Tires / Tyres... Need some guidance

[strawfordt]

Hello all.

I have read a lot of the posts concerning tire selection but am slightly confused and need some more help.

I drive a 1998 Boxster that as far as I can tell has the 17" wheel option. I live in Canada and only drive the vehicle in spring summer and fall. I never drive in weather under 50deg F and rain driving is very limited also.

I gather from what I have read the Michelins are the right choice for most boxsters. I wonder if this is true for my conditions also?

My next question is the type of Pilot Sport that I should be buying. Some of the shops are trying to sell my Michelin Pilot Sport A/S. Seems to me that this is an all season version of the Pilot Sport. Does anyone have an opinion on this recommendation? I looked into the Pilot Sport PS2's and it would appear that the PS2's will not fit my front wheels My current Bridgestones are 205/50R17 on the front and 255/40R17 on the rear. how can I get PS2's all around or is there a better idea?

I know squat about the sizing and the selection of tires and would appreciatew some guidance.

Thanks

Edited May 8, 2008 by strawfordt

[kabel]

There are at least three version of the Pilot sport series the Pilot Sport A/S (All Season), Pilot sport, and the Pilot Sport PS2. Either of the last two would suit your needs in my opinion.

You can also go plus size on the fronts and have a 225/45/17 put on. Lots of us are now running the 225 on the front, I for one feel the car handles better with that size. As you mentioned there are multiple threads about "which tires are best" it's all very subjective and most based on little back-to-back comparisons.

I'm no expert in the field but I have driven on a variety of tires on boxsters and on miatas and I've quoted another member many times before from another thread and I agree with him when he said:

I have PS2's on my car now and unless I am flat broke, I am going to keep putting them on my boxster. Excellent traction in all sorts of weather...

:D

[djantlive]

did you check out tirerack? you'll have all the tires choices listed with reviews to compared with. like kabel said, you can run plus size on front if 205 is not available in PS2. plus size can be chosen on tirerack as well.

besides PS2, there are other high performance tires such as RE050, PZero, S02 that are N spec (porsche approved).

[grover]

You can also go plus size on the fronts and have a 225/45/17 put on. Lots of us are now running the 225 on the front, I for one feel the car handles better with that size. As you mentioned there are multiple threads about "which tires are best" it's all very subjective and most based on little back-to-back comparisons.

Hey, this opens up a SLEW more tires that just don't come in 205/40-17, including Star Spec, RE-01R and Pilot Sport PS2. Is there any drawback to the larger tire? Does is mess up the speedometer/odometer or screw with the PSM at all? Is there any difficulty getting 225/45-17s on stock rims? Are new spacers and bolts required?

FYI, if anyone is interested, I compiled a list of Tirerack's testing of high-end tires:

Looking strictly at Tirerack's dry track scores (225/45R17 on a 2008 BMW E90 325i Coupe for the first 4, and a 2006 for the others):

8.67 Dunlop Direzza Sport Z1

8.64 Yokohama ADVAN Neova AD07

8.64 Dunlop Direzza Sport Z1 Star Spec

8.58 BFGoodrich g-Force T/A KD

8.39 Kumho Ecsta MX Extreme Performance Summer

8.30 Goodyear Eagle F1 Asymmetric

8.26 Bridgestone Potenza RE-01R

8.24 Sumitomo HTR Z III

8.23 Michelin Pilot Sport PS2

8.20 Bridgestone Potenza RE050A Pole Position

8.15 Continental ContiSportContact 3

7.96 Yokohama ADVAN Sport

7.46 Hankook Ventus R-S2 Z212

0.98-0.99g BFGoodrich g-Force T/A KD

0.98g (=) Yokohama ADVAN Neova AD07

0.98g (-?) Goodyear Eagle F1 Asymmetric

0.98g (-?) Kumho Ecsta MX Extreme Performance Summer

0.97g (-?) Dunlop Direzza Sport Z1

0.96g (+?) Dunlop Direzza Sport Z1 Star Spec

0.96-0.99g Bridgestone Potenza RE-01R

0.96g (-?) Michelin Pilot Sport PS2

0.95g (+?) Sumitomo HTR Z III

0.95g Hankook Ventus R-S2 Z212

0.94-0.96g Bridgestone Potenza RE050A Pole Position

0.94-0.97g Continental ContiSportContact 3

0.92g (+?) Yokohama ADVAN Sport

They unfortunately switched cars between some of the tests, and tires they tested twice (even on the same car) scored differently in subsequent tests, but I'm hoping the overall numbers are at least reasonably comparable for a cross comparison. Given the apparent +/- 0.04g margin of error in Tirerack's testing and the 0.04g spread between 11 of the 12, it's hard to really say any of these tires is a clear winner or loser per Tirerack's testing. The Neova's did exactly 0.98g in 3 tests on two different cars, though, so they're at least consistent!

Edited April 3, 2009 by grover

[Topless]

Ok. Now you have reams of raw tire data. Time to apply this data to your driving habits and pick a winner. All tires are a compromise. There is no 1 tire that does everything well. All have a mix of grip, longevity, road manners, noise, and price. Here are three driver profiles you may find useful:

Type 1 Driver- Car is a daily driver doing 10-20k miles/yr. Cost, longevity, and road manners are more important than ultimate grip. Nexen 3000, Sumitomo HTRZ III, or a performance all season tire would be a good choice here. They don't cost much, have good grip, ride nice and last a very long time.

Type II Driver- Car is a weekend joyride with occasional Auto-X, track days. 5-10k miles/yr. Max grip and road manners are more important than cost or longevity. Mich. PS2, Bridge. RE050A Pole Position are good choices.

Type III Driver- Car is a weekend warrior. You live for track days, Auto-X and canyon carving. 3-6k miles/year. You take your track days seriously but don't want to drive around town on R-comp tires. Max grip is everything. Ignore the cost or longevity. You don't care if the ride is more harsh or a little louder. You are in a PCA points race in Stock class and you want to win. Dunlop Direzza Star spec, Yoko AD07, or Bridge RE01R, are your best choices here.

Yes a 225/45/17 tire will mount on your stock rim with better grip and no fitment issues.

I hope you find some clarity in this. Good luck and happy shopping!

Edited March 23, 2009 by Topless

[grover]

Yes a 225/45/17 tire will mount on your stock rim with better grip and no fitment issues.

I hope you find some clarity in this. Good luck and happy shopping!

Great to know, thanks! Would a 245/45-17 fit? It's 7mm talled, and a half inch too big for the rim, but oh so tempting for the extra width... Edited January 16, 2009 by grover

[Topless]

Yes a 225/45/17 tire will mount on your stock rim with better grip and no fitment issues.

I hope you find some clarity in this. Good luck and happy shopping!

Great to know, thanks! Would a 245/45-17 fit? It's 7mm talled, and a half inch too big for the rim, but oh so tempting for the extra width...

It might fit without rubbing but there are downsides: You will need at least an 8" wide wheel to get the benefit of the wider tread. The taller tire may disturb your PSM/ABS because the rolling circumference is so different than your rears. Hydroplaning through standing water will be much more likely with a 245 up front. There is also an issue with failed power steering systems on tracked cars with 245 tires on the front.

The tried and tested sizes in 17" are 225/45/17F, 255/40/17R for street use and Boxster spec racing.

Or a track tool with 245/40/17 all around. (Not recommended for a novice as the rear of the car will rotate more easily and hydroplaning is more likely in the rain.)

[grover]

To update (04 Boxster S), I bought the Star Specs, 225/45-17 front and 255/40-17 rear. Autocrossed it over the weekend and WOW, what a difference! It drives like a completely different car now. The understeer is gone, replaced by just enough oversteer to help rotate through the corners, and I can really feel the difference in grip over the "old" BFGoodrich g-force sports she had on when I bought her. I went from 50th percentile every race last year to 6th fastest raw time (out of 76 ppl) in the club, and just 4.8 hundreths of a second from a top 10 PAX finish.. Of course, it was pouring down rain and the tires were brand spankin' new which helped (my class assumes r-comps), but still, I am VERY happy with the Dunlops AND the wider front tires :) I gave the PSM quite a workout, too, lol... Never had to worry much about oversteer before!

Now all I have to do is figure out what pressures to use... and how to drive better! :drive:

edit: somehow wrote 255/55-17 rear tires and didn't catch it... I went 20mm wider up front, but did stick with stock 255/40-17 rear dimensions.

Edited April 3, 2009 by grover

[Topless]

Thanks for the update Grover. My current PS2s should be toast in about two months. I will seriously consider those Dunlops.

[ekam]

I ordered the Z1 Star Specs couple of days ago... should be able to put them on when weather gets warmer which should only be weeks away.