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Old 07-04-2010, 07:36 AM   #1
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Don't mix and match different brands and/or models of tires. As some of the members have indicated, tires have certain characteristics that are unique and peculiar to themselves alone. I agree, that you should either replace just the tires that are worn with the same brand and model, or opt for 4 new tires that are the same. I would caution you to steer clear of the Goodyear Eagle F1's. Despite their good performance, they produce a
ride that is harsh enough to knock your dental work out. Furthermore, they were a bastard to road force balance . In fact, on a couple of occasions 2 out of the 4 tires where so far out of "spec" that they would not balance within acceptable figures and consequently had to be replaced . Unfortunately, Goodyear only agreed to warranty 1 of them .
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Old 07-11-2011, 05:56 PM   #2
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I call BS on the alarmism about mixed tires. The front and rear are of a different size on these cars anyway. Sure, there may be some incremental change in the balance of how the car behaves and I would like a matched set of all four for extreme conditions, as going to the track - but for street traffic, where at least I never go anywhere near such margins that this would be significant, I'll happily be e.g. replacing worn rear tires before the front tires.

The safety rules for this would be not to mix on the same axle and not to have significantly worse shape tires in the rear than up front so as to avoid surprising oversteer.

edit: oops, didn't note the dates. Sorry for kicking a dead horse.
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Old 07-11-2011, 06:33 PM   #3
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The manufacturer, retailer (Tire Rack) or you the driver can neither predict or explain the handling of your car if you mix brands. A great tire may be on a car that handles terrible or a crappy tire may work surprising well. These combos have not been evaluated or tested, so it's anyone's guess how well or safe the car will perform. Yrs ago grandpa bought any tire that was on sale and bought 1,2, 4 or whatever and didn't have a problem. But all tires were crappy then and he wasn't driving a performance sports car (not my gramps anyhow). Dad always bought recapped snows for the rear. That was common and worked fine.
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Old 07-11-2011, 09:10 PM   #4
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This is always an interesting topic, reading opinions as different as the colors of a rainbow.

FWIW I'll throw in my 2cents as I am sort of the crash test dummy of tire choices and mix-n-match. So far just tests, no crashes I have rarely run 4 of the same tire on the street.

First of all the OP is on 19s so he has few good choices and they are all pretty $$$$. Of the size he needs only the Bridgestone Potensa RE050A will be a close match in terms of wet traction, ride quality, and dry grip. The Continentals will be ok but not much savings so might as well stick with PS2s. The Nitto Invo is a decent tire but not a close match to PS2s. I would not put 2 on the rear. None of the other tires mentioned as substitutes in this thread are available in that size. This was a pretty good comparison test for those of us on 17-18 wheels:
http://www.caranddriver.com/reviews/comparisons/09q2/tire_test_nine_affordable_summer_tires_take_on_the _michelin_ps2-comparison_tests

Over the years I have swapped mismatched tires around a lot and while most have been a pretty close match, a few sets were horrible. For kicks we ran a set of Conti Sport contact 2s on the front and put on a set of Kumho All Season tires on the rear and ran a session at Spring Mountain to see what would happen. It was terrible... like driving on unpredictable ice with a lot of breakaway oversteer. I managed a few off in the dirt moments and decided these tires didn't play well together. We pulled the Kumho's and ran Sumi's on the rear... balance restored. A good match and the tires were excellent on the dry track and even later in the rain.

I am currently running out an older set of Pilot Sports on the front and put Nitto NT05 on the rear on my 17 street wheels. The Nitto's have a much higher level of dry grip and are pretty good in the rain. They are more of an extreme performance tire than the Pilot Sport so the result is more "push" and the ABS will kick in early under heavy braking in the wet or on painted surfaces. I can live with that on the street. The NT-05 rears never let go. Once I finish off these front Pilot Sports I may go with NT-05s all around.

I guess the moral of the story is: if you are going to mix-n-match, make sure your rears have better wet/dry grip than your fronts and the car will be predictable. The closer you match tread style and tire compound, the better your balance will be.
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Old 07-11-2011, 10:07 PM   #5
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He's right but get this..

Quote:
Originally Posted by Bobiam
The manufacturer, retailer (Tire Rack) or you the driver can neither predict or explain the handling of your car if you mix brands. .

bobiam is correct but in my case The Tire Racks recommendation for snow tires for the SLK230 was absolutely dangerous. Add to that the fact the tires were the same brand and Tire Rack said " these new Blizzaks should be compatible with the Blizzaks you have on the front.

As one of the other posters offered, the front and rear of the car acted like they weren't connected to one another and the car wanted to change ends, if you made any sudden turns with the steering wheel.

Totally wrong information from them and I won't do business with them again. Their recommendation was dangerous to say the least.

So if you want to mismatch brands go right ahead it's your life, just let me know what roads you take so I can go a different way!
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Old 07-12-2011, 10:40 AM   #6
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Anyone ever drive a car with a spacesaver spare tire? Did you adjust your driving accordingly? How about a new Cayman R with a slow leak in the right-rear tire, leaks to 10psi? Drive your 1967 El Camino SS 100 miles on the freeway at 85mph to buy a used refridgerator & drive 85mph back home? Are any of these vehicles unsafe to drive? Does the driver need to make adjustments to their driving style to allow for the reduced capability of their vehicle? A driver should never exceed the capability of their vehicle or driving skill. It's like building a race engine: the weakest link will break first. Tires are no different, if you choose to downgrade the handling capability of your car you must adjust your driving to suit the weakest link.
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Old 07-23-2011, 08:15 AM   #7
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I haven't had to replace the rubber on mine yet. Why would the rear tires wear at a rate 2:1 faster than the front? According to one poster and not previously challenged or questioned. Very curious.
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Old 07-23-2011, 08:48 AM   #8
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The rears typically wear faster than the fronts since they are doing all of the work in moving the car (propulsion) and Porsche drivers tend to be a little (hah!) lead-footed. And the majority of typical driving is mostly in a straight line so the fronts are just along for the ride and not really doing much work.

Fronts will typically wear at the same rate as the rears if you are doing a lot of canyon carving or other driving where you're spending a lot of time cranking it in the corners. In this case, the understeer built into the car will cause the fronts to scrub and wear at a rate similar to the rears.

If you track at lot, you are cornering hard on a fairly continual basis so you may find the the fronts wear even faster than the rears, especially if you haven't adjusted your tire pressures correctly and/or increased negative camber to minimize understeer and even out the wear across the tire (inside to outside).
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