Ask The Editors: Are We Still Centralizing Mass?

The last quad standing also happened to be the recipient of some impressive mass centralization.

Actually, no. You’re right in that you don’t hear as much about it these days but that’s not because it was just the buzzword of the era. Mass is interesting thing when it comes to something as complex as a moving machine being propelled by a bunch of moving internal components. Sometimes, small motions (like say your piston rocketing up and down its cylinder bore) can be exaggerated depending on where it is positioned on the machine.

Imagine for a moment if you were to lift something heavy – your instinct tells you to keep is as close to your body as possible rather than to extend your arms all the way out then try to lift. Whether you realized why you did this or not, you were maximizing centralization of mass. The effects of the weight would feel amplified out at the end of your outstretched arm as opposed to tucked in tight.

We try for a similar effect with our quads. Moving a majority of the engine weight into the center of the chassis not only nullifies some of the gyrations of the engine’s internal motion (that we’d experience in the saddle as vibration), it also makes the ATV handle more neutrally.

Again, if you are having trouble visualizing this – imagine if your engine was suspended on a rod sticking off the front of your quad. What would this do to how it handled? Engine position can make a big difference and engineers try to use the space they’re allotted within an ATV frame’s geometry to keep mass centralized and suspension unburdened so that it can devote its travel to absorbing the terrain.

The only reason we’re not hearing as much about these innovations these days is that the 450cc stock race class evaporated. Yamaha is the only player left standing and the YFZ450R stopped receiving updates many years ago. When every major manufacturer had a manual clutch 450 on offer, the machines started getting annual updates to maintain the edge over the competition. Many manufacturers (Yamaha especially) were putting big bucks into geometry tweaks to centralize engine mass and word of this was in the magazine tests/ sales brochures.

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