Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/127975
the good work at Cycle News. You keep me abreast of the sport that I Jove. John Rolstead O'Fallon,IL And again Just a note to say that I very much enjoy reading Alan Cathcart's road tests and other articles. John Houtman Endwell, NY Normal bad? Paul Carruthers' comments about Doug Henry being normal ("Teardown," Issue #50, January 6) really tweaked me. It is this attitude and mentality (I think Webster defines it as NASCAR syndrome) that is eventually going to kill one of the greatest aspects of motocross and motorcycling. Motocross is one of the few avenues of life where people from all walks of life come together to enjoy something they have in common and love. Role modeLs should be admired for their accomplishment; and what type of pe0ple they are, not by their appearance. The last thing motorcycling needs is an "us vs. them" mentality - we have enough problems as it is. Come as you are, be what you are, and if the rest of the world doesn't like what they see, then screw 'em. Sam Kistler Denver,CO Normal good? I just read Paul Carruthers' piece called "Teardown" on Doug Henry. Paul, I beg to differ with you when you assert that Doug i n't better than anyone else - I believe he is. He is plainly a better person than many of the tattooed pseudopimps that have become the hotshoes of mainstream Supercross. And if I hear one more whiny-assed littLe punk crying about the power of the YZ400, I'm gonna find him and show him what a 500cc two-stroke roost is like. You never hear anyone saying, "Gosh, how in the hell does he wres.tIe that bea,t to a win? That thing outweighs my bike by 20 pounds." Or, "Man, I wish my bike would stall Like that so I wouLd have to kick the hell out of it if I fell off it." If it was up to me, and I'm glad it isn't, HeIUY would get next year's title on default - a a show of appreciation for ba ttling back from pure hell and coming back to kick some serious ass. It's really too bad there aren't more guys like Doug Henry around. Let's hope that Ricky Carmichael steers clear of the tattoo parlor, because maybe there's another classic racer right under our noses. Shawn McAtee Yorba Linda, CA Keep the sensors I am writing on behalf of the teams listed a t the end of tltis letter in regard to the AMA Pro Racing bulletin issued on October 27, 1998, specifically regarding the front-wheeL-speed rule change. It is clear that the AMA wishes to keep traction controL from being used in the Superbike class. It is also clear that the AMA wouLd Like to minimize the amount of refereeing of this rule. We are sympathetic with your position, but ask you to consider the following comments. In the AMA Superbike Tour, there are currently seven factory teams arid at leasb six support/privateer teams using onboard data-acquisition systems of some sort. RegardLess of the brand (EFI, Pi Research, Marrelli, 2D, Aim, etc.), all of the systems have common functions and a common use. One of the common features is the front-wheel-speed measurement. Front-wheel speed is pivotaL to the entire data-anaLysis process. Together with some form of inertiaL sensor, front-wheel speed is used to create a digital representation of the racing line or "track map." Subsequently., logged data is then related to this track map via the front-wheel-speed measurement. From this relationship (referred to as "positionaL data"), one can generate a broad spectrum of reports and plots for analyzing the otherwise insurmountable quantity of logged data. Vehicle speed and corresponding distance traveled is computed under the assumption of a fixed rolling radius. eglecting the dynamic behavior of the tires (deformation due to loading, tire growth, changes in compound properties, etc.), the rolling radius of the rear tire can change by 19 percent from upright to full lean. Factoring into the equation wheeL spin and rear-end drift/hop, it becomes readily apparent that tlle positional data derived from ilie rear wheeL is far too inaccurate for use in the anaLysis of vehicle/rider performance. The front tire is better in this respect, wiili about 12 percent variation, but it is still not ideal. By itself, frontwheel speed is only marginally suitable for determining vehicle speed and deriving positional data. We have painfully and carefully buiLt databases and associated empiricaL corrections, which make the front-wheel-speed measurement viabLe for use in assessing vehicle/rider performance. A motorcycle in motion on a race course is a highly dynamic and complex system. Given the mechanical complexity of this system, it would require a tremendous amount of empirical work to make a functional traction-control system regardless of the process used. Specifically, front-wheel speed is not a suitable process variable due to the dramatically unequal changes in rolling radius front to rear. Front-wheel lift augments the problem. There are several traction-control chemes iliat can be implemented on a motorcycle, none of which require wheeL-speed measurements. Here are five obvious ones: use of accelerometers/inertia sensors; use of torque/strain measurements; use of d/dt (rpm); optical ground-speed measurement; open-loop control as a function of rpm, throttle position, and gear position. Currently, none of the data-acquisition systems in use support bidirectional communication with the various manufacturers' proprietary engine- management systems. In fact, we believe that none of the data-acquisition systems even support one-way communication with non-aftermarket engine controllers. Let us stop for a moment and consider the privateer and his/her use of a data-acquisition system. Given that even the most prevalent privateer/support teams have maximized their limited resources (i.e., budget, parts, tires, person power, etc.), it seems iliat improving the rider's racing technique would be the route of greatest return. Wiiliout the support of tlle factory engineers and the suspension manufacturers, the privateer is left with a small but very useful core of data that he/she can interpret (rpm, throttle, gear, speed and position). Armed with this smalL core, the privateer can begin to analyze his/her performance, thereby improving an otherwise optimized package. Given the highly optimized nature of the Superbike class, it is crucial that the rider is up to speed before any significant setup changes are made. This effectively makes Friday's quaLifying session the first opportunity to gather useful data. Count out Sunday morning's warmup; it's too late at that point, and we are effectively left with one isolated session (Saturday morning) to get setup data for the race. This problem is augmented by the fact that certain changes (e.g., internal gear ratios) cannot be made between sessions, and must be left for the end of the day. We feel very strongly about this ruling and have made a Significant effort to collectively express our views to you. We hope that we have expressed our views clearly. Aliliough it is the AMA's intent to regulate traction control, this ruling does nothing but degrade the development of motorcycle racing in the Superbike class. As participants and enthusiasts, it is the growth and advancement of the sport that keeps us as well as the fans coming back for more. Ammar Bazzaz Chino, CA The above letter - penned by Bazzaz, who is a research engineer for Yoshimura Suzuki, and sent to AMA national technical manager Rob King - was endorsed by the following individuals: Don Sakakura, Yoshimura Suzuki; Larry Griffis, Yamaha Motor Corp. USA; Rob Muzzy, Muzzy Ko.wasaki; Ray Plumb, American Honda; Larry Ferracci, Fast By Ferracci Ducati; Rick Hobbs, Erion Racing; Keith Perry, Team Valvaline Suzuki; Don Tilley, Tilley Harley-Davidson Racing; Terry Gregoricka, Bell County Blue Bayou Harley-Davidson Racing; Richard Stanvoli, Attack Racing; Rad Greaves, Dega Racing.:. Editor Letters to the editor should be sent to Voices, Cycle News, P.O. Box 5084, Costa Mesa, CA 92628-5084, faxed to 714/751-6685 or e-mail, editor@cyclenews.com. Published letters do not necessarily reflect the position of Cycle News, Inc. Letters should not exceed 200 words and all lellers are subject to editing. Anonymous letters will not be considered for publication. All letters should contain the writer's name, address and daytime phone number ... Editor. ~ :> '" c: ..., '" 5