Had a play with a MTB with mechanical brakes … WOW … they are extremely powerful.
I gently squeezed the brake handle with my little finger and I did an endo!
(hmm … endos, last time I did one of those I broke my arm .. perhaps not a good idea?)
A little bit of research has revealed that people have a very high opinion of the Avid BB7. The Avid Juicy Seven also got good marks, but they are hydraulic and much more expensive.
Avid BB7 Mechanical Disc Brakes
The most heralded cable actuated brake in the world
Finally a cable-actuated disc brake that works like disc brakes should. Avid has obsessed over the design and it shows. It has power and a light action at the lever. Throw in the Caliper Positioning System (CPS) which ensures perfect, effortless alignment of the caliper to the rotor and you have an affordable, high performance disc brake.
Features & benefits
Caliper Positioning System
CPS allows the caliper to easily adjust, perfectly to the rotor – no trial and error
Easy Spring Adjustment
Simple micro-adjust spring tension is achieved with an Allen head set screw
Easy Cable Anchor Bolt
No barrels or threading a needle – same as a rim brake
Clean Sweep?¢‚Äû¬¢ Rotor Design
Special rotor design to ensure full brake pad is scraped clean at all times
Fully Sealed
Fully sealed to keep elements out and performance in
Tools Free Pad Replacement
No tools needed to replace pads
Standard Disc Hub Mount
Same offset and bolt hole pattern as Hayes
Mounts
Front – Fits both common standards
Rear – Fits international only
Finish
Matte Gray
Weight
361 grams (front)
367 grams (rear)
Benefits of Mechanical Disc Brakes
– Consistent braking performance
– Simple and easy to understand
– Trail serviceable
There’s nothing like taking a corner on a technical line at 9,000 feet to get you thinking about your brakes. Thing is, that’s really not a good time to be thinking about anything but the trail.
Introducing Avid’s Caliper Positioning System?¢‚Äû¬¢(CPS) disc brakes – a must-have in wet, sloppy or extended downhill conditions. (Now many of your technical cross country riders will ask that they not be forgotten.) The Ball Bearing disc brakes are smooth, quiet and intensely powerful. Built to deliver that on-demand control and confidence you’ve come to expect from Avid. And one more thing: They’re a cinch to install.
In the spirit of Avid design, the CPS disc brakes are designed to spend very little time installing and adjusting the brakes – so you can spend more time riding. Throw in fully adjustable brake pads and spring tension and well, you know the rest.
Disc Brake Details
Caliper Positioning System (CPS)
The patent pending Caliper Positioning System allows for effortless, fast and accurate alignment of the caliper to the rotor. No shims or trial and error required. To align the caliper:
– Install the caliper and lever onto the bike
– Install the wheel, with the rotor attached
– Slightly loosen the CPS bolts (2)
– Adjust the brake pads, use the adjuster knobs, until they are firmly contacting the rotor
– Tighten the CPS bolts
– Back off the pad adjuster knobs up to 1/2 turn each.
Other advantages: Our mount tolerances are measured in millimeters, not 1000’s of an inch like others. In case of a crash, the rider can simply readjust the caliper with an allen wrench, and eliminate drag – no way with other disc brakes.
Brake Pads
A new sintered pad eliminates unwanted squeal when wet and improves pad life. Due to a custom pad formula the brake pads exhibit power from the very first ride. The performance will improve once the pads are fully seated. The pads are designed to be installed without tools and can be easily replaced.
Clean Sweep Rotor Design
The rotor is designed to prevent warping. It is also designed to fully scrape the pad surface; thus preventing uneven pad wear and keeping the entire pad surface, not just part of it. Scraped and clean.
Fixed Cable Housing Stop
This dramatically reduces the effect of various cable routings on brake performance. Most mechanical disc brakes are very sensitive to the angle at which the cable housing terminates at the caliper. To minimize the effect of a rotating cable stop, Avid uses a fixed stop.
Cable Anchor Bolt
No need to have to thread a needle with the inner wire. Avid uses the same cable anchor fixing method that is used on the Avid rim brakes. Another assembly line and dealer time saving detail.
Spring Tension Adjustment
Avid uses a simple allen set screw to infinitely adjust to the desired spring tension. There is no need to loosen bolts and reposition brake arms in 2 or 3 holes to set spring tension.
Sealed Mechanism
The caliper is fully sealed to prevent contamination. Seals are located behind the brake pad and on the brake arm. Cable stop seals are also provided to prevent any contamination of the cable. No other mechanical disc provides this level of sealing. The result is improved long-term brake performance and less maintenance.
Ball Bearing Mechanism
The use of precise ball bearings allows the brake to maintain consistent performance and superb power.
Tensioned Truss Construction
Using a 1-piece cast body supported by two tensioned truss bolts, the mechanical caliper is the strongest and stiffest disc brake on the market. The result is an incredibly stiff brake which allows more braking energy to applied to the rotor. The effect is very similar to the FVA design used in the Avid rim brakes. The less brake boss splaying, the more efficient the brake. The less the disc brake caliper flexes the more energy reaches the rotor.
Side-Pull Brake Lever Compatible
The Avid Ball Bearing disc brake is specifically designed to use side-pull brake levers. This allows for matched brake levers in case a disc brake is paired with a rim brake. While any side-pull brake lever is compatible, it is strongly recommended that the Disc version of the Speed Dial levers be used. Speed Dial levers are especially beneficial since disc brakes are very sensitive to various leverage ratios. No other lever offers the range or micro-adjustability of Speed Dial levers.
Additionally, since adjusting for brake pad wear at the barrel adjuster limits the amount of lever travel, it is recommended that brake pads be adjusted at the caliper, not the lever.
Disc Brake Specs
Hub Specifications
Front hub offset – 10.16 mm
Rear hub offset – 15.00 mm
Bolt hole circle – 44 mm
6 Bolts
Rotor Size
Front diameter – 160 mm
Rear diameter – 160 mm
Thickness – 1.8 mm
Pad Clearance – .6 – .8 mm
Fork Mount
Mechanical Post Style – 74 mm standard
International – Yes, with mounting bracket
Rear Mount
Mechanical International – Yes, with mounting bracket
Perpendicular Style – No [Perpendicular = Hayes = 22 mm
International = Parallel = 51 mm]
Cable Guides
Mechanical Line – Hydraulic frame cable guides with “step-down” ferrules work ideally with standard cable/housing
http://www.sram.com/en/avid/discbrakes/ballbearing7/ballbearing7.php
http://www.mtbr.com/reviews/disc_brake_system/product_20482.shtml
http://www.mtbr.com/reviews/disc_brake_system/product_122524.shtml