Boxster approved tires

[Rail26]

I remember seeing a thread on the "approved" tires by Porsche. Here is an article I came across that may help out if you are interested. Mine came with the Bridgestones...Not sure if I like them yet.


Article:
Porsche has approved the Bridgestone Potenza S-02 N3, the Continental SportContact N1, the Michelin MXX3 Pilot SX N2 (which I have), the Pirelli PZero Direzionale and Asimmetrico N3, and the Yokohama AVS S-1Z N1. They also specify the sizes which are 205/55-16 front, 225/50-16 rear, 205/50-17 front, 255/40-17 rear, and 225/40-18 front, 265/35-18 rear. Porsche has tried to categorize these tires to compare their relative merits using a "sports," "all-around" and "comfort" rating. Only the Michelins and Pirellis are described as "sports" tires. The others are "all-around" (Bridgestone) or "comfort" (Yokohama and Continental). So choose the tire that best describes your driving style. If you get really annoyed at a harsh ride, get one of the "comfort" tires. If performance is more important to you, get one of the "sports" tires. If you can't decide, get the "all-around" tires.

[Brucelee]

Will they next be telling me what car wash liquid to buy?

[BuffaloBoxster]

That and the Bridgestones scored better on Tire Rack's survey for performance than the Pirellis. I've got the Bridgestones myself and they're a great performing tire.

[deliriousga]

....in the right size.

In general, check the traction and wear ratings for grip. AA best for traction. A lower wear rating means softer, stickier tire for performance driving with a higher speed rating, but more road noise and they don't last as long. Higher wear rating gives you a harder tire for a more comfortable drive, lower on the performance scale, lower speed ratings, longer lasting and less road noise.

Pick the one that suits you best in your budget, preferably not Michelin or Bridgestone (personal reasons).

Personally, I get better performance, ride and wear from the Kumho tires than I did from the Bridgestones that came with it.

[Rail26]

Out of curiosity, I checked the reviews on the B-stones on TireRack.com and they didn't really come highly recommended. I have been keeping tabs on all the traffic on this site concerning tires...seems like Kuhmo and Michelin have been favorites?

I think I am going to change my tires out for train wheels or sharpening wheels anyway. I imagine the tread life is quite impressive!

[Pilot2519j]

Pick the one that suits you best in your budget, preferably not Michelin or Bridgestone (personal reasons).

Personally, I get better performance, ride and wear from the Kumho tires than I did from the Bridgestones that came with it. [/QUOTE]

I bought tires and the Tire Center STS the old WTC installed Marshall tires which allegedly are Kuhmo racing tires. The installation and the tires turned out to be a complete fiasco since STS did not have high speed tire balancing and the clown doing the work installed clip on weights on the Carrera rim. The number of things wrong in the install was scary and I still had a car that the tires were not balanced right. I went to Silver Star and the manager balanced the tires for free. I decided that the engineers of Porsche know which tire is better and insures you the best braking and handling performance better than any clown from a tire center. What you buy is your choice but I would stick to what is recommended. I had S0-3 on my 2001 S-4 I had a lot of problems with them, tranning & blowouts and they are not cheap either. I now have Michelin Pilots and even though they screwed up the Indy F-1 they seem to work real nice with the car.

[socratic]

An interesting recurring theme in the Tirerack.com reviews is that no matter what the tire, from the less expensive Kumhos to the ultra expensive Micheline Pilot Sports and P-Zeros is that traction, especially wet weather traction, goes away significantly after about 1/2 of the tire wears away. Also road noise supposed dramatically increases around that time too.

I'm curious why they can't design a tire that is more consistent through its life.

Also if the above "theme" is true, then I should buy the inexpensive Kumhos and ditch them after 1/2 the tread is gone. Performance should then easily top the supposedly higher performance Michelins and Pirellis which would be at their mid-point in their lives (or past it since they may be softer). Cost wouldn't be much different and you'd be always getting excellent traction versus some probably skitterish results as the so-called high-end tires reach the end of their lives.

By the way, I am runnnig the Kumhos; they came with my 2001 (purchased used). Am very happy with them. Rides smooth and quiet, just like I like them to. I'm one of those who would gladly sacrifice the "ultra max super" grip for nice soft ride, quiet running, long life and a gentle predictable breakaway at the limits of adhesion. --traits which, I gather, are polar opposites when it comes to the so-called high-end tires.

[boxstter]

I have the Ecsta's on our TT coupe and they are louder than a freight train after about 10k. They grip is good and the ride is nice but the noise is ridiculous. Are your's really a decent noise level?

[Brucelee]

On the Boxster, I think tire tread is related more so to the specific dynamics of the Boxster chassis and alignment. Similar situation on the 911, negative camber.

The back tires where on the insides quite quickly. I am not sure the tire makers can do much about this?

I could be wrong but that is what the alignment guys tell me.

The tires on my C5 lasted longer if that is any measure??

[limoncello]

I've been reading dozens of the Tirerack reviews over the past couple of weeks. Some thoughts:
a. Boxsters are somewhat unique in their reaction to tires, i.e., something that works great on a BMW 3 series may or may not work well on the box. So I've been filtering for Porsche and/or Boxster comments. Even the 911 comments vary from Boxster comments.
b. Boxsters go through tires. Better grip=softer rubber=wear.
c. Type of use and location affect peoples' opinions of their tires. Track users look for different characteristics than street users (grip, wet weather, noise, wear). People who may hit snow occassionally think differently than Floridians. Etc.
d. Lots of personal opinions - tires are a matter of taste. You see a lot of: Reviewer A: Just got my new Pirellis, way better than my old Contis. Next review: Just got my new Contis, way better than my old Pirellis. Exact opposites. Tough to summarize that type data.
e. Some data isn't available. Many reviews (including Boxsters) on S03s. Fewer on PS2s. Maybe over time...

My conclusions:
a. There is no "perfect tire" for all Boxsters. People vary, uses vary.
b. Pirellis are not-so-good on wet surfaces. Lots of data on that one.
c. New tires are better than older tires. No surprise. Also explains why everyone likes their new tires better than their old tires regardless of the brands involved. Go figure.
d. Alignment is CRITICAL on the Boxster. Do often at a good shop.

My personal choices (may work for the next person):
a. The Sumitomo HTRZ II is a good tire for me on the street. It grips wet or dry. Noise is OK but the tires are fairly new. It's a bargain at under $100 per tire. For cruising the mountain roads with the wife they're perfect.
b. Didn't really like the Sumi's on the track. I'll play with pressures next time I'm out, but it may be a lost cause.
c. Track reviews for Boxster tires are in fairly short supply. Most of the reviews cite spirited street use. Based on the limited data available, I will either go with S03's or Toyo RA-1s (people say they also do well on wet). There were a good number of track-based reviews on the S03s - people said they were progressive in release and recovery at the limits. Toyos similar, and they're cheaper than the S03s. Fewer reviews on Toyos, though.
But it's all guesswork - will know more after I switch. Gotta wear the Sumi's a little more and figure how to hide the expenses from the spouse.

Random thought: The Box has endless grip. I almost wonder if going to a slightly harder compound would wear better and actually behave better at the same time? Continually seeking "more grip" on the boxster seems almost pointless - it has plenty. I'd settle for predictable behavior on the track and a tire that lasts a little longer.

[deliriousga]

Originally Posted by boxstter

I have the Ecsta's on our TT coupe and they are louder than a freight train after about 10k. They grip is good and the ride is nice but the noise is ridiculous. Are your's really a decent noise level?

Which Ecsta's do you have? 711, 712, ASX? The Ecsta ASX are bi-directional and have the lowest noise level and longest wear. The 711 & 712 are uni-directional and very soft for a tacky traction, but the wear faster and have a higher noise level.

One thing that's important with the Boxster, and probably the TT, is to get those puppies balanced often. About every 3K miles. Since they cannot be rotated, they are more likely to start forming cups over time if they are slighltly out of balance. That can cause a bunch of road noise.

If you use a bi-directional tire like the Ecsta ASX, you can rotate them side-to-side when you get them balanced. That has helped us with preventing cupping.

[SD987]

Somewhat in line with Pilot's comment, I'm curious why people wouldn't run N-rated tires? I understand that folks like to do their own research and draw their own conclusions, however, I have to think that Porsche is well aware of the importance of tires on their cars and have worked directly with the manufacturers in fine-tuning. I picked up Porsche's 'Tires - Porsche Approved Original Equipment Spring/Summer 2005' and I'm not seeing Sumi, Kumhos, Toyos, probably for a reason.

I'm not being critical of someone else's choice, to each his own, but I am curious about their rationale.

[deliriousga]

Originally Posted by SD987

I picked up Porsche's 'Tires - Porsche Approved Original Equipment Spring/Summer 2005' and I'm not seeing Sumi, Kumhos, Toyos, probably for a reason.

No offense taken. I understand where you are coming from. It's the same with all car companies recommending particular items for their cars. Here are a few reasons Kumho tires and others are not "Porsche recommended" that may help you understand the rationale for it.

1) Payolla: They did not pay Porsche enough for advertising or give a deep discount to use them on the factory cars. Sorry, but that's just how the business world ticks. Don't get me wrong, I don't think Porsche would recommend sorry tires just because they were paid more by that company or got a deeper discount for the tires on the new cars (we're not talking about Ford here). They picked several that met the specs they were looking at, tested them and said "what can you do for us if we recommend yours instead of theirs".
2) National loyalty: All but one of the recommended tires are made in EU countries (I' think Yokos are made in Asia). I applaud them for that, but it is a factor in another EU company's decision.
3) Availability: Porsche is not going to take the time to test a tire for their car if it's not in every car tire place on the planet. They are not going to recommend it if their customers are going to be ticked off by a 1-3 week wait for the store to get the right size in. As for Kumho, they are relatively new tire company to the non-racing market place. Their tires have only been available at retail tire stores for a couple of years. They are not stocked as well as others until they prove to the retailer they can sell enough to get them out the door once they are ordered. The others mentioned are also too small to have widespread availability of sizes used by Porsche.

Personally, I am very anal about our Porsches and will not use cheap parts, etc. in them just to save a buck. Anything I use in our Porsches meets or exceeds their standards and that is why I went to Kumho tires. All of the Kumho tires mentioned are W or Z rated. The W rated are 10mph past the top speed of the Boxster and the Z rated are way past the top speed. They also have AA traction ratings, higher than all of the Porsche recommended tires.

The final reason I buy Kumho tires, or any other brand but Michelin is, simply, they are not a French owned company. (Yeah, I like the national loyalty thing too. )

Hope that helps with understanding the "why" part of the equation.

[bigislandboxster]

Thats a BIG reason people look elsewhere for tires instead of Porsche approved tires.....People who put 10,000+ miles a year on their tires don't want to be replacing them annually, so they look for more bang for the buck.....I don't think you can blame them either. I have Pirellis on my '98, bought used, and they are a sharp looking tire for the Porsche, handle real well on dry surfaces(especially with the Sport Suspension) , but wear pretty fast, and where I live it rains a lot as well, and we know what that means! On a dry track these would be excellent....Driving the car everyday means I'll be shelling out $1000+ a year for balancing, wheel alignment and new tires......Why wouldn't one look for tires which are a few hundred cheaper a set, perform well, and last almost twice as long?

[boxstter]

Quote:

Which Ecsta's do you have? 711, 712, ASX? The Ecsta ASX are bi-directional and have the lowest noise level and longest wear. The 711 & 712 are uni-directional and very soft for a tacky traction, but the wear faster and have a higher noise level.

I haven't had them rebalanced recently - never really thought that would affect the noise level but hey everyone here sounds like they know tires pretty well so I will give it a shot. Lots of good input on this thread .

[deliriousga]

Originally Posted by boxstter

I haven't had them rebalanced recently - never really thought that would affect the noise level but hey everyone here sounds like they know tires pretty well so I will give it a shot. Lots of good input on this thread .

If they have already cupped, then a re-balance won't help much with the noise. Most shops give you free lifetime balancing when you buy the tires so do it often when you get new ones.

[RandallNeighbour]

I've decided to buy some el-cheapo sumitomos like my Boxster idol, Toolpants. If they're good enough for him, they're good enough for me. That's my story and I'm sticking with it.

I have Kumho Excsta MX's right now and they're wearing alright I guess. I can't really tell because I had a bent rear strut and a bent front sub frame that I corrected last month and these tires have about 6k on them. I cannot say if they are quiet, loud, sticky or slick because I have nothing else by which to compare them. The next set of tires will help me see if they are good or not.

I chose the MX's over the less expensive Kumho's because the Tire Rack guy told me these would not get loud as they aged, which he said is a known problem with the cheaper Kumho's if they are not rotated. I have learned since then though that one can knock the rubber off the rim and put it on the other side to force a rotation of sorts, which is what I did four months ago.

I'm driving to San Jose next week from Houston though, and doggonit, I bet at least one of them will have a bald spot by the time I make it back home.

One thing I know for certain... If you want to start a hot debate on this forum, start saying one tire is better than any other or talk about oil weight preferences. Opinions on these topics are like navals... everyone has one, that's for sure!

[limoncello]

Agree that tires seem to be a touchy subject. Wonder where can I get a good set of whitewalls for the boxster to use in parades?

[Rail26]

Probably the same place you could get neon lights and one of those chain license plates. I personally think the giant wing on the back would be a nice addition as well as the rotating hubcap things.

[socratic]

Originally Posted by boxstter

I have the Ecsta's on our TT coupe and they are louder than a freight train after about 10k. They grip is good and the ride is nice but the noise is ridiculous. Are your's really a decent noise level?

I have the Kumho Ecsta Supra 712 tires. They came with the 2001 I bought back in Feb. They were pretty much new when I got them, maybe 2000 miles on them max when I got them. I've since put on another 4000 miles on them.

As I mentioned, I am after a smooth and quiet ride and so far these tires are fine. The Boxster's wonderful suspension and chassis deliver great handling. A grippier tire would likely provide a higher max G load but at the trade off of lower tread life, possibly noiser ride, and, more importantly (and more undesireable) for me a sharper breakaway. The Boxster corners very fast already. The last thing I need at high cornering speeds is for the tires to suddenly give way. In another thread I mentioned this already but I had my choice of two 2001 Boxsters, one with new Continentals and the one I have with new Kumhos. The Kumhos were decidedly smoother riding and quieter. The breakaway at the limit was more predictable and gentle in that the Kumhos gradually started to slip and the Contis held on longer but had a sharper break. This was observed in a direct A-B comparision on the same roads and corners. Please be aware that this is my first Boxster so I am not an expert, certainly not when I was test driving them.

As far as a comparison to noise, my other vehicle is a 2004 Lexus RX330 riding on Michelin tires. It's pretty quiet. And tire noise with the Boxster on the Kumhos is not so loud that I'm annoyed compared with the Lexus, and that's with the top down(!)

The Kumhos are still fairly new and so I do not have any feeling for its tread life. Nor do I now how badly traction and noise will deteriorate with age. But having said that, I am currently completely satisfied with the Kumhos.

Oh, one other thing, and this won't be necessarily a relevant comparison, but I had Pirelli P-Zeros before on a front wheel drive sports sedan. They were harsh riding and noisy. When I replaced them with, at that time, Bridgestone RE-71 Potenzas, it was a night and day difference. I offer this tidbit only to let others know that I know what "harsh ride" and "noisy" mean and not a statement comparing P-Zeros to Kumho 712s.