The BST carbon fiber wheels...
The BST carbon fiber wheels provided a significant weight reduction compared to the stock wheels. Add the Brake Tech Ceramic Matrix Composite brake rotors, which provide incredibly strong levels of stopping power, and the handling characteristics of our ZX-10R changed dramatically.
By now you've probably read our 2010 literbike shootout in last month's issue. You'll also notice that our previous class champion two years running, the Kawasaki ZX-10R, didn't quite have what it takes to edge out the competition for a third time. Call us stubborn, but we wanted to see what we could do to the Ninja to reclaim that euphoria we had when we named it the class champion the past two years. Short of putting the bike on a complete diet and stripping away all non-essential bits, the simplest method we could think of to help the bike transition was a set of carbon fiber wheels from BlackStone Tek, better known as BST. It's no secret that the benefits from reducing unsprung weight increase exponentially with speed, so we decided to up the ante even further with a set of Axis Ceramic Matrix Composite rotors from Brake Tech. The Holy Grail when it comes to braking performance, these rotors provide numerous advantages over the stock steel rotors. And lastly, not that the ZX-10R needed any more power, we added an M4 full exhaust system to reduce weight nearest to the bike's center of gravity.
We wanted to expose the Kawi to the same conditions we faced when we originally complained of its handling woes. The crucible for our project bike would be "The Fastest Road in the West," or Willow Springs International Raceway, in Rosamond, California during a trackday with our pals at Trackdaz (www.trackdaz.com). Despite the nickname, this high-speed track also features hard braking zones and quick transitions that'll expose our ZX-10's agility in no time.
Vortex provides the rear sprocket...
Vortex provides the rear sprocket for the BST wheels as the standard ZX-10R unit isn't compatible with the mounting pattern-a feature we're not keen on. Fortunately, Vortex can provide a number of different gearing options and in different pitches as well. We chose to stick with the stock chain and gearing combination.
With our ZX-10R having a rough time transitioning from side to side quickly, a call to Brock's Performance, the sole distributor in the U.S., landed us a set of BST carbon fiber wheels. Its monocoque construction means there are no seams or joints-the wheel is one solid unit. Further reduction in weight is realized with the hollow spoke design. BST designs and manufactures the wheels to have the bulk of its weight concentrated in the hub for a significant reduction in rotational inertia. Not only does this help the bike steer quicker, but it also improves acceleration and deceleration. Despite its lightweight construction, BST ensures its wheels to be strong enough to endure the rigors of street use, not just track duty. Unlike other lightweight wheels, however, BST wheels don't retain the standard sprocket mounting pattern of the donor motorcycle, meaning a specific sprocket from Vortex is required. At $3750.00 for the wheels and another $74.95 for the sprocket, the upgrade is by no means cheap.
Before we mounted tires on them, we weighed the front wheel at six pounds and the rear wheel at just over 8.5 pounds, sans tires. Fit and finish are what you'd expect from high ticket items like these with no wheel weights required for balacing. On track the difference in transitional effort required by the rider was noticeable, especially in the quick flick from full left lean exiting the downhill, off camber turn five, which immediately leads uphill to a flick right up and over turn six. In fact, the wheels might have worked too well as the lack of weight up front caused ferocious headshake driving out of turn six. Something the stock steering damper had no chance of quelling, even when set to its stiffest setting. Headshake aside, a side effect we didn't take into consideration was the reduction in rider fatigue after a full day at the track. Our testers noted they were simply less tired after riding. So are they worth it? If you've got the money to burn then by all means. You'll be glad you did. For the rest of us, carbon wheels will just remain high-dollar luxury items.
Because we couldn't leave well enough alone, we wanted to make sure our ZX-10R had every advantage possible in the agility department. To do that, we replaced the standard brake rotors with fully floating Ceramic Matrix Composite pieces from Braketech USA. Using now de-classified Stealth Bomber technology, Braketech claims these binders to outperform even carbon/carbon systems. Among the many benefits over carbon is that CMC rotors work with standard calipers. And depending on the application, Ferodo can provide appropriate pads, sold separately of course. Second, they are not thermally sensitive-meaning you don't have to drag the brake lever to get the brakes to optimum working temperature-one can feel the advantages from the first squeeze of the lever. This does not mean the pads and rotors don't require a proper break-in, however. In fact, according to Braketech, bedding of the pads and rotors is even more important with the CMC system. They're also fully functional in the wet, unlike carbon brakes, eliminating the biggest hurdle with the latter and the need to swap back to steel discs when the weather turns sour. And of course, these CMC discs weigh next to nothing: both front rotors combined tipped our scales at 3.16 pounds-that's almost half the weight of the original rotors.
No doubt this helped our bike turn-in easier, but we're convinced the combined light weight of the wheels and the ferocious stopping power of the CMC rotors slowed our ZX-10R at a very impressive rate. Then again, this was never a complaint we had with the stock braking system anyway. Initial bite is soft with the SRAC pads provided by Ferodo-the suggested compound for hard trackday/racing usage-but braking power progressively gets stronger the more pressure is applied to the lever-to the point that it challenges you to push your braking markers further than you ever have before with steel rotors. The higher coefficient of friction with the CMC/SRAC combination improved stopping distance compared to the stockers noticeably. Even after numerous laps, the brakes never showed any signs of fade, in fact getting stronger as the day wore on. Despite the material, the brakes work as claimed and don't require any "warm-up" time at all. And this was all from standard rubber lines. At $1250.00 for the rotors and an extra $77.00 for the pads, these brakes are not cheap, but that's the price for technology.
For the rear we decided to...
For the rear we decided to leave the stock rear brake disc alone as its weight savings are miniscule. The M4 exhaust includes a hanger that attaches to the stock passenger foot peg assembly; meaning if you want this system, you're going to have to give up two-up rides.
Like we said earlier, we decided to up the ante a little with a full titanium exhaust system from M4 Exhausts weighing a tick over 11 pounds. M4 claims power advantages of up to 16 horsepower and three foot-pounds of torque. We'll document our real-world findings in part two of this saga as we've got a few things still up our sleeves for this bike.
Unfortunately, this is where the advantages end. We experienced issues with our system as one of the header pipes was significantly misaligned with the rest, causing a faulty seal at the cylinder head. Once we got the resulting exhaust leak sorted, the next issue was an improperly aligned collector that pointed directly at the shock linkage. Some backyard engineering of the mid-pipe was in order to allow it to mount to the collector without being damaged by the shock linkage while riding. For $1,097, these flaws are simply unacceptable. All told, the full system did feel a bit more powerful according to our seat-of-the-pants gauge, and power delivery did seem more manageable with less peaks or flat spots.
As a whole, each of the three modifications we performed worked as advertised to make our ZX-10R handle like we remember it the past two years. But the bike still has one major flaw: some of our testers during our literbike test complained of a lack of rear ride height. With the lightweight wheels this problem rears its ugly head again. This just goes to prove you can't change one aspect of a motorcycle without it affecting something else. With that said, stay tuned for stage two of project ZX-10R as we throw more goodies on it to see if we can realize its true potential.