At first I thought this was going to be just another rear brake disc guard like the shark fins offered by several other companies, that simply bolts to the Honda rear brake caliper mount. Instead, the Flatland Racing Rear Brake Disc Guard is a whole new mount for the rear brake caliper assembly and brake disc guard, that not only protects the rear brake disc better than any other guard I’ve seen, it even corrects a previously unknown weakness in the original design from Honda!

First let’s back up a second and take a closer look at the final element of that last sentence: “A weakness in the original design from Honda?” That’s a pretty bold statement coming from a non-engineer who’s never designed anything more than helmet, knee, and elbow impressions in the dirt a few yards past a tree I almost missed. And I readily admit that if you stay with the plastic guard supplied by Honda, then the mounting arms probably are adequate. The trouble with this picture, however, is that the rear brake disc is not well protected by the stock, plastic piece, so we naturally want to replace it with a sturdier, aluminum shark fin that offers real protection. But then, as it turns out, the mounting arms for the shark fin aren’t adequate!

“But how do you know this, oh great master of the muddy facial implant maneuver?” Because when I removed the stock mount for the rear brake caliper and brake disc guard, I found that the mounting arms were already bent and weakened! “Weakened” might not be the best word for this, however, since discovering just how weak those mounting arms are to begin with!

I suppose brake disc damage depends on the hardness of the disc, or perhaps the hardness of the object that struck and damaged the disc. I’ve seen bent discs and broken discs, and both are bad news! If a brake disc is bent, it generally prevents the wheel from turning when the bent disc locks up in the brake caliper. If the disc is broken, it tends to destroy the brake caliper as the broken edges of the disc pass through the caliper assembly. So in either case, the brake caliper has to be removed in order to ride the bike out of the woods, and you no longer have that brake to help you safely descend hills.

Now let’s take a closer look at the natural progression of protection for the rear brake disc:

First we might have no protection at all. One might get by for years, or one might ruin the rear brake disc on the very first ride. Having no protection at all is probably a very foolish choice, since even the stock plastic piece is better than nothing at all. It also costs very little, and weighs hardly anything. It offers good protection against minor dings and scratches, and modest protection against modest impacts. Against major impacts, however, the stock plastic piece is hardly better than no protection at all.

Next we have the standard aluminum plate commonly called a “shark fin”, presumably because it looks rather like the upside-down shark appendage made so popular(?) by the movie “Jaws”, the box-office smash hit that drove many of us from the dangers of ocean beaches to the relative safety of the woods in the first place! Trail riding may yield its share of bumps and bruises, but darn few trail riders have been eaten by sharks! (We can discuss bears some other time.) The popular shark fin offers great protection against minor dings and scratches, very good protection against modest impacts, and can offer equally good protection against major impacts... if the shark fin mounts solidly. As it turns out, however, the stock Honda CRF250R/X mounting arms for the rear brake disc guard are not very strong. When I removed my stock mount, I immediately discovered that both of the little (surprisingly little, in fact) mounting arms for the brake disc guard were bent, and one has a tiny but visible crack beginning to form. A few more impacts, I fear, would likely have torn off the shark fin and the two little mounting arms.

Finally we come to the current ultimate in rear brake disc protection, which now appears to be the Flatland Racing Rear Brake Disc guard. It utilizes the familiar shark fin, of course, but only as part of its stronger and improved mounting system on its trick-looking, billet aluminum brake caliper and disc guard mount. The end result is a whole new mount that offers greater strength and better reliability, with a weight penalty of less than 3 oz.! (i.e., the Flatland Racing mount weighs just 2.9 oz. more than the parts it replaces.)

What more can I say? If you frequently ride in rough terrain, you naturally want the best brake disc protection you can get, and the Flatland Racing Rear Brake Disc Guard offers exactly that! It took me about an hour to install, but the improved strength and reliability made it all worthwhile. This one’s a keeper!

CRF's Only Review by Gordon Banks, July 2005
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