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Bridgestone’s New RE-71R; The New Street Tire Track Day King? PART ONE

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Bridgestone’s Potenza RE-71R

 

At a recent SpeedSF Track Event day at Mazda Raceway Laguna Seca, a participant brought up the old Bridgestone test article. “Hey, you guys tested the RE-11A awhile back. How come you haven’t told us about the new RE-71R yet?”

We recalled a conversation had with our friends at Bridgestone during the previous RE-11A test in which they alluded to a new tire further down the product pipeline. This was a tire that they claimed would be much more interesting, but likely a few years away from being released. This got us thinking; was the RE-71R THE tire that the Bridgestone guys were telling us about? We had to find out for ourselves. We contacted our partners at Bridgestone, told them what we wanted to do and they agreed to provide us with a set of tires for us to test.

A few weeks later, a new set of 275/35/18 tires were ready to be mounted. Instead of testing them on an unfamiliar autocross track, we instead elected to test the tires at a venue and a method we do know a lot about; turning fast laps on a road course. Andrie prepared the tires for his street and track-driven BMW E46 M3; a mildly-prepared passenger car with minimal modifications other than suspension work still suitable for daily driving.

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Fresh RE-71R tires ready to go, mounted on identical wheels

The tire Andrie would be testing the RE-71R against would be his personal favorite street tire; the Dunlop Direzza ZII Star Spec. While some track-day drivers prefer the Bridgestone RE-11A, the Hankook RS3, Advan AD08 or others, Hartanto has always preferred the Star Specs. He should know, too; during Prima Racing’s foray into time attack, Hartanto extensively tested every street tire in the 180-200 treadwear category, notching hundreds upon hundreds of laps in the process. Throughout it all, the Star Specs topped his list as the fastest, most consistent tire.

The site of the test would be none other than Buttonwillow Raceway Park’s CW13 layout; the very same configuration used as the US-based time attack measuring stick and a track which also plays host to numerous club races throughout the year. We would run the incumbent Dunlop Direzza Star Spec II in a warm up session, plus run the tires again in the following session, thus giving Andrie back-to-back sessions with the Star Specs and establishing a benchmark.

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Buttonwillow’s CW13 Layout

 

The weather was on the cooler side, with ambient temperatures in the low 50s. Hartanto set a 1:59.698 in his mildly-prepped E46 M3 in the warmup session with the Star Specs.

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Photo courtesy of CaliPhotography

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First session out; running on Star Specs

Hartanto then ran in the following session to get a few more laps on the Dunlops, this time going even faster with a 1:58.994.

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Photo courtesy of CaliPhotography

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Second session, back to back with Star Specs

Here’s where things got interesting;

In the third session, Hartanto switched over to the RE-71R tires. In his first session on the new tires, he clocked an astonishing lap time of 1:56.247.  We were all taken aback. “There’s still more time in these tires,” Hartanto exclaimed. “They drive like an r-comp tire. I need to change how I drive with these tires now. I am really impressed. They’re pushing (understeering) more than I’d like them to, but that’s also because I wasn’t expecting this level of grip.”

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Photo courtesy of CaliPhotography

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First session on RE-71R and we’re VERY impressed

With the next session, Hartanto pushed the car harder to get a better feel of the tires’ limits, yet kept his times within the same range. Unfortunately, flags cut the session short. Of his three laps, he was still able to register a 1:56.563 lap. Andrie was determined to go faster, convinced that there was more pace in the tires.

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Photo courtesy of CaliPhotography

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Flag-shortened session on RE-71R

Hartanto managed to run one more session on the RE-71R rubber during the SpeedSF Challenge session. During this extended session, Hartanto and the Bridgestone-shod BMW M3 rattled off a number of remarkably fast laps, two in the 1:55 range, with his fastest time a 1:55.468. “This behaves much more like an r-comp tire. I’m really surprised,” Hartanto exclaimed, shaking his head in amazement.

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Photo courtesy of CaliPhotography

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SpeedSF Challenge session with RE-71R

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“I anticipated a slight improvement. Most of these tires are all pretty close to each other. The RE-71R is a significant step above. The lateral grip and the braking are remarkable for this type of tire. 3.5 seconds is a LOT of time. There’s no other way to get around saying that. It’s substantial,” Hartanto remarked.

“That being said, around Buttonwillow, the car is loaded up nearly all of the time, so an incremental improvement in grip is magnified over the course of the entire lap. I would like to try driving these again at a track like Laguna Seca and see how they compare to another tire, now that we’ve seen how they stack up against the Dunlops.”

Not only were the tires a marked improvement, they were fast enough to net Andrie a surprise first place finish in the SpeedSF Challenge time trial and set a new record for his class at Buttonwillow’s CW13 configuration.

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Andrie is all smiles with his FOF Class trophy

Are Bridgestone’s RE-71R tires the fastest non-competition performance tire currently on the market? Based on the results of this simple test, probably. Was it difficult to compose this story without it sounding like an op-ed piece? Without the lap times to support the content, it would have been difficult, given the difference in performance. Hartanto’s observation about the nature of Buttonwillow’s layout skewing the lap time delta is worth noting, however the fact still remains that the RE-71R tires were noticeably faster.

All of us at Prima Racing would like to extend a huge thank you to Bridgestone Tire for allowing us the opportunity to put their new Potenza RE-71R tire to the test. We would also like to say thank you to SpeedSF Track Events for allowing us to carry out the test during one of their track days.

Next up, Prima Racing will test the tires again. This time, the test will be carried out over a two-day track event at Mazda Raceway Laguna Seca where we will examine the durability over extended lapping and multiple heat cycles. Stay tuned as we put the RE-71R tire up to another head-to-head test; this time we’ll up the ante by making a direct comparison to a very popular R-compound tire.

Be sure to follow Andrie Hartanto on Facebook to stay up to date on all of the latest Prima Racing developments.

To join us at one of SpeedSF’s upcoming track events, sign up at their website, http://www.speedsf.com/.

Lastly, for more amazing details on Bridgestone’s Potenza RE-71R tires, check out the link here, Bridgestone Potenza RE-71R

Part Two is up here Part 2 Bridgestone RE71-R test