Michelin Pilot Sport Tires

The 1998 Z3 came equipped with Michelin Pilot SX MXX3 tires (when equipped with the factory 17" wheel option). For the most part, these tires are very capable. However, they are of an aged design that has been in production for many years. To illustrate these points, Michelin reports that the Pilot SX MXX3 was installed on 88% of the sport vehicles marketed in Europe in 1995. As of this writing, the tire is being phased out.

The tire did have some drawbacks. It did not handle well in rain and it had a low wear rating. The former I thought wouldn't be a problem as I live in Southern California where we don't get much rain. However, the lack of rain actually exaggerated the poor wet handling of the tire when we did get rain. Because I was not used to driving in rain, when it did rain, I found myself having to temper my normally aggressive driving style. Additionally, the lack of regular rains tended to allow road dirt and oils to accumulate on the roadway. When it did rain, the water simply hydrated the oil and dirt causing very slick conditions as compared to a locale where regular rain would tend to keep the roads clean of this muck. Under these conditions, the MXX3 basically hobbled an otherwise very sporty vehicle.

The wear rating of 140 also meant that these tires would not last long. Being as the difference in front/rear wheel sizes on the 2.8 Z3 prohibited rotation, as well as the camber settings, varying tire pressures (actually over inflated from the factory), and a spirited right foot all contribute to tire wear, I was not too surprised that my stock set of rear MXX3 tires lasted just over 18K miles (the fronts had many more miles left on them). The rear tires actually had a few more miles on them; however, with the rainy season approaching, I was not going to risk trying to drive in conditions described above on balding tires that normally have poor wet handling with a full amount of tread.

The Search Is On

My initial plan was to simply get another set of MXX3 on the rears and wait for them to wear. The thinking was that by the time the second set of rear MXX3 wear out, the fronts would be ready for replacement and I could avoid mixing brands by replacing the rubber all around with a different tire. However, with most well laid plans, there is always those little details that get in the way. In this case, it was that Michelin was phasing this tire out. As such, supplies of the tire were apparently limited for the sizes used on the Z3. Tire shops having MXX3s in stock were actually instructed to release only one tire at a time for emergency replacements (like anyone would replace only one, leaving a new and worn tire on the same axle).

With my ever widening search for a single location to obtain a pair of tires, I chanced across a Discount Tire that, while they could not give me a pair of MXX3s, did offer me a set of Pilot Sports. The shop had received a single set for evaluation (This was in May '99, the tire was released in Sept '99), and they said they would be more than happy to sell them to me. I had heard fairly good reviews of the tire, but was somewhat weary of trying out a new design. The fact that they were a different tire (albeit the same manufacturer and product line) compared to the fronts further put me off.

My search for a pair of MXX3s continued another day before determined that no shop within 100 miles would release a pair of MXX3 even if they had them. I called the manager who I had talked to at the Discount Tire to determine if the tires were still available (the clerk who answered the phone insisted that there was no such tire - I guess because his computer told him so).

When I arrived, the manager took me in back and showed me a stack of not 2, but 4 Michelin Pilot Sports...in sizes matching both the front and rear of my Z3. I was very tempted to buy the complete set. However, the fact that I had plenty of tread left on the front tires along with the price of $265 for each of the rears and $260 for each of the fronts prompted a decision to only have the rear tires replaced (if the manager had given most any kind of deal on the whole set, I probably would have taken all 4).

As you can see from the pictures below, the tire design is a drastic departure from the MXX3.

SX MXX3	Sport

Treadwear: 140 Rating: W, Y, Z Traction: A Temperature:A	Treadwear: 240 Rating: Y, Z Traction: A Temperature:A

Some points I noticed right away:

The huge center channels and side grooves look like they would channel large amounts of water.
The unidirectional design and tread edges running as diagonal to the road surface as possible help to eliminate road noise.
The edge of the tread is very sharp leaving as much of a patch as possible on the roadway, and giving more traction during cornering.

Impression

Here are some claims that Michelin makes of the Pilot Sport over the MXX3 (the only text I could find was in French and was translated on Alta Vista, so exact quotes are paraphrased).

Thanks to its directional sculpture, Michelin Pilot Sport is 1dB/30% quieter than the Michelin Pilot SX MXX3.

12% improvement in cornering performance, on wet surfaces, when compared to the Michelin Pilot SX MXX3

So far, the tire has lived up to all its hype. I have actually gotten to the point where I was trying to make it break loose in the rear, and it steadfastly holds. Shortly after I installed the tires, I installed a set of Eibach sway bars. The bars greatly improve handling, but transfer a great amount of force to the tires during cornering...and they still hold.

I had noticed an increase in understeer after putting on the new rear tires. I suppose much of this can be attributed to the natural tendency of the Z3 to understeer, the reduced tread on the front tires, and the greater traction of the rear tires (both in wear and design). When I added the new sway bars, I set them to help compensate for the understeer. I would expect that different settings may be necessary once the fronts are replaced (probably with Pilot Sports) and the understeer is further reduced...hopefully to a perfect balance...but more likely to a slight oversteer condition.

I never though the original Pilot MXX3s were particular noisy, so I don't notice any dramatic reduction in tire noise...however, I also do not notice any increase.

As for traction in water, they are a world apart from the MXX3. It is no longer my own car, but only my fear of the other idiots on the road who do not know how to drive in the rain that make me change my driving style in the wet.

As of this writing, I have put about 10k miles and not noticed any appreciable wear on the tires - expect for perhaps a little scrubbing of the tread edge where I was getting really aggressive during the HG-HB Drive.

According to the information on the Pilot Sport I could find, Michelin apparently decided to reduce their target market by dropping the W speed rating.

I'm not sure why this makes a difference looking at the ratings as the "149MPH and over" rating of Z would include the W rating of 168MPH as well as the even higher Y rating of 186 MPH. I suppose this simply means that if you do go above 149 MPH, make sure you don't stay long at 168 MPH before getting to 186 MPH. Perhaps there are other design factors.

Whatever the factors, it looks like they succeeded. From what I understand, the reason for the inability to obtain this tire commercially is that most of the sport auto manufacturers (including BMW for its ///M and 5 series cars, Dodge for the '99 and '00 Vipers, etc.) previously using the Pilot SX MXX3 are gladly and hurriedly switching the Pilot Sport.

So here is how I would rate the Michelin Pilot Sport against the Pilot SX MXX3. The rating scale is-5 to +5 with zero representing on a par, a positive number represents better rating, and a negative represents lesser rating.

Wet Handling: +4
This is perhaps biased on the horrible wet conditions here in So Cal. In an area where rains are more constant, I imagine the tire would hold up even better as compared to the MXX3

Dry Handling: +3
I never had too much problem with the MXX3 in the dry. This extra rating is somewhat a mixed blessing as I used to love being able to make the backend slide around in a controlled fashion - great for terrifying an unsuspecting passenger. This really isn't possible with the Pilot Sports as they just stick too much, and any unreasonable attempt to pitch the rear end out would probably result in no control when it does.

Wear: +2.5
I gave this one a middle ground between par and extremely better. This is a rating that may change with time, but if the first 10K miles of wear is any indication, the rating will go nowhere but up.

Noise: +0.5
The MXX3 was never really a noisy tire in my experience, and the Sport really doesn't improve on it much.

Price: -1
These tires actually cost a few bucks more than the MXX3 would have (if available). With the number of other tires with comparable capabilities, they are still a bit pricey.

Pilot Sport Tires

In the Beginning

The Search Is On

Impression