Pics & Review of My Bilstein PSS10 Lowered Red Turbo by cannga

6 minute(s) of a 612 minute read

11-26-2013

Tire Update

I now have had 4 popular tires in my Turbo and following is an updated evaluation for anyone interested:

1. Michelin PS2 (rear lasted about 12k miles)

2. Pirelli Corsa (this is an R compound tire, not normal street tire, lasted about 1 year/10k miles both front and rear)

3. Michelin Pilot Super Sport (lasted about 2 years, from 8/2011 to 2013, 20k miles!)

4. Bridgestone RE 11

What to consider in a tire, for the enthusiasts? 

1. Traction Self explanatory. More traction is better, but in general usually means shorter life.

2. Sidewall Stiffness (not talking about the rubber compound, but the *sidewall* construction)

Everyone knows about traction, the stickier the better of course; not frequently discussed is the importance of tire sidewall stiffness. The sidewall of a tire is a critical factor in suspension tuning; yes the tire is part of the suspension system and will affect body roll and weight transfer as much as stiffer springs! The tire therefore involves a trade-off, just like the rest of the suspension, and this trade-off again is about ride vs. handling. Stiffer tire is good for handling, but bad for comfort, and vice versa. 

*Street tire tends to has soft sidewall, and therefore is more comfortable, but will also cause the car to lean more in corners.

*R comp tire (Michelin Cup, Pirelli Corsa, Toyo Roxes R888 - made for track, but legal on normal road) has stiff sidewall and will noticeably decreases body lean. The difference is significant and easily noticeable, a night and day change. These tires of course should not be used on wet road and are not as comfortable.

Tire Comparion Michelin PS2 vs. PSS

Comparison is difficult because there was a gap in between my usage of the 2. But to best of my memory, all IMHO:

1. Equal road noise, equal comfort between PS2 and PSS. 

2. PSS has better dry traction (objective data, faster time at same track) per Michelin's claim, also per user's opinions, although this is obviously anecdotal and subjective.

3. PSS does seem to last forever - very true to Michelin claim. Remarkable for such a high performance tire to have such long tread wear and I believe best in industry (tirerack has tread wear rating for comparison, where PSS is among highest for hi-perf tire IIRC). I believe tread wear is where PSS is a game changer: everyone makes high performance tire, but to make it last so long and cost so little is where this tire shines.

4. PSS is about 10% heavier than PS2. 2-3 lbs per wheel. Increased unsprung weight means worse steering, handling, braking, accel., etc. Particularly bad at outer part of wheel, as in the tire. How important is 10%? Up to drivers.

5. In US, it's unheard of to have problems with warranty claim from using non N Michelin tire. I could be wrong but I would be shocked if there is such a confirmed case, based on non N tire alone.

6. PS2 is being phased out. If you have a non-fixable flat, finding replacement in future could be difficult.

7. PSS also has claim of special construction between inside and outside part of wheel for wet + dry handling. I believe wet performance is either very similar or might even be better per Michelin claim.

I think that all things considered, PSS is actually the better choice for reasons above. Basic tire construction doesn't change but the compound used in the construction of the tire has changed/improved and PSS has the newer technology (twaron, etc.). The only negative is the increased weight - about 2-3 lbs per weight, a touch disappointing since this is unsprung weight is at outer part of wheel, where it would cause the most harm to handling, steering, etc.

Tire Comparison R Comp (Pirelli Corsa) vs. Street Tires (Michelin PS2 and PSS)

General comments for those new to this: R comp tire is street legal, track oriented tire. They come standard in GT2 and GT3, as opposed to Turbo, which has street tire. R comp tire has 3 important characteristics:

1. The sidewall stiffness of R Comp's is significantly stiffer than street tires. Tirewall stiffness is critical because this is part of the overall suspension system. Tirewall stiffness is an integral part of suspension tuning and matching: stiffer tire means less leaning, less weight transfer.

2. The tire compound itself however is actually softer, wears much faster, and has significantly superior dry traction. The gain in dry traction is easily felt and utterly remarkable. It sticks like crazy glue and like magic. I was skeptical previously how much this gain is for amateur drivers - *NOT* anymore.

MHO: If you are nutty about motorsports, once in your life try R compound tire. This one should be on everyone's bucket list. :-)

3. Very poor wet traction and actually dangerous when it's wet. When it rains, all bets are off with these tires - you must slow down or better yet not driver at all IMHO.

4. When new, the Pirelli Corsa was reasonably quiet and not too stiff, but as the tire aged, it did become extreme noisy on freeway and was quite a bit stiffer.

Tire Comparison Bridgestone RE 11 vs. Michelin PS2 and PSS

RE11 is stiffer than PSS, about 1/2 way between PSS and cup tire with respect to stiffness. The stiffness reduces ride comfort but makes handling and steering so much more precise and fun. Body roll is reducing noticeably compared to PSS. The key is that the reduction in body roll makes the car corners as if it is on rails. This is the best my car has ever felt when it comes to steering and handling, short of the Pirelli Corsa cup tire (which I don't want to use because it is so dangerous on wet roads). Really the car corners beautifully with these babies.

Road noise is about same between RE 11 and PSS. Traction is close enough that without instrumented, professional-level testing, I doubt I could ever tell a difference. Wear: I don't expect RE11 to last nearly as long as PSS, which IMHO is a game changer with respect to performance tire: 20k miles in my Turbo - unprecedented.

Before you run out and order these tires, please note my bias: I place handling above all so I tend to sacrifice comfort a little more than normal people . I also live in a hilly/mountainous area so body roll has to be minimized for my taste. If you find yourself with same preference, I would recommend them without hesitation. I think of RE 11 as cup tire with less dry traction, but without the wet road danger ;-). Cheaper, sporty, SO MUCH fun!