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Features / 10-01-18

The Best of Both Worlds

Putting the new Bridgestone Potenza S007A to the test


By Georges B. Ramirez Photos by Bridgestone

 

I recently joined the posse that tested Bridgestone’s new POTENZA, the S007A.  We were based out of the magnificent city of Rome but headed south toward the Bridgestone Technical Center Europe, roughly 10 minutes before Aprilla. The facility was beautifully manicured and had multiple buildings that focused on the various elements of testing as well as manufacturing the prototypes. The plant tour brought us through several phases of tire development.

Initially, they introduced us to the rubber itself.  We interactively tested two balls that looked and felt identical, but were made of different compounds. One bounced like a super ball while the other barely at all.  Similarly, they were rolled down a small three-inch slope; one ball rolled a couple of feet while the other rolled right across the room, clearly ideal for the frugal motorist.

In the next room was the team that worked on the rubber at a microscopic level.  Here, they showed us how to detect various blemishes at different levels of magnification.  Apparently, the smoother or denser-looking it is, the better.  It reminded me of asphalt, as it is from the smallest hole that problems can start.

As for the practical tests, using data collected through the years, they create the initial prototypes on computers.  They then identify several areas of roads in Europe that can give them a broad spectrum of conditions and have people with different driving styles drive through them while a barrage of sensors and technicians record every little detail.

All this data also gets downloaded into all these machines in the testing rooms where they can repeatedly simulate the same test conditions. Added to this, they create the most extreme weather and temperature conditions in the test rooms.  This allows them to test the tires till they burst, shred to bits, or simply come apart.  Interestingly, when you look into the windows of these rooms, you see bits of rubber all over the place, evidence of the violent end to these tires.

In another instance, one particular machine simulates a 500 km/h test for supercars.  Supercars enter the 300 km/h and upwards realm, so looks like they got that covered as well.  Actually, an enlightening part of our initial briefing was that aside from the tires such as the S007A that are designed to perform on various sports cars, many of the automakers will have them make a variant “A specific” to one of their own car models.

And naturally, after all this, comes testing the actual tire on a test track. This facility had multiple tracks that all looked very impressive to me.  But, to my surprise, we were sent twenty minutes further south to the new Bridgestone Technical Center Europe Spa,  which was developed when they needed to expand the track facilities to accommodate higher speed testing. Now, this was really incredible.

So, let’s get started with the good part – the driving experience.  They divided us up into three groups, sending us off to three different exercise tracks.  I personally felt lucky with the order that was dealt out to us, as the size and speed of each course got progressively bigger and faster.  Initially, we walked over to what they called the “small lake” in English.   It is a purpose-built “Wet Track” with sections that are constantly wet from the ground level while other areas have water being sprayed into the air to simulate rain fall.

As the new S007A tire was designed for sports or performance cars, they had prepared two VW Golf R’s, which other than their paint color, were identical.  One was out-fitted with the new S007A and the other with its predecessor the S001, providing us with a direct comparison between the two.  There is no better way to notice subtle differences in the tires than to jump straight into the other car immediately after.

I started with the older S001 which was actually good. I was having a ball zipping around the wet track.  Fast switch-backs and sweeping bends mixed with tight and loose S’s splashing around was fun!  When I jumped into the other Golf R with the S007A, I was surprised, in spite of a clear explanation given to us earlier of the behavior characteristics that we could expect.

It had a combination of the improved grip and this extremely responsive steering characteristic that stood out at this point.  The car would start moving the moment you moved the steering wheel, and the improved grip lessened the amount of sliding in general, making me the driver work a lot less and technically making it easier for me to drive faster through the track.  I believe when they asked me my thoughts as I stepped out of the car, I summed it up by saying “It’s so precise!”

From there, we moved onto the dry track that was laid out in a huge open area, which they referred to as the “Big Lake.”  Paved with asphalt and the absence of anything to hit but the cones that defined the track, there was no holding us back!

Here we had two Audi TTs, and again, one fitted with the S001, and the other, the S007A. The track was primarily a series of varying winding turns forming a loop around this paved area. About midway through, there were two lanes on the right that end up at the same bunch of turns you started with. On the first run, you turn into a slalom lane, then on the second, you take the brake, evade lanes, and finally, you finish off with bigger and faster winding turns of the loop itself.

Again, I noted the similar characteristics of the tires, though it was especially evident in the straight line slalom because the moment you turn-in the slightest bit late or push out slightly too far, the error grows exponentially at every turn thereafter.  So, the precise characteristic of the S007A got me to the end of the slalom easily and without any issues.  In comparison, the spongier response of the S001 had me backing off and getting on my brakes by the last two turns of the slalom. Even on the faster turns, it was evident, the car with the new tire was quieter and didn’t push out as much. Its precision allowed for less backing-off or correction, but instead, it pointed into the corners better.  Like I said, precise, accurate, and just so much easier to drive fast.

The third and last exercise was definitely the most exciting one. The very “High Speed” track! A huge oval track with 36 and 37-degree banked turns and all.  They had told us that the instructor for this exercise was an ex-Formula One race driver by the name of Stefano.  I wasn’t quite sure as it had been many years ago, but I asked him “Are you Stefano Modena?”  Lo and behold, it was Stefano!  He actually raced with us in the Philippines in 1982 in what was then the JRC Kartway before becoming an F1 driver and he was now going to take us on the high-speed track in a 4-door BMW M3.  Awesome!

I have never been on an oval course nor severely banked corners for that matter, but I was surely glad it was him driving us around because it was extremely fast!!!  My initiation to the G-forces on the bank was more than I imagined. You are pushed down partly sideways, and God help you if you are not strapped in!  We were flying! We were still gaining speed in excess of 270 km/h before slowing down for the second banked turn.

As we exited this turn and entered an excessively wide straight, he calmly started weaving from one side to the other. It felt as though we were right on its edge, and yet, it didn’t feel unsettling.

Then on the last turn of our last lap, Stefano slowed it down and drove at the bottom of the bank.  Here, it was virtually flat and he purposely let the tail come out, gradually increasing the sideways posture before reeling it back in.  He did this repeatedly while calmly explaining to us what was going on and what to listen for.  I quickly blurted out the word predictable, and Stefano quickly corrected me and used the word progressive, which pretty much summed up the S007A perfectly.

This enables one to anticipate the amount of grip you are about to lose or gain, and that is certainly reassuring when you’re driving fast or on the edge. Some tires can grip really well and then at one point just snap on you. The progressive nature of this tire’s grip kind of gives you a “heads up” if you will, which provides that bit of time to react appropriately.

At the end of the test sessions, I asked their Consumer Tire Development Specialist, Kawakita Akihiro, how they were able to achieve this and still maintain a good level of ride comfort, as one normally compromises one for the other. He explained that there was a softer part between the tred and the Kevlar-reinforced side walls that worked like a bushing of sorts.  A nice eye-opener in that regard, and a novel way of getting the best of both worlds, definitely leaving me impressed.