Bridgestone developed the S21 to achieve what every commuter/canyon carver looks for—a tire that can hold its own on a track, while still being reliable in the wet and not needing replacement every 3,000 miles.
Claiming better handling in the dry and a 30% increase in life over its predecessor, the S20 Evo, the S21 is a step forward in performance for Bridgestone. These advances have been realized through Bridgestone’s Ultimat Eye. In Bridgestone’s words, “ULTIMAT EYE™ reproduces highspeed riding conditions in the laboratory that are equivalent to those of an actual vehicle, enabling tire contact surface behavior to be visualized.” This translates to being able to run tires up to 248 MPH with crazy lean angle, while monitoring the behavior of the tire in a controlled setting.
But what does this mean to us, the laymen? A perfectly controlled environment is not what anyone lives in, and it sure as hell doesn’t describe the rough roads, potholes, highways, cold mornings, and 20 minute commutes I put my tires through. Ultimately, I want a tire that can handle the abuses of day-to-day Pacific Northwest torture AND end a track day sticky, hot, and coated with rubber boogers.
Is this possible? I think so. Does the S21 do it? Time will tell, but it is off to a very good start. While I make no claims to be a tire expert, or a proficient racer, I will say that I have enjoyed my time on the S21s. With the feeling that you are definitely not on a touring tire, via ample turn-in and ability to warm up quickly, the S21s definitely perform the way of a track-focused tire and prove that whatever money was spent on Ultimat Eye was well worth it for track performance. That being said, after putting them through 2,000 street miles and five track days (equalling roughly 750 miles), I am happy to report that I have plenty of tread left. This is all on a sport bike weighing in at 487 lbs wet, with 100 bhp and my 200 lbs hanging on for dear life.
The tread life is the key feature that is often speculated, but rarely documented. Below is my experience thus far:
50 miles and one track day
1000 miles and three track days
2000 miles and five track days
Photos Via: Essential Moto