Downhill disc brakes are powerful but heavy. Cross-country disc brakes tend to be less powerful yet they are lighter-weight. Are these nasty generalizations, or true statements? Among the companies trying to break through this stereotype is Formula with their 4 Racing downhill disc brake. At 390g, it is definitely cross-country light--but is it powerful enough for downhill racing? Read on.

The 4 Racing is a 4-piston, open system hydraulic disc brake. Knowing this, you may wonder how it is so light-weight. Although still structurally sound, the rotor is a beautifully machined bit of nothing. There are more holes in this rotor than in Bill Clinton's morals. Not only is there a generous portion of holes in the contact area of the rotor, but holes can also be found on the full length of the rotor arms themselves. Overall, construction on the 4 Racing is beautiful. The forged caliper body is anodized a shiny bronze color; the levers are two-finger levers with reach adjustment. They are very comfortable and are reminiscent of Shimano XT levers in shape.

It's no secret that a good 4-piston design can pack a lot of power. The 4 Racing uses 4 pistons to push two pads to the rotor. With this design, the contact patch is not very tall, yet is very long. This allows Formula to use a rotor with a small contact area--helping to keep the weight down. The rotor is slightly larger than normal at 185 mm, which also leads to a more powerful brake. Each piston is smaller than those in two-piston designs. Smaller pistons mean less weight and quicker response. Because of the small piston size, Formula can make a powerful 4 piston caliper that is also small and lightweight.

The 4 Racing is a powerful disc brake. I found that on most rides, using one finger to brake was more than adequate. Like most hydraulic disc brakes, modulation was good--although not the best I've ridden. The 4 Racing isn't the most powerful brake on the market, but it's enough to handle downhill. I was confident riding faster and braking later, knowing that these brakes would see me through.

I should point out that I had a problem with the pads creeping closer to the rotor. This wasn't a result of riding, but generally came from periods of inactivity--especially if the wheel was removed (like on a bike rack). The brakes I tested were pre-production prototypes, and Formula assures me that the problem has been fixed for production.

Summary: I loved the Formula 4 Racing. Through riding these brakes, I learned that you don't need to sacrifice weight for power in disc brakes. Formula has produced a wonderful brake that is downhill tough, but cross-country light. I'd recommend the 4 Racing to anyone who can afford $225 a wheel. If you can't afford them, don't take them for a test ride--you'll be hooked ... I know I am. As for me, I'm heading over to the bank to withdraw $450. See you there.

Jon Sharp is a contributing editor to GearReview.com specializing in mountain biking.

For more information, contact:
ThorUSA
www.thorusa.com
- or -
KHS Bicycle Parts
1-800-507-6444
www.khsbicycleparts.com