DVD Review: "Twiddling Knobs"

Suspension Tuning Is Critical, So Donít Be Afraid!

story by Pete Brissette, Created Nov. 12, 2007
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If you're an experienced rider you've probably developed a pretty reliable sense of what other motorcyclists value after having observed them for just a few minutes. Of course we all know you can't judge a book by its cover, blah, blah, blah. Yet, many of us have had our suspicions affirmed a time or two after witnessing the riding of someone we guessed was probably more show than go.

You know the type. Loud, race-like exhaust, flash paint job, enough sponsor decals to incur an FIM sanction, premium riding gear (including pristine knee pucks) and probably what is a hopped-up motor, or at least a Power Commander III. Then we see that same rider climb aboard and ride away in style, feet and legs deployed like outriggers on an Alaskan seiner, paddling to a stop yards before the intersection comes up. Yep, they're a demon on wheels.

This rider needs another expensive bolt-on about as much as Daytona Bike Week needs one more set of ass-less chaps. What he or she could use is an appointment with no less than three riding schools and to get their suspension tuned. Admittedly, getting to and paying for a riding school isn't so easy, but learning how to set-up and tune your suspension can be. And for that we have Dave Moss of Catalyst Reaction Suspension Tuning to thank.

Moss recently teamed-up with Vision Wells On Track Video Productions to create "Twiddling Knobs." The DVD is subtitled "Suspension Tuning for Sport bikes with Dave Moss," but that's not nearly as interesting as the main title (cheeky ex-pat Brit!). The video is meant to be a primer on the principles of suspension and how best to tune it.

If you consider suspension tuning a black art, you're not alone; many folks feel the same. "Twiddling Knobs," according to Moss, is aimed at the beginner, and as such the DVD starts off with a suspension "seminar." Here Moss presents a variety of bikes (all Triumphs) to illustrate the many different types and performance levels of suspenders found on most motorcycles. Covering the most basic twin coil-over shocks with stepped collars for preload adjustment only, to fully-adjustable sportbike forks and shocks, you get a good sampling, and in no time you'll be clued into what's on your steed.

Unfortunately, it's not really until Moss gets to the Daytona 675 that we start to get some good close-ups of the various adjusters (compression damping, rebound damping, preload, etc.). This was troubling, as the 675 was about one of the last bikes covered in the "seminar." Irrespective of this nuance, the section is a good starting point for suspension newbies.

Beyond Suspension Seminar (section 1), the remaining menu titles are: 2. Garage Talk; 3. Up Close On Track; 4. Thunderhill On Track; 5. Special Features; and 6. Suspension Data Sheets (available only by loading the DVD into a computer).

In Garage Talk, Moss compares a set of OEM forks from a modern sportbike (late-model R6) to that of the unobtainium Öhlins products, primarily to illustrate some of the weak points of OEM suspension as well as how to locate adjustment points and the types of adjusters used. The Öhlins components demonstrate the other end of the spectrum, that being suspension that goes beyond the basics and offers more fine-tuning not normally found on stock suspension, although this is changing each year as OEMs hone their sportbikes. In this section I was hoping for some disassembled or cut-away views of suspension componentry in the hopes of demystifying what happens inside. Alas, it was not to be, and I felt there wasn't quite enough "garage" in Garage Talk.

The next section is titled Up Close On Track, and is probably one of the most useful portions of the DVD. Here the footage is entirely of either the front or rear wheel of a bike that's being ridden around the infamous Willow Springs Raceway in Rosamond, CA. What Moss and team do here is go through the extreme end of adjustments so the viewer can see how the bike reacts. A thin green line appears horizontally on screen to serve as a constant reference point. As the bike circles the track you're able to see just how much the wheel/suspension travels. The side-mounted view of the camera allows you to watch the suspension in action while still being able to look down track and through turns as if you were sitting in a sidecar mounted on the side of the bike. Throughout this section we get running commentary from Moss that's filled with a lot of simple but invaluable nuggets about how and why the bike is reacting like it is.

"Twiddling Knobs" has one more on-track section called, Thunderhill On Track. This is similar to the Willow Springs segment, but this time Moss is riding and giving on-the-fly commentary while a few support riders provide different camera angles. Like the Up Close On Track section, Moss' commentary is constantly offering years of experienced advice on how to overcome certain situations with suspension tuning, riding, track types, etc. There's a lot of good note-taking opportunities, but the problem with the Thunderhill portion is that camera views are simply too jittery (like most on-board bike videos) to be of any use in reconciling what Moss is explaining against what were supposed to be seeing the bike do. Better luck next time.

From beginning to end in this DVD, Moss admonishes the viewer to ensure that their bike is set up properly for rider weight by setting sag, to change spring rates if need be, defining cavitation and how a suspension "bounces" based on rebound damping, etc. But of all things, sag (a measurement of suspension movement after sitting on the bike) is mentioned the most, yet how to perform the setting doesn't come until the end of the video, buried inside the Special Features section.

The primary drawback is that the DVD isn't linear, nor is it as rudimentary as I would've hoped. It seems there's a fair amount of presumption that the viewer already has a good grasp of a number of things.

This, I suspect, isn't Moss' fault so much as it is Vision Wells' lack of direction. In the end, a fair amount can be learned from "Twiddling Knobs," and the Up Close On Track section alone is almost worth buying the DVD. So, put down those rear-sets and learn how to tune your springers, because all is not lost...

Prior to "Twiddling Knobs," Dave Moss created another suspension DVD called "An Introduction to Sportbike Suspension by Dave Moss of Catalyst Reaction." This, my eager suspension-tuning friends, is by far one of the best DVDs on the subject. This production was the collaboration of Moss and OnTheThrottle.tv.

Like "Twiddling," this video covers a lot of the basics, but it also covers a lot more actual tuning work. Camera angles are plentiful and stable, important close-ups abound, and the audio is impeccable. Production quality on this two-disc DVD is very high, like something you would expect to see on television.

This DVD package isn't necessarily set out for the beginner as much as it is for someone who is a sportbike nut, is familiar with his or her machine and has been around a race track at least once. But that's not to say the avid street rider can't glean some very helpful information.

The brilliant use of race footage is interspersed for illustrative purposes while Moss discusses one or more aspects of suspension. It's a great way to get a sense of what's being discussed. Furthermore, Moss goes into the nuances of tire circumferences, how different brands of sportbike tires affect geometry and suspension, the importance of proper chain slack, tire pressures, always starting from the right then counting the clicks back when zeroing-out damping adjustment and balancing the chassis. Lots and lots of details to digest.

The video shines brightest in the Reading Tires section on disc 1, and the entirety of disc 2 is exceptional in what it sets out to accomplish. The portion on how to read tires on the first disc can be eye-opening, and will most likely have you watching it several times in amazement at how much tire wear can reveal about suspension. Things like cold tearing, hot tearing, debris build-up, cupping or scalloping of a tire's tread, geometry tears and heat cycling are covered at length on both discs.

When you've had your fill of the intricacies, disc 2 gives us actual case studies with real-world bikes ridden by the average schmo at an actual track day. Four different bikes are covered: a Ducati 998, an older Yamaha R6, an MV Agusta F4 and an Aprilia RS250 for good measure. Each of these bikes receive a scrutinizing assessment from Moss as his seasoned eye goes straight to the tire where he instantly sizes up what the bike's suspension is doing. Within a matter of minutes he's able to describe tire wear, tell us that too much or too little rebound damping is the cause and how other settings may be impacting the bikes performance. He goes on to tell us that by making a few clicks here and there (which he does in detail) we can expect tire wear to change in certain aspects.

Off goes the rider after some preliminary changes, and before we know it the video brings us back into the garage with rider to give us a report. Here Moss points out changes taking place on the tire, whether it's what he wanted or not, and how the rider has improved since the previous adjustments. This gives the viewer an invaluable lesson in what a bike's suspension is all about and how to manipulate it to the rider's advantage. Disc 2 is priceless in my opinion. If you can't buy this DVD, consider stealing it if only to get that second disc.

"An Introduction..." is a quality video that's very informative and throws in just enough irreverence to keep the viewer entertained while being schooled in suspension tuning. It's just a tick under two hours and retails for $24.95. "Twiddling Knobs" is roughly 90 minutes long and sells for $19.95.

Either DVD can be found on Moss' own site, feelthetrack.com, or both DVDs can be purchased together from OnTheThrottle.tv for $39.95. At that price someone interested in learning about motorcycle suspension would be foolish not to by both DVDs. The videos are great tools that will probably do more to improve your riding than any high-performance bling-bling ever will.

 

"Twiddling Knobs"
A Vision Wells Production
Copyright 2007 Catalyst Reaction and Vision Wells
94 Minutes, Stereo, NTSC

"An Introduction to Sportbike Suspension"
Shock Media Productions, LLC
Copyright 2007
117 Minutes, Stereo, NTSC

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