13 July 2016

Sometimes Things Connect

The husband of a friend came very close to making a complete donation via donorcycle several times.

Notably these attempted donations have the same mechanism in common: he slammed on the brakes and went over the handlebars.

In our litigious society it was baffling to me that Yamaha would make a bike that could do that when just anyone can buy one and attempt a panic stop.

Turns out that the bike was no longer stock.

The click moment happened when watching the film, "Hitting The Apex".

There's a scene where a very small contact is made between two bikes and the outside cycle careens out of control.  The contact severed a small wire and that disconnected the rear wheel speed sensor, which made the engine management computer unable to detect wheelspin and retard throttle input.

What my friend's husband, and his crotch-rocket buddies were doing was buying race-spec tires, brakes, and engines, but not adding the race-spec sensors and controllers; so when he grabbed a handful of front brake, the stock Yamaha ABS basically said, "nope, that can't be" because the change in wheel speed was too far out of its parameters to deal with and let him lock up the front because the BACK was stopped too (being in the air and all).  Add in the reaction speed of the system being matched to much smaller brakes slippier tires and you've got some disaster looming.

I'm led to believe that the race ready ABS and traction system has a wheel speed rate change system that would detect that the wheels had simple slowed down way too fast for it to be a legitimate stop and pulse the brakes.

1 comment:

  1. The guy must have 9 lives... but shouldn't push it. He's probably used most of them by now...

    ReplyDelete

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