[motorcyclistonline] - MC Tested: Bridgestone RS10 Motorcycle Tires

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Performance Tires, Purpose-Built for Small Bikes


Smaller bikes like the KTM RC390 are lighter and less powerful than their 600 and 1,000cc counterparts, so it makes sense that tires for small bikes are built differently than tires for larger bikes. While the rest of the RS10 lineup carries a W speed rating (up to 167 mph), these RS10s have a lower H speed rating (up to 130 mph) and lower load rating as well. That means the carcass, sidewalls, and tread are more flexible. These H-rated tires also have a single-compound tread as opposed to the three tread compounds found on the larger W-rated tires.




One of the exciting perks of being a journalist is that you occasionally get to test prototypes or not-yet-released products. Such was the case with Bridgestone’s new RS10s, which the company sent me ahead of the tires’ official release for some early feedback. Now that the tires are publicly available I’m free to share my findings.

The KTM’s stock Pirelli Diablo Rosso IIs are solid performers and premium for the class, but they’re too stiff for fast track riding, as I discovered during our Small Sportbike Tire Test (click here). The tires that won that shootout were Bridgestone’s S20 Evos. Those tires are touted as hypersport street tires, and they’re ideal for fast street riding and the occasional track day.

These RS10s (the RS stands for “Racing Street”) are more performance-oriented buns that Bridgestone says are stickier than the S20 Evos and may even be suitable for racing. To see just how well the new rubber works, I levered a set of RS10s onto my long-term KTM RC390 and headed out to Chuckwalla Valley Raceway.

If you just want to know how the RS10s stack up to the S20 Evos, then here you go: The RS10s offer considerably more grip and better handling. Both traction and feel/feedback are improved over the S20 Evos, and I was able to turn some respectable lap times—about 2 seconds faster than on the S20 Evos. Below is some onboard video I recorded during the testing day with the RC.


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The rear is definitely up to A-group track day riding and likely racing as well. I had very few slides—all of which were bump induced—and when the rear slid it did so progressively and hooked up again immediately. On smooth pavement edge grip is fantastic and the tire was capable of handling full throttle at full lean. Tread wear was very good despite Chuckwalla's brutally abrasive surface, and I suspect the tires would endure another two or three track days. Granted, the weather peaked at just 65 degrees during my test, so wear may be more accelerated and grip may be different during hotter weather.

The front tire worked similarly well, but due to front-end feedback issues inherent to the RC390 I wasn’t quite as comfortable testing the front tire’s limits. Regardless, I had much more confidence in the front end than before, and even if feedback wasn't spectacular grip proved good and I was willing to simply trust the tire and flick the bike into corners. Again, the only slides I experienced were bump and/or rider induced. It’s worth noting that I’m running upgraded fork internals, namely fully adjustable Andreani cartridges that you can read about here.

The RS10s are original equipment on the Yamaha YZF-R1 and the new Kawasaki ZX-10R, but the tires I tested are distinctly different from what comes on those superbikes. Bridgestone says the biggest changes pertain to the tread compounds and carcass structure, which on these tires are basically softer and more flexible to suit the lighter weight and lower power output of smaller bikes.



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Used and Abused


This is what the rear RS10 looks like after 130 track miles. Not bad, right? That’s some nice, even wear. I was running the tires at 31 psi front and rear off the warmers, which netted me an off-the-track hot carcass temperature of about 135 degrees up front and 160 degrees out back. The tread wear looks really good given how abrasive the Chuckwalla track surface is.




The RS10s are available in 110/70-R17 front and 140/70-R17 and 150/60-R17 rears, all of which have an H speed rating. And because the RS10s are aimed specifically at track riding, they’ll only be available through race-tire vendors. Pricing is expected to be about $130 for the front and $173 for the 140 rear; the 150/60-R17 tire isn’t available yet and won’t be until later this spring.

As for the RS10’s race worthiness, I intend to put that claim to the test later this month when I run the RC390 in a few lightweight classes out at Chuckwalla. Check back later for more updates on the RC390 and more info on how the RS10s work when there’s a trophy on the line.

BRIDGESTONE RS10 TIRES

PRICE: $130 (front), $173 (rear)
CONTACT: bridgestonemotorcycletires.com

MC GRADE: A

Verdict: Sticky, durable, and fairly affordable, the RS10s are a great fit for anyone that wants to excise their small-bore sportbike on the track.





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