just took my wheels off when I changed my suspension and saw the insides of my rears are bald. just tried to order off of tirerack but no Michelins PS1's or 2's - onl the ribs.....

Any ideas where to get PS1's????

tia

 

went to the michelin website - under their available sizes for the PS1 or PS2, they do not have 285/30/18

however, when i searched under car type, it says i need 285/30/18

are these no longer manufactured? i realized that my tread pattern is consistent with PS2's although it only says Pilot Sport on my tread wall - not PS2???

think i might just head down to discount tire and start over with 4 new ones

 

Correct......PS2s do not come in 285........unfortumately in 285 your choices are limited (IMHO).......PS are not PS2s.....PS have been around longer (I have on my 993) which often means they may not nec be around that much longer (if in the future want to replace, say the backs after while keeping the fronts).

Personally, Contis would be pretty low on my list (happy to get them off the Turbo)........between SO2, SO3, SO2A........I'd definately consider SO2A......(SO3 a big seller but not a good tire IMHO)
I've just taken Ribs off the cab (after 2 sets......and am trying Goodyear F1's for kicks....heard some good things on those.

 

i've heard good things about the goodyear F1's as well.

i see that the PS2's come in some sizes that are near mine. would any of these sizes fit on my car (standard 18" carrera 5 spokes 10" wide) ???:

275/35/18
295/30/18
295/35/18

if one of these would fit, what would be the trade off for getting this size rather than finding a tire in the correct size of 285/30/18?

tia as usual

 

You don't want to do that!!!!! Don't mix brands & patterns!!!! By the way, can't you use 295's?

 

i figured it out so problem solved

thanks all!

 

Is there an explanation for this rationale somewhere? I'm certainly not disagreeing with it. I have some ideas of why this might be, but am truly curious for the legit explanation.

Everyone always says don't mix and match, but nobody ever offers a reason why. Please entertain my curious mind, so I can feel right about passing this knowlege on to others.

 

It has to do with the different characteristics from the tires potentially causing an inbalance in the handling: either more grip in the front or rear.

In reality, do a blind test and most of the time drivers wouldn't be able to tell that you mixed tires....Assuming that you are using the same types of tires all around (i.e. hi-perf vs all season)...

Especially in today's PSM world, if you are a daily driver person, it just couldn't matter that much...

Take my old Viper for example. I took it to the track and cooked the hell out of the rear tires so they had significantly less traction after that. The fronts didn't change. Now even though they were the same tires all around, the traction of the rear was much less than the front. So what did I do? Pay more attention when power sliding through a corners until I sold the car...

 

We advise against mixing on any car but more-so for 911's. Why? Many reasons.

1. Staggered wheel fitments require different tire sizes front and rear. Different sizes grip differently and the suspension is set up to compensate.

2. Tires from different mfgrs have different compound hardnesses. EX: Michelins are harder on average than Pirelli. Mixing could result in loss of "feel" and linearity under harder conditions.

3. Some tires are wider than others in the same size. Running a wider back tire than average (EX: S-03's are sized a bit bigger than average) in the back could result in more understeer if the front tires are not changed with them.

4. Tire construction. Running XL tires on one axle and not another could result in less "feel" and predictibility.

5. N-spec. Porsche-spec tires are tested by Porsche and provide the maximum performance. That's why they are constructed differently, and that's why it's recommended to keep them all around or not at all.

6. Tread design. Asymetrical tires should not be mixed with directional tires as it could result in tread patterns that "fight" one another for the line the car follows.

7. ***** rating. A Y rated tire (186 mph) is constructed differently than a V rated tire (149 mph). The Continental Sport V-Maxx coming out will be rated to 224 mph and will be raising the bar again. IF ANYTHING, NEVER MIX ***** RATINGS.

In many cases a car's performance characteristics are designed and tuned around the tire size. One thing I have learned from being in the biz and actually driving all of these tires on the same platform (BMW 330i's are our test cars)- they can be dramatically different in how they perform from one to another. Some feel the same in the dry but are night and day different in the wet - and vice/versa. Some work great cold but get slippery as they heat up. I have taken three identical cars and run a mis-matched set on one car, all four of the mismatched car's fronts on another car, and all four of the rears on the third car and they have all three felt completely different. On the same day, on the same track, on the same car. I take several calls a week from people who have decided to mix tires on "regular" cars and can't figure out why the car feels "funny". Many times the driver cannot put their finger on what the problem even is - just that it isn't like it was before they mixed.

We believe Porsche works harder at tuning the performance of the car to the tires than anyone else does. That's why tires are "N-speced". And given that since they go through rears at such a faster rate than the fronts, owners are always tempted to try what's new before doing a complete swap (every other time).

It's a tough subject to put your finger on due to the variables involved, but the one constant is the fact the performance is ALWAYS the best if the same tire is used on all four corners. We've proven it, and I have seen the difference myself. And it can be more significant than you think.

 

Damon,

Thanks a lot for that in depth explanation. Much of that I had only assumed previously. Now there is no reason for assumptions.

Tomorrow I'm having new rears installed (decided to give the Goodyears a try since I couldn't find the correct sized PS2's anywhere until May). My fronts have plenty of tread left so I was reluctant to change those as well. I previously had Pirellis on the car (fronts are still pirellis) but there is no way I was going to buy pirellis again, very dissappointed in them. I decided it was worth getting rid of decent fronts if problems arose from the mis-matched tires than it was to buy a set of rear pirellis again. Hopefully all goes well, but I may be ordering a pair of goodyears for the front soon if I notice anything I don't like about the handling as a result of the mis-match.

Wish me luck. And I'm glad all has been cleared up now. From the way people posted about this topic earlier one might think your car would explode from mis-matching tires since it appeared to be the ultimate taboo, yet nobody explained why. Maybe it was just common knowledge.