Some of the features that distinguish the Santana/Formula hydraulic disc brake from disc brakes found on other bicycles are the following-
1) Opposing caliper pistons. Formula was the first to employ this design in a bicycle brake instead of less expensive, single-sided systems. This design avoids the rattle and rub inherent to systems with floating discs or calipers.
2) Positive pad retraction. Many bicycle disc brake systems are "blessed" with the same pad retraction system used on cars and motorcycles. If you ever get the wheel of a car or motorcycle off the ground, spin it and you'll see what we mean. Positive pad retraction means a properly seated and adjusted Formula disc brake is absolutely quiet and friction free.
3) A 203 mm (8-inch) rotor. Santana's tandem-specific version of Formula's best brake uses the largest diameter rotor available to bicycles today. The large disc increases the brake's mechanical advantage, stopping your bicycle quickly while maximizing heat dissipation and minimizing pad and rotor wear.
4) An insulated rotor. If you check out the really powerful racing motorcycles you'll find an insulated, or riveted, rotor that will survive temperatures that would permanently warp a one-piece rotor design.
5) A remote master cylinder. By mounting the master cylinder and fluid expansion chamber on the down tube, our design fights cable stretch and allows you to use any traditional cable-operated brake lever on the market. Whether you prefer STI or Ergo (or even old Suntour) you can combine this brake with your favorite lever.
6) Automatic heat compensation. Every time the lever is released even for a split second-the system automatically adjusts itself to compensate for changes in heat and atmospheric pressure. The Formula brake, unlike many others, won't rub or "pump- up" during a long descent.
7) Sealed Reservoir. Because bicycles are commonly stored, serviced or transported on their sides or even upside down, bicycle disc brakes need a tightly sealed fluid reservoir that can resize itself without leaking. The Santana/Formula remote master cylinder includes a variable- capacity, sealed fluid expansion chamber more advanced than any you will find on a car or motorcycle.
Why only one disc brake?
Some folks have wondered about having a disc brake on the front as well as the rear. A traditional bicycle rim brake is, in fact, a disc brake, one that is incomparably light and elegantly simple in operation. A tandem needs just ONE non-rim brake to dissipate heat that would otherwise cause rim or tire failure. As a heat sink, a disc brake will function equally well at either end of the bike.
But shouldn't this brake be in front?
There are many reasons this brake has been mounted at the rear of your tandem as opposed to the front. Those reasons include the fact that due to the increased weight two riders exert on the rear wheel, it is virtually impossible to lock up the rear wheel under the most extreme braking- this makes it a wonderful location for such a smooth stopper. (After all, the braking power of an unarticulated V-brake-, one without a parallel-push mechanism-is already strong enough to lock up a tandems front wheel.) Next, a tandem's cable-operated rear brake is far less efficient than its front brake because of cable stretch. Hydraulic actuation, unlike cable actuation, is unaffected by length. For both these reasons it makes better sense to mount a tandem's disc brake at the rear wheel. Additionally, due to Santana's 160mm rear spacing we've got plenty of room for our brake's larger disc and more powerful calipers. The spacing constraints of a road tandem's standard front fork means fitting a front disc will require either a special wider hub and fork (read nonstandard front wheel and fork) or a severely dished front wheel that is prone to collapse during a tandem's low-speed turns. While we're comfortable redesigning any component we think deficient for tandem use, fact is, we think our current front wheels and forks are great products.
'It FEELS all wrong!'
Our most often encountered criticism from new owners is that the brake feels 'mushy." On a normal rim brake, this would be an understandable concern. A spongy-feeling rim brake is usually caused by energy- robbing flex of the brake arms and pads. Fortunately, that's not the case with a hydraulic disc brake, as we've said before this brake requires a different way of thinking. While we could "fix" the lever feel by trading brake modulation for decreased lever throw, the result would be on-off braking with too-little leverage to allow the power of your hand to control a heavily loaded tandem. Instead, this entire brake system was designed to take advantage of every bit of stroke available with today's drop bar brake levers. This not only improves stopping power, your hands have more strength when you are using clenched as opposed to fully outstretched fingers. In other words, we've optimized power instead of feel, and geared the lever so that its most effective range of modulation occurs where you have the greatest hand strength and are therefore least likely to encounter hand fatigue.
The important thing to remember is that as long as the lever feel is a bit soft or spongy, your new brake is probably operating correctly. If the lever instead feels firm, like a traditional rim brake, something is definitely amiss.
A second issue among new owners is that this brake doesn't seem to provide enough stopping power. The Formula disc brake, like the disc brake on cars or motorcycles, requires a break-in period. And while a car's power-assist masks the initial inefficiency of a new brake, on bicycles and motorcycles the braking improves dramatically once the pads have been seated and readjusted. Within 200-400 miles (and after you have seated and readjusted the pads) we think you'll agree this brake provides great control, fantastic modulation and incredibly short stopping distances.
To tighten this brake, loosen the cable.
A hydraulic disc brake with a cable-actuated remote master cylinder is unlike all other bicycle brakes. With this unique brake the characteristics, lever feel and adjustment procedures are all different. For instance, your experience with rim brakes might cause you to think that the cable of a perfectly adjusted disc brake is too loose.
When someone discovers the situation, 99% of all enthusiasts and mechanics will find the adjuster and tighten the cable to achieve a firmer lever feel. And while the lever will indeed FEEL better, an over tightened cable will not improve stopping power. Further, over tightening the cable by even the smallest amount will inevitably create problems with the hydraulic system.
How does this happen? We'll explain this as we go. In the meantime please be aware that a cable-hydraulic disc brake operates in a counterintuitive fashion, almost exactly the opposite of any rim brake or even disc brakes found on most mountain bikes.
Because living with a new disc brake involves relearning old tricks, do not attempt any readjustment until you've read this manual and familiarized yourself with the operation of this brake.
Since the operation of this brake is not intuitive, we believe your safety and ultimate satisfaction will depend on your willingness to read this manual and learn how to adjust the pads and cable tension. If you have never bothered to become proficient at making simple gear and brake adjustments on your previous bikes, we encourage you to reevaluate your choice of brakes with your dealer.
If the time comes that it is more convenient for you to have this brake serviced by a dealer, please make sure they have a copy of this manual. If not, loan them yours.
Surviving the mother of all descents
As long as the descent is straight enough, few teams will overheat a rim drum or disc brake. The explanation is simple: As long as you and your partner donít mind riding fast, wind resistance will hold your speed in check, even on a long or steep hill.
Overheating typically occurs on a steep descent where the road is so curvy, rough, or crowded that a speed of less than 45 mph is required. Some roads are so twisted or rough as to require a speed of less than 15 mph. In these cases a tandem can burn out a brake or blow a tire within a half-mile. No brake, not even this Formula Disc, will endure a mile of 18% descent if your speed is constrained to 15 mph. The best brakes for holding a tandem's speed in check, however, like this Formula brake and the Arai drum brake, will progressively fade instead of failing without warning.
Given this situation, the following is the best strategy for steep, slow descents:
On a treacherous downhill use the Formula Disc Brake to control your overall speed. Use your rim brake only sparingly, such as braking for a particular switchback or to help you maneuver around a chuckhole. As the Formula brake heats up the brake lever will feel firmer as expanding fluid 'pumps up' the system and seems to pry the lever from your fingers. To reset the feel it is only necessary to momentarily release the lever to allow the expanded fluid to reach the master cylinder reservoir. Flicking the lever open once every half-mile is all it takes to maintain a good lever feel. Later, as the pads and rotor get very hot, fading will occur, causing you to have to squeeze the lever progressively tighter to maintain consistent braking. Finally, when the disc brake has faded to the point that you can no longer use it alone to maintain your desired speed, the only safe thing to do is to use the front rim brake to bring the bike to a complete stop. Within five minutes, less on a cool day, the disc and pads will have cooled enough to allow you to safely continue.
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