front? That's what I ran when I had 8s & 10s. I also think a 245/285 split will give you a little better balance.</strong><hr></blockquote>
You are quite right. But, the 245/35 works best on an 8.5" wheel and not many companies offer that size.
[quote]<strong>Re the SO3s-- they're pretty great tires, but I understand the new compound is significantly harder than the old SO2s (or is this more urban myth?).</strong><hr></blockquote>
No it's not. Another issue is the fact that the newer tires have bigger grooves to dissipate water. This usually means less rubber on the road or a smaller contact patch.
03-31-2002, 08:15 PM
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[quote]Originally posted by DCLee:
<strong>If you're planning on using Bridgestones for the street plus track days, I guess my question is--why? This is an awfully expensive tire to grind down in a weekend of track fun.</strong><hr></blockquote>
Good point Lee, I agree the BFG's are kind of expensive if you are going to do regular track events ( a couple a month during the season) The guys that do that would be better off with one of the other R compound that have been suggested, but for guys that want to do a couple events a year, there isn't much of a tire wear issue.
Best scenario for a guy that can't tow his car is to run the T1-s for daily driving and rain tires and use a tire trailer like what EJ has to bring the extra set of wheels and tools. Of course another option that most of my friends use is to bring the extra wheels and tires to my house for me to haul to the track.
Greg
<strong>If you're planning on using Bridgestones for the street plus track days, I guess my question is--why? This is an awfully expensive tire to grind down in a weekend of track fun.</strong><hr></blockquote>
Good point Lee, I agree the BFG's are kind of expensive if you are going to do regular track events ( a couple a month during the season) The guys that do that would be better off with one of the other R compound that have been suggested, but for guys that want to do a couple events a year, there isn't much of a tire wear issue.
Best scenario for a guy that can't tow his car is to run the T1-s for daily driving and rain tires and use a tire trailer like what EJ has to bring the extra set of wheels and tools. Of course another option that most of my friends use is to bring the extra wheels and tires to my house for me to haul to the track.
Greg