[Inkedupfatboy]

Don't know if any of this has been posted or not but it seemed good to do so.

 

http://www.carbibles.com/tyre_bible.html

 

http://www.autoevolution.com/news/porsch...06761.html

 

http://www.autoevolution.com/pdf/news_attachements/porsche-issues-tire-recommendations-for-older-models-including-the-356-106761.pdf most of it's in German

 

Most of it's in German if you get to the PDF...it's at the bottom of the second link in case the link doesn't work...

968 is down on page 10 as you scroll.

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[94SilverCab]

"But then you own a Porsche so you can certainly afford four new tyres...."

 

Jay

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[Peter B]

I had a good time at "track night in America".  This was my first time on the track.  Having real track tires was a big help, but I picked up a lot of used tire-rubber that I think affected my grip at the later sessions.  I have to heat up and scrape this stuff off my tires.  I had no idea this happens. 

 

Tire sizing question:  Can I substitute a 245/45R17 for a 255/40R17.  Doing this will let me get the Mich PSS as they have it for the fronts (225/45-17).  These guys are on some kind of special at Tire rack for $644 plus all of shipping, installs and so on.  I wasn't hearing the difference between the PS2's and Pilot super sports before.  I didn't get that the more expensive PS2 was our done by the less expensive PSS (but not cheap either).  

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[Bulti]

The 255/40 R17 is an OEM size, so if you got the correct (OEM) rims you are good to go. A 9 or 9,5 inch rim would be ideal for 255 tyres.


The 245/45 and 255/40 aren't quite the same in terms of diameter (-2,8%). But I obviously don't know the legal limits for altering tyre sizes in Oregon ;-). I guess that the 255 should be 'more legal' in any case. The 245 would be illegal on my car over here.


Check out this tyre size calculator: https://tiresize.com/calculator/

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[Peter B]

Follow-up.  The Tire Rack guy, this time (not last time), recommends 245/40-17.  Quote "no problem".   This was recommended over 245/45-17.  

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[MCL968]

FYI, since Tire Rack is local, we can get our tires there directly, and Costco will mount and balance them for $15 a wheel. You should check if they will do the same in Portland.

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[Peter B]

Thanks MCL968.  I check Costco for just straight sales -- best deal by far.  Have 70$ off coupon.  Set of 4 PSS for 590$ installed.  I have to tear up my current tires in an Autocross or something first, but I "reserved them".  

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[flash]

the tire rack guy should find a new gig.  based on having looked at this size before, a 245/40 will be too small on the O.D. and will mess up your speedo (it already reads high and this will make it worse), fuel economy, and possibly the ABS.  make sure of the outside diameter measurement.  you are looking for 25" with no more than a 2.5% variance.  that being said, a 245/45 is too tall by more than the 40 is too short.  tough call.  i think i would rethink the model tire, and find one that fits right

 

by the way, what the heck happened to the specs on tires on the tire rack site?  you used to be able to see the width, diameter and such, and now can't.  that sucks.

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[Waylander]

as I use my car not very often, I just bought some cheap tyres

 

I don't really drive in the rain (living in England it rains a lot)

 

I bought GT Radials Champiro HPY, they have been really good for the money

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[Bulti]

We can't even buy Michelin SS in the OEM 17' sizes over here. That really sucks.


?? But now I see Tire Rack doesn't sell them anymore either?!

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[Peter B]

According to "tire size calculator" link from above the 245/40R17 is 24.7" OD versus 25.0, with a 1.2% difference.  I'm hoping this is OK (I double checked the math).  The reviews on the Mich PSS look great.  

 

On your point Flash, I would be more worried if the car had ESC.  Has anyone else tried this yet.  I'm giving up 10mm of width in the back.  

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[flash]

keep in mind that every tire is different.  the calculators work within a "nominal" condition.  that's why the tire rack site used to be so great.  it had the actual specs.  the michelin site specs it at indeed 24.7"

 

come to think of it though, the speedo pickup is on the front, and that tire is 25" so it should read "right".  you'll just be spinning a few more rpms to get any particular speed.  this will cost fuel, but will make the car a bit quicker off the line.

 

it's not the end of the world, and frankly the decreased width would balance out some of the understeer

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[Peter B]

Thanks for double checking the tire dimension.  When I get these installed (~ 4 weeks because I'll be in Japan on business), I make sure I give them a thorough evaluation .   If one can get a set of Mich Pilot Super Sports for less than 600$, this may become a popular choice.  

 

Reading the Web, the PSS offers similar to better performance to the PS2, with varying opinions.  These are less expensive and last longer, so they've become quite popular.  The only issue is that they have not rolled them out to all sizes.  R17 isn't a performance rim anymore (I guess), so no 255/4017;  they must be saving money on the molds.

 

The PSS scores the highest on the Tire-rack tests.  I read a good many reviews from Porsche owners, mostly 911's.  They mostly like them.  A few folks track them with "good" results.  It's funny to read the reviews because Porsche, then BMW drivers usually are the most critical of their tires.  

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[flash]

i loved them on the SL550.  i probably would have put them on the X5 if they were available in the right size.  i was hoping they would come on the targa, as they are a stock tire on some 911s, but no dice.

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[Stilly50]

I recently put Contintals on my 968 CS. I previously had Yokohamas and khumos. They handle well, but I can't push them realy hard with speed limmits and cops. What has impressed me the most is the reduction in road noise. These tyres are so quiet. 

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[Peter B]

Reporting on Michelin Pilot super sports.  First, got them at Costco, but they wouldn't put them on because the backs are 245 wide.  I had to go elsewhere.   This cost me an extra 35$.  I'll live.   This delay gave me time to sign up for autocross, give my old tires a proper thrashing as a send-off and have a good time with it.  

 

First impression with the new tires = I got a new car!  They are so much more quite and feel smoother.  My old Sumitomo HTR-ZIII's where 8 years old, noisy and poor grip, especially in the rain.    The PSS grip is much better.   They have done well in the rain.   I haven't really pushed them yet (traffic).  Actually I have a little (85 around a few corners).   Seems easy so pushing it didn't come to mind.  There is no lag or squishy feeling with the steering at all.  This is why I stayed away from the Conti-DW (hearsay - I'm not sure if this is true).    By the way, the DWs are on sale on Tire Rack (400$ for a set of 4 for the stock 17" rims).  

 

I will give a full report on the PSS when I really get a chance to push them more.   

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[williamoss]

Reporting on Michelin Pilot super sports.  First, got them at Costco, but they wouldn't put them on because the backs are 245 wide.  I had to go elsewhere.   This cost me an extra 35$.  I'll live.   This delay gave me time to sign up for autocross, give my old tires a proper thrashing as a send-off and have a good time with it.  

 

First impression with the new tires = I got a new car!  They are so much more quite and feel smoother.  My old Sumitomo HTR-ZIII's where 8 years old, noisy and poor grip, especially in the rain.    The PSS grip is much better.   They have done well in the rain.   I haven't really pushed them yet (traffic).  Actually I have a little (85 around a few corners).   Seems easy so pushing it didn't come to mind.  There is no lag or squishy feeling with the steering at all.  This is why I stayed away from the Conti-DW (hearsay - I'm not sure if this is true).    By the way, the DWs are on sale on Tire Rack (400$ for a set of 4 for the stock 17" rims).  

 

I will give a full report on the PSS when I really get a chance to push them more.   

That is odd Peter as I got my Michelin's at Costco in Tigard. And they had no issues in putting on the fronts or the rears. And now I get them balanced every 6000 miles and they do that for free.

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[MCL968]

I could use a little advice from the forum regarding tire sizes.

 

I will be getting new rubber for my 17" ATP 5 spoke wheels in spring. The wheels are 7.5x17 et 52 and 8.5x17 et 52.

 

I will be running them with 5mm spacers on all 4 corners.

 

What do you suggest? While I would like to drop the front a little or raise the rear a little to change the stance, I am reluctant to mess with the ground clearance or the speedometer accuracy. The stock suggestions are based on slightly different rims and may or may not apply to these rims.

 

Thanks!

 

Matt

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[Peter B]

Tire News.  I was going to buy the Conti-DW's for my Audi A6 Avant.  I found they have a new tire that is targeting the Mich Pilot Super sport.  The new tire is the Conti ExtremeContact Sport.  I got a set and so far I'm impressed.  Great grip and no muchy feeling, like the DWS and to a lesser extent DWs.  I'll comment more as I get more miles on them on the Audi.  

 

Best part is Conti made them in the 968 17" rims sizes.  I wish I had waited on getting the Mich PSS.  I thought I'd share the review and the news.  

 

They are also cheaper.   Set of 4 is 570$ + ship and so forth.   

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[tejon007]

Well, I like Toyo tires (have them on my 914) and Hankook. 

 

I'm running Hankook Ventus V12 Evo2 255/35SR 18 on rear & 255/40ZR 18 on the front of my 968...but, I've used the R-S3s many times on one of my other cars.  I think the R-S3s are a very good performing tire and value, but they don't last even 20,000 miles on the street...

 

You can get the Hankooks for a 17" rim size & the V12s last longer.

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