Tires again....
 

Was checking my tire thread on my original Pirellis after 17K miles on them and I was hoping to keep going but I found a nice surprise on my left rear.



https://www.6speedonline.com/forums/...ine=1403368294







Front do not look bad. Have any of you replaced the rear Pirelli with the Michelin and left the front original to age a bit more? Or should I change all four to the Michelin?
https://www.6speedonline.com/forums/...ine=1403368294

with 17k of aging, you would not be running these at 150 mph across the Mojave anyway, so it looks far enough away from the inner sidewall that you can plug and patch it if the tread still has enough depth.
here is something shocking you should know...Americas Tire Company will plug AND patch a nail hole FREE...no charge whatsoever incl rebalancing ... no need to be a previous customer . They consider it a goodwill public service . Enjoy complimentary bottle of water while you wait.

If you can't fix the rear, I would have to go with replace all four, ensures good ride and IMO, a mixed set of tires just looks cheap, you have a great car, treat it nice...

If you are planning to do any track events, you may have to have the same make and model of tire front and rear. I saw that was a requirement for DEs at The Ridge here in Washington.

I had to replace my oem rear 305 pirellis at 7K miles because one if them had a nail!!

Front and rears HAVE TO be the same make. Otherwise the car can throw different fault codes at you and will not perform as expected. With PDCC cars it can even damage / mistune the suspension. It's amazing how tight the tolerances level is in these cars.

If it is a DD, I would patch it from the inside and drive them until the tread wears out. If you do any track events, replace all four but I'm guessing that you don't given that you have 17k miles on them. I'm halfway through my 4th set at 10k miles.

Under no circumstances would I mix tires. On some old pickup truck maybe, but nor a car with all those modern systems.

Don't want to be too cheeky, but I'd keep the tires and swap the 911 for a nice Ford Taurus. If you've got 17K miles on those tires, you're probably driving the car just like you would a Ford Taurus. My less cheeky response is to go ahead and plug the one tire and keep driving like you normally do; then simply replace all four tires once your tire wear warrants it.

These were my PZEROs with 11k miles on it. And they still had some grip. Now replaced with a Sport Cup 2, hehe.

http://d.pr/i/LSPx/4vWJJhLw+
http://d.pr/i/xBC0/21qzUUfx+
http://d.pr/i/19kr/2QyBcOXY+

Sounded plenty cheeky...

Although your advice is sound

I would think the nail has penetrated the tire but have been very lucky in the past by running over broken screws and nails that weren't much longer than what's visible. Never know until you pull it out.

The thought of replacing one versus all at that mileage is something the owner of a $100K+ car should never have in their brain. Don't plug either, but patch from the inside, and replace all 4 when needed. Also recommend you get a tire warranty since this little bit of money seems to put you back.

Good thing there's no such thing as rain in Spain!! :p

Well I'll be the odd man here, I replaced the rears at 9K miles due to a nail with MPSS, but left the Pirellis on the front. I've done a number of spirited drives (but no track events) and felt no difference in the handling, no messages or other problems. I do have PASM+ but do not have PDCC. The car is a daily driver.

You don't mix tires mainly due to wet weather handling, cornering, and braking characteristics. Glad your faired ok, but it's not a smart thing to do.

Cheeky?...that was mean man. This is my daily drive and I drive as spirited as I can in residential streets.
Anyway, this morning I was able to repair the rear left and placed an order for all 4 Michelin tires. Have to wait several weeks for the Michelin rears as they are back ordered.

Got 23k out of the PZeros and replaced them with MPSS. Just under 800 miles and the new tire picked up a huge road hazard. I plugged it and drove a few hundred miles before the replacement was available. Tire insurance paid for a replacement.

I'm quite amazed that folks are getting over 10K on these summer Pirelli tires...just wow

The aggregate used in pavement varies across States and cities. Tires last a long time where I live versus where I grew up (Charlotte NC). The pavement in NC is very grippy and shreds tires. Here in San Antonio there's little grip and tires last a very long time. I'd rather have pavement like in NC, even though it means purchasing tires sooner.

Got 9.5k mi on mine. Actually liked them better than the MPSS replacements;)

Agree. After 2 sets of MPSS and driving both to the end, no more. The tire is not that impressive. I believe the PS2 will out perform it. At this point I'm willing to think in different directions. I like my current P Zeros. But I'm open. If Michelin ever produce a N version of the PSS, I'd consider it again. I'm under the belief N versions are different compounds, not just a rubber stamp (no pun intended).

In Washington, Oregon, Northern California and Idaho Les Schwab Tire Centers will do this too.

Notwithstanding the mileage I got out of the PZero tires I replaced them with Michelins. I have noticed that the tires run cooler as evidenced by the lower running pressures at high ambient temps. They are also more comfortable less jarring than the Pirelli tires.

The roads in Pennsylvania suck and most are maintained by that paragon of corruption, the Commonwealth of Pennsylvania. They dig, patch, pave and start over again each time leaving more bumps and holes. One only has to travel south on 81 to Maryland to see an immediate improvement south of the border- same traffic volume results in vastly different existing road surface.

Tspyder/Steve997s,
Were you running comfort-pressure @ partial load?
PSS dont like high pressure.

Who is the best retailer for the michelins? Tirerack?

Yep, some a-holes seem to feel their way of using a car is the only "right" way, and everyone else should be driving a Taurus..

In reality probably 1 or 2% of the people track or drive their car's super aggressively. But the premadona's think they know it all. In reality I often wonder if these are really 15 year olds playing on their x-box pretending that they even own a car.

Most of the serious car guys I personally know in real life tend to be much more realistic, but somehow on the internet they come out of the woodwork. DDing in areas with good pavement and not necessarily terrorizing everyone in the neighborhood or highway lead to significantly longer tire tire life.

Also where you live has a great impact, I once saw a chart that indicated the "roughness" of pavement by region and in some areas it is dramatically higher. For the masses who simply drive their car like normal people... patch your minor nail holes, keep your tires while there is safe tread on them (as long as their age is reasonable) and ignore the self proclaimed "experts" who would encourage you to throw away 4 good tires because one got a small nail in the tread.. Maybe this isn't the recommendation for trackers.. but for the other 99% of DD's it is just fine..

I hear you man....


Anyway, I am probably benefiting from a road surface which is much less abrasive than normal as here in phoenix most of the roads have been rubberized.


http://www.azdot.gov/business/enviro...vement-program

I tend to under pressure by a few PSI so the tires heat up quicker. I've tried recommended PSI too and nothing I ever tried helped. I also have an air compressor at home so all my experiments were based on absolute cold tire pressures.

The PSS is designed to last longer than the PS2. I'd rather have the most grip I can get, especially in a 911 which has all sorts of grip issues when cornering.

the number one " expert " piece of advice to take with a major grain of salt goes something like this " I replaced the worn out *%#^ noisy OEM tire with the board recommended aftermarket SuperMcQuiets and I agree that so far , with 100 miles on them , they are SOOOOOO smooth and silent compared to the OEM "

If you replace any worn tire , with even the same tire, it will be " SOOOOOO " quiet , but what you never read is someone who , back to back same day , drives the same car on the same road with brand new set of OEM vs brand new set of that aftermarket tire .

Yep, similar for me.. Lots of concrete and freeways.. in a warm relatively dry environment area. I believe a lot of southwest and in the west the roads tend to be much less abrasive than in cold wet areas which pave their roads (for lack of a better term) more abrasively for obvious reasons..

yep, the crappiest new tire usually seems better than the best worn out tire.

[QUOTE=bluepr0;4139947]These were my PZEROs with 11k miles on it. And they still had some grip.

What causes the big missing chunks?

[QUOTE=wanderfalke;4140337]High heat usually, caused by high speeds. Plus tires can "chunk" meaning bits break off. Tires also blister and cup in the tread blocks and when so those "out of round" bits wear differently than the rest of the tire.

My only nitpick with the MPSS is that they don't seem to have as high a cornering limit as the OEMs. I live off of one of the premier driving roads in socal so I have a fairly fine sense of handling limits. I virtually never broke the Pirellis loose like I can with the MPSS on my daily drive.

I'm running std pressure/full load (ie, 36/44) for a couple of reasons. First, that is the pressure that the factory set when I took delivery in Zuffenhausen; and second, I tend to prematurely wear the outside edge of tires on every vehicle I've owned unless they are set to the upper range of of rec pressures. Even wear, tread life, and handling are more important to me than comfort.

Never heard that MPSS work better with lower pressures, and they do fine on my 650 at higher than normal pressures. Maybe I'll give lower pressures a try on the 991.

Spyder

Try 31/34. I think you will be very pleased.

Until you hit a sharp bump and bend the wheel. Truly I wouldn't ever go less than a few PSI under recommended as handling, cornering and braking may suffer. The point is to let the suspension handle road irregularities, not the tires. The right tire pressure keeps the contact patch and deflection correct for the car design. Too less and during aggressive cornering you may actually put some of the sidewall in contact with the ground. But just for a second until the tire rolls off the rim ;)

If you take a look at your manual you will find that these are the recommended "comfort" pressures for winter tires (31/39 for summer tires on a CS2 with 20" wheels). There is no risk of the tire rolling off the rim but Porsche recommends keeping the speeds below 150mph at this pressure. In addition I know from personal experience that the MPSS do not grip well over 40psi whereas the P0s are less sensitive to higher pressures.

If Spyder's cold temps are 36/44 and hot temps are 3-5 psi higher, it is no surprise that he feels less grip than from the P0s. In addition, as the max pressure according to Michelin is 50 psi, he is probably more at risk for a blowout with those pressures than rolling off the rim at 31/34.

If you have lots of potholes where you drive than I would try 3-4 psi higher, but if you want maximum grip from the MPSS then hot pressures should be less than 40. And at 31/34 or a few psi more you will be fine, but will want to reset the TPM to comfort. Hot temps will probably be 3-5 psi higher on the street and 8-10 psi higher on the track. I have pulled a over 1.3G lateral and 1.2G under braking routinely at these pressures with no problems including minimal outside shoulder wear (SPASM but no PDCC)

With that said, only do what you are comfortable doing.

Johns991 is right;
Use Comfort Pressure w/o Full Load for 20" Summer Tires.
That gives you the low [31/34] pressure you need for PSS to work properly.
This pressure is fully factory recommended.

Part Load is how most people use a 911, so the Full Load setting is overkill.

What? You recommend reading manuals and facts over faith? No wonder you are under such cornering pressures!

hilarious
LMAO, yeah go figure. Amazing what you can learn with that interweb thing everybody is talking about.

So what is the consensus for optimal tire pressure for maximum wear out? (as opposed to maximum tire performance)?

Because a winter tire's character is so different from a summer tire I don't see the logic to apply winter tire pressures to summer tires. Winter tires are much softer rubber, and need the extra deflection to generate the sufficient heat needed in order to grip cold tarmac. In 2 sets of MPSS I tried many lower ranges of PSI and didn't find any real advantage, although consistently used cold pressures as much as 3 PSI lower f/r in an attempt to get more heat in the tire. In the end, it doesn't hurt to trust Michelin's engineers and they recommend 36/44 for a 991 S with 20" wheels on MPSS tires. You won't find this in your owner's manual, but alas on the internet. My P Zero's at -3 PSI (or at the comfort setting) grip far better than both sets of MPSS I had. I'm just hoping the grip lasts over the life of the tire. We'll see.