205 To 225 & Falken Azenis

[jbirkholz]

I just purchased a 2000 Boxster S with 205/50-17 and 255/40-17 tires that are pretty worn. Will changing the front to 225/45-17 reduce understeer? Will the ride be noticeably worse? Will there more of a tendancy to hydro plane in the rain?

I read most of the postings to the PCA Tech Q&A regarding tires. They seem pretty adamant that you only stick with "N" approved tires. I use the Boxster for autocross, track days, and daily driver. I am considering the Falken Azenis based on their autocross prowess. Has anyone had experience with the Falken Azenis? Is there a better tire?

[ar38070]

Use of N rated or non N rated tires is one of those religious things.

Use non N rated tires if you like them.

225/45-17 up front will reduce understeer and many people use that size.

No idea about the Falkens, though I see that there are several models of the Azenis so you probably want to say which model you are talking about.

[Highlander]

Good Ax street tires are the Azenis, Kumho Ecsta MX and I have heard some people like the Hankook Ventus R-S2 Z212. I autocross my M3 in the SCCA STU class on a set of Azinis 615 and they are a great tire.

Running a 225/45-17 is a distinct performance improvement with no noticable degradation in ride quality - at least in my experience.

"N" ratings... Porsche has a commercial and marketing agreement with some tire companies. In exchange for running some additional tests on their tires, Porsche "recommends" (through the "N" rating) those tires for the manufacturer. The rabid and blind following of the "N" rating is more a testiment to the Porsche marketing machine than anything else.

Of course, the above is all IMNSHO. ;)

Graeme

[MikenOH]

Graeme:

How do you like the 615's? How do they compare to Victoracer or any other R compound tire?

[Highlander]

Graeme:

How do you like the 615's? How do they compare to Victoracer or any other R compound tire?

<{POST_SNAPBACK}>

The 615's are not anywhere close to being an "R" rated tire. With 2 drivers at an autocross, they easily overheat - not quite as easily as the older Azenis 215, but still way more easily than a Victoracer. They also simply do not have the grip of even a Yokohama A032R (and that's saying something). As street tires go, they have exceptional grip and do seem to work way better in wet conditions that a Bridgestone S03 or BFGoodrich TA. However they are still street tires.

Graeme

[MikenOH]

The 615's are not anywhere close to being an "R" rated tire. With 2 drivers at an autocross, they easily overheat - not quite as easily as the older Azenis 215, but still way more easily than a Victoracer. They also simply do not have the grip of even a Yokohama A032R (and that's saying something). As street tires go, they have exceptional grip and do seem to work way better in wet conditions that a Bridgestone S03 or BFGoodrich TA. However they are still street tires.

Graeme

All right, then, if you were looking for a tire to do double duty--auto-x & DE events in a 987 Boxster, which would it be.? I like the Victoracers but the sizes don't work for the new car. I also need something I can drive 100 miles to an event and not be too concerned about getting caught in a shower

The SSR seems to be gone; any other similar choices or would a good max performance tire do the trick?

Thanks for any help.

[ar38070]

In a 987 you are basically screwed at this point in time as porsche uped the tire diameters and R compound tire manufacturers have not yet caught up.

[Highlander]

I wouldn't worry too much about overall tire diameter. In fact, at the track and especially at an autocross, the lower effective gearing you get with slightly smaller tire diameters is a good thing.

Personally, my track setup is currently 274/40-17 rear and 255/40-17 front. I run with PSM on for the first session each day until my brain gets a chance to warm up. Everything feels like it is working to normal operating parameters even with the significantly larger diameters.

Graeme

[ar38070]

While you can use any size tires you want, 986 sizes are about 5% smaller than 987s. This, at least according to Porsche, is outside the acceptable range for PSM and ABS.

Graeme, your tires fall within guidelines. The 255/40 is the stock diameter, the 275/40 is 3% larger.

So you can use 986s on 987s though 1) it will look a little strange as the tire fender gaps will be even larger than stock (shades of ghetto riders or SUVs) and 2) you may observe unusual behavior in the PSM and ABS.

[Q-Ship986]

"N" ratings...  Porsche has a commercial and marketing agreement with some tire companies.  In exchange for running some additional tests on their tires, Porsche "recommends" (through the "N" rating) those tires for the manufacturer.  The rabid and blind following of the "N" rating is more a testiment to the Porsche marketing machine than anything else.

<{POST_SNAPBACK}>

I think this is a common misconception. What Porsche is doing is just a little bit more, or slightly different, than most car companies already do with their original equipment tires.

I suppose you could consider the "N" mark as a rating, but it is unlike other ratings that are tire/automotive industry standards, i.e. speed ratings. It is really a specification. A Porsche specification. Porsche works with different tire companies on tire specs, often years in advance of model introductions.

It is an iterative process, whereby tire companies create prototype tires that are intended to meet the car company performance requirements (i.e. ride comfort, handling, noise, wear, etc.). Sometimes the targets are moved along the way for reasons such as changing prototype vehicles and because car companies sometimes react to changes in the marketplace and customer desires. Once a tire design/construction is approved by the car company, it is usually run for a few model years. If a vehicle is 'refreshed' or 'redesigned,' the tires can change too. Size, tread design, compounding, etc.

What Porsche does is uniquely and conspicuously identify for their customers the tires that they spent all the time, effort, and expense to develop, test, and approve. GM does this with their TPC specs. BMW has tire companies mark their tires with a star on the sidewall. Other car companies simply require unique DOT coding, or a construction code on the sidewall.

Of course, the customer can take it or leave it. The car company has a lot to optimize with their product, including the tires, and some tire performance parameters mean little to the average consumer. Tire impact on fuel economy comes to mind (although, maybe not so unimportant to U.S. consumers these days....).

So, this is not about marketing, and it is certainly not about running just a few more tests. The 'N' spec is what it is, a spec. A part number identifier. A way for you to replace your tires with a part developed, tested, and blessed by the car company just like any other part...shock, spring, MAF, RMS, etc., etc. Unlike most parts on your P-car, Porsche gives you lots of choices for each tire model. The last brochure I saw had 4-6 different brands/models of tires for each major chassis.

Just because a tire is marked with an 'N' doesn't mean you can't do better, or that you can't pick a tire that gives you a desired performance gain in one area versus another. You just need to know what you're doing and what to expect. YMMV.

--Brian

[adsach]

.....

Just because a tire is marked with an 'N' doesn't mean you can't do better, or that you can't pick a tire that gives you a desired performance gain in one area versus another.  You just need to know what you're doing and what to expect.  YMMV.

--Brian

<{POST_SNAPBACK}>

Nicely put Brian. You managed to explain why N rating may be of value to both Porsche and the consumer without recommending slavish addiction to N tires.

Thanks for the balanced contribution.