Quick help needed - How to minimize center tread wear?
10-26-2018, 03:08 AM
#1
Intermediate
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Quick help needed - How to minimize center tread wear?
Advice would be appreciated as I find myself in a bit of a bind... I'm currently running 305/30/19 PZero Corsa's (the 80 treadwear) on the rear. They are at 6/32 tread depth on the inner and outer tread, but down to 3/32 on the center tread. (down to the bars on the center). I'm getting a lot of tire noise but the dry grip seems fine. I was going to put on winters this week anyway, but due to a family emergency I have to drive 1k miles leaving tomorrow.
I normally run 33/39 PSI front to rear, unloaded. I noticed when I stopped in for an oil change yesterday the dealer put them back to 36/44.
Which would be better to minimize the wear on the center tread? Can I deflate a bit more than 39 on the rears and be ok - say down to 37 rear?
It won't be a fully loaded, just myself and an overnight bag... Yes, I realize I can just rent a car but I prefer driving the 911 :-)
I normally run 33/39 PSI front to rear, unloaded. I noticed when I stopped in for an oil change yesterday the dealer put them back to 36/44.
Which would be better to minimize the wear on the center tread? Can I deflate a bit more than 39 on the rears and be ok - say down to 37 rear?
It won't be a fully loaded, just myself and an overnight bag... Yes, I realize I can just rent a car but I prefer driving the 911 :-)
10-26-2018, 08:15 AM
#3
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You can run 32/37 and be fine. Keep a 5-6 lb differential front to rear.
10-26-2018, 09:00 AM
#4
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On "normal" tires, this is true. But, on our BIG fat, high performance, low profile tires, it's just the complete opposite. Center wear on our tires is more likely to be UNDER inflation. Other causes include; alignment, and aggressive acceleration.
10-26-2018, 10:32 AM
#5
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Thx guys. The alignment was checked and redone to spec when I bought it 3k miles ago, so doubt it's that.
I would never incur aggressive acceleration
Based on this input, I'm thinking it might be best to keep running 41psi rear or maybe pump up to 44 for this trip?
I would never incur aggressive acceleration
Based on this input, I'm thinking it might be best to keep running 41psi rear or maybe pump up to 44 for this trip?
10-26-2018, 10:35 AM
#6
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I'd check the accuracy of your tire pressure gauge first. What are your DOT code dates??
10-26-2018, 11:06 AM
#7
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My digital gauge reads 44, same as what the dealer documented 48 hrs ago. I'm limited on time this morning for further calibration.
Date code 3615 on all four tires. Thx!!
Date code 3615 on all four tires. Thx!!
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10-26-2018, 07:01 PM
#8
This is typical of Pirelli tires in general, especially on these cars. They will wear the center tread first, while every other brand will wear the inner tread first, even with the same alignment of on the same vehicle. Summer tires, all season, doesn't matter.
Every other theory or solution is just a band aid. Drive them until they're worn out, and replace with something else if this is a concern. But is completely normal for the tire in question, and I have personally seen it on hundreds of Porsches.
Every other theory or solution is just a band aid. Drive them until they're worn out, and replace with something else if this is a concern. But is completely normal for the tire in question, and I have personally seen it on hundreds of Porsches.
10-26-2018, 08:28 PM
#9
Drifting
I’m nearing the end of the fourth set of rear tires on my ‘09 and every one of them showed more wear on the inner edge as they were used up. One set of Michelins, one set of Bridgestones and two sets of Hankooks. I have run my rear pressures as high as 46 and as low as 38. Didn’t make any difference. All street driving, BTW.
Last edited by Iceter; 10-28-2018 at 12:45 PM.
10-27-2018, 02:23 AM
#10
Nordschleife Master
This is typical of Pirelli tires in general, especially on these cars. They will wear the center tread first, while every other brand will wear the inner tread first, even with the same alignment of on the same vehicle. Summer tires, all season, doesn't matter.
Every other theory or solution is just a band aid. Drive them until they're worn out, and replace with something else if this is a concern. But is completely normal for the tire in question, and I have personally seen it on hundreds of Porsches.
Every other theory or solution is just a band aid. Drive them until they're worn out, and replace with something else if this is a concern. But is completely normal for the tire in question, and I have personally seen it on hundreds of Porsches.
10-27-2018, 10:37 AM
#11
Great info. Never heard that one. I've got a combined 120,000 miles now on three 997's, all of it on Michelin tires. All of them have worn out the rears consistently on the INNER 2"-3" no matter how perfectly aligned and no matter what toe setting. Some alignment/toe configurations have lengthened the life of the rears somewhat but I never got more than 12,000 miles out of a set of rears and at that time the cord was visible at some areas. All three cars were lowered which I know doesn't help but I've never seen center wear on either car so must be a Pirelli issue as you say.
As far as wear goes, all you can do is play the minimize camber and toe game while not letting the rear end feel light. And that's specific to different drivers as some are more comfortable with feeling the car "move" or rotate than others.
It's all about that weight over the rear for the most part, and exactly why Panameras do the same thing on the opposite end.
Last edited by Ptech1; 10-28-2018 at 03:15 AM.
10-27-2018, 11:13 AM
#12
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One of several reasons that I don't like Pirelli's over other brands (aside from the Trofeo R), along with cracking earlier than most other brands. Sometimes within 3 years or less...
As far as wear goes, all you can do is play the minimize camber and toe game while not letting the rear end feel light. And that's specific to different drivers as some are more comfortable with feeling the car "move" or rotate than others.
It's all about that weight over the rear for the most part, and exactly why Panameras do the same thing on the opposite end.
As far as wear goes, all you can do is play the minimize camber and toe game while not letting the rear end feel light. And that's specific to different drivers as some are more comfortable with feeling the car "move" or rotate than others.
It's all about that weight over the rear for the most part, and exactly why Panameras do the same thing on the opposite end.
- The shape of the tire across the width is actually crowned rather than flat, or
- the Pirelli tires don't have much structure across the tread width and the centrifugal force makes it bow out in the center at speed (like a top fuel drag car if you've ever watched those spin up)
10-27-2018, 12:01 PM
#13
Drifting
I have never heard that about Pirelli, but am prepared to accept that explanation. I suppose it’s possible that the P Zero Neros (which I assume is the tire we’re referring to) has a softer compound in the middle of the tread, which could also explain the phenomenon. But, alignment and pressure are the two most likely culprits whenever a tire wears unevenly.
As another point of reference, my wife’s first E550 cabriolet came from the factory with aggressive toe and camber specs on the rear (ridiculously so, for a touring car), and the one set of Pirelli P Zero Neros we ran on it wore out on the inside edge, just as our 911 tires do.
As another point of reference, my wife’s first E550 cabriolet came from the factory with aggressive toe and camber specs on the rear (ridiculously so, for a touring car), and the one set of Pirelli P Zero Neros we ran on it wore out on the inside edge, just as our 911 tires do.
Last edited by Iceter; 10-28-2018 at 12:46 PM.
10-27-2018, 12:19 PM
#14
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Good point Iceter. A softer compound in the center could certainly be a 3rd reason.
10-28-2018, 10:52 AM
#15
I have never heard that about Pirelli, but am prepared to accept that explanation. I suppose it’s possible that the P Zero Nero’s (which I assume is the tire we’re referring to) has a softer compound in the middle of the tread, which could also explain the phenomenon. But, alignment and pressure are the two most likely culprits whenever a tire wears unevenly.
As another point of reference, my wife’s first E550 cabriolet came from the factory with aggressive toe and camber specs on the rear (ridiculously so, for a touring car), and the one set of Pirelli P Zero Neros we ran on it wore out on the inside edge, just as our 911 tires do.
As another point of reference, my wife’s first E550 cabriolet came from the factory with aggressive toe and camber specs on the rear (ridiculously so, for a touring car), and the one set of Pirelli P Zero Neros we ran on it wore out on the inside edge, just as our 911 tires do.
Pirelli? "Your center tread is starting to show secondary rubber". Not every time, but more often than I can count. Especially when the new 991 and 981 chassis were sold with nothing but Pirelli P Zero for 20" wheels for years until other N spec tires became available.
As far as why? I would agree with compound choice and structural support across the tread. Every brand has it's quirks. Bridgestone options are known for having dramatically stiffer sidewalls and beads for example, which in turn makes them feel harder sooner as they age than the Michelins and Pirellis.