I tend to pride myself on knowing all the features that automotive and motorcycle engineers designed into my vehicles. Given this, I tend to be inordinately surprised when I happen across features I hadn’t actually known about from day one. (Or from the day I took the time to fiddle through all the settings, as in the case of the Cadillac CTS’s central display’s confusing menu system.)

This past Thursday, I took my 1996 Honda Pacific Coast (aka PC800) to school to swap out the front tire. Part of this job involves removing one of the front brake calipers. I looked at both of them and decided the right side was easier to remove. While it was off, I went ahead and cleaned the brake pistons. At that point, my OCD demanded I do the same thing for the left caliper. When I went to look at how to remove the left caliper, I realized it was strenuously different than the right caliper.

Then I noticed why it was different. It uses Honda’s TRAC system* (“Torque Reactive Anti-Dive Control”), which was evidently all the rage back in the early 80’s. Kawasaki had a different anti-dive system**, as did Harley-Davidson***, and apparently everyone decided anti-dive was bogus a few years later. Despite this, Honda added TRAC to the Pacific Coast for its 1989 debut, and it stuck around through the late-90’s when the bike was discontinued.

We had learned a bit about the anti-dive technologies of the 1980’s in class, and I had reverse-engineered a cross-sectioned example to understand specifically how Honda’s TRAC product worked — but I figured I would probably never ride one to see how it really worked. So, yeah, I felt a bit silly when I realized that I had been riding a bike with TRAC for several years. I never thought the bike had an especially firm front suspension when braking hard, so clearly whatever it does isn’t all that worthwhile.

* Honda’s TRAC system uses the reaction of the brake caliper during braking to push a piston on the fork tube. This piston changes the fork’s compression damping characteristics. It didn’t work all that well. ** Kawasaki’s anti-dive added a slave cylinder to the front brakes that pushed a piston on the fork that changed the compression damping. Besides not working any better than Honda’s system, Yamaha’s system made the brakes feel mushy, so a lot of people completely disconnected the anti-dive hydraulic circuit. *** Harley’s anti-dive system actually changed the spring rate of the front forks by changing the volume of air compressed above the fork oil. I’m told it worked pretty well, but since Harley wasn’t really selling performance or sport motorcycles, no one cared, so they discontinued the anti-dive system. **** I am always available to discuss decades-old technology that didn’t work all that well. Road tests of the Pacific Coast come with the implicit promise that you will not be impressed with the suspension but will think the rear trunk is super-cool.

For a little more about 1980’s anti-dive, see this article at carbibles.com.

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