[New Tire Test] Bridgestone’s Ultimate Street Tire! A Track Comparison and Review of the “Battlax Racing Street RS12” vs. Its Predecessor, the RS11

Bridgestone’s newly released “BATTLAX RACING STREET RS12” is the successor to the previous “RS11” model and is a premium sports tire designed to handle everything from winding roads to track driving.In this article, we conducted a comparative test ride with the RS11 at Tsukuba Circuit Course 1000 to uncover the tire’s evolution.

⚫︎Summary: Editorial Department ⚫︎Photography: Hiroyuki Ogawa / Editorial Department
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Tester: Webike Staff - Kusuyama

In charge of this test report is Webike staff member Kusuyama, who has extensive experience in tire testing. He also has a wealth of experience competing in amateur races and owns the test bike, a CBR600RR. This time, he even handled the tire change!

Bridgestone’sStrongest Dry Gripfor Public Roads

BRIDGESTONE BATTLAX RACING STREET RS12

The development theme for the RS12 was to deliver the highest dry grip of any Bridgestone tire designed for public roads.To achieve this,thecompound, tread pattern, and structurehaveallbeencompletelyredesignedfromthe previous model,the RS11.

First, while retaining the “3LC segmented structure”—which uses different compounds for the tire’s center and shoulders—from the RS11, a newly developed racing compound has been incorporated into the shoulder area.Furthermore, by allocating a wider section of this compound to the front shoulder and a narrower section to the rear shoulder, the tire achieves both straight-line stability and high cornering grip. In particular, the rear tire significantly reduces surface roughness caused by wear, minimizing any loss of grip even after repeated laps on the circuit.

A new race-derived compound has been adopted for the shoulder area (red section).

The newly designed tread pattern completely eliminates grooves from the shoulder area on both the front and rear tires, resulting in a slick edge. This significantly increases the contact patch during cornering compared to the RS11.

Furthermore, the front tire marks the first time Bridgestone has adopted the "HE-MS BELT"—based on its track record in the EWC (Endurance World Championship)—in a production tire.Compared to the conventional MS BELT, the belt material has been changed to a more elastic one. This maintains uniform contact pressure even when load is applied during braking, improving road-following performance and contributing to stable grip when entering corners.

Thanks to these changes, its performance on the circuit surpasses the RS11 in every respect. Circuit tests have shown a 0.7% reduction in lap times, and grip degradation over multiple laps has also been minimized.

While the RS11 had slight grooves on the shoulder, these have been completely eliminated on the RS12. The groove ratio in the shoulder area has been significantly reduced.

The HE-MS BELT, a first for BS’s consumer tires, incorporates a highly elastic material in the tire’s belt. It maintains uniform contact pressure even under high loads, delivering stable grip.

It outperforms the RS11 in every aspect, including dry grip. In a comparative test at the Pannonia Ring circuit in Hungary, it reportedly achieved a 0.7% reduction in lap time (test vehicle: BMW S1000RR).

Supple, with outstanding cornering performance,and quick to warm up!

The comparative test between the RS12 and RS11 was conducted at Tsukuba Circuit Course 1000 using a Honda CBR600RR in ST600 specification.First, we ran two 20-minute sessions on the RS11, then switched to the RS12 and ran two more sessions. Assuming participation in a track day where riders drive their own bikes, tire warmers were not used.

The bike used for the test was a 2012 model CBR600RR. It is a race-spec machine designated as an ST600 model.

We compared the RS11 and RS12 under the same conditions on the same day. We mounted them on the spare wheel and brought them to the Tsukuba 1000 race.

RS11: Shows its true potential with aggressive weight control

On the first run with the RS11, it was somewhat difficult to gauge front-end grip, and the rear also experienced a prolonged slide when exiting the final corner. For the second run, I lowered the tire pressure slightly below the manufacturer’s recommended level (*),which allowed me to feel the tire’s true grip. I was then able to brake late into the corner and generate strong cornering force.

My best lap time on the RS11 was 37.120 seconds. However, at that pace, the front end exhibited a bouncy behavior, and there was also a slight slide at the rear.While this could likely be resolved with suspension adjustments (which we did not perform this time as we prioritized testing), I was left with the impression that the RS11 truly demonstrates its true potential through aggressive riding techniques—such as intentionally squishing the tires with hard braking to apply load.

*Please note that any changes to the manufacturer’s recommended tire pressure are at your own risk.

The RS11 gives the impression that it truly shines with aggressive riding that applies substantial load.

By intentionally holding the brakes when entering a corner, you can generate strong cornering force.

RS12: Great cornering and easy to handle!

Building on the results of the RS11, the RS12 took to the track with tire pressure set slightly lower than recommended and delivered a completely different feel from the very first lap. Even at cruising speeds, there were no fine vibrations, and it felt completely safe. When approaching corners, the front end turned in cleanly even without holding the brakes.

Furthermore, if you squeeze the brakes harder on entry, you can feel the entire tire flex, and the intense camber thrust delivers overwhelming track-holding ability.It corners so well that the racing line itself shifted further inward compared to the RS11.It provides reassuring feedback at all speeds, offering a level of ease that benefits everyone from beginners to experts.

Its warm-up performance is also astonishing.After just four laps from fresh, it hit the 37-second range—on par with the RS11—and by the second run, I was able to lean it over so far on the second lap that my knee was scraping the ground. The ability to immediately ride at a high pace without tire warmers is an immeasurable benefit for riders who drive their own bikes to track days.

Incidentally, the RS12’s best lap time was 36.733 seconds, achieving a lap time reduction of about 1%. The supple feel, reminiscent of slightly lower tire pressure, was impressive. Moreover, even while lapping at a pace in the low 37-second range, it showed absolutely no signs of slipping, maintaining a high level of confidence throughout.This is likely due to the benefits of the race-spec compound.

The RS12 allows the front end to turn in cleanly without holding back on the brakes. Its ease of handling shines regardless of speed.

By deliberately testing without tire warmers, we were able to confirm the RS12’s excellent warm-up performance. This is a reliable feature for those who drive to the track on their own.

Highly recommended for vehicles equipped with RS11 tires as original equipment

Furthermore, upon inspecting the tread surface after driving, while the RS11 showed signs of roughness due to tire spin, the RS12 maintained a very clean wear pattern—likely because it consistently gripped the road surface without slipping. This suggests we can have high expectations for its longevity when enjoying repeated sports driving.

Also,whilethe test car used for this evaluationwas an ST600 specification with modified suspension, it felt like the RS12 would be able to deliver high performance even with suspension settings close to stock or tire pressures adhering to the manufacturer’s specifications for the user base it targets—those engaging in both public road driving and track days.The evolution from the RS11 is immense, and the result lives up to Bridgestone’s claim of being a next-generation premium sports tire.

Incidentally, while the RS11 was selected as original equipment for new supersport models such as the Yamaha YZF-R1/R9 and the Kawasaki Ninja ZX-10R (previous generation)/Ninja H2, the RS12 is the perfect replacement for these vehicles.As a natural evolution of the RS11, this tire should offer outstanding performance from the street to the track.

The RS11 after two 20-minute runs at Tsukuba 1000. Wavy wear patterns are visible on the shoulder of the rear tire.

The RS12 after two 20-minute runs. While it posted faster lap times than the RS11, there was very little wear on the shoulder.

RS11. Both front and rear tires show short grooves carved into both shoulder areas.

RS12. With the grooves gone, both shoulder areas are now completely slick.

RS12 Size Lineup / Price

<Front>
120/70ZR17 M/C (58W) TL: 31,350 yen

<Rear>
180/55ZR17 M/C (73W) TL: 46,420 yen
190/55ZR17 M/C (75W) TL: 48,510 yen
200/55ZR17 M/C (78W) TL: 51,370 yen

*Available in 1 front size and 3 rear sizes

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