Tire Thoughts

I've been researching C4S tire options since the rears are in need of replacement. The fronts are fine with a lot of tread left on them. Any thoughts on mixing and matching brands front and back? I've always replaced a full set on my cars so I've never really thought about this before and it seems strange to consider putting Bridgestones (or whatever brand) on the back with Michelins (or whatever brand) on the front. Any concerns with wonky handling or anything else? Should I just replace them with whatever brand is in front and then worry about researching options when I replace the set? -Eric

not an issue mixing brands really as long as they're similarly rated and max performance. And it's the summer as well for now. Other possibility is to order all 4 tires new now, and keep the front two as spares. But I personally would mix and match front to rear as long as the tread is about equal.

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It's customary to replace the rears with whatever brand is in front. Mix and match might lead to vibration.

The car currently has PS2s at all 4 corners. The fronts have a decent amount of tread left. I'm just trying to decide whether or not I should replace the whole set with an alternate brand, get a couple of PS2s for the rear or, alternatively, pick up a couple of Advan 08s or similar tires for the rear (i.e., mix and match). -Eric

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Please Explain

This is the debate I'm looking for. I've had a lot of people say exactly what is being said in this thread: "You should know better, just get a pair of PS2s for the rear" and "mixing and matching is fine as long as they're the same type of tire." So, which is it and why? -Eric

If just driving on the street, mixing tires will not be an issue as long as you replace each axle set... If tracking the car the different grip levels of the tires can wreak a bit of havoc. This could either be seen as an issue or a new learning curve for car control! :-) On the cheap end of the spectrum, hankooks are great, after installing a set on the rears just recently, I was very pleased to find that they seem to be much quieter than the tires they replaced (sumitomos). I will be replacing the fronts as well with the hankooks shortly, and then will have a matched set again, keeping the purists happy! (fronts are dunlops and outlive 2 sets of rears...)

This is like debating politics, religion or brand of oil. Do what you feel comfortable with. Do you like to experiment and think for yourself or go by the book and do only what the manufacturer recommends? I'm a maverick and pretty obstinate. I'll generally do things contrary to what others and authority recommends. By far it usually works out for the better. I don't believe in one size fits all and like to customize everything to my own needs. I believe manufacturers make things to work OK for everyone and not exceptional for anyone. I think I can do better on most things to suit my personal needs. Go with your gut!

Different tires, even tires of the same make with different amounts of wear, will give different levels of grip. So long as the car is being driven well within the limits of grip, you'd never notice the difference. The issue is at the edge of traction, when you're panic stopping, or hit a corner too fast for conditions, and one of the sets of tires loses grip while the other still has a little grip left. This isn't necessarily a problem- it's a rare condition when front and rear lose grip at *precisely* the same time- but it can lead to unpredictable behavior if the weather changes and your car suddenly goes from understeer to oversteer! Conventional wisdom when replacing with the same brand/model is to put the newest tires on the rear, as they will almost invariably have more grip than worn tires of the same make/model under all conditions and keep the car understeering nice and predictably. With different type tires on front and back, though, you can never tell. Sticking with tires in the same performance class helps reduce the risk, but different tires have different characteristics at different temperatures and in different wet weather conditions, etc- those awesome grippy tires may be great in most conditions and give you lots of confidence, yet may stiffen more than your other set at colder temps and surprise you when you least need the surprise. At the end of the day, it's your call. If you're specifically talking about RE11s in the rear and PS2s in the front, I think the risk would be minimal, but you can never eliminate it completely.

Here is the "by the book" recommendation. I happen to follow the "book" for all of my cars that any family member drives or rides in. I learned about this recommendation before I purchased the 996 but because of cost I did consider other options. In the end I decided to follow my gut and follow the book. So I can be of no help with actual experience of mix and match or the use of non porsche approved tires. I do not track my car at this point but I do drive anywhere from mild to wild and I decided not to contribute to any risk of the item that keeps my car on the road. "It is recommended that only matching tires be used on Porsche vehicles. Since many Porsche vehicles are fitted with differently sized tires on their front and rear axles, this means matching the tire make, tire type and N-specification. If a vehicle was originally delivered with N-specification tires that have been discontinued and are no longer available, it is recommended to change all four tires to a higher numeric N-specification design appropriate for that vehicle. Mixed tire types are not permissible." "It is also important to know that while Porsche N-specification tires have been fine tuned to meet the specific performance needs of Porsche vehicles, the tire manufacturers may also build other tires featuring the same name, size and speed rating as the N-specification tires for non-Porsche applications. These tires may not be branded with the Porsche N-specification because they do not share the same internal construction and/or tread compound ingredients as the N-specification tires. Using tires that are not N-specific is not recommended and mixing them with other N-specification tires is not permissible." What I do have experience with is thinking that I only needed winter tires if I drove in the snow. I quickly learned that it is not about "snow" tires it is about tire compound and temperature. In cold weather my summer tires have as much grip as a hockey puck. I do use "n" spec winter tires as well.

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I have sumis on the rear and Dunlops on the front and have no issues, vibration, handling, or otherwise. I don't track my Porsche, but I do spirited driving with my 911 everytime I drive.

I just put some Extreme Contact DW's by Continental on my car. Something over 1k is what it cost. Tires can't be beat in the rain since they look to be pretty much the same as racing tires for the rain. The original track tests had them beating out some of the big name summer tires even in dry conditions. I'm not even past the break in or 100m yet and I dumped the old front tires even though its just like you where the fronts were good for another year.......maybe. I do know right now the tires sound quite plus they seem to ride nicely. Others have tried them and they aren't super expensive like some of the name brands the conti tire beat during track tests. I saw the test in a magazine more than a year ago but could never find the story online. I noticed when taking the tires to be mounted that they were made in the Czech Republic and Portugal. I'm not sure if they are the USA specs or european tires. Next time out I'll have to check for DOT markings. I'll be real happy if they are euro specs. Here's a guy doing a personal test of the dry wet snow DWS version of extreme contact's. He says they aren't bad if you want to run the tires all year round. They are ultra high performance besides pretty good in the snow. http://www.youtube.com/watch?v=ZZnvJT-4YT8&feature=related http://www.eurotuner.com/techarticle...s/viewall.html http://www.youtube.com/watch?v=3cq5ANbFOZg Keeps a mustang on the road when wet so they can't be that bad http://www.youtube.com/watch?v=Ztf43ZfF2PA The tire was actually developed in europe by Continentals european division. It was selling really good so the parent company brought it over here. Continental doesn't play sales like other companies do high performance tires. They make industrial and car tires and even put tires on military vehicles during WW1. Performance tires are just a drop in the bucket for them which is good because it keeps the price down. Anyway only snow cruising I see is in Afghanistan. We outlawed that miserable stuff in Hawaii except for on top of the mountains past the 9,000 foot mark. Good luck figuring what to do. Some go for extra rims of the beater variety and put snow tires on them if they want to cruise in the Pcar during snow season. The DW is dry wet while the DWS is dry wet and snow in case you don't know the lingo. I wouldn't use the DW's in snow since the center tread is slicks and the outer isn't too far from it. Good luck shopping.

To the OP. You think the front tires are good because they have lots of tread? Is you car still in transit? Do you know the date of manufacture on the front tires? I believe you car has been in storage. If so for how long? If your tires are over 5 years old and have been sitting (even in a climate controlled storage facility) I would replace all 4. You'll be glad you did. If you don't intend to track your car, there are some very resonably priced tires out there for the 996.

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Hopefully your "new" C4S will come with it's owners manual so you can see for yourself what the "recommended" tires are including maximum tread depth variation between the tires to prevent problems with the AWD differentials. I believe it is 2 or 3/32" diff between all tires. Also summer only tires are dangerous to drive in sub 40 degree temps.

The April, 2011 TSB with Porsche's recommendations for tires for the C4S is available on www.renntech.org .

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Lots of great comments and advice. Thanks for everyone's feedback so far! I'm probably somewhere in between "by the book" and "maverick" with "by the book" tendencies which is why I raised the question in the first place. lol I know the Porsche answer is 4 new tires every time. The attorneys and engineers make that requirement for liability and "optimal performance" purposes respectively. I was just looking for thoughts on whether it's really necessary and what the downsides might be for not following the requirement. I tend to be a spirited driver but I've never had any of my cars on a track (although I'd love to some day). I have been to an autocross and intend to return but it's certainly not part of my weekend routine by any stretch of the imagination. I'm also not a big fan of bad tires (who is?) and if a bad tire combination might be disruptive to the driving experience when I push my car around a corner then I'm not really interested. My R came off the showroom floor with PZeros and they were a horrible combination with the car's active chassis and stock suspension. I replaced the OE springs with a firmer set that improved the situation but I would never go back to PZeros again. If a mix makes no difference then, regardless of what's 'required,' I might give it a shot...but it doesn't sound like that's necessarily the case. I was just using them as an example. If I'm going for a matching set then I'm picking up some PS2s for the rear, however, if I'm looking at 4 new tires then I'm open for suggestions. I have summer only tires on my R and winter/snow tires for when it gets cold. Summer tires are about as pliable as granite in cold weather. They're completely useless in cold weather -- regardless of precipitation. 1) The dealership told me the fronts were good during the PPI and the prior owner told me that he replaced them shortly before putting the car into storage. 2) Yes, it's still in transit and will be for about a week. 3) I don't know the manufacture date but I will/can certainly check when the car arrives, although from what I can tell they're not that old. 4) The car was in storage for over a year. The storage place turned the tires to keep them from flat-spotting. Based on my conversations with the owner though, the tires are only a couple of years old. Right...and I know the fronts have more than 5mm tread depth. Assuming stock PS2s start their lives with about 8mm tread, then I should hopefully be within a good zone. If not, then I might just need 4 new tires. Thanks again for everyone's thoughts. -Eric

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Replace the rears with PS2's that way by next year you'll need 4 new tires at the same time.

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You'll get lots of responses. But I think the one that quoted the owners manual is probably the best one. Now some have mixed tires and report no problems. Me? I've gone through more tires than most and I've never mixed brands, even N numbers. These cars are so communicative that I do not want to risk mixing tires only to find out I made a mistake. I am fussy enough to detect and regret the degradation in the car's feel and yet cheap enough to stick with the tires until it is time to replace them again. So, I avoid the possibility and never mix tires and never stray away from N-rated tires either. So, what should you do? Well, my advice is if the fronts are ok buy new rear tires that match the fronts, brand for brand, style for style, N number for N number. Unless you know the car's alignment is spot on I'd suggest at teh same time you get the alignment checked/adjusted properly. I have to touch upon this alignment business: Correct alignment is critical to maximizing tire life. The difference can be significant. I have tires on my Turbo that are now approaching 20K miles of service and still they are not down to the wear bars. (Close but not yet there.) With a bad alignment -- unbeknownst to me -- the rear tires were worn out in around 8K miles. The next time the rear tires need replacing the fronts will almost certainly need replacing too -- I replace the front tires every other time I replace the rear tires. Now a side note is that while the front tires often have reasonable tread left the front tires get hard and slick and sometimes noisy so I replace the fronts mainly for peace and quiet and some safety concern. Ok where was I? Oh yeah. Try to replace the rears with the proper matching tires. When it comes time to replace all 4 you can think about straying away from the tires Porsche recommends. If you want to stray now...well, it is your car. However, you take a chance the car will not feel right and you could possibly go through no little expense in trying to sort this out only to find out the difference in tires is the cause. Sincerely, Macster.

If I was in your position, I would simply buy a pair of PS2s for the rear. On my Carrera 4, the rear Pilot Sports wore out while the fronts still had 6/32nds left. Since the Pilot Sports were discontinued at the time, I could not match them front to rear. I ended up switching to Continental Extreme Contact DWS tires and have been very pleased with them so far.

Please call me if I can help!

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Can you cut me a deal on a pair of PS2s? -Eric

i am rather conservitive and agree with Macster. two sets of rears per each set of fronts. if you dont like what you have, each second set of rears and one set of fronts replace all four with a new brand. you can experiment with performance and price. did we not purchase well engineered and awsome 996 cars from porsche? i believe the designers have arrived at a great solution specifying n tires. should we question their choice of tires? one can spend significantly more on items that that dont really help the handling of your pcar.

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Not necessarily; consider all the modifications people need to make to turn Porsches into competitive race cars. And that's not placebo effect, there are actual quantitative track times to prove it. The simple truth is that these are awesome cars, but also represent a large number of compromises. For instance, Porsche did not spec wheel/tire size and alignment for performance, they specced it to keep trophy wives out of ditches. You need to make significant changes to both to "unlock" the true potential of your 996. Also, N-spec is nothing but marketing. There are much better (and cheaper) tires on the market. Don't think of Porsche's insistance on the same tires front/rear to be for performance; it's not- it's for liability. They gained a nasty reputation in years past of being a dangerous car and hitting lots of things backwards, and are did their damnedest on the latest models to induce nice safe boring understeer in every condition conceivable.

On the C4 it's important to make sure that the overall diameter front to rear is within spec which I think is 5% but I can't find it at the moment. Don't assume that a 295/30/18 from manufactirer X has the same height as a 295/30/18 from manufactirer Y, and will be within 5% of your front tires.

Personally, regardless of whether on not you want to mix and match, the PS2 is a fabulous tire and you can't go wrong with them. I plan on keeping PS2s on my car as long as they make them (summer rims only).

i only know that a few months ago i was commuting 250 miles one way (so twice each week) for eight months. in the middle of that beating i needed new rear tires, and was told a different brand than the fronts(michelins) would be fine. put on sumitomos. i couldn't get back to dallas soon enough. thought the car was going to swerve off the road every time i changed lanes. it was like the front and the back of the car were not connected. like a small bendy-bus. got back, put michelins on -- fine again.

sjfehr, i agree with your thoughts. i guess i was thinking about street sports cars not race cars.

Finished breaking in the conti extreme contacts and I'm glad I have 19" rims because the side wall flex is annoying instead of being on rails. Although they are rain tires. I didn't think they would feel so soft on 19" rims. I'll see if I can get used to not being on rail road tracks anymore. They sure smooth the road out, I'll give them that much.

I'm BAAACK... I just bought Sumitomo tires for my C2. 600 bucks for the set. Like them better than the Conti's

Any thoughts on mixing "Pilot Sports" in the front with PS2s in the rear? I previously stated (incorrectly) that I had PS2s on all 4 wheels but they're actually just "Pilot Sports. The fronts are like new. They still even have those little rubber dangly things (using their technical name) on them. I was thinking that I should just buy 2 new PS2s for the rear this week but then I noticed that the fronts were actually just Pilot Sports...which I don't think are available any longer. Ooops. If I need to or should just go with 4 new tires then I might have 2 newish Pilot Sports for sale! lol Anyway, thoughts on mixing PS and PS2s? Just as bad as mixing any other tires? -Eric

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+1 on this. If you are ok driving in snow with only two winter tires then go ahead and buy two only. If you are really budget conscious...buy two. If you don't care about the way your car handles then buy two. I would never do it not even on my Family car. To keep in mind that 80% of those guys who say it makes no difference have no clue! None of the go ahead and do it guys here have even mentioned matching the softness of the tire compound....is it a 200wear? 400wear? You should really talk to a Pro...Damien???

I spoke to both a local dealer and Tire Rack and both said not to match Pilot Sports with Pilot Sport PS2s. I'm going to go with a new set. Now I just need to review my options! -Eric

The pilot super sports are awesome. But sizes are limited.

Pilot Super Sports aren't available yet -- Tire Rack didn't think they'd be available for fitment on the C4S until next year.

As you guys already know, I wrestled with the same decision for the winter tires with my '02 C4 Cab and i ended up getting a set of 17" turbo twists with Nokian's for the winter driving. The Nokians provide great winter traction but the tires are narrower and obviously you are giving up performance as well but if you are looking to driver her during the winter months, its a safe bet. Don't skimp on winter tires or you'll end up spending a lot more on body work when you are plastered to the side of a tree somewhere on the Merritt during one cold winter day.

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Russel, I'm not looking for a winter tire. I've got snows for my Volvo (which also has AWD) so I'm planning on using it for the Winter months when it gets cold/snowy. Nevertheless, I need to replace the Pilot Sports on the Porsche now because the rears are close to showing their cords. -Eric

Got it. Let me know what you end up with so you can save me the troubles when i need to get a new set.

I'm not a big fan of mixing tires. Under normal operating conditions on the street, it won't matter, but in that one instance where you need the car to perform at the limits to avoid an incident, it could have an impact on handling. It's a judgment call that each person has to make on their own. I prefer a matched set.

I'm going with a matched set -- that much is decided. I'm just trying to decide which set! I'm still waffling between a set of PS2s and the Sumis based on all of the information on Rennlist. Before really researching options I was prepared to buy a set of PS2s. I've had them, PZeros and S02/S04s on my other cars in the past but I also recently, out of sheer curiosity, tried a set of Khumos just to see what all of the hubbub (good and bad) was about. My commute is relatively minimal and the Kumhos were so cheap compared to the PS2s (and the PZeros they replaced) that I figured I really had nothing to lose if I wanted to take them off after a season and sell them. At the time, I remember expecting the Khumos to be decent enough to keep but ultimately not worth purchasing again. Much to my surprise, while I think I can tell the difference between the two in every day driving, I'm not sure how much of it is in my head!? The Khumos grip very well in the dry and wet, and they are worlds better than the PZeros they replaced in every way imaginable (noise, comfort, handling). Are they as confidence inspiring as PS2s? No...but they're also communicative enough that I've never feared an unexpected meeting with a tree, for example. So, my positive experience with the Khumos has me wondering about a set of Sumis for the Porsche which, according to the nice folks at Tire Rack, is a great tire and is about a year ahead of the Khumos in design. While I wish they were n-spec, my only material concern about the Sumis is that the Load Index for the rears of the Michelins and Bridgestones (and even the Kumhos) is 98 (1653lbs) whereas its 94 (1447lbs) for the Sumis and I don’t how to determine the potential impact, if any, of that deviation. -Eric