is it ok to mix tires?
07-23-2005, 01:02 AM
#16
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There may be a bit more to it.
First, I don't know that you can trust manufacturers circumferences to be the same brand to brand. My that, I mean that one manufacturer will say 2 different tires are the same diameter, and will be correct. But, a 100cm circumference from manufacturer A may not be the same 100 for manufacturer B, so you would need to measure them yourself, or risk screwing up your differential.
Second, different brands wear far differently. Say you had Contis (which wear slowly, and the rears may last 25,000 miles) and you switch to Pirellis, where the rears may last 12,000 miles. You may never wear them out at a point that you replace both front and rears simultaneously. When you stay with one brand, the rears last about half as long as the fronts, so your second rear tire change puts you on 4 new tires.
Third, the foul weather grip may be far different. In dry conditions, at street speeds, different grip levels mean little, especially with ASC on. But in slush, the variation in front rear grip can be extreme. For example, Pirellis have better cold weather and slush grip than Contis.
Lastly, the different tread patterns look stupid to your fellow Porsche owners, who will notice. They will think your wife has left you and taken all your assets. Otherwise, you would change all 4, or stay with the same brand. To totally avoid that, you will need to stop saying "thread" which applies to fiber and the web, but not tires. Practice saying "tread" which is what tires have.
First, I don't know that you can trust manufacturers circumferences to be the same brand to brand. My that, I mean that one manufacturer will say 2 different tires are the same diameter, and will be correct. But, a 100cm circumference from manufacturer A may not be the same 100 for manufacturer B, so you would need to measure them yourself, or risk screwing up your differential.
Second, different brands wear far differently. Say you had Contis (which wear slowly, and the rears may last 25,000 miles) and you switch to Pirellis, where the rears may last 12,000 miles. You may never wear them out at a point that you replace both front and rears simultaneously. When you stay with one brand, the rears last about half as long as the fronts, so your second rear tire change puts you on 4 new tires.
Third, the foul weather grip may be far different. In dry conditions, at street speeds, different grip levels mean little, especially with ASC on. But in slush, the variation in front rear grip can be extreme. For example, Pirellis have better cold weather and slush grip than Contis.
Lastly, the different tread patterns look stupid to your fellow Porsche owners, who will notice. They will think your wife has left you and taken all your assets. Otherwise, you would change all 4, or stay with the same brand. To totally avoid that, you will need to stop saying "thread" which applies to fiber and the web, but not tires. Practice saying "tread" which is what tires have.
07-23-2005, 02:18 AM
#17
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IMHO, some comments a little too paranoid. I think several people have posted that Porsche allows for up to a 4% variance in diameter. 4% is a full inch! Your rolling diameter will also vary with your tire pressure and load. Considering that a typical tire has 1/4" of usable tread, a bald one is -1/2" in diameter than a new one. I would not recommend putting tires of "very" different compounds, construction, or age on the same car. That would include putting the exact same tire mixed with old tires that are heat-cycled to death and rock-hard. I would not mix ContiSports with PS2s--too different. I would recommend using a little common sense, freely consider non-N rated tires, but at the same time, don't be afraid to spend money if appropriate.
07-23-2005, 10:30 AM
#18
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Originally Posted by Woodster
I have 1999 bridgestone s02's on the front of my 993tt. I have 2004 So2's on the rear.
I am changing the fronts due to "checking" and small cracks in rubber between the treads,
I am going to the So3 Pole Position for the fronts now and when my rears wear out
(probably by summer's end) I will change the Rears to So3 pole position. I like the look
and performance of the So3's better (and so did Viken!).
mk
I am changing the fronts due to "checking" and small cracks in rubber between the treads,
I am going to the So3 Pole Position for the fronts now and when my rears wear out
(probably by summer's end) I will change the Rears to So3 pole position. I like the look
and performance of the So3's better (and so did Viken!).
mk
Bad idea. Also here is what Viken said about the SO-3's. https://rennlist.com/forums/showpost...07&postcount=9
07-23-2005, 11:47 AM
#19
Originally Posted by Alexander Stemer
Lastly, the different tread patterns look stupid to your fellow Porsche owners, who will notice. They will think your wife has left you and taken all your assets. Otherwise, you would change all 4, or stay with the same brand. To totally avoid that, you will need to stop saying "thread" which applies to fiber and the web, but not tires. Practice saying "tread" which is what tires have.
07-23-2005, 01:47 PM
#20
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KJ,
I have been thinking. I may have come off as being too harsh. So I did a search, and found this thread from a year or so ago. Its everything you could ever want to know about mixing tires on a Porsche.
Enjoy.
https://rennlist.com/forums/993-forum/103509-tire-experience.html
I have been thinking. I may have come off as being too harsh. So I did a search, and found this thread from a year or so ago. Its everything you could ever want to know about mixing tires on a Porsche.
Enjoy.
https://rennlist.com/forums/993-forum/103509-tire-experience.html
07-24-2005, 01:30 AM
#21
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hey Phil, I was about to reply why you were being a jerk hehehe..
but yeah thanks for that thread. As you can see it seems to be a common question. I really don't plan on doing mixed brands.. just was curious about what the pros here really think, and it is obvious what their stance is.
And A.Stemer.. yes TREAD.. thanks. Gee I'm actually pretty peeved too with common English mistakes like "YOUR" vs "YOU'RE", and "AFFECT" and "EFFECT".. but that one with tread is being a bit picky.
Is it me or it seems some people here get annoyed with what they feel are stupid questions but that's what the forum is about, discussions, and exchange of ideas. Condescending tones from the older folks (age and membership on this forum) should really be reserved for trolls, not young enthusiasts like me.
but yeah thanks for that thread. As you can see it seems to be a common question. I really don't plan on doing mixed brands.. just was curious about what the pros here really think, and it is obvious what their stance is.
And A.Stemer.. yes TREAD.. thanks. Gee I'm actually pretty peeved too with common English mistakes like "YOUR" vs "YOU'RE", and "AFFECT" and "EFFECT".. but that one with tread is being a bit picky.
Is it me or it seems some people here get annoyed with what they feel are stupid questions but that's what the forum is about, discussions, and exchange of ideas. Condescending tones from the older folks (age and membership on this forum) should really be reserved for trolls, not young enthusiasts like me.
07-24-2005, 02:08 AM
#22
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I'd normally replace the faster wearing rears with the same brand/model. Drive till the fronts are near gone, then replace all 4. Oh, you can do lots of crazy launches with the new rear tires so they can catch up to the fronts faster 
07-25-2005, 08:45 PM
#23
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You said "some track work" I think? I wouldn't even think about mixing tires on track. Certainly the brand mix would make me concerned but the difference in tread would be a real concern! Plus the differences in heat cycles etc.
On the street with correct diameters I guess other than maybe looking a little odd, you could get away with it, again I'd have concern with the tread depth and ultimate grip in inclement weather; particularly with "spirited" driving. I'd try to keep the wear ratings as close to the same as possible.
It doesn't sound like a dumb question to me....Porsche's eat rear tires and you run into this dilemma constantly. I have always changed all four.
On the street with correct diameters I guess other than maybe looking a little odd, you could get away with it, again I'd have concern with the tread depth and ultimate grip in inclement weather; particularly with "spirited" driving. I'd try to keep the wear ratings as close to the same as possible.
It doesn't sound like a dumb question to me....Porsche's eat rear tires and you run into this dilemma constantly. I have always changed all four.
07-26-2005, 12:18 PM
#24
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FYI, I replaced the rears on my first 964 with a different brand (I believe they were pilots) and I ended up taking them back within a week to get the same yokahama's that were on the front because the car became VERY darty when going over uneven pavement. It was truly unsafe. I have no idea if it was the car, the type of tires, etc. All I do know is that I will never do that again on any of my 911's.
